A primer on backup battery systems for power outages

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A primer on backup battery systems for power outages

Post by willthrill81 »

There has recently been an active thread about generators, and the topic of backup battery systems came up. I mentioned that I had a lot of information about that topic, and some expressed interest in the topic, so that's why I'm starting this thread.

Literal volumes have been written about the operation of lead acid batteries alone. This is meant to be an overview of the topic from the perspective of a homeowner looking to construct a simple but reliable battery system capable of helping them cope with a loss of grid power. It is not intended for those who are regularly relying on their batteries, such as those living off-grid, though many of the same principles apply there as well.

What Type of Battery to Use

Those who live off-grid and are using through their batteries every day might be better off financially in the long-run with lithium-ion or other types of batteries, but for those who are only occasionally cycling their batteries, lead acid batteries are still clearly the best choice. While there are other types of lead acid batteries, the four that are most appropriate for backup battery systems are deep-cycle batteries, marine batteries, golf cart batteries, and absorbed glass mat batteries. The first three of these are all types of flooded lead acid batteries.

When it comes to lead acid batteries, there are some big trade-offs that must be made in their construction and operation. When a lead acid battery of any type is at any time less than fully charged, lead sulfate crystals start to form on the lead plates inside, and this process can never be completely reversed. Depending on how depleted the battery is and for how long, these lead sulfate crystals can usually be largely removed by simply recharging the battery. 'Advanced' recharging techniques can also go a long way toward removing these lead sulfate crystals, but their damage can never be entirely undone, and the battery will eventually lose its ability to hold a good charge. The battery should be replaced with a new battery well before this point, and the lead plates in the old battery will be recycled to make new batteries. If the battery is maintained properly, it should last at least five years and may last ten years or even more.

If you want to get a lot of power out of a battery very quickly (i.e. seconds), such as for starting the internal combustion engine in a vehicle, then the battery must be constructed with many thin plates of lead that resemble a sponge in order to provide a lot of surface area that's exposed to the acid inside. This is referred to as a starting battery. However, lead sulfate crystals will quickly develop if the battery isn't recharged very soon. A typical vehicle battery can only be fully cycled (i.e. taken down from 100% to 0% and then recharged back up to 100%) about ten times or so before it's effectively worthless. In the normal operation of vehicles, only a very small proportion of the battery's capacity is used for a few seconds to start the vehicle, and the vehicle's alternator fully recharges the battery in short order, so this trade-off isn't a big problem in that context. But for battery backup systems, this is a big problem, as noted in the next paragraph, and starting batteries should never be used outside of an emergency.

If you want to get a little power out of a battery over a longer period of time (i.e. hours or days), as needed in a backup battery system, then the battery should have relatively few plates of lead, and the plates are much thicker than in a starting battery. This is referred to as a deep-cycle battery. Lead sulfate crystals will still form on the lead acid plates and eventually damage them, but this process is much slower. A deep-cycle battery can be fully cycled about 200 times, far more than a starting battery can. Deep-cycle batteries are available at many fewer places than are starting batteries, but most RV parts stores and solar equipment dealers sell them.

Marine batteries offer a compromise between starting batteries and deep-cycle batteries. Their plates are thicker than those of starting batteries but thinner than those of a deep-cycle battery. These batteries are designed to be able to start boat motors and then to provide a much smaller amount of power to an electric trolling motor. These can be fully cycled roughly 100 times. These are acceptable for battery backup systems.

Golf-cart batteries, at least those made by reputable manufacturers like Trojan, are also deep-cycle batteries, but they are nearly always referred to as being distinct because they are designed for, you guessed it, golf carts. They are designed to be very durable, which is definitely needed when half-drunks are driving golf carts around like lunatics over rough terrain with lots of sudden starts and stops. They even have extra space inside the battery under the lead plates for lead sulfate crystals to drop down into and accumulate without shorting out the battery. Golf cart batteries are usually 6 volt batteries, so two of them must be connected to each other in series to effectively create a single 12 volt battery. Note that some golf cart batteries are 8 volts (not really usable in this context), and some are 12 volts and can be used as is without any connection to other batteries. Also, golf cart batteries are quite heavy. One of the most popular models is the Trojan T105, and it weighs 62 lbs. That said, golf cart batteries are ideal for battery backup systems that do not need to be mobile. They are available at golf cart dealers, warehouse centers like Costco and Sam's Club, and some other big box stores.

Absorbed glass mat (AGM) batteries are the safest lead acid battery because the sulfuric acid inside has been absorbed into glass mats. There are starting AGM batteries and deep-cycle AGM batteries. Deep-cycle AGM batteries can be purchased but are very uncommon. While they do last somewhat longer than flooded lead acid batteries, the cost of AGM batteries is roughly double, so they are financially less viable. About the only reason that someone should use an AGM battery for a battery backup system is if they are concerned that someone like a small child might try playing with them, open the top, and spill sulfuric acid on themselves, though I've never heard of this ever happening. The weight of lead acid batteries generally makes moving them very difficult for small children.

How How Much Power a Battery can Provide and Battery Lifespan

When it comes to lead acid batteries, there is a strong link between how much power can be used and how long the batteries will last. To understand this, you need to understand some basic electrical terminology; please note that these are not precise, technical definitions. Electrical power is somewhat analogous to plumbing. Voltage refers to electric pressure, similar to water pressure. Amperage (AKA amps) refers to the volume of electricity, similar to volume of water flow. Watts are a unit of electrical power and a measure of electrical consumption. Watts are equal to volts multiplied by amps (W = V x A).

The voltage of most battery backup systems (and that used by most non-hybrid or electric vehicles) in the U.S. is 12 volts, while the power used by most items is 120 volts, though large electrical appliances usually use 240 volts (e.g. stove/oven, water heaters, clothes dryers, furnaces, central air conditioning units, well pumps). A watt hour refers to using one watt for one hour. So if you use 100 watts for two hours, you have used 200 watt hours of power. (Incidentally, the power you buy from the grid is sold in 1,000 watt hour (AKA kilowatt hour or kWh) increments.) Note that batteries' capacity is always provided in terms of amp hours (AH), so to determine the watt hours of the battery, simply multiple the amp hours by the battery's voltage.

A group 27 marine battery typically has around 90 amp hours of power. That's a 12 volt battery, so that works out to 1,080 watt hours of capacity. A pair (remember that they have to be used in pairs in a 12 volt system) of golf cart batteries will typically have about 150 amp hours of power, which is 1,800 watt hours of capacity.

However, there are some important caveats. First, as you increase the power you draw from a lead acid battery, you reduce its available capacity. If you draw 12 watts from a 12 volt battery, which is 1 amp (12 watts / 12 volts = 1 amp) of current, you will actually get more power out of the battery than it is rated for. If you draw 1200 watts from a 12 volt battery, or 100 amps (1200 watts / 12 volts = 100 amps), you'll only get about 60% of the battery's rated capacity. This is referred to as Peukert's law, and online calculators exist to help you determine the exact amount of the reduction in capacity.

Second, the more deeply you discharge a lead acid battery, the more you permanently reduce its lifespan. As I noted earlier, a deep cycle battery that is fully (100%) cycled will be effectively dead after about 200 such cycles. But if you reduce the depth of the cycle, such as only taking the battery down to a 50% charge (usually referred to as state of charge or abbreviated as SOC; sometimes the inverse is used and referred to as the depth of discharge or abbreviated as DOD), it will last for closer to 500 cycles. The graph below illustrates this relationship.

Image

This means that you don't want to draw a lead acid battery's capacity too far if you can avoid it in order to maximize the battery's cycle lifespan. That said, in an emergency situation, by all means use the power in a battery if you need it. It's more important that you have the power you need when you really need it than to try to get more cycles out of the battery.

Now that you understand this, you can start to better understand the answer to the question that everyone always asks when this topic comes up: how long will the battery last? It depends (mostly) on (1) the capacity of your battery, (2) the amount of power you draw from the battery, and (3) how long you draw that power from the battery. If you have a 90 amp hour battery (1,080 watt hour capacity = 90 amp hours x 12 volts) and draw 20 watts from it continuously, the battery will last for 54 hours. If you try to draw 500 watts from that same battery, it won't even last two hours, due to Peukert's law. This is why battery systems in general are best used for either small amounts of power for long periods of time or large amounts of power for very short periods of time. Large amounts of power for large amounts of time are not appropriate for battery systems; that's when generators and such are needed (more on that below).

If you need more power than what a single battery can provide, you can connect multiple batteries that are identical to each other in every way to expand the size of your system and create a battery bank. This is better for the batteries because they are all charged and discharged at a slower pace, which is generally best anyway, and it's simpler for you. It's important for the batteries being connected this way to be identical (i.e. same manufacturer, same type, same age, etc.); otherwise, the whole system will be brought down by the weaker batteries, and the other batteries could be damaged. If you already have a battery (or multiple) and want to expand the size of your system at a later date, you will not be able to connect the new batteries to the old ones, and you'll need a separate charger for the new batteries.

