Prolong battery cycle life by limiting charge to 80%?

[disappoint]

No one is going to mention why this is happening?

My theory is that what damages batteries is heat. Some of the energy you send to the battery during charging is lost to heat, which damages the battery. The same goes for discharging, especially if you discharge it fast.

The significance of this, if true, is that to improve battery life (# cylces of charge/discharge) you should charge it slower, instead of charge it less. This way you would get the benefit of long device usability time while improving number of cycles.

 

[MrSquished]

I just stick the phone on the charger before bed and grab it in the morning. Anything wrong with this system?

I have an LG V20 with a removable battery that costs $20, so even if I kill a battery in a year I have cheap recourse to put in a new one.

 

[lxskllr]

My theory is that what damages batteries is heat. Some of the energy you send to the battery during charging is lost to heat, which damages the battery. The same goes for discharging, especially if you discharge it fast.

The significance of this, if true, is that to improve battery life (# cylces of charge/discharge) you should charge it slower, instead of charge it less. This way you would get the benefit of long device usability time while improving number of cycles.

Not sure if it's heat, but almost everything does better if you change its state slowly. I prefer charging my phone from a 500ma usb port rather than the fast charger. How long it takes doesn't matter if I'm sleeping.

 

[disappoint]

Not sure if it's heat, but almost everything does better if you change its state slowly. I prefer charging my phone from a 500ma usb port rather than the fast charger. How long it takes doesn't matter if I'm sleeping.

Oh it's heat alright. The physicists have a name for this phenom (just like the hot AMD microporkcessor, this is no coincidence) they call it heat death.

They're fairly certain the whole damn universe will end this way because God is fscking blasting energy in too fast because of it's gender identity issues and fscking is the most fun one can have under the son. At least that's what I was taught in my "Here's how the universe came about mofo" class in Elementary parochial school. Maybe.

 

[clamum]

According to the article posted in the OP, the number of cycles a Li-ion battery will go through (basically, longevity) correlates negatively with the Depth of Discharge, basically your starting charge level minus the ending charge level. So charging your phone to 100% and not plugging it into the charger until it's way low, like 10% or so, is a ~90 DoD compared to charging it to 100% and plugging it in when it's still at 80% charge (~20 DoD).

I've always fully charged it and waited as long as possible to charge it again because, strangely enough, I thought it was "healthier" for the battery. Turns out that's actually the opposite. Guess I'll start plugging my phone in at work/home when I'm on the computer. I still think I'm gonna pick up a smart outlet or two and try the 100% shut-off thing cause I'm a nerd.

 

[rh71]

I just stick the phone on the charger before bed and grab it in the morning. Anything wrong with this system?

I do this as many do because of simplicity - and since many people are saying heat is what causes degradation, wouldn't it be ok since it is no longer charging (or hot) when I unplug in the morning? At idle after 100%, does it really top off constantly since it drains so little?

I was on a Note 3 for 3 years and often did this without feeling like the battery was degrading.

 

[manly]

According to the article posted in the OP, the number of cycles a Li-ion battery will go through (basically, longevity) correlates negatively with the Depth of Discharge, basically your starting charge level minus the ending charge level. So charging your phone to 100% and not plugging it into the charger until it's way low, like 10% or so, is a ~90 DoD compared to charging it to 100% and plugging it in when it's still at 80% charge (~20 DoD).

I've always fully charged it and waited as long as possible to charge it again because, strangely enough, I thought it was "healthier" for the battery. Turns out that's actually the opposite. Guess I'll start plugging my phone in at work/home when I'm on the computer. I still think I'm gonna pick up a smart outlet or two and try the 100% shut-off thing cause I'm a nerd.

This was true (always discharge fully) for NiCd batteries, because they exhibit a memory effect. Unfortunately, many product manuals still use the same charging instructions even though NiCd batteries are fairly uncommon. You'll still see them in some low-end consumer electronics, such as older Oral-B toothbrushes.

 

[lxskllr]

This was true (always discharge fully) for NiCd batteries, because they exhibit a memory effect. Unfortunately, many product manuals still use the same charging instructions even though NiCd batteries are fairly uncommon. You'll still see them in some low-end consumer electronics, such as older Oral-B toothbrushes.

The 'memory effect' of NiCd was always a little overstated. You really only got that with precise charge cycles that consistently short stroked the charge at a specific point(40% discharge for example). Typical use with a randomized charge schedule didn't cause many problems.

That said, holy shit did old battery tech suck! Not many people mention batteries in their list of modern marvels, but it's one of the greatest things ever. Power dense, and they aren't a pita to deal with. They also last forever. Not even counting the huge size, imagine how many NiCd or NiMh battery packs it would take to keep your phone going 2-3 years, when you can do it with one lithium pack.

 

[rh71]

This was true (always discharge fully) for NiCd batteries, because they exhibit a memory effect. Unfortunately, many product manuals still use the same charging instructions even though NiCd batteries are fairly uncommon. You'll still see them in some low-end consumer electronics, such as older Oral-B toothbrushes.

Apparently the Roomba also uses Ni-Cd. The manual says to always keep it charged though.

 

[Rubycon]

It's much easier going the other way and using 20% as 0% and never let it go below that level.
Pack degradation occurs faster with full discharges even though 0% isn't really 0%. Lithium polymer packs are considered fully discharged when their average cell open terminal voltage is approximately 3V. It can be higher or lower and that is up to the OEM upon programming the charger.

Upper levels aka 100% is always going to be 4.2V. Exceeding this even by just a tenth of a volt (100mV) on a regular basis not only damages the cell but increases the chance of thermal runaway which is very bad. You would not light a road flare in your pocket!

 

[IntelUser2000]

Discharging it to 0% is worse than keeping it at 100%.

Heat makes it worse. Which is why laptops degrade batteries so fast - users keep it plugged in while using it, so the battery is at 100% all the time and system is running hot. Tablets and Smartphones get hot but not as plugged in Laptops.

Lithium battery chemistry can do anywhere from 0-4.20+ volts. Battery life is always degrading at any voltage, but the industry has determined that below 3.0V and above 4.20V the life degrades unacceptably.

That's because Lithium battery chemistries have a much flatter curve for voltage and capacity, but I'm sure you know this. It tends to keep its voltage under load far better than other battery chemistries. 3V I assume is pretty close to real 0%. Also, electronics tend to have minimum operating voltage. Many low power circuits will not start until the battery is at 1V. 3V may be the lower limit for a Smartphone.

Another is that Lithium chemistries don't like going under 3V. If you are into RC hobbies warnings are everywhere not to let batteries go under certain voltage.

 

[Red Squirrel]

I read something about a "military" way of charging lithium batteries, and it's to never charge them beyond a certain voltage, I don't remember what it was, like 3.9v or something. Basically you get less capacity but longer life and many more charge cycles out of it. If designing a product it's probably not a bad idea to do this so it will last longer.