Li-Ion battery age

[dwasifar]

I assume Li-Ion batteries will eventually die of old age if they're not worn out from use first, right?

Typically how long does that take? If you have a rarely-used tool that's say eight years old, how much of its original battery capacity will have been lost to Father Time?

 

[MayerMR]

I assume Li-Ion batteries will eventually die of old age if they're not worn out from use first, right?

Typically how long does that take? If you have a rarely-used tool that's say eight years old, how much of its original battery capacity will have been lost to Father Time?

After 8 years nearly any battery is going to be toast. That said, Li-On batteries tend to start to have pretty significant drops in usability after full charge at around 2 yrs, in my experience.

 

[tom-ky]

Got 2 that are 6 years old without noticeable difference. they may **** out tomorrow.

 

[American Locomotive]

Lithium batteries do not degrade with age as far as I know. Their degradation is related to cycles. I have a few devices with 10 year old lithium batteries that still have near full capacity - they just don't get used very often so the batteries have very few cycles.

 

[Richard Cranium]

thanks locomotive for your info.

 

[Ole Slewfoot]

the correct answer is 'it depends'.

http://jes.ecsdl.org/content/163/9/A1872.full

Nissan guarantees a Leaf battery will have at least 66% capacity after 8 years, even if you drive it 12K/yr.

 

[seber]

Those charts don't mean much without a guide to the abbreviations.

 

[mobiledynamics]

out of the 28'ish M18 batteries, I do 2 things. All of them get labled 1, 2, 3, 4, etc.
Depending on the intent of how I use them, I may do a full charge and then use them to 75% for storage. And or drain a few, bring them to full, keep them in storage shortly and then use them 75.

For the most part though, if it's like going to be in storage unused, I do shoot to keep them at 75

 

[Ole Slewfoot]

It's all in the link ending in '.full'

cliffs; if you store them charged less than 20%, over 66%, in hot weather, your performance may degrade worse than twice as fast, with some variation depending on cell composition.

 

[jonshonda]

I have always been curious as to the data on charging and storage procedures for batteries, yet no manufacturers bother to make smart chargers. RC cars use LiPo batteries, and those chargers have several smart functions, but I would imagine RC owners are more savvy when it comes to actually knowing how to use their equipment?

From what I understand, most major brands battery powered devices are outselling corded devices by substantial amounts, so we know what the trend is. What I don't like, is knowing that sooner or later you WILL need to replace a very expensive part of the tool. For this reason, if I buy a tool I don't plan to use a lot and mobility isn't a huge factor in the decision (jig saw, sanders, table saw, etc), I buy corded.

 

[ddawg16]

Li batteries have good self discharge characteristics and don't degrade much with constant use.

The biggest issue is allowing a cell voltage to drop below 2v.

The worse thing you can due is to run a battery down until the BMB shuts it off to protect it....and then not recharge is soon. If you let it sit for a month or two, good chance the battery will self discharge below the 2v/cell.....at that point, the cells are pretty much Li paper weights.

 

[6PTsocket]

I assume Li-Ion batteries will eventually die of old age if they're not worn out from use first, right?

Typically how long does that take? If you have a rarely-used tool that's say eight years old, how much of its original battery capacity will have been lost to Father Time?

All rechargable batteries are rated for so many cycles (discharge and recharge). Certain types do not like to be deeply discharged (car batteries) or left discharged (any lead acid or NiCd) Lithium Ion batteries are so fussy that they can be permanantly damaged from over discharging, so external circuitry disconnects them when the voltage gets too low. So the life a battery lives in terms of how many charges, fast charging, time left discharged, temperature, all contribute to how long a battery lasts. Under lab conditions it will be good for so many full cycles. In the real world it will be less.

Sent from my SM-G900V using Tapatalk

 

[PhysicsDude]

Li batteries have good self discharge characteristics and don't degrade much with constant use.

The biggest issue is allowing a cell voltage to drop below 2v.

The worse thing you can due is to run a battery down until the BMB shuts it off to protect it....and then not recharge is soon. If you let it sit for a month or two, good chance the battery will self discharge below the 2v/cell.....at that point, the cells are pretty much Li paper weights.

This has been my experience. It takes a long time for a charged li-ion cell to completely self-discharge below 2v (probably 2-3 years?), but an already discharged battery sitting will happen within a few months

That's the biggest downside to Li-ions is they're more prone to catastrophic failures. Once you abuse one, its toast, little chance of reviving it. With modern BMS they're very robust against overdischarge, overcharge, overheating, etc, but storing a dead battery without charging it for 6+ months is probably the most common way you'll kill one.

I've had good luck topping off my li-ion batteries (cell phones, power tools, flashlights, etc.). Keeping them above 50% most of the time will prolong their life as opposed to draining them close to 0% before charging, the opposite of older Ni-Cd and Ni-Mh batteries.