How to Get Power from a Battery

There are basically two ways to get power from a battery: direct current (DC) power directly from the battery or alternating current (AC) power via an inverter connected to the battery. I'll start with DC power, which will be 12 volts. Anything that plugs into a 12 volt power socket in a vehicle can be run from a 12 volt battery system. To do this, you need a 12 volt adapter plug socket, which clamps directly on to the terminals of your battery, like the one shown below.

Image

That only gives you one socket though, so it's usually a very good idea to plug a 12 volt socket splitter into your adapter; these are widely available and generally give you three or four sockets to plug into, and many also provide USB outlets. One of these is shown below. Be aware that with a single adapter plug socket, you can only draw about 150 watts of power. The power cords generally have a maximum rating of 15 amps, which is 180 watts in a 12 volt system. If you need to draw more than that, you'll need to use multiple adapters (like the one shown above).

Image

It's also a very good idea to get a voltmeter that can be plugged into one of the sockets of the splitter in order to allow you to visually check on the status of your battery. This will give you a rough idea of how charged your battery is.

To get 120 volt AC power, like the standard outlets in your house normally provide, from a battery, you need to use an inverter. An inverter will take 12 volt DC power and invert it to 120 volt AC power. These will either have a 12 volt plug or connect to your battery with clamps or terminal lugs, which look like washers connected to a cable, that are connected very tightly to your battery's terminals with washers and wingnuts. The smallest inverters, which only have a 12 volt plug, will only output about 150 watts since that's about the most that can be drawn from a 12 volt plug. Inverters of very large size can be purchased, but it's vital to keep in mind that inverters do not magically multiply your battery's capacity. A 2,000 watt inverter being used at full capacity will completely drain a 90 amp hour battery in about 20 minutes. Running very large appliances that use 240 volt AC power, like electric furnaces and water heaters, is not realistically feasible with the type of battery system discussed in this thread.

Disclaimer: This post is provided only for information purposes. I do not warrant any of the information contained herein. You accept any and all risks from engaging in any activity discussed in this post.
Last edited by willthrill81 on Sun Oct 25, 2020 10:07 am, edited 2 times in total.
“It's a dangerous business, Frodo, going out your door. You step onto the road, and if you don't keep your feet, there's no knowing where you might be swept off to.” J.R.R. Tolkien,The Lord of the Rings
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Re: A primer on backup battery systems for power outages

Post by willthrill81 »

How to Charge a Battery

Most novice battery users inadvertently ruin their first battery (or two) by failing to keep it properly charged. I've already outlined how a lead acid battery that isn't 100% fully charged is having some amount of permanent damage being done to it. Also, lead acid batteries will self-discharge at the rate of 3-5% per month, so it's important that you don't recharge a lead acid battery and then just let it sit without being on a charger. As such, unless you're using your battery for backup power, it should be left on an automatic, 3-stage charger, all the time. When the battery is below about an 80% capacity, the charger will charge at its highest charging rate, at a slower rate from 80%-95% capacity, and an even slower rate from 95%-100% capacity. The smallest automatic charger you should consider should be rated for at least 6 amps, and a 15 amp charger or larger charger is much better. It can be confusing when you're looking at chargers, but you need to ignore the amperage shown when it is immediately followed by 'engine start', a feature designed to quickly charge a starting battery enough to enable the vehicle it's probably attached to to start; this feature is inappropriate for charging a backup battery.

When determining how long it will take to charge a battery, it's important to keep in mind that roughly 25% of the power that goes into a lead acid battery will be lost due to heat created in the process. Also, once a lead acid battery is charged to 80% capacity, an automatic charger will start slowing down the charging amperage, which is healthy for the battery's longevity but means that it can take just as long to take a battery from an 80% charge to a 100% charge as it takes to charge it from 0% to 80%. If you're charging a battery from something like a generator during a power outage, it's generally a poor use of fuel to run the generator for the sole purpose of recharging the battery past 80%. Of course, if you're running the generator anyway, you should absolutely be charging your battery at the same time.

If you don't have a generator or your generator becomes inoperable, you can connect an inverter to the battery of your vehicle and power your battery charger from the inverter. Be sure to run the vehicle the entire time that you are charging your backup battery.

In a real emergency when you have no other choice, you can also recharge a lead acid battery by connecting it directly to the battery of your vehicle with jumper or booster cables, starting the vehicle, and letting the vehicle run. How long the vehicle should run depends on how discharged it is, but if the backup battery is dead, you'll need to run the vehicle for at least 30 minutes, and an hour would be better. Note that such rapid charging of the backup battery is not healthy for the battery and creates much more hydrogen gas (discussed in the next section) than does normal charging, so don't allow anything that might cause a spark to get close to the battery, wear eye protection and gloves, and make and break the final connections with the jumper cables at the vehicle's battery and not the backup battery (to avoid any sparks close to the backup battery).

Battery Maintenance and Safety

All of the lead acid battery types discussed above need a little periodic maintenance except for AGM batteries, which are completely sealed. Any time you're working with a lead acid battery, you should wear eye protection and gloves. Also, it's a good idea to wear old clothes since even the tiniest drop of battery acid that touches your clothes will eventually burn a hole right through them. The batteries will have a cap on top that can be usually opened with a flat head screwdriver and a little prying action. Use a flashlight to look down inside each of the cells, of which there will be six on a 12 volt battery and three on a 6 volt golf cart battery. There are little plastic tabs that go down into the cells, and the acid inside should just touch these tabs. If it does not, you need to slowly refill them using distilled water only, available at all grocery stores, and a small funnel. This only needs to be done about once a year unless you're using the battery often.

Some are concerned with lead acid batteries creating flammable gasses. It's true that the charging process does break apart some of the water in the sulfuric acid into its elemental components, hydrogen and oxygen, and hydrogen is very flammable. However, under normal situations, the amount of hydrogen released is tiny, and it immediately races upward at the incredible speed of 45 miles per hour as it's the lightest element in the universe. It does not 'linger around' like propane gas or gasoline fumes can, waiting for a spark to ignite them. As long as the battery isn't kept in an air tight container when it's being charged, the hydrogen gas will quickly escape and not pose any problem. I've never heard of any problems of this sort with a home battery system.

Using a Battery in Conjunction with a Generator (or a Vehicle)

As discussed above, batteries have a rather limited amount of power compared to other power sources such as generators. A single 90 amp hour battery has approximately the same amount of electrical power as one quart of gasoline run through a portable generator. However, in order to get power from a generator, that generator must be actively running and consuming fuel, and generators must run at at least a certain speed. Power they produce that is not immediately used is wasted, and the fuel consumed to produce that power is wasted as well. However, a battery can provide power exactly when you need it and only the power you need. Further, batteries are completely silent, which is not true of even the quietest generator.

Thus, the best practice for minimizing fuel consumption is to
(1) run your generator only when you need to power fairly large loads for a significant period of time (e.g. refrigerator, freezer, air conditioner, electric space heater, gas furnace),
(2) recharge your battery when your generator is running, and
(3) use your battery to power small loads.

For the typical household, this practice might mean that a generator is run for an hour or two in the morning to cool down the refrigerator, charge the battery, and run any other items with significant loads, and the generator is then powered down and the battery used for small loads. This process is repeated in the evening, and it might be needed in the early afternoon as well.

You'll note that running a generator in conjunction with a battery backup system like this is very much akin to the way that hybrid vehicles work, when the batteries are used some of the time, and the gas engine is used some of the time.

If you don't own a generator, you can also recharge a lead acid battery using your vehicle. As noted above, this can be done with just jumper cables but only in emergencies when you have no other choice. It's far better to connect an inverter of adequate size to your vehicle's battery and then connect your normal battery charger to the inverter. Keep in mind that most vehicles at idle will only output about 400 watts of power, so if you're using a 15 amp battery charger (180 watts) from it, running a refrigerator or freezer is about all that the vehicle can keep up with before you will begin draining its battery.

Ideal Uses for a Battery Backup System

As discussed above, battery backup systems are ideal for providing small amounts of power when needed. This means that small battery systems are not appropriate for powering appliances like refrigerators, freezers, coffee makers, toasters, and the like. Anything that produces or 'moves' heat should generally not be run from a battery system unless the need is great because the battery system will be depleted very soon. A modern refrigerator drawing 150 watts of power will fully drain a 90 amp hour marine battery in about seven hours of the refrigerator's compressor actively running (kept closed at 70 F, a modern refrigerator's compressor will run about 50% of the time, in which case this battery would be depleted in about 14 hours). A Keurig coffee maker will fully drain the same battery after making only 8-9 cups of coffee. Such large loads should be powered from a generator or, if needed, an inverter connected to a vehicle that is running while the inverter has a load on it.

