Lithium ion yard equipment batteries

Questions on how we spend our money and our time - consumer goods and services, home and vehicle, leisure and recreational activities
Post Reply
Topic Author
Triple digit golfer
Posts: 6091
Joined: Mon May 18, 2009 5:57 pm

Lithium ion yard equipment batteries

Post by Triple digit golfer »

Hi all,

I just swapped my electric weed wacker for a battery-operated one (also bought a blower) because I was so tired of fighting with the extension cord and having to navigate around all my trees and bushes and running the cord into downspouts.

I love the convenience of the battery-operated equipment over gas or electric, and it is much cheaper than gas powered equipment, too. However, on one fully charged brand new 20v lithium ion battery, I got maybe 15 minutes of run time. I had to switch to my spare battery to finish cleaning up with the blower after mowing.

I've read some conflicting information on how to store/operate/care for lithium ion batteries.

Many people say never run them until depleted, to always leave a little "in the tank." I don't know if this is true or necessary.
Many people say to not store them fully charged, but at 30-40%. Is this true? I like the idea of fully charging them after use, and having them ready for next time. What is the alternative, to use both batteries but only run them down partway, then store them WITHOUT charging, then charge them right before the next time I need to use them?

Just looking for opinions of people with experience. Thanks.
jebmke
Posts: 11935
Joined: Thu Apr 05, 2007 2:44 pm
Location: Delmarva Peninsula

Re: Lithium ion yard equipment batteries

Post by jebmke »

15 minutes, wow! I've been thinking about switching from my corded blower -- it really is awkward to use for leaves in the fall. But I have three sections of 12-15,000 square feet each to clear - 15 minutes isn't going to do it. I don't like the 2-cycle gas blowers so I suppose that means looking at 4-cycle ones.
When you discover that you are riding a dead horse, the best strategy is to dismount.
squirm
Posts: 3077
Joined: Sat Mar 19, 2011 11:53 am

Re: Lithium ion yard equipment batteries

Post by squirm »

Buy a couple replacement batteries, look at the watt-hr on the label, get the largest ones. You can run them to empty but li-ion don't like that. They also don't like heat. On the other hand these are just tool batteries and not a tesla.
You might want to look at Greenworks or Kobalt 80v yard tools. Very nice battery design with plenty of cooling vents. Even when charging, there's a fan that cools the battery. These batteries hold 144watt-hr too.
User avatar
lthenderson
Posts: 5423
Joined: Tue Feb 21, 2012 12:43 pm
Location: Iowa

Re: Lithium ion yard equipment batteries

Post by lthenderson »

Triple digit golfer wrote:I love the convenience of the battery-operated equipment over gas or electric, and it is much cheaper than gas powered equipment, too.
I doubt this statement is true over the life of the equipment if you count the cost of replacement batteries on these things.

Modern lithium batteries don't discharge completely. There is always "a little in the tank" even when they stop working. If you are storing the batteries long term, like 6 months or longer, storing them half charged is better. For regular use, it really doesn't matter as long as the battery temperature doesn't get too hot. So for the summer, I would leave them fully charged for convenience and during winter, put them away after the last use without charging them fully. Note: you can kill a battery if you leave it completely discharged for long periods of time so don't run it completely out and then store it all winter.
User avatar
Nate79
Posts: 6723
Joined: Thu Aug 11, 2016 6:24 pm
Location: Delaware

Re: Lithium ion yard equipment batteries

Post by Nate79 »

Triple digit golfer wrote:Hi all,

I just swapped my electric weed wacker for a battery-operated one (also bought a blower) because I was so tired of fighting with the extension cord and having to navigate around all my trees and bushes and running the cord into downspouts.

I love the convenience of the battery-operated equipment over gas or electric, and it is much cheaper than gas powered equipment, too. However, on one fully charged brand new 20v lithium ion battery, I got maybe 15 minutes of run time. I had to switch to my spare battery to finish cleaning up with the blower after mowing.

I've read some conflicting information on how to store/operate/care for lithium ion batteries.

