large battery-operated fans

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Nyc10036
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large battery-operated fans

Post by Nyc10036 »

Ryobi has a battery-operated fan rated at 2400 CFM for $140 without the battery and charger on Home Depot.
https://www.homedepot.com/p/RYOBI-18-Vo ... /307730215

How long can one fan realistically run on one battery?
What is 2400 CFM compared to a regular house fan?

There is a smaller fan that sells for $50. No CFM listed.
https://www.homedepot.com/p/RYOBI-18-Vo ... /205022215

I am trying to help a friend out who does not have access to electricity at certain areas on her farm.

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tyrion
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Re: large battery-operated fans

Post by tyrion »

For the Ryobi fan if you look at the 'questions and answers' section there are some comments from people about how long it lasts. Sounds like 2-4 hours on high (depending on battery size and health) and 10+ hours on low.


I have a bunch of Ryobi tools. It all generally works well. The batteries do eventually degrade, but still work. They just don't charge up all the way like they used to.
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Nyc10036
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Re: large battery-operated fans

Post by Nyc10036 »

Do the Ryobi batteries quickly degrade?
By that I mean if we use it every day how long will take before it only charges to 80% similar to what happens with laptop batteries.

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walkabout
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Re: large battery-operated fans

Post by walkabout »

You might also consider an energy-efficient (if there is such a thing) and a larger power bank like a Goal Zero ( https://www.amazon.com/dp/B00D5RVMAM/re ... X47PXMYZ2D ). We have a similar Goal Zero, but with the lithium ion battery, which is much lighter than the lead acid version. The Goal Zero is not cheap, but there are similar large capacity power banks out there.
livesoft
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Re: large battery-operated fans

Post by livesoft »

A fan that uses 1 Watt per hour can run 24 hours with a battery that has 24 Wh of remaining capacity. This is just math. Now the battery may not be 100% efficient, so allow for maybe 5% to 10% loss.

So a fan that draws 1 W of power will use 1 Watt in an hour.

A multimeter can tell one the current draw and the voltage, so the power (Watts) can be calculated.
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telemark
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Re: large battery-operated fans

Post by telemark »

I have a Vornado electric fan that runs from a 24V DC power adapter. You might be able to put together a battery to run that, and it should be more efficient than running an AC motor from a power inverter.
quantAndHold
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Re: large battery-operated fans

Post by quantAndHold »

livesoft wrote: Sun May 02, 2021 10:20 am A fan that uses 1 Watt per hour can run 24 hours with a battery that has 24 Wh of remaining capacity. This is just math. Now the battery may not be 100% efficient, so allow for maybe 5% to 10% loss.

So a fan that draws 1 W of power will use 1 Watt in an hour.

A multimeter can tell one the current draw and the voltage, so the power (Watts) can be calculated.
Following on to this, it looks like the Ryobi fan uses 18 watts, and the Ryobi batteries are 2 amp hour 18 volt batteries.

Doing math (amps x volts = watts), the batteries are 36Wh. And the fan runs at 18w on high. So 2 hours(ish) on high, more on low.

For the price of that fan and batteries, would it be cheaper to just have an electric outlet installed where you need it?
Yes, I’m really that pedantic.
Nebraska_Drought
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Re: large battery-operated fans

Post by Nebraska_Drought »

In situations like this, solar can be great. Now, if they need the fan going at night, then they will need to have a battery in their solar setup as well.
Afty
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Re: large battery-operated fans

Post by Afty »

livesoft wrote: Sun May 02, 2021 10:20 am A fan that uses 1 Watt per hour can run 24 hours with a battery that has 24 Wh of remaining capacity. This is just math. Now the battery may not be 100% efficient, so allow for maybe 5% to 10% loss.

So a fan that draws 1 W of power will use 1 Watt in an hour.

A multimeter can tell one the current draw and the voltage, so the power (Watts) can be calculated.
These Ryobi batteries have 72 Wh of capacity new (18V * 4 Ah). I'd guess that a fan would use between 20-60 Watts. So you're looking at 1-3 hours of runtime per battery.
badger42
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Re: large battery-operated fans

Post by badger42 »

We're talking about a farm, I'd suggest a more general purpose solution.

They probably already have a charger that can charge 12V lead acid batteries.

12V 35AH SLA battery - $100 or so
Cheap 200W-ish inverter with clamps - $25 or so
Fan - standard 20" box fan, $20

Math: you don't want to run the SLA batteries flat (they don't like that)
60W for the fan (approximate)
12V 35AH SLA battery is 420 watt-hours
If you call that 300 watt-hours usable, that's 5hr before recharging for the fan.

+1 on the solar if you need extended run-times, or anything more powerful than a standard household box fan, or both.
Solar with the right controller could also keep the battery charged and ready to go, if this for occasional use, even with a pretty small/cheap panel

(Li-Ion solutions are more elegant, but an awful lot more expensive unless you already own the batteries, eg I have a sub-$100 inverter that will use the Ryobi 40V yard tool batteries, but the batteries themselves are more like $200 for the equivalent wattage. Lighter though of course.)
iamlucky13
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Re: large battery-operated fans

Post by iamlucky13 »

Nyc10036 wrote: Sun May 02, 2021 10:16 am Do the Ryobi batteries quickly degrade?
By that I mean if we use it every day how long will take before it only charges to 80% similar to what happens with laptop batteries.
I would not call it quickly, but they do degrade over both time and cycles. Longevity varies a little bit depending on the cell type, and a lot depending on how it is used.

It seems to be fairly common to see ratings of 300-500 cycles of 80% discharges to reach 80% of original capacity. If they're not discharged as deeply, it can be quite a few more cycles. If you really want to optimize for cycle life, don't let the charger fully top them off, although it's debatable whether the cost savings are worth the extra attention this takes.

My current set of batteries are probably 4-5 years old, and have generally not been used very heavily - probably charged every 2-3 months on average for tool use. About 2 years ago, I also got a Ryobi hand vacuum that gets frequent use, so my two smallest batteries (1.5 Ah) have been getting charged probably weekly since then, alternating between the two batteries. No noticeable loss of capacity so far.

I could easily see a contractor wearing out a battery pack in a year or two, while they might last an infrequent use homeowner over a decade (and probably need replacement due to power output decreasing over time more so than capacity loss). Storing them in a hot location will accelerate their aging.
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Watty
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Re: large battery-operated fans

Post by Watty »

Nyc10036 wrote: Sun May 02, 2021 10:00 am I am trying to help a friend out who does not have access to electricity at certain areas on her farm.
A better solution is that you can get small gasoline generators for around $200.

https://www.homedepot.com/b/Outdoors-Ou ... rtby=price

They could run several large ordinary fans and other equipment.

They would also be handy to have in a power outage, with the usual cautions about using them outdoors to prevent carbon monoxide poisoning.
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BolderBoy
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Re: large battery-operated fans

Post by BolderBoy »

Nyc10036 wrote: Sun May 02, 2021 10:00 amI am trying to help a friend out who does not have access to electricity at certain areas on her farm.
How will she get to those "certain areas"? By motorized conveyance? How long will the fan need to operate? Depending upon the answers I would be inclined to use an inverter to power a 120VAC fan.
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