The items that are ideal to be powered from a battery backup system include LED lights, anything that runs on USB power, AA and AAA battery chargers, modems/routers, laptop computers, very small fans, and the like via extension cords. Two watt LED lights can produce a lot of light and represent only a tiny draw on even a small battery backup system. It only requires about 5-7 watts to charge a smartphone, and most tablets only require about 10 watts to charge. A single AA battery only has about 4 watt hours of power (compared to 1,080 watt hours in a 90 amp hour 12 volt battery), so you can recharge many of these. Many small flashlights, headlamps, and radios operate on AA and AAA batteries, so these are very handy to have during a power outage. Also, many of these items do not require an inverter at all and can be run directly from a 12 volt power source. This is especially true of USB powered devices, so having multiple 12 volt chargers is a good idea, and don't forget that you can just borrow them from your vehicle if you have some there. AA and AAA battery chargers that will operate on 12 volt DC or 120 volt AC power are also available and affordable.

I know that some people really need to see a picture to wrap their mind around all of this. Below is a photo (not mine) of a simple backup battery system with labels on everything.

Image

Disclaimer: This post is provided only for information purposes. I do not warrant any of the information contained herein. You accept any and all risks from engaging in any activity discussed in this post.
Last edited by willthrill81 on Fri Oct 09, 2020 10:20 pm, edited 2 times in total.
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Re: A primer on backup battery systems for power outages

Post by mervinj7 »

hey Will,
What's your opinion on the newish portable Lithium Ion "solar power station"? Some of my neighbors have been using it for their medical fridges. In our PG&E territory in CA, there is a high chance of a rolling blackout. They are typically 1-2 hours but some outages have been as long as 10 hours. Some of the larger ones include:

https://ecoflow.com/products/ecoflow-de ... 81k4_hoa45
https://www.jackery.com/products/explor ... er-station
https://www.indiegogo.com/projects/blue ... er-station
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Re: A primer on backup battery systems for power outages

Post by LadyGeek »

willthrill81 wrote: Tue Aug 18, 2020 1:35 pm How How Much Power a Battery can Provide and Battery Lifespan

When it comes to lead acid batteries, there is a strong link between how much power can be used and how long the batteries will last. To understand this, you need to understand some basic electrical terminology; please note that these are not precise, technical definitions. Electrical power is somewhat analogous to plumbing. Voltage refers to electric pressure, similar to water pressure. Amperage (AKA amps) refers to the volume of electricity, similar to volume of water flow. Watts are a unit of electrical power and a measure of electrical consumption. Watts are equal to volts multiplied by amps (W = V x A).
For completeness, Joules are units of energy and measure power over a period of time. 1 Joule = 1 Amp at 1 Volt for 1 Second.

Your home electricity is billed for the total energy you use for the month. The energy is given in different units, known as a "kilowatt hour".

1 kWh = 1,000 Watts for 1 hour

Your home uses alternating current and is not a battery. However, the principle is the same. Batteries discharge over time, which is energy.
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Re: A primer on backup battery systems for power outages

Post by willthrill81 »

mervinj7 wrote: Tue Aug 18, 2020 1:52 pm hey Will,
What's your opinion on the newish portable Lithium Ion "solar power station"? Some of my neighbors have been using it for their medical fridges. In our PG&E territory in CA, there is a high chance of a rolling blackout. They are typically 1-2 hours but some outages have been as long as 10 hours. Some of the larger ones include:

https://ecoflow.com/products/ecoflow-de ... 81k4_hoa45
https://www.jackery.com/products/explor ... er-station
https://www.indiegogo.com/projects/blue ... er-station
The EcoFlow only has 1,260 watt hours of capacity. You could buy a lead acid battery of that size, a 15 amp charger, and a 1,000 watt pure sine wave inverter for around $400 rather than $1,400. True, the EcoFlow will recharge faster and is lighter and more portable, so it's a question as to whether those benefits are worth an additional $1,000. This is also true of the Jackery, though it's only $1,000. The Indiegogo seems ridiculously expensive.
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Re: A primer on backup battery systems for power outages

Post by RCL »

None of the batteries I have purchased within the last few years have the AH defined.
Apparently there is quite a variance in the experts opinions regarding converting RC to AH.
Do you think RC/.6 is suitable for figuring AmpHours?...Thanks
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Re: A primer on backup battery systems for power outages

Post by willthrill81 »

RCL wrote: Tue Aug 18, 2020 4:47 pm None of the batteries I have purchased within the last few years have the AH defined.
Apparently there is quite a variance in the experts opinions regarding converting RC to AH.
Do you think RC/.6 is suitable for figuring AmpHours?...Thanks
I thought about addressing reserve capacity (RC) in the OP but didn't want to make it even longer.

Unless specified otherwise, a battery's reserve capacity refers to how long in minutes that the battery could provide 25 amps of power. The notable exception to this is golf cart batteries, which are based on a 75 amp draw. A few manufacturers calculate reserve capacity using different power draws, so try to find those if you can. My experience is that you can usually find the amp hours of a battery by searching online, but not always.

To convert this to amp hours, you multiply the reserve capacity (in minutes) by the amps being drawn (usually 25) and then divide by 60 (minutes in an hour). For instance, a marine battery with 150 minutes of reserve capacity has a total of 62.5 amp hours (150 x 25 / 60 = 62.5). If it was a golf cart battery and a 120 minute reserve capacity, you would assume a 75 amp draw, and the battery would have 150 amp hours (120 x 75 / 60 = 150); remember that golf cart batteries which are 6 volts must be connected in series (by connecting the negative terminal of one battery to the positive terminal of the other) so that the pair can be treated as a single 12 volt battery.
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Re: A primer on backup battery systems for power outages

Post by ray.james »

Great post willthrill. I have no knowledge in this area and plan to read this again slowly.

One thing it seems, for people planning to run a refrigerator, the wattage needs jump immediately. A single 12 V battery is enough for running aux power, some tv, charge electronics, a table fan.(or a portable cooler in camping trips.) Refrigerator food is good for 2-3 days. Given the refrigerator volume and storage, I think most people do not need for refrigerator coverage but it is a nice thing to have.


During recent outage, I am thinking of getting an inverter to draw power from the car battery.
(https://www.amazon.com/BESTEK-Inverter- ... B07JJSW48V)
So far it is not bad but this will work for me even during my camping trips & emergencies. Between that and a portable propane grill one should be covered.
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Re: A primer on backup battery systems for power outages

Post by Miriam2 »

Regarding backup battery systems for computers & electronics during power outages -

We have a universal power source battery that provides surge protection only on its outlets on one side of the battery and battery backup & surge protection on the outlets on the other side of the battery. It is an APC User Manual Back-UPS BN4001 120 Vac. We have our computer and modems plugged into the battery backup & surge protector side outlets.

https://www.apc.com/shop/us/en/products ... V/P-BN4001

Yesterday we had a big zap power outage for a minute and the UPS battery backup side died. Could not revive it, red light blinked the battery was dead, unit is 7 years old. My computer and modems connected to it are OK, so it did protect them. We re-plugged them into the power surge side of the UPS battery, which still works.

Should we change the battery in this UPS, or is it better to buy a new UPS battery backup & surge protector? The directions indicate this is a fairly dangerous battery to deal with.

Is this part of what you're talking about Willthrill for power outages?
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Re: A primer on backup battery systems for power outages

Post by willthrill81 »

ray.james wrote: Tue Aug 18, 2020 5:16 pm Great post willthrill. I have no knowledge in this area and plan to read this again slowly.
Thank you. I know that it's a lot to digest.
ray.james wrote: Tue Aug 18, 2020 5:16 pmOne thing it seems, for people planning to run a refrigerator, the wattage needs jump immediately. A single 12 V battery is enough for running aux power, some tv, charge electronics, a table fan.(or a portable cooler in camping trips.) Refrigerator food is good for 2-3 days. Given the refrigerator volume and storage, I think most people do not need for refrigerator coverage but it is a nice thing to have.
Yes, modern refrigerators do not have crazy high power requirements like electric stoves, furnaces, and water heaters, but it is out of the realistic reach of a small backup battery system. Even one comprised of four golf cart batteries (which would weigh about 250 lbs. and cost at least $450) would only be able to keep a refrigerator going for about two days.
ray.james wrote: Tue Aug 18, 2020 5:16 pmDuring recent outage, I am thinking of getting an inverter to draw power from the car battery.
(https://www.amazon.com/BESTEK-Inverter- ... B07JJSW48V)
So far it is not bad but this will work for me even during my camping trips & emergencies. Between that and a portable propane grill one should be covered.
That's a modified sine wave inverter, and in my experience, the compressors used in modern refrigerators and freezers will only operate on a pure sine wave inverter. I've just received the one below, also a Bestek inverter, and it works perfectly. The current cost is $159, a fraction of what such a unit would have cost a few years ago.

https://www.amazon.com/BESTEK-Inverter- ... 234&sr=1-4

Using propane for space heating and cooking is far superior to doing so with electricity in a grid-down situation.
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Re: A primer on backup battery systems for power outages

Post by willthrill81 »

Miriam2 wrote: Tue Aug 18, 2020 5:55 pm Regarding backup battery systems for computers & electronics during power outages -

We have a universal power source battery that provides surge protection only on its outlets on one side of the battery and battery backup & surge protection on the outlets on the other side of the battery. It is an APC User Manual Back-UPS BN4001 120 Vac. We have our computer and modems plugged into the battery backup & surge protector side outlets.

https://www.apc.com/shop/us/en/products ... V/P-BN4001

Yesterday we had a big zap power outage for a minute and the UPS battery backup side died. Could not revive it, red light blinked the battery was dead, unit is 7 years old. My computer and modems connected to it are OK, so it did protect them. We re-plugged them into the power surge side of the UPS battery, which still works.