Many people say never run them until depleted, to always leave a little "in the tank." I don't know if this is true or necessary.
Many people say to not store them fully charged, but at 30-40%. Is this true? I like the idea of fully charging them after use, and having them ready for next time. What is the alternative, to use both batteries but only run them down partway, then store them WITHOUT charging, then charge them right before the next time I need to use them?

Just looking for opinions of people with experience. Thanks.
What brand do you have?
bloom2708
Posts: 8360
Joined: Wed Apr 02, 2014 2:08 pm
Location: Fargo, ND

Re: Lithium ion yard equipment batteries

Post by bloom2708 »

I had a Black & Decker 18v weed eater/blower combo with 2 batteries.

Each battery lasted about 15 minutes. The concept is good. Battery powered just didn't work for me. The worst part was, the charger (slow) that came with took ~9 hours to charge each battery. 9 hours for 15 minutes. :oops:

I went back to a gas trimmer and a broom instead of the blower. I brought the Black & Decker to the thrift store.
Last edited by bloom2708 on Tue Jun 13, 2017 11:44 am, edited 2 times in total.
"We are here to provoke thoughtfulness, not agree with you." Unknown Boglehead
Topic Author
Triple digit golfer
Posts: 6091
Joined: Mon May 18, 2009 5:57 pm

Re: Lithium ion yard equipment batteries

Post by Triple digit golfer »

The Brand is Black & Decker. The weed wacker and blower with two batteries and charger were $100, so not a big deal if I only get a couple seasons out of them before throwing them away in frustration or the batteries just poop out.

This is the combo I bought:

http://www.homedepot.com/p/BLACK-DECKER ... /204691351
Texanbybirth
Posts: 1401
Joined: Tue Apr 14, 2015 12:07 pm

Re: Lithium ion yard equipment batteries

Post by Texanbybirth »

I have the GreenWorks 25223 Mower and 24322 Blower. (I didn't pay anywhere near the prices listed for either of these.)

I love the mower. I bag our yard most sessions (due to "being able to" mow only every other week :D ) and I can do the whole yard (8000 sg ft lot minus 2500 sq ft house) on one (MAYBE 20 minutes of the second) battery. The glory of push button start is not lost on me, as for years I had my own lawn-mowing business as a young pup.

The blower is good, but even with 4A the battery is a bit of a disappointment. I can maybe get 20 minutes at full power. After blowing into piles, I sweep and dump the clippings into a yard bag. I've not used it to suck up leaves, but will try it this winter after not doing so last winter.

I also use the Core Power trimmer, which has been a workhorse over the years. I can easily do our whole yard (trimming and edging) on one charge.

(I've been using all of the above since Summer 2013.)
“The strong cannot be brave. Only the weak can be brave; and yet again, in practice, only those who can be brave can be trusted, in time of doubt, to be strong.“ - GK Chesterton
go140point6
Posts: 162
Joined: Thu May 07, 2015 3:31 pm

Re: Lithium ion yard equipment batteries

Post by go140point6 »

I have the 40V system from Ryobi (I think the 16" mower model, they seem to have a bigger 20" now), the string edger, and hedge trimmer... all run on the same batteries which is nice. I purchased from Home Depot back in early 2013 and it came with 2 batteries. One battery stopped holding a good charge about mid-2015 and I replaced with with a new one at that time. The other original battery seems to still be going strong. The original "bad" battery actually still works, just doesn't last very long any more. I rotate the good batteries to make sure they get even use, and use the bad one when I need just a bit more. I can quite easily mow front and back lawn and edge both on the two full batteries (if I don't let the grass get to big), but my total lawn is not very big... maybe between 1500 and 2000 sq ft or so I guess...

I've been happy with it, although I do suspect over time it's going to cost more than a gas powered model. Batteries are about $100, maybe a bit cheaper if you get lucky online...
sandramjet
Posts: 308
Joined: Thu Oct 23, 2014 11:28 pm

Re: Lithium ion yard equipment batteries

Post by sandramjet »

I had a Toro battery powered mower for years and loved it. It didn't have any fancy batterys, just basic conventional ones....much to my surprise the batteries outlasted the rest of the mower. But when I replaced it 3 years ago, I "upgraded" to a Kobalt Li-Ion mower. :oops: Specs looked much better, etc... but the batteries lasted only 2 years, and you can't buy replacement batteries anymore for it. I ended up tossing it away and going back to gas :(
strafe
Posts: 1015
Joined: Sat Mar 03, 2007 12:49 pm

