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Charging a lithium battery to 80% only?

electronics.stackexchange.com

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Re: Charging a lithium battery to 80% only?

#21

Post by p1necone »

belltaco wrote: post #14

I wish they would label it so that it shows 100% charge when it's actually charged 80%, and then give an option to 'overcharge' a configurable amount till 125% (the current 100%). That way it will make people aware that they are reducing the battery life by overcharging, and be picky when they overcharge. But this won't happen because reduced battery life is a big direct and indirect(by reducing performance like Appl…

I'm pretty sure most (all?) manufacturers already do (the first part of) this. 100% can't be the point at which the battery literally stops taking new charge - if you did that they'd catch fire all the time.

It's just that the manufacturers idea of what "100%" should be generally skews more towards the immediate battery life end of the tradeoff, whereas some users prefer to have "100%" closer to the maximizing long term lifetime end of the scale.

Some devices do let you configure stuff like this - I know my android phone will let you cap max charge at an arbitrary level (although it won't report that level as 100%). Many laptop bioses will have a similar setting (good idea to set this to ~50% if you're using the laptop plugged in all the time, or just using it like a server with a builtin UPS).

Re: Charging a lithium battery to 80% only?

#22

Post by trustingtrust »

belltaco wrote: post #14

I wish they would label it so that it shows 100% charge when it's actually charged 80%, and then give an option to 'overcharge' a configurable amount till 125% (the current 100%). That way it will make people aware that they are reducing the battery life by overcharging, and be picky when they overcharge. But this won't happen because reduced battery life is a big direct and indirect(by reducing performance like Appl…

Almost nobody cares about saving batteries. Those are replaceable and cheap to replace every couple of years.

Innovating more battery life and leaving 20% battery life on the table sounds extremely pointless for what costs 20-30$ a year but lets you use the device all day instead of just shutting before the end of the day.

Re: Charging a lithium battery to 80% only?

#23

Post by p1necone »

trustingtrust wrote: post #22
belltaco wrote: post #14

I wish they would label it so that it shows 100% charge when it's actually charged 80%, and then give an option to 'overcharge' a configurable amount till 125% (the current 100%). That way it will make people aware that they are reducing the battery life by overcharging, and be picky when they overcharge. But this won't happen because reduced battery life is a big direct and indirect(by reducing performance like Appl…

Almost nobody cares about saving batteries. Those are replaceable and cheap to replace every couple of years. Innovating more battery life and leaving 20% battery life on the table sounds extremely pointless for what costs 20-30$ a year but lets you use the device all day instead of just shutting before the end of the day.

> Those are replaceable and cheap to replace every couple of years.

If you specifically seek out devices with cheap replaceable batteries, sure. But this isn't the case with a lot of devices.

Re: Charging a lithium battery to 80% only?

#24

Post by Casteil »

I've used the 80% max charge setting on a 15 pro since the first week or so. FWIW, it seems Apple has it charge to 100% occasionally (about once a month) even with the setting active.

I wish you could have iOS artificially adjust/map the visible battery level reading to your 0-80% limit (as 0-100%) - starting at 80% gives undue battery anxiety... but the other reason I use the 80% limit is that it still lasts DAYS and I don't have to think about charging it every day. That and battery longevity is nice on a phone that may go on for 5+ years.

Re: Charging a lithium battery to 80% only?

#25

Post by fiddlerwoaroof »

p1necone wrote: post #23
trustingtrust wrote: post #22

Earlier quoted context omitted.

Almost nobody cares about saving batteries. Those are replaceable and cheap to replace every couple of years. Innovating more battery life and leaving 20% battery life on the table sounds extremely pointless for what costs 20-30$ a year but lets you use the device all day instead of just shutting before the end of the day.

> Those are replaceable and cheap to replace every couple of years. If you specifically seek out devices with cheap replaceable batteries, sure. But this isn't the case with a lot of devices.

Replacing an iPhone battery is cheap, especially compared to replacing the whole phone: at the Apple Store it’s either $99, $69 or $49 and I’ve had other stores do it for like $40. That’s not too bad for a once every couple years cost.

Re: Charging a lithium battery to 80% only?

#26

Post by helf »

windex wrote: post #15
Zak wrote: post #12

I've been using ACCA[0] for years to limit charge on my phone, usually to 60%, but higher when needed. I also limit the charging speed most of the time. It performs like new despite the phone being over three years old. I'm determined to keep it usable as long as I can because I prefer its size and analog headphone jack over what's available now. Actually replacing the battery, however looks like a big hassle, so I'm…

If phones with easily replaceable batteries arrive due to legislation, it would be one major win, less waste and more peace of mind.

[dead]

Re: Charging a lithium battery to 80% only?

#27

Post by usefulcat »

Zak wrote: post #12

I've been using ACCA[0] for years to limit charge on my phone, usually to 60%, but higher when needed. I also limit the charging speed most of the time. It performs like new despite the phone being over three years old. I'm determined to keep it usable as long as I can because I prefer its size and analog headphone jack over what's available now. Actually replacing the battery, however looks like a big hassle, so I'm…

I've been trying a similar experiment for several years now. I have a four year old iPhone, and for most of its life, the battery level has been kept between 30% and 70%. Settings => Battery => Battery Health and Charging says that the maximum capacity is 91%.

No idea whether that's better or worse than average, but I mention it so others can compare. I can say that this is the first time I've tried this experiment, and this phone has already outlasted any previous phone I've had.

Re: Charging a lithium battery to 80% only?

#28

Post by tobias2014 »

Here are some good references on this with actual measurements, see e.g. table 4 on how many discharge cycles you can get out of a certain maximum voltage / charging level: https://batteryuniversity.com/article/bu-808-how-to-prolong-...

https://batteryuniversity.com/article/bu-204-how-do-lithium-... https://batteryuniversity.com/article/bu-501a-discharge-char...

On Thinkpads you can use tp_smapi to set charge start and stop thresholds https://wiki.archlinux.org/title/tp_smapi

Re: Charging a lithium battery to 80% only?

#29

Post by Kirby64 »

Casteil wrote: post #24

I've used the 80% max charge setting on a 15 pro since the first week or so. FWIW, it seems Apple has it charge to 100% occasionally (about once a month) even with the setting active. I wish you could have iOS artificially adjust/map the visible battery level reading to your 0-80% limit (as 0-100%) - starting at 80% gives undue battery anxiety... but the other reason I use the 80% limit is that it still lasts DAYS an…

Any BMS needs to charge fully to have the most accurate charge capacity, so it’s no surprise it automatically charges to 100% occasionally. Shouldn’t really matter for longevity if you’re doing it rarely.

Re: Charging a lithium battery to 80% only?

#30

Post by quickthrower2 »

trustingtrust wrote: post #22
belltaco wrote: post #14

I wish they would label it so that it shows 100% charge when it's actually charged 80%, and then give an option to 'overcharge' a configurable amount till 125% (the current 100%). That way it will make people aware that they are reducing the battery life by overcharging, and be picky when they overcharge. But this won't happen because reduced battery life is a big direct and indirect(by reducing performance like Appl…

Almost nobody cares about saving batteries. Those are replaceable and cheap to replace every couple of years. Innovating more battery life and leaving 20% battery life on the table sounds extremely pointless for what costs 20-30$ a year but lets you use the device all day instead of just shutting before the end of the day.

Let the user choose! Some people tether their phone a lot and use the battery only when out. For them 80% max is OK.
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