Should we change the battery in this UPS, or is it better to buy a new UPS battery backup & surge protector? The directions indicate this is a fairly dangerous battery to deal with.

Is this part of what you're talking about Willthrill for power outages?
Universal power source systems like that are only designed to operate for a few minutes, just long enough to shut down a desktop computer and similar items. The specific model you linked to is only rated to provide a 100 watt load for a maximum of 12 minutes. The type of system in the OP would have far more capacity than that, even for a desktop computer.

That said, if you have a desktop computer, it's not a bad idea to use a UPS with it if you could lose critical data in the event of a sudden power outage; replacing the battery in yours is probably not a bad idea. But a UPS is not a substitute for a backup battery system of the sort described in the OP.
“It's a dangerous business, Frodo, going out your door. You step onto the road, and if you don't keep your feet, there's no knowing where you might be swept off to.” J.R.R. Tolkien,The Lord of the Rings
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Re: A primer on backup battery systems for power outages

Post by canderson »

This is why I wish the Powewall was more affordable. We live in a dense urban environment and a generator isn’t an option. We have no fireplace and forced air ac/gas so in a outage we would be out of luck (and in winter terrified of frozen pipes).

Interesting post even for a simpleton non-technical person like em.
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Re: A primer on backup battery systems for power outages

Post by Miriam2 »

willthrill81 wrote: Universal power source systems like that are only designed to operate for a few minutes, just long enough to shut down a desktop computer and similar items. The specific model you linked to is only rated to provide a 100 watt load for a maximum of 12 minutes. The type of system in the OP would have far more capacity than that, even for a desktop computer.

That said, if you have a desktop computer, it's not a bad idea to use a UPS with it if you could lose critical data in the event of a sudden power outage; replacing the battery in yours is probably not a bad idea. But a UPS is not a substitute for a backup battery system of the sort described in the OP.
Thank you! Which one is the "backup battery system of the sort described in the OP?" :confused What do you use to protect your computer with a backup and surge protector system?
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Re: A primer on backup battery systems for power outages

Post by indexfundfan »

If you have power tools like Ego or Ryobi, they make small inverters for you to utilize the power of the batteries. I find it very convenient since I have a couple of batteries lying around.
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Re: A primer on backup battery systems for power outages

Post by ray.james »

Miriam2 wrote: Tue Aug 18, 2020 6:17 pm
willthrill81 wrote: Universal power source systems like that are only designed to operate for a few minutes, just long enough to shut down a desktop computer and similar items. The specific model you linked to is only rated to provide a 100 watt load for a maximum of 12 minutes. The type of system in the OP would have far more capacity than that, even for a desktop computer.

That said, if you have a desktop computer, it's not a bad idea to use a UPS with it if you could lose critical data in the event of a sudden power outage; replacing the battery in yours is probably not a bad idea. But a UPS is not a substitute for a backup battery system of the sort described in the OP.
Thank you! Which one is the "backup battery system of the sort described in the OP?" :confused What do you use to protect your computer with a backup and surge protector system?
Miriam,
One thing with UPS is- ability to stop discharge and then hook it again a day later. They are designed to be on discharge the moment they are not charging. As such it works for sudden power loss but not for emergency storage of power. Please correct me if there are new systems that can do this.
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Re: A primer on backup battery systems for power outages

Post by hudson »

willthrill81,

If I had one of these batteries in my home, what would I use it for?
I use a 1000VA UPS for my desktop, modem, google wifi, and a switch.
If I had a backup battery in addition, what would it do for me?
I also have one of those car battery jump devices like this with a 12V DC adapter

https://www.amazon.com/gp/product/B000J ... UTF8&psc=1
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Re: A primer on backup battery systems for power outages

Post by inbox788 »

willthrill81 wrote: Tue Aug 18, 2020 1:35 pmHow to Get Power from a Battery

There are basically two ways to get power from a battery: direct current (DC) power directly from the battery or alternating current (AC) power via an inverter connected to the battery.
Great writeup. I'll have to come back to this as reference.

Just wanted to add that the user should consider what power he's going to need. One key reason for battery backup is keeping cell phones and other electronics (communications/entertainment/battery banks/etc.) charged up and many are 5V USB or USB-C/PD these days.

While it's convenient to plug the adapter into an AC circuit, there's a lot of conversion steps going on and each step wastes valuable power. Just add up all the power or current you will use and don't go over.

I've found car adapters like these quite useful in improving the conversion efficiency. I haven't tested it, but I figure reducing the number of conversions and bypassing the inverter would use less power.

https://www.amazon.com/Anker-Charger-Po ... 07PGT7LSR/
https://www.amazon.com/Charger-Adapter- ... 0779D7DFG/
https://www.amazon.com/Anker-Charger-Po ... 07RL2N8YY/

And if I'm running off battery, regardless of how little power a device might draw when off or fully charged, I try to keep things unplugged, just to be sure.
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Re: A primer on backup battery systems for power outages

Post by LadyGeek »

For a computer battery backup system, I size my UPS for the amount of time I need to save my work and shutdown the computer. About 5 minutes of run time for the PC and monitor is all I need. My printer is not on the UPS.

Once I shutdown my PCs (I have 2 PCs and 2 UPSs), I'll bring my generator online and switch to my laptop to save power.

The UPS is also helpful when the power coming into the house intermittently drops a phase - which can happen during a storm.
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Re: A primer on backup battery systems for power outages

Post by iamlucky13 »

indexfundfan wrote: Tue Aug 18, 2020 6:27 pm If you have power tools like Ego or Ryobi, they make small inverters for you to utilize the power of the batteries. I find it very convenient since I have a couple of batteries lying around.
Plan on very limited runtimes from these, so limit their use to plug-in applications that are important to you. If they can even give clean enough power to start a fridge, you might get a couple hours from one of the larger Ego batteries. You might get the better part of a day running a modem to keep the internet going for your laptop.

You could light up a room for potentially several days using a single bulb table lamp with an LED bulb.
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Re: A primer on backup battery systems for power outages

Post by whomever »

Great writeup!

=================

"the newish portable Lithium Ion "solar power station"?"

We have the smaller Jackery (240??). They are convenient plug-n-play systems. We use it for extended car camping trips with a 50W solar panel. You don't have to understand anything; you just charge it from the solar panel (or the cigarette lighter if the vehicle is operating), and use it to charge/run cell phones, AA rechargeables, or our car camping hot weather luxury, a USB fan.

For fixed use at home, those kind of things are expensive but convenient, if your loads are light enough.

============
I also have a baby solar system - a lead acid battery, a solar panel, and a controller, wired to the cigarette lighter type outlets Will mentions above, and USB chargers plugged into some of those. I did it on a lark - the 50W panel was maybe $60, the controller was $10 (it's cheap, not good :-) ), and the small battery was maybe $75, Maybe another $30 for the ancillary stuff - auto fuse box, outlets, USB widgets. Scrap plywood for an enclosure. I mostly use it to charge the family eneloops, just because.

But you could scale it to a 'run the fridge for a few days and charge the neighborhood's cell phones' type system pretty simply. I kind of like the idea that I can charge AA's through an infinitely long outage.
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Re: A primer on backup battery systems for power outages

Post by LadyGeek »

I should also mention that there are battery backup products for your car. Wait.. what? Google "Car battery jump starter".

I have one for my 2020 Toyota RAV4 and keep it under the driver's seat. In the event of an unplanned power outage (dead battery), it has enough capcity to start my car. It needs to be charged every 3 months.

