Is it bad to keep tool batteries fully charged?

[Red Squirrel]

I know lithium ion batteries do not like to be kept fully charged in storage but do power tool batteries take this into account by not actually fully charging even when it says it's charged? Or should I be sure to keep them stored at like half charge?

I have quite a few Ryobi batteries that I've accumulated and was just thinking about that as I would hate for them to degrade from not being used.

 

[herm0016]

my rigid stuff gets used at least weekly, and i try to charge one battery while im using one, so most of them sit most of the time at some mid charge state and i grab which ever one is lowest, use it up and switch to the next to try to keep all of them in rotation. grab the lowest to charge and the next one to use, etc. never leave them in the tools is really the key, they all have a little draw when off for the electronics and draining them to almost nothing is much worse than leaving them fully charged all the time.

 

[drnickriviera]

I've checked my makita packs and they charge to 4.0v per cell, so well under full charge of 4.2. Charge your pack and check the voltage. 18v packs should be 5 cells in series

 

[Sukhoi]

Good to know about the Makita packs, as that's what I own. Have never bothered to check the fully charged voltage.

It's correct that Li-ion batteries don't like to be stored fully charged, but they also don't like to be stored empty. That's even worse. You can get copper going into solution which then results in copper dendritic growth. Copper doesn't blast away as easily at high temperatures from dendritic shorting as lithium dendrites, and are more likely to cause a catastrophic short.

The 4.0 V from Makita sounds like roughly an 80% SOC, which is a good initial storage level (though a bit higher than truly ideal). Then you have a while for them to discharge before getting to worryingly low voltage.

 

[Fanatical Meat]

^^^pretty much above
Best practice assuming they are not being used is probably a yearly or seasonal charge. Store them as close to room temperature as possible

 

[BoomerD]

Huh...who knew?

I have (mostly) Ridgid cordless tools. I charge the batteries, put them on the shelf above the chargers...and there are USUALLY 2 batteries on the charger at any given time...the NEWEST of the batteries is at least 5 years old, the oldest ones are 9-10 years old. I HAVE NOT measured the voltage in them, but I also haven't noticed much...if any reduction in service time.

 

[shortylickens]

I know lithium ion batteries do not like to be kept fully charged in storage but do power tool batteries take this into account by not actually fully charging even when it says it's charged? Or should I be sure to keep them stored at like half charge?

I have quite a few Ryobi batteries that I've accumulated and was just thinking about that as I would hate for them to degrade from not being used.

Rechargeable Batteries Guide | NiMH | Li-ion | NiCd

www.microbattery.com

 

[Red Squirrel]

I've checked my makita packs and they charge to 4.0v per cell, so well under full charge of 4.2. Charge your pack and check the voltage. 18v packs should be 5 cells in series

Good to know I will need to double check what the Ryobi ones end up showing after a full charge.

 

[mindless1]

Your charger is what it is, and Ryobi 18V batteries aren't that expensive in the 4Ah and lower capacities. The main thing is do not excessively top off your cells, and after a deep discharge, do not let them sit uncharged for a long period of time before charging.

If you have quite a few, I suggest buying bare tools instead, then planning on rotating out fewer batteries. I have several Ryobi 18V tools but only bought ONE Ryobi tool complete with battery and charger, then got the 2 pack of 4Ah at Home Depot for $80 and bare tools for everything thereafter. You can save a lot of money that way, then only pay for new batteries when you need them.

 

[bigi]

I've been trying to help the batteries and have been watching how I store mine. I have 6 18V Makita ones and 5 56V ones.

Now, with the current prices of 18V Makita batteries I just stopped that. No need to worry. Even if you keep those at fully charged, it will take years to degrade.

For the price, just buy a new set or a new tool with batteries. 2x5ah ones are $150. Those last forever.

Also, from my limited research, Makita batteries and charging system is the best form known bunch. Their BMS is top notch.

So, yea, if you store them for months 60% SOC will do best.

 

[BoomerD]

I need some decent rechargeable "C" cell batteries for my most commonly used flashlight. Cheapo...Duracell branded from Costco...takes 4 "C" batteries. Unfortunately, nimh rechargeables are only 1.2v instead of 1.5v...that's a 20% drop in voltage...with (I presume) a 20% drop in brightness. I have several 18650 batteries laying around...3.8v...but they're too long to work.(and too skinny for the tube)

 

[Red Squirrel]

C cells are going to be a challenge, don't see those in use much anymore especially rechargeable.