Re: Lithium ion yard equipment batteries

Post by strafe »

EGO makes the best consumer-grade battery powered lawn equipment on the market right now. You get what you pay for.
jharkin
Posts: 2665
Joined: Mon Mar 28, 2016 7:14 am
Location: Boston suburbs

Re: Lithium ion yard equipment batteries

Post by jharkin »

Battery powered equipment will never get run time comparable to gas powered tools until a quantum leap in battery technology is found. The best lithium ion tech still only has 1/50th the energy density of gasoline, and even if you factor in the average 20% thermal efficiency of a gas engine against the very best lithium ion/brushless motor electric, the battery powered unit is still at a more than 10-1 disadvantage in endurance.

Image


To get the longest lifespan from a Lithium Ion you should:

Try to avoid letting the battery get hot in discharge or charge.
Ideally never charge it completely full.
Never discharge completely empty.
Store it as close to 50% charged as possible.

There are measurable increases in lifespan from shallow discharges, its on the order of every 10% reduction in charge/discharge adds close to 500 cycles to the lifespan. This is how hybrid cars get 7-10 year battery lives while phones get 2 years, the automakers program them to only use about 60% of the real capacity of the battery as the usable range (i.e. charge up to 80% full, and then discharge to 20% full).

This article explains in detail:
http://batteryuniversity.com/learn/arti ... _batteries
iamlucky13
Posts: 2208
Joined: Sat Mar 04, 2017 5:28 pm
Location: Western Washington

Re: Lithium ion yard equipment batteries

Post by iamlucky13 »

Triple digit golfer wrote:I got maybe 15 minutes of run time. I had to switch to my spare battery to finish cleaning up with the blower after mowing.
That sounds low, but I see from a later post that you have a very low cost pair of tools. You have to expect limited performance from that set. If you bought one of the expensive Greenworks or similar kits, I'd be a bit worried about that kind of performance, but those have 4+ times the battery size and higher power motors.
Triple digit golfer wrote:Many people say never run them until depleted, to always leave a little "in the tank." I don't know if this is true or necessary.
Many people say to not store them fully charged, but at 30-40%. Is this true?
Almost all modern lithium-ion battery packs have a built-in protection circuit to prevent over-discharge. While it is optimal not to run them down until the protection circuit shuts off the battery repeatedly, the effect on battery longevity of doing so is not particularly large as long as you don't store it discharged.

However, if you do run a battery all the way down to "empty," you should charge it at least partially, rather than leaving it uncharged, especially if not going to be used for a while. If the battery continues to self-discharge, after a couple months it may reach a point of no-return. If it sits long enough fully-discharged, it could even become a fire hazard if charged again due to damaging chemical reactions that occur at very low voltages in this type of battery (but your charger will refuse to charge it if the initial voltage is too low).

It is often said that the optimum storage condition is 30-40%, because the aging effect is very slow at that level, but it should still take a long time (usually more than a year) for self-discharge to completely drain the battery. The particular kind of a high-drain cells used in tool batteries is not the longest lasting, but still does very well in storage up to about 60% state of charge, then takes a light dip, and but is still decent - only about 5-10% capacity loss in laboratory tests after 1 year if stored at room temperature and fully charged, compared to 3-5% loss if stored half charged.

Which leads to the next point: temperature affects aging, and the effect is compounded at high states of charge.

Looking at a test done by university researchers, if stored at full charge at 77 degrees F (25 Celsius), they saw 7% capacity loss after 10 months. If stored at 104 degrees (40 C), they saw about 18% capacity loss, and at 122 degrees (50 C), they saw almost 25% capacity loss. Clearly, a sweltering garden shed is a bad place to store batteries. At half charge, however, things were much better: about 3%, 7%, and 12% capacity loss.
Source: http://jes.ecsdl.org/content/163/9/A1872.full

This is without the batteries being used. In real life, the capacity loss would be a bit higher simply due to cycling of the batteries.
Triple digit golfer wrote: What is the alternative, to use both batteries but only run them down partway, then store them WITHOUT charging, then charge them right before the next time I need to use them?
It depends how much effort you want to put into it.