My car (and a lot of others) has an automatic stop-start feature. Press on the brakes when you stop and the engine turns off. Press on the gas and the engine automatically starts. There's an entire technology that's dedicated to stop-start battery design. I'm not an expert, but you can google for the details. The important point is that the replacement battery must be rated for stop-start.
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Re: A primer on backup battery systems for power outages

Post by telemark »

Miriam2 wrote: Tue Aug 18, 2020 5:55 pm Regarding backup battery systems for computers & electronics during power outages -

We have a universal power source battery that provides surge protection only on its outlets on one side of the battery and battery backup & surge protection on the outlets on the other side of the battery. It is an APC User Manual Back-UPS BN4001 120 Vac. We have our computer and modems plugged into the battery backup & surge protector side outlets.

https://www.apc.com/shop/us/en/products ... V/P-BN4001

Yesterday we had a big zap power outage for a minute and the UPS battery backup side died. Could not revive it, red light blinked the battery was dead, unit is 7 years old. My computer and modems connected to it are OK, so it did protect them. We re-plugged them into the power surge side of the UPS battery, which still works.

Should we change the battery in this UPS, or is it better to buy a new UPS battery backup & surge protector? The directions indicate this is a fairly dangerous battery to deal with.

Is this part of what you're talking about Willthrill for power outages?
The battery probably went bad sometime in the previous seven years. They're designed to be replaceable, so I would just buy a new battery. Try taking the old battery out first--this is pretty easy if you can handle a screwdriver--and if you're comfortable with doing that then go ahead and buy a replacement. I get mine at the local Batteries Plus, because I'm usually in a hurry and they will recycle the old battery. But you can usually find better prices online.

And as willthrill said, these are for brief outages only. Not least because of the annoying beeping sounds they make.
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Re: A primer on backup battery systems for power outages

Post by hudson »

Miriam2 wrote: Tue Aug 18, 2020 5:55 pm Regarding backup battery systems for computers & electronics during power outages -

We have a universal power source battery that provides surge protection only on its outlets on one side of the battery and battery backup & surge protection on the outlets on the other side of the battery. It is an APC User Manual Back-UPS BN4001 120 Vac. We have our computer and modems plugged into the battery backup & surge protector side outlets.

https://www.apc.com/shop/us/en/products ... V/P-BN4001

Yesterday we had a big zap power outage for a minute and the UPS battery backup side died. Could not revive it, red light blinked the battery was dead, unit is 7 years old. My computer and modems connected to it are OK, so it did protect them. We re-plugged them into the power surge side of the UPS battery, which still works.

Should we change the battery in this UPS, or is it better to buy a new UPS battery backup & surge protector? The directions indicate this is a fairly dangerous battery to deal with.

Is this part of what you're talking about Willthrill for power outages?
Over the years I've worked with hundreds of those little UPSs. Sometimes, we replaced batteries, sometimes we didn't. With the small units, after 3-4 years, I learned that it paid to go new because sometimes, you replaced the battery and that didn't fix the problem. With a 7 year old UPS, I wouldn't hesitate to replace it. We'd keep dozens of UPS batteries on a shelf, so we could swap the battery in no time. A person with a single UPS has to go to a lot of trouble to get a battery and replace it; it's easier to go new.
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Re: A primer on backup battery systems for power outages

Post by linuxizer »

Here's the link to the generator thread, for posterity:
viewtopic.php?f=11&t=322105&newpost=5441323

Some more thoughts:
- RefurbUPS and similar sites offer new batteries in used UPS's. APC makes an extended run line of UPS's. Think beefy fan for cooling, designed for continuous use on rated loads, with large battery capacities compared to their rated loads, and the ability to daisy chain additional battery packs for truly huge run times.
- Whatever battery solution you have, make sure it's a few feet off the ground in case of flooding.
- The best battery is the one that is charged, especially if not using a generator. So I have favored buying inverters for the 60V lawn tools we have (huge capacity; 5++ charges of a laptop), and USB adapters for our 18V drill batteries (powers quite a few cell phone charges off a single battery, and we have 4 or 5 sitting around).
- If you buy a AA/AAA charger, it's worth the extra for a true smart charger and for one that charges each battery separately. I have an older one that only charges the pairs, and it's a giant pain (and likely hurts batteries) because I can never manage to keep them paired off.
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Re: A primer on backup battery systems for power outages

Post by willthrill81 »

Miriam2 wrote: Tue Aug 18, 2020 6:17 pm
willthrill81 wrote: Universal power source systems like that are only designed to operate for a few minutes, just long enough to shut down a desktop computer and similar items. The specific model you linked to is only rated to provide a 100 watt load for a maximum of 12 minutes. The type of system in the OP would have far more capacity than that, even for a desktop computer.

That said, if you have a desktop computer, it's not a bad idea to use a UPS with it if you could lose critical data in the event of a sudden power outage; replacing the battery in yours is probably not a bad idea. But a UPS is not a substitute for a backup battery system of the sort described in the OP.
Thank you! Which one is the "backup battery system of the sort described in the OP?" :confused What do you use to protect your computer with a backup and surge protector system?
For a desktop computer, a UPS is a very good idea because it provides you with the uninterrupted power you need to shut the computer down. But that's not what I'm describing in the OP, which is a system that you build yourself to your own needs at far lower expense than a pre-built 'solar generator' or something similar.
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Re: A primer on backup battery systems for power outages

Post by willthrill81 »

hudson wrote: Tue Aug 18, 2020 6:43 pm willthrill81,

If I had one of these batteries in my home, what would I use it for?
I use a 1000VA UPS for my desktop, modem, google wifi, and a switch.
If I had a backup battery in addition, what would it do for me?
I also have one of those car battery jump devices like this with a 12V DC adapter

https://www.amazon.com/gp/product/B000J ... UTF8&psc=1
The UPS is only designed to work for a matter of minutes, giving you time to either shut down those devices or switch to another power source, like a separate backup battery system. You can build your own battery system with many times the power of a UPS, and you could use it for all the items you listed as well as others (e.g. lights, anything charged from a USB, AA and AAA battery chargers, radio, small fans).
“It's a dangerous business, Frodo, going out your door. You step onto the road, and if you don't keep your feet, there's no knowing where you might be swept off to.” J.R.R. Tolkien,The Lord of the Rings
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Re: A primer on backup battery systems for power outages

Post by -ryan- »

I have several power outage redundancies, including a heating source installed in my home that can operate with no electricity, a large gasoline generator, a small gasoline inverter generator, my pickup has an onboard 400watt inverter, and I have a deep cycle battery for my camper that can be used to provide power.

In addition, I have a folding solar charging system for my camper battery so if the power is out but it is reasonably sunny the battery can be charged/maintained via natural sunlight. Otherwise, if the battery is on the camper it is always being maintained via either the onboard solar system or the shore power hookup. In the off season the battery is on a battery maintainer 24/7. It's an emergency power source I hadn't thought of much until this year, but a good additional backup.

For that matter, the camper itself is a nice backup as well in the warmer months since it is setup for boondocking.
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Re: A primer on backup battery systems for power outages

Post by 000 »

LadyGeek wrote: Tue Aug 18, 2020 7:35 pm For a computer battery backup system, I size my UPS for the amount of time I need to save my work and shutdown the computer. About 5 minutes of run time for the PC and monitor is all I need. My printer is not on the UPS.

Once I shutdown my PCs (I have 2 PCs and 2 UPSs), I'll bring my generator online and switch to my laptop to save power.

The UPS is also helpful when the power coming into the house intermittently drops a phase - which can happen during a storm.
I've often wondered how I would know to "save my work and shutdown the computer" if I was temporarily away from it. Does the UPS emit some kind of alert? How have you approached this?

Thanks
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Re: A primer on backup battery systems for power outages

Post by willthrill81 »

canderson wrote: Tue Aug 18, 2020 6:13 pm This is why I wish the Powewall was more affordable. We live in a dense urban environment and a generator isn’t an option. We have no fireplace and forced air ac/gas so in a outage we would be out of luck (and in winter terrified of frozen pipes).
You might be surprised. I've seen people run small inverter generators from the balconies of their apartment. The good ones don't make much more noise than a printer, especially at low loads. When we briefly lived in an apartment, I kept a marine battery connected to a small charger under the kitchen sink. :D

You could heat an apartment surprisingly well with a small propane heater like a Mr. Buddy. We have several of the 20 lb. (i.e. the kind used with grills) tanks in reserve just in case we need to heat at least one bedroom in the house for a couple of weeks.
canderson wrote: Tue Aug 18, 2020 6:13 pmInteresting post even for a simpleton non-technical person like em.
Thank you. Maybe you could figure out a way to put some of the ideas to work in your situation.
“It's a dangerous business, Frodo, going out your door. You step onto the road, and if you don't keep your feet, there's no knowing where you might be swept off to.” J.R.R. Tolkien,The Lord of the Rings
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Re: A primer on backup battery systems for power outages

Post by willthrill81 »

000 wrote: Tue Aug 18, 2020 9:25 pm
LadyGeek wrote: Tue Aug 18, 2020 7:35 pm For a computer battery backup system, I size my UPS for the amount of time I need to save my work and shutdown the computer. About 5 minutes of run time for the PC and monitor is all I need. My printer is not on the UPS.