I just want a flashlight that takes 18650's and has on/off and no stupid flash modes. But it seems every flashlight out there is using the exact same controller chip that you have to keep cycling through all the modes and every time you turn it on it's a random mode. I found out by fluke that an 18650 fits perfectly in 3/4" copper pipe, so I may try to make my own flashlight some time and use that as the body.

 

[BoomerD]

C cells are going to be a challenge, don't see those in use much anymore especially rechargeable.

I just want a flashlight that takes 18650's and has on/off and no stupid flash modes. But it seems every flashlight out there is using the exact same controller chip that you have to keep cycling through all the modes and every time you turn it on it's a random mode. I found out by fluke that an 18650 fits perfectly in 3/4" copper pipe, so I may try to make my own flashlight some time and use that as the body.

I bought two 21700 batteries recently for my vaper...the company had the best prices I could find for what's supposed to be thebest batteries...and they sent me a "free gift" along with the batteries...an inexpensive (their retail $9.99) flashlight that runs on both 18650 and 21700 batteries...and, yep...it has the stupid "cycle through the various flashing modes" chip.

Ama on has the rechargeable "C" batteries...that's not difficult...it's the reduction in voltage from 1.5v to 1.2v that's the issue for me.

 

[Fanatical Meat]

I have a similar but different question. I should have a Ryobi cordless jigsaw & 1.5 amp battery arrive today. I have no use for the battery at this time, should I charge the new battery or leave it as is?
*it was only $20 more for a spare battery so what the hell
*pretty sure it is a lithium battery checked it is a 1.5 Ah lithium battery

 

[bigi]

^keep it at 60-70% SOC.

 

[Greenman]

I've never even considered how best to store batteries. They get charged when they're dead and tossed in the tool box when not in use. I have no idea how many I own, maybe a dozen or so? A few of them have to be five or six years old. I do keep an eye on the 60v 9 AH batteries as those are expensive.

 

[Fanatical Meat]

I've never even considered how best to store batteries. They get charged when they're dead and tossed in the tool box when not in use. I have no idea how many I own, maybe a dozen or so? A few of them have to be five or six years old. I do keep an eye on the 60v 9 AH batteries as those are expensive.

Yours likely get regular use so it isnt a problem.
Mine could easily go a year without use and that use could be trivial like used for 2 minutes.
But yeah, without reading this thread I would have had zero concern about storing a lithium battery. While I know all batteries go dead over time even if unused, I know to keep lithium batteries as close to room temp as possible, I know they need to be charged occasionally even when stored.

 

[Greenman]

I have a couple Ryobi tools that only get used once or twice a year, and only have one battery for them, it gets the same treatment. Haven't had any issues with it either.

A little of topic, but the Ryobi tools I own aren't bad at all. The pex band crimper is awesome. Since Ryobi is the only company that makes one, it's the best electric band crimper on the market.

 

[mindless1]

Yeah, I don't worry much about it. Are you going to keep monitoring the charging to get them to a certain % (which requires leaving them off the charger for a period of time before determining final charge voltage, then repeating the process) or build a special charger for that instead of letting the charger top them off? A custom current limited, CV charger at ~4.0V is the only way I'd consider it reasonable.

IMO the main thing is, don't leave them sitting for years in a deeply discharged state, yet don't top them off if they still have enough capacity to get you through the next job.

However I'd find a use for the 1.5Ah or 2Ah packs, either an impact driver, drill or flashlight, using the smaller batteries for that to leave more remaining cycles in the larger battery packs for the tools that benefit more from them.

 

[Red Squirrel]

That's the thing it's kind of tricky to try to track them. I'll make sure not to let them sit completel discharged but if I charge them chances are I'll end up charging them fully as it does not take that long. I guess if it's a concern I could mod one of my chargers (mostly use it because of the physical attachment part) to act as a discharger where it discharges down to a specific voltage. I'm thinking I would keep the charger part and add a toggle switch for a separate circuit. But that sounds like work. So if it's not a huge concern I'll just make sure not to let them sit out discharged. I guess one solution could be to put a timer on the charger too, have it charge for like 5-10 minutes and then shut off. Not perfect, but it would basically get some charge in without fully charging them.

Right now I kind of have them scattered about the house, some fully charged, some slightly discharged.