I'd say the minimum you should do is remove the batteries from the charger once the charge is complete. Topping off frequently will maximize the aging effect. Also find an area of your garage that tends to stay relatively cool to store them (eg: bottom shelf, on the north side of the garage).

Perhaps if you fully drain one battery, but only partially drain the other one, charge the fully drained battery, but mark the half-drained one (my method is just to put a piece of tape on the terminals). When you next use your tools, put the half-drained battery on the charger, then start your work.

If you want to go the next step, at the end of the season when you're not expecting to use them for a while, charge the batteries up, then use them for about half of the normal runtime before putting them on the shelf.

That's about as far as I'd go unless you want to obsess over optimizing your battery life.

A quick note on winter storage: lithium-ion batteries are ok being stored below freezing (freezing is actually close to the ideal storage temp), but should be warmed up above freezing before use, or used for a very light duty application for a couple minutes to warm it up that way.
highercall
Posts: 56
Joined: Wed Jun 04, 2008 6:16 pm

Re: Lithium ion yard equipment batteries

Post by highercall »

strafe wrote:EGO makes the best consumer-grade battery powered lawn equipment on the market right now. You get what you pay for.
Agreed! I have the ego blower, hedge trimmer and chain saw. Would not hesitate to buy again. I have a 2.5ah and 5.0ah battery.
likegarden
Posts: 3038
Joined: Mon Feb 26, 2007 5:33 pm

Re: Lithium ion yard equipment batteries

Post by likegarden »

I mow my lawn and do not need a blower to clean up after it, therefore do not need that extra blower with Lithium Ion battery.

I simply run my mower with the catcher on it first around all parts of the lawn to be mowed, and therefore no clippings get blown on road, driveway and plantings and need to be cleaned. That procedure seems to save me a lot of time too.
Last edited by likegarden on Tue Jun 13, 2017 5:28 pm, edited 1 time in total.
squirm
Posts: 3077
Joined: Sat Mar 19, 2011 11:53 am

Re: Lithium ion yard equipment batteries

Post by squirm »

You shouldn't expect the batteries to last like gas, the trick is to have multiple batteries that can charge.

I have a Kobalt 80v Chainsaw and a Stihl 24". I have four batteries, guess which i use much more often? The Kobalt, and I'm sure I use a chainsaw much more often then most here. By the time the batteries are depleted, I'm due for a break which i recharge in multiple chargers.
User avatar
whodidntante
Posts: 9569
Joined: Thu Jan 21, 2016 11:11 pm
Location: outside the echo chamber

Re: Lithium ion yard equipment batteries

Post by whodidntante »

strafe wrote:EGO makes the best consumer-grade battery powered lawn equipment on the market right now. You get what you pay for.
Any experience/opinion on the Echo line?
User avatar
whodidntante
Posts: 9569
Joined: Thu Jan 21, 2016 11:11 pm
Location: outside the echo chamber

Re: Lithium ion yard equipment batteries

Post by whodidntante »

In my opinion the disruptive innovation will be universal batteries. Right now, we all recognize we take in on the chin when we need to buy a battery pack. The markup is huge, and you could be out of luck if the company folded or decided it was not profitable to support your obsolete stuff.
squirm
Posts: 3077
Joined: Sat Mar 19, 2011 11:53 am

Re: Lithium ion yard equipment batteries

Post by squirm »

whodidntante wrote:In my opinion the disruptive innovation will be universal batteries. Right now, we all recognize we take in on the chin when we need to buy a battery pack. The markup is huge, and you could be out of luck if the company folded or decided it was not profitable to support your obsolete stuff.
That would be nice, but I don't see it happening.
Hockey10
Posts: 870
Joined: Wed Aug 24, 2016 12:20 pm
Location: Philadelphia suburbs

Re: Lithium ion yard equipment batteries

Post by Hockey10 »

I store my batteries inside the house. That way they avoid the freezing cold in winter and the scorching heat (like today) in the summer. This also might be a deterrent to a thief who might sneak into my garage when I am not looking. Both the weed wacker and the leaf blower are useless without the battery attached to them.
Post Reply