Once I shutdown my PCs (I have 2 PCs and 2 UPSs), I'll bring my generator online and switch to my laptop to save power.

The UPS is also helpful when the power coming into the house intermittently drops a phase - which can happen during a storm.
I've often wondered how I would know to "save my work and shutdown the computer" if I was temporarily away from it. Does the UPS emit some kind of alert? How have you approached this?

Thanks
When you lose power, you generally know it if you're in the house because the lights go out and everything suddenly stops. But yes, every UPS I've seen starts making a very annoying beeping sound when power is lost to let you know that you need to shut down the system. Most only give you around ten minutes or so of power.
“It's a dangerous business, Frodo, going out your door. You step onto the road, and if you don't keep your feet, there's no knowing where you might be swept off to.” J.R.R. Tolkien,The Lord of the Rings
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Re: A primer on backup battery systems for power outages

Post by 000 »

willthrill81 wrote: Tue Aug 18, 2020 9:28 pm
000 wrote: Tue Aug 18, 2020 9:25 pm
LadyGeek wrote: Tue Aug 18, 2020 7:35 pm For a computer battery backup system, I size my UPS for the amount of time I need to save my work and shutdown the computer. About 5 minutes of run time for the PC and monitor is all I need. My printer is not on the UPS.

Once I shutdown my PCs (I have 2 PCs and 2 UPSs), I'll bring my generator online and switch to my laptop to save power.

The UPS is also helpful when the power coming into the house intermittently drops a phase - which can happen during a storm.
I've often wondered how I would know to "save my work and shutdown the computer" if I was temporarily away from it. Does the UPS emit some kind of alert? How have you approached this?

Thanks
When you lose power, you generally know it if you're in the house because the lights go out and everything suddenly stops. But yes, every UPS I've seen starts making a very annoying beeping sound when power is lost to let you know that you need to shut down the system. Most only give you around ten minutes or so of power.
Are there any that can automatically switchover to an alternate power source?
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Re: A primer on backup battery systems for power outages

Post by willthrill81 »

-ryan- wrote: Tue Aug 18, 2020 9:24 pm I have several power outage redundancies, including a heating source installed in my home that can operate with no electricity, a large gasoline generator, a small gasoline inverter generator, my pickup has an onboard 400watt inverter, and I have a deep cycle battery for my camper that can be used to provide power.

In addition, I have a folding solar charging system for my camper battery so if the power is out but it is reasonably sunny the battery can be charged/maintained via natural sunlight. Otherwise, if the battery is on the camper it is always being maintained via either the onboard solar system or the shore power hookup. In the off season the battery is on a battery maintainer 24/7. It's an emergency power source I hadn't thought of much until this year, but a good additional backup.

For that matter, the camper itself is a nice backup as well in the warmer months since it is setup for boondocking.
It sounds like you're very well prepared! :thumbsup

Having redundancies, especially for critical systems in your home, is very wise. I'm shocked at how few people we know who could heat their home if they lost grid power. The natural gas lines are generally much more reliable than the electrical grid, and being able to heat with natural gas but no grid power seems essential to me. In our case, we could power our natural gas furnace with about 500 watts of power (i.e. the circuit board, igniter, and blower are electric) from a generator or a running vehicle (temporarily), and we also have a natural gas fireplace that can be run with no electrical power at all, though the 30 watt blower really does help and could be run for a long time from our small battery backup.

Solar panels are great, but I'm glad that you acknowledged their big limitation: they only work when you have good sunshine. While we too have a solar panel for recharging a battery, we are in no way dependent on it working in order to have power. It's just a nice bonus.

And yes, if you have an RV, you have a very nice off-grid place to stay. When we lost power here five years ago, we slept in our camper and ran the generator all night to power the RV's air conditioner since it was very hot at the time.
“It's a dangerous business, Frodo, going out your door. You step onto the road, and if you don't keep your feet, there's no knowing where you might be swept off to.” J.R.R. Tolkien,The Lord of the Rings
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Re: A primer on backup battery systems for power outages

Post by willthrill81 »

000 wrote: Tue Aug 18, 2020 9:31 pm
willthrill81 wrote: Tue Aug 18, 2020 9:28 pm
000 wrote: Tue Aug 18, 2020 9:25 pm
LadyGeek wrote: Tue Aug 18, 2020 7:35 pm For a computer battery backup system, I size my UPS for the amount of time I need to save my work and shutdown the computer. About 5 minutes of run time for the PC and monitor is all I need. My printer is not on the UPS.

Once I shutdown my PCs (I have 2 PCs and 2 UPSs), I'll bring my generator online and switch to my laptop to save power.

The UPS is also helpful when the power coming into the house intermittently drops a phase - which can happen during a storm.
I've often wondered how I would know to "save my work and shutdown the computer" if I was temporarily away from it. Does the UPS emit some kind of alert? How have you approached this?

Thanks
When you lose power, you generally know it if you're in the house because the lights go out and everything suddenly stops. But yes, every UPS I've seen starts making a very annoying beeping sound when power is lost to let you know that you need to shut down the system. Most only give you around ten minutes or so of power.
Are there any that can automatically switchover to an alternate power source?
I'm not aware of any UPS systems that would do that, but there is a product out there that would do what you want when used in conjunction with a UPS. It's called an inverter with an automatic transfer switch (like this one). It will plug into both a regular 120 volt outlet and also connect to a lead acid battery, like one of those described in the OP. When grid power is functioning, it uses that to power the items connected to the inverter, but when grid power is lost, it switches to the battery and inverts that to produce 120 volt power. You would plug the UPS into the inverter, basically extending the battery capability of the UPS by however big the battery connected to the inverter would be. However, you would still need the UPS because it can take a second or so for the inverter to switch from pulling grid power to using battery power, and a desktop would go dead during that second.

Aside from that, the only other thing I'm aware of that would do what you want is a standby generator used in conjunction with an automatic transfer switch, which is usually set up to restore power to at least select circuits 30 seconds after grid power is lost, but that will cost upwards of $10k, while the above inverter with an automatic transfer switch would be no more than a few hundred dollars.
“It's a dangerous business, Frodo, going out your door. You step onto the road, and if you don't keep your feet, there's no knowing where you might be swept off to.” J.R.R. Tolkien,The Lord of the Rings
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Re: A primer on backup battery systems for power outages

Post by willthrill81 »

LadyGeek wrote: Tue Aug 18, 2020 8:35 pm I should also mention that there are battery backup products for your car. Wait.. what? Google "Car battery jump starter".

I have one for my 2020 Toyota RAV4 and keep it under the driver's seat. In the event of an unplanned power outage (dead battery), it has enough capcity to start my car. It needs to be charged every 3 months.
We have one like that too with an internal lithium-ion battery. Thankfully, we haven't had to use it yet, but I've heard nothing but good things about them. It's pretty amazing that they seem to work as well as they do considering that many of them only have about 37 watt hours of power (10,000 mAh x 3.7 volts), compared to the roughly 1,000 watt hours of a typical automotive battery.
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Re: A primer on backup battery systems for power outages

Post by inbox788 »

telemark wrote: Tue Aug 18, 2020 8:36 pmThe battery probably went bad sometime in the previous seven years. They're designed to be replaceable, so I would just buy a new battery. Try taking the old battery out first--this is pretty easy if you can handle a screwdriver--and if you're comfortable with doing that then go ahead and buy a replacement. I get mine at the local Batteries Plus, because I'm usually in a hurry and they will recycle the old battery. But you can usually find better prices online.

And as willthrill said, these are for brief outages only. Not least because of the annoying beeping sounds they make.
Old ones used somewhat standard batteries and could be replaced. Newer ones are being designed to be disposed, though there are youtube videos showing how to change the batteries. Search for your model for more specific instructions and details. I've heard of people going to garage sales and thrift shops picking up dead UPS units for their electronics and rejuvenating them with new batteries.

As far as the annoying beeping, I taped one over so it wasn't so noisy, but I really should have just yanked out the tiny speaker, and might do that sometime. A newer UPS I bought has (this one or similar https://www.apc.com/shop/us/en/products ... l/P-BN450M ) can silence some/most alarms.
000 wrote: Tue Aug 18, 2020 9:25 pmI've often wondered how I would know to "save my work and shutdown the computer" if I was temporarily away from it. Does the UPS emit some kind of alert? How have you approached this?
I got one of these ( https://www.amazon.com/gp/product/B0019804U ), but never got around to setting it up with the cable and software. My system gets random crashes, so I'm used to random power downs, and I live with it.