 

[jmagg]

Interestingly enough, Today I got tired of getting my hands filthy from oily gas from my 15 yr old Homelite, and decided to get a new battery string trimmer. I noticed that Dewalt and most others will sell the tool only. I had 2 20v Dewalt batterys that had been sitting around for no less than three years after the Dewalt drill died an early death after heavy use. I put the batterys on the charger and after a few blinks the charger went solid red. Tried the second batt and that blinked for about 15 seconds and went solid indicating both batterys were full, with no use for 3 yrs, after living on a shelf in the garage in somewhat extreme hot/cold conditions. Somewhere along the line I may have charged them once. Both tested above 20v. At this point I'm still very wary, but went and got the tool only. I cannot believe the batterys are still good, and completed the trimming with a single 20v 1.3ah batt. Reverse first world problems yo.

 

[mindless1]

^ Glad you can reuse the batts, but I would consider going 3 years w/o a cordless drill, far more of an issue than using a 2 cycle trimmer.

I love my Redmax 2 cycle trimmer, very powerful, not picky about old fuel, runs like a scalded dog. It's 19 years old. My strategy is anything you're going to use more than single-digit # times per year, should be contractor grade if a 2 cycle, or really a 4 cycle too if smaller than a lawnmower engine. Then again that might apply to cordless tools too.

 

[Red Squirrel]

I love that we're seeing more battery stuff, even yard tools now. I have a 18v Ryobi trimmer and it's great. Gas ones have always been finicky to deal with if you don't get the mixture just right and feel so inefficient to use. Burning all that gas and polluting, just to make a piece of string spin. With electric you just put the battery in press the trigger and go.

Got a chainsaw too which is same idea. The Chainsaw I have is a 18v model, if I wanted a saw to go in the bush with I'd want to go bigger though. I imagine the higher voltage batteries last longer too so you're not swapping as often.

One thing I found when I was cutting a large tree with the chainsaw is you do need to swap batteries often so it kind of sucks when you're up in the tree and run out of juice, but if I was doing that full time I'd probably just have a pouch or backpack or something so I can carry extra batteries on me. I got into the habit of always having batteries on the charger and before doing a more complex climb I would grab a fully charged one. In an off grid setting it's still great to have everything electric though, no need to rely on having gas. In my case I was not off grid but I plan to eventually buy off grid property so I always think about this stuff.

 

[jmagg]

^ Glad you can reuse the batts, but I would consider going 3 years w/o a cordless drill, far more of an issue than using a 2 cycle trimmer.

I love my Redmax 2 cycle trimmer, very powerful, not picky about old fuel, runs like a scalded dog. It's 19 years old. My strategy is anything you're going to use more than single-digit # times per year, should be contractor grade if a 2 cycle, or really a 4 cycle too if smaller than a lawnmower engine. Then again that might apply to cordless tools too.

I replaced the Dewalt drill with Rigid the day after confirmed death. Can't live 2 days without a cordless drill. Rigid doesnt make a line trimmer.
It bothers me replacing the Homelite trimmer since it still works fine and starts easy, but it needs a tank,hoses (which are a pia), carb gaskets, and the entire reel assembly. Its time.
I have a couple acres, but can get it all with the rider beside odds and ends, which the smallest Dewalt battery handled, so dont really need a gas trimmer.

 

[jmagg]

I love that we're seeing more battery stuff, even yard tools now. I have a 18v Ryobi trimmer and it's great. Gas ones have always been finicky to deal with if you don't get the mixture just right and feel so inefficient to use. Burning all that gas and polluting, just to make a piece of string spin. With electric you just put the battery in press the trigger and go.

Got a chainsaw too which is same idea. The Chainsaw I have is a 18v model, if I wanted a saw to go in the bush with I'd want to go bigger though. I imagine the higher voltage batteries last longer too so you're not swapping as often.

One thing I found when I was cutting a large tree with the chainsaw is you do need to swap batteries often so it kind of sucks when you're up in the tree and run out of juice, but if I was doing that full time I'd probably just have a pouch or backpack or something so I can carry extra batteries on me. I got into the habit of always having batteries on the charger and before doing a more complex climb I would grab a fully charged one. In an off grid setting it's still great to have everything electric though, no need to rely on having gas. In my case I was not off grid but I plan to eventually buy off grid property so I always think about this stuff.

Not sure if I would go electric with a chainsaw, especially off grid. I have a small Husqvarna 2 stroke that will most likely outlive me.