Any time I drive or sit at my desk, my cell phone goes on a charger. Any time I'm done using a cordless tool for the day that I think I've used more than 10% of the battery, I throw it on the charger.

 

[Mr_B]

You always going loose some cell capacity in any battery platform, good cell at best after 8yrs will of lost 20 to 40% of it's rated capacity.
Batteries have got much better but it certainly not an environmental solution for cars, if got 2 or 3 tools using same battery platform they work out great, single tool with dedicated battery used a little is a waste, true logic and environmental sense would be standardise batteries/chargers for power tools, unfortunately money trumps logic .

 

[dwasifar]

What I'm taking away from this is that the original question may be too simplistic, but an attempt at a simple answer anyway would be "cycles matter a lot more than time." Right?

 

[MayerMR]

What I'm taking away from this is that the original question may be too simplistic, but an attempt at a simple answer anyway would be "cycles matter a lot more than time." Right?

I think that's a fair point. When I responded initially with "~2 years" I was trying to keep it simple and estimated an relatively regularly used Li-On battery rather than one that sits for long periods. But you've gotten some great responses here!

 

[jimreed2160]

My last job was running IT support in a hospital where we had hundreds of Li ion powered clinical devices. Battery failures were an issue and I researched the problem extensively. Here is what I found out.

1. Li ion batteries are all made a little differently and those differences can affect longevity. You have to study the manufacturers information.
2. Most Li ion batteries are good for 500-800 charge cycles.
3. Some Li ion batteries have a 3-5 year shelf life, whether used or not.
4. Heat reduces life of Li ion batteries.
5. Li ion battery test equipment is expensive.

As a result of my research, we began dating all batteries we received. If equipment malfunctioned with a 4+ year old battery, the battery was usually discarded. Equipment in 24/7 units that failed got fresh batteries because they could reach 500 charge cycles in less than six months.

I date all of my li ion batteries and they seem to be lasting more than five years. But I have low duty cycles and I also give away my old tools. Best advice to prolong life is to keep the batteries cool (not in hot garage or hot car).

 

[J.harris]

I have always been curious as to the data on charging and storage procedures for batteries, yet no manufacturers bother to make smart chargers. RC cars use LiPo batteries, and those chargers have several smart functions, but I would imagine RC owners are more savvy when it comes to actually knowing how to use their equipment?

A RC charger doesn't charge any different from the charger you get with a cordless tool, constant current until you get the 4.2v per cell then it maintains that voltage while slowly dropping the current until fully charged. RC chargers do come with discharge functionality that allow you to fully discharge the battery or discharge to storage voltage 3.8v per cell.

Lipo batteries designed for fast discharge high amp draw applications require more knowledge and care from the end user. These batteries require you to keep them at storage voltage while you aren't using them, they degrade if you store them at full charge. You also cannot discharge them past a certain point, if you do especially under high amp draw they will swell and lose performance.

This is a $350 12s 5ah 45C battery, at full charge it is 50.4v and is rated for a 225 amp draw, something that is quite possible with the right helicopter. A drill will never reach this amount of power draw so the battery can be designed with cells that tolerate being stored at full voltage with no user maintenance.

 

[ddawg16]

If you look at the life of a Li battery in a cell phone.....
Assume it gets charged once a day every day of the year....that is 365 charge/discharge cycles.

The typical cell phone goes 2-4 years....some more....and usually get replaced for reasons not related to the battery....

Hence, it's not unusual for a cell phone battery to see over 1500 cycles or more.

Hence....cycles is not a major driving factor....Heat/Cold and level of discharge are.

 

[Bretny]

I have m18 batterys that are 8yrs old. They still work. There so old they dont make 1.5ah anymore. It will still outlast a 3ah kobalt

 

[pcmeiners]

One issue with Li ion batteries, if you get them cheap, a very good chance they are 2 or more years old..that is about 20% lost capacity.

As to life, I have a Dell laptop from 2001 which still maintains a good capacity. It has never been used much so I guess the number of cycles makes a difference in the batteries life.

 

[jimreed2160]

If you look at the life of a Li battery in a cell phone.....
Assume it gets charged once a day every day of the year....that is 365 charge/discharge cycles.

The typical cell phone goes 2-4 years....some more....and usually get replaced for reasons not related to the battery....

Hence, it's not unusual for a cell phone battery to see over 1500 cycles or more.

Hence....cycles is not a major driving factor....Heat/Cold and level of discharge are.

Manufacturers can tweak their battery packs for optimization of a few factors but not all. The application of the intended device drives that adjustment. Comparing cell phone batteries to tool batteries is not valid because the applications are too different.