PowerChute
https://www.apc.com/shop/us/en/categori ... /N-1b6nbpp
000 wrote: Tue Aug 18, 2020 9:31 pmAre there any that can automatically switchover to an alternate power source?
Such as? Short of an automatic transfer whole house generator, the available power choices are limited, especially automatic. I have plugged a laptop into a UPS for double backup, but there's really minimal benefit with the automatic built-in power management in the laptop.
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telemark
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Re: A primer on backup battery systems for power outages

Post by telemark »

inbox788 wrote: Wed Aug 19, 2020 2:55 am
telemark wrote: Tue Aug 18, 2020 8:36 pmThe battery probably went bad sometime in the previous seven years. They're designed to be replaceable, so I would just buy a new battery. Try taking the old battery out first--this is pretty easy if you can handle a screwdriver--and if you're comfortable with doing that then go ahead and buy a replacement. I get mine at the local Batteries Plus, because I'm usually in a hurry and they will recycle the old battery. But you can usually find better prices online.

And as willthrill said, these are for brief outages only. Not least because of the annoying beeping sounds they make.
Old ones used somewhat standard batteries and could be replaced. Newer ones are being designed to be disposed, though there are youtube videos showing how to change the batteries. Search for your model for more specific instructions and details. I've heard of people going to garage sales and thrift shops picking up dead UPS units for their electronics and rejuvenating them with new batteries.
The model in question has a very common and easily replaceable battery.
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Re: A primer on backup battery systems for power outages

Post by hudson »

willthrill81 wrote: Tue Aug 18, 2020 9:23 pm
hudson wrote: Tue Aug 18, 2020 6:43 pm willthrill81,

If I had one of these batteries in my home, what would I use it for?
I use a 1000VA UPS for my desktop, modem, google wifi, and a switch.
If I had a backup battery in addition, what would it do for me?
I also have one of those car battery jump devices like this with a 12V DC adapter

https://www.amazon.com/gp/product/B000J ... UTF8&psc=1
The UPS is only designed to work for a matter of minutes, giving you time to either shut down those devices or switch to another power source, like a separate backup battery system. You can build your own battery system with many times the power of a UPS, and you could use it for all the items you listed as well as others (e.g. lights, anything charged from a USB, AA and AAA battery chargers, radio, small fans).
Years ago, where I worked, there was a demand for a mobile computer cart. I asked an electrical engineer/computer specialist over the phone how to do that. He immediately said, "deep cycle marine battery." I didn't go with his suggestion, because I didn't want to build my own; I wanted to buy one already engineered. I finally found a suitable battery cart that did the job....with battery and charger built-in. I just had to add a small industrial computer and a monitor. Hospital and medical facilities now have those rolling cordless computer carts everywhere. I never checked to see if they use deep cycle batteries.
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Re: A primer on backup battery systems for power outages

Post by linuxizer »

UPSs come in different classes. Once you’re past the cheapie consumer models, you can get 220v systems, rackmount systems, double conversion, extended run, etc.

Because they come from the corporate market which disfavors used stuff you can get refurb ones for way less than the original price. Don’t buy too old as the capacitors also wear out at some point, but usually it’s the battery which should be new on a refurb unit. ALL of these built in the last decade or two will have a serial or USB port to notify your computer to shut itself down gracefully. There’s proprietary software to do this for Win, or built in drivers for Linux.

I have an extended run model powering our WiFi. Access points not at the main spot where FIOS comes in to the house are powered through PoE so they run off the same UPS. Should last the better part of a day, and more run time can be added inexpensively. The equipment is on a shelf 4ft off the ground in the basement with plastic sheeting on the shelf above in case a pipe leaks.

Double conversion might be a better choice for a UPS planned for generator use. They don’t attempt to switch over to the battery, they just always convert to battery and back again. If your generator makes dirty power this can prevent issues where it constantly switches to and from the battery as the dirty power has particularly dirty moments. Our generator is an inverter so hoping not an issue but haven’t tested yet.

The other option for a bigger battery bank is to get an inverter/charger. These are designed for the RV market mostly, and handle the charging and passthrough when there’s power, the inverting to AC from batteries when there’s no power and switching seamlessly between. These run $300+ so it would need to be a big battery bank to be worth it. Probably should think about where you’d house them as well for shocks/leaks.
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Re: A primer on backup battery systems for power outages

Post by hudson »

willthrill81 wrote: Tue Aug 18, 2020 9:23 pm You can build your own battery system with many times the power of a UPS, and you could use it for all the items you listed as well as others (e.g. lights, anything charged from a USB, AA and AAA battery chargers, radio, small fans).
willthrill81, Is this what you are talking about? https://www.doityourself.com/your-proje ... goes%20out
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Re: A primer on backup battery systems for power outages

Post by LadyGeek »

willthrill81 wrote: Tue Aug 18, 2020 9:57 pm
LadyGeek wrote: Tue Aug 18, 2020 8:35 pm I should also mention that there are battery backup products for your car. Wait.. what? Google "Car battery jump starter".

I have one for my 2020 Toyota RAV4 and keep it under the driver's seat. In the event of an unplanned power outage (dead battery), it has enough capcity to start my car. It needs to be charged every 3 months.
We have one like that too with an internal lithium-ion battery. Thankfully, we haven't had to use it yet, but I've heard nothing but good things about them. It's pretty amazing that they seem to work as well as they do considering that many of them only have about 37 watt hours of power (10,000 mAh x 3.7 volts), compared to the roughly 1,000 watt hours of a typical automotive battery.
It's also amazing when you consider those units have reverse voltage protection, which means they have to overcome about 1 diode drop's worth of voltage. (I got the idea to buy one from recommendations in the auto enthusiast forums.)

Actually, anything that takes a battery has reverse voltage protection which is usually a series diode. The units those batteries power are actually working with a DC voltage that's about 0.6 V lower than what the battery supplies.

The 0.6 V is an estimate, as it will vary based on the type of protection - anything from a Schottky diode to a MOSFET.
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Re: A primer on backup battery systems for power outages

Post by Point »

I was looking at doing just this with my 2 AGM deep cycle batteries and small solar panel with charge controller. Put them
In a doghouse, point the panel at the sun. Continuous battery charging done. Add fuse, cigarette lighter outlets and usb outlets. 12V charging done. Add inverter to handle 200 watt load from refrigerator or freezer, done. Need more solar charging? Add suitcase panels, done!
whomever wrote: Tue Aug 18, 2020 8:18 pm Great writeup!

=================

"the newish portable Lithium Ion "solar power station"?"

We have the smaller Jackery (240??). They are convenient plug-n-play systems. We use it for extended car camping trips with a 50W solar panel. You don't have to understand anything; you just charge it from the solar panel (or the cigarette lighter if the vehicle is operating), and use it to charge/run cell phones, AA rechargeables, or our car camping hot weather luxury, a USB fan.

For fixed use at home, those kind of things are expensive but convenient, if your loads are light enough.

============
I also have a baby solar system - a lead acid battery, a solar panel, and a controller, wired to the cigarette lighter type outlets Will mentions above, and USB chargers plugged into some of those. I did it on a lark - the 50W panel was maybe $60, the controller was $10 (it's cheap, not good :-) ), and the small battery was maybe $75, Maybe another $30 for the ancillary stuff - auto fuse box, outlets, USB widgets. Scrap plywood for an enclosure. I mostly use it to charge the family eneloops, just because.

But you could scale it to a 'run the fridge for a few days and charge the neighborhood's cell phones' type system pretty simply. I kind of like the idea that I can charge AA's through an infinitely long outage.
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Re: A primer on backup battery systems for power outages

Post by Jack FFR1846 »

willthrill81 wrote: Tue Aug 18, 2020 9:45 pm
000 wrote: Tue Aug 18, 2020 9:31 pm
willthrill81 wrote: Tue Aug 18, 2020 9:28 pm
000 wrote: Tue Aug 18, 2020 9:25 pm
LadyGeek wrote: Tue Aug 18, 2020 7:35 pm For a computer battery backup system, I size my UPS for the amount of time I need to save my work and shutdown the computer. About 5 minutes of run time for the PC and monitor is all I need. My printer is not on the UPS.

Once I shutdown my PCs (I have 2 PCs and 2 UPSs), I'll bring my generator online and switch to my laptop to save power.

The UPS is also helpful when the power coming into the house intermittently drops a phase - which can happen during a storm.
I've often wondered how I would know to "save my work and shutdown the computer" if I was temporarily away from it. Does the UPS emit some kind of alert? How have you approached this?

Thanks
When you lose power, you generally know it if you're in the house because the lights go out and everything suddenly stops. But yes, every UPS I've seen starts making a very annoying beeping sound when power is lost to let you know that you need to shut down the system. Most only give you around ten minutes or so of power.
Are there any that can automatically switchover to an alternate power source?
I'm not aware of any UPS systems that would do that, but there is a product out there that would do what you want when used in conjunction with a UPS. It's called an inverter with an automatic transfer switch (like this one). It will plug into both a regular 120 volt outlet and also connect to a lead acid battery, like one of those described in the OP. When grid power is functioning, it uses that to power the items connected to the inverter, but when grid power is lost, it switches to the battery and inverts that to produce 120 volt power. You would plug the UPS into the inverter, basically extending the battery capability of the UPS by however big the battery connected to the inverter would be. However, you would still need the UPS because it can take a second or so for the inverter to switch from pulling grid power to using battery power, and a desktop would go dead during that second.

Aside from that, the only other thing I'm aware of that would do what you want is a standby generator used in conjunction with an automatic transfer switch, which is usually set up to restore power to at least select circuits 30 seconds after grid power is lost, but that will cost upwards of $10k, while the above inverter with an automatic transfer switch would be no more than a few hundred dollars.
There are UPS units that can take input power from a number of sources. I'm familiar with this type: https://www.synqor.com/ups/index.html

This uses double conversion. Input power is converted to a "mid bus". That is then converted to a true sine wave output. Input power is prioritized: AC power, and if not present, 28Vdc power, and if not present, battery. The output is always fed by conversion from the mid bus. There is no transfer switch. Input power never goes to the output directly. If power goes away, there is no glitch, like there would be in a transfer switch type unit. There are options to add external batteries to extend time of use.

From another job, for units with battery backup that utilize a transfer switch and have some amount of time to switch over, it's possible to keep the system up for a couple hundred miliseconds that it takes for the batteries to come on line using supercaps. I designed a system to do this for a RAID system that needed 1kW for 200 ms. It was not trivial. Output for this system went directly to the internal 12V bus.

I expect nobody to be buying these for their house. They're in the $10k range.

(I worked for them, so know these systems very well)
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Re: A primer on backup battery systems for power outages

Post by hudson »

Jack FFR1846,

Wow...a serious UPS! ...no expense spared.
There are folks who want to try to get 100% up time.
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Re: A primer on backup battery systems for power outages

Post by go_mets »

willthrill81 wrote: Tue Aug 18, 2020 9:26 pm You could heat an apartment surprisingly well with a small propane heater like a Mr. Buddy. We have several of the 20 lb. (i.e. the kind used with grills) tanks in reserve just in case we need to heat at least one bedroom in the house for a couple of weeks.
I got hammered on another message board by an EMT for suggesting using a Mr. Buddy.
For the record I do have a Mr. Buddy.
The EMT wrote about all the people he had to haul to the hospital from CO poisoning.

.
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Re: A primer on backup battery systems for power outages

Post by go_mets »

Thank you for the primer.

Given that a 100Ah lead acid battery weights 65-70 pounds,
Will a 50Ah one be enough to peridocially run a full-size side-by-side refrigerator for 2-3 days?
These are about 45 pounds.
I am looking at the ones sold by Advance Auto Parts who have a store nearby:
https://shop.advanceautoparts.com/web/S ... E_LOW_HIGH
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Re: A primer on backup battery systems for power outages

Post by neilpilot »

go_mets wrote: Wed Aug 19, 2020 8:13 am
willthrill81 wrote: Tue Aug 18, 2020 9:26 pm You could heat an apartment surprisingly well with a small propane heater like a Mr. Buddy. We have several of the 20 lb. (i.e. the kind used with grills) tanks in reserve just in case we need to heat at least one bedroom in the house for a couple of weeks.
I got hammered on another message board by an EMT for suggesting using a Mr. Buddy.
For the record I do have a Mr. Buddy.
The EMT wrote about all the people he had to haul to the hospital from CO poisoning.

.
You would think, in addition to the safety element of the Mr Buddy O2 sensor, no one would be without working CO alarms in their living space. But based on the number of fire deaths that occur in homes that don't have a working smoke detector, I suspect CO monitors are also not ubiquitous.
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Re: A primer on backup battery systems for power outages

Post by go_mets »

neilpilot wrote: Wed Aug 19, 2020 8:20 am
go_mets wrote: Wed Aug 19, 2020 8:13 am
willthrill81 wrote: Tue Aug 18, 2020 9:26 pm You could heat an apartment surprisingly well with a small propane heater like a Mr. Buddy. We have several of the 20 lb. (i.e. the kind used with grills) tanks in reserve just in case we need to heat at least one bedroom in the house for a couple of weeks.
I got hammered on another message board by an EMT for suggesting using a Mr. Buddy.
For the record I do have a Mr. Buddy.
The EMT wrote about all the people he had to haul to the hospital from CO poisoning.

.
You would think, in addition to the safety element of the Mr Buddy O2 sensor, no one would be without working CO alarms in their living space. But based on the number of fire deaths that occur in homes that don't have a working smoke detector, I suspect CO monitors are also not ubiquitous.
I mentioned that I had three (3) CO monitors in my home.
One that is in the ceiling and two of the portable ones that I bought myself and which have 9V battery backup.
That was going to be my safety backup.
In addition, I was planning on turning off Mr Buddy when I went to bed.
Still got hammered.


.
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Re: A primer on backup battery systems for power outages

Post by smitcat »

go_mets wrote: Wed Aug 19, 2020 8:19 am Thank you for the primer.

Given that a 100Ah lead acid battery weights 65-70 pounds,
Will a 50Ah one be enough to peridocially run a full-size side-by-side refrigerator for 2-3 days?
These are about 45 pounds.
I am looking at the ones sold by Advance Auto Parts who have a store nearby:
https://shop.advanceautoparts.com/web/S ... E_LOW_HIGH
If you want to support any full sized refrigerator and open the door from time to time over 3 days batteries will not suit your goal without a robust charging system for the batteries. By the time you add the charging system(s) (solar, small genset, wind) required you might as well get a suitably sized small generator.
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Re: A primer on backup battery systems for power outages

Post by go_mets »

smitcat wrote: Wed Aug 19, 2020 8:48 am
go_mets wrote: Wed Aug 19, 2020 8:19 am Thank you for the primer.

Given that a 100Ah lead acid battery weights 65-70 pounds,
Will a 50Ah one be enough to peridocially run a full-size side-by-side refrigerator for 2-3 days?
These are about 45 pounds.
I am looking at the ones sold by Advance Auto Parts who have a store nearby:
https://shop.advanceautoparts.com/web/S ... E_LOW_HIGH
If you want to support any full sized refrigerator and open the door from time to time over 3 days batteries will not suit your goal without a robust charging system for the batteries. By the time you add the charging system(s) (solar, small genset, wind) required you might as well get a suitably sized small generator.
Have you tried this yourself?

My calculations:
My refrigerator says it is 11.5A which I am guessing is the average current draw per hour.
So if I run 1 hour per day and the battery is 50Ah.
It would seem I would get 4 days out it.
My main goal is to not have the food spoil so I would try to avoid opening the door.
.
smitcat
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Re: A primer on backup battery systems for power outages

Post by smitcat »

go_mets wrote: Wed Aug 19, 2020 9:13 am
smitcat wrote: Wed Aug 19, 2020 8:48 am
go_mets wrote: Wed Aug 19, 2020 8:19 am Thank you for the primer.

Given that a 100Ah lead acid battery weights 65-70 pounds,
Will a 50Ah one be enough to peridocially run a full-size side-by-side refrigerator for 2-3 days?
These are about 45 pounds.
I am looking at the ones sold by Advance Auto Parts who have a store nearby:
https://shop.advanceautoparts.com/web/S ... E_LOW_HIGH
If you want to support any full sized refrigerator and open the door from time to time over 3 days batteries will not suit your goal without a robust charging system for the batteries. By the time you add the charging system(s) (solar, small genset, wind) required you might as well get a suitably sized small generator.
Have you tried this yourself?

My calculations:
My refrigerator says it is 11.5A which I am guessing is the average current draw per hour.
So if I run 1 hour per day and the battery is 50Ah.
It would seem I would get 4 days out it.
My main goal is to not have the food spoil so I would try to avoid opening the door.
.
"Have you tried this yourself?"
Very common on boats where there are larger battery banks and very good inverter/chargers with battery condition monitors.
Less common on RV's where weight becomes more important than on boats where extra weight is more easily supported for larger battery banks.
You can visit boating and RV sites that speak about these issues and get much greater details is you like.

Your calculations are not real world - the run hours will be higher and any need to access the refer will add loads. Ambient air temps outside the unit will affect run time as well.
We had a 14 cubic foot top and bottom refrigerator/freezers in boats in the past and they were 120 and 12 volt driven which made the battery power a bit more efficient. With much larger batteries we could not go for 3 days without the generator or shore power.

When you plug a kilowatt into the refrigerator what does it say when it is running?
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