Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Charging a lithium battery to 80% only?

electronics.stackexchange.com

Post reply on HN
Print view View original

111–120 of 362 posts

Re: Charging a lithium battery to 80% only?

#111

Post by appointment »

negative_zero wrote: post #89

There is so much confusion, misinformation and naive testing about this topic. I've only learned about this "80% battery thing" when researching EVs recently and it seems to have been (maybe) spawned by the Nissan Leaf many years ago. And now it's appearing on HN seemingly once a week. What has changed? Is someone running an information(or disinformation) campaign? Blog or app to promote? I've not spoken earlier for…

I think people are confused because of the advice to not charge above 80% on fast DC chargers, but that is about the exponential reduction in safe charging speed at high state of charge, not battery degradation (excepting old versions of the Nissan Leaf with bad battery management).

If you fast charge to above 80% you are wasting your own time and the time of other people waiting to charge, so manufacturers usually quote fast charge times for a 10% to 80% charge, which is both more realistic and make the cars look better.

Re: Charging a lithium battery to 80% only?

#112

Post by onetimeuse92304 »

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…

Some more responsible device manufacturers are doing this. For example, the industrial equipment I worked with charges batteries much more sustainably, also by charging it with less current.

Remember, there are multiple factors when it comes to batteries degrading. Voltage (how far the battery is charged) is one of them, but so is the charging current (how fast) and also the temperature during and outside of charging.

Personally, I usually use slower chargers for my laptops and phones to prolong the device lifetime.

Re: Charging a lithium battery to 80% only?

#113

Post by starky »

Panzer04 wrote: post #20
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…

Top charge in a lithium battery is very arbitrary. Most batteries can tolerate going higher than the specified 4.2v, up to 4.3 or 4.35v - but the cycle life degradation is not worth the extra capacity.

This is exactly the answer. Especially with Li-Ion cells everything is a compromise. You can extend the life of the cell by a fair amount, but then it won't last as long before you have to re-charge. Similarly, if you charge it quicker, then it reduces the lifetime of the cell.

I honestly don't understand how people worry about their batteries in their devices so much. I give pretty much zero care into how I treat the battery in my devices other than to try to charge them before it drops down too low (which is where most of the damage occurs if you do it repeatedly) and I can only think of 1 or 2 times where my devices battery has worn out before I end up replacing it.

Re: Charging a lithium battery to 80% only?

#114

Post by yunohn »

sherry-sherry wrote: post #95
JBiserkov wrote: post #90

Earlier quoted context omitted.

And that's without power saving mode? Impressive! Have you configured anything like "disable background network activity"? Do you force close the apps?

>Do you force close the apps? Don't do this unless an app is unresponsive/not working correctly. It will just make apps slower to restart, using more power than it would if left to suspend/un-suspend as it's meant to.

TBC the discussion is around idle battery usage. Presumably, backgrounded apps will contribute to that. FWIW I do notice a difference, especially depending on what apps are open. Whether closing apps increases battery drain during reopening them for intentional activity is a different question.

Re: Charging a lithium battery to 80% only?

#115

Post by FooBarWidget »

glandium wrote: post #108
artimaeis wrote: post #16

Earlier quoted context omitted.

I just picked up my 2017 iPad Pro. It was last charged Nov 15. Been sitting by the bed mostly unused since. Currently at 80% charge. I haven’t experienced what you’re describing on an Apple device since they switched the laptops away from Intel chips. In my experience, the OS does matter. I can’t believe how bad the rest of the industry is at this. Amazon’s Kindle line is incredible at this IME, but those are pretty…

I have the exact opposite experience. My 2013 MBP can keep its charge for months while suspended/hibernated. My first-gen M1 MBA will deplete the battery in a week under the same conditions.

My 2016 MBP drops from 65% to 30% in a month even when it's turned off.

Re: Charging a lithium battery to 80% only?

#116

Post by rekoil »

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…

> by reducing performance like Apple does with old iPhones

What Apple did was clock down the CPU of iPhones with degraded batteries in order to reduce peak load which would otherwise result in crashes that would have made the device borderline unusable below some charge percentage.

Yes, they should have shipped the feature off by default and with a toggle, but the feature itself was amazing as it let already old phones last longer than they otherwise would have.

Apple deserves a lot of shit for their bullshit surrounding replacement parts, but this particular topic is something they get an undeserved amount of shit for in my opinion.

Re: Charging a lithium battery to 80% only?

#118

Post by actionfromafar »

rekoil wrote: post #116
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…

> by reducing performance like Apple does with old iPhones What Apple did was clock down the CPU of iPhones with degraded batteries in order to reduce peak load which would otherwise result in crashes that would have made the device borderline unusable below some charge percentage. Yes, they should have shipped the feature off by default and with a toggle, but the feature itself was amazing as it let already old phon…

They didn’t explain what it did. The feature was amazing, the presentation misleading.

Re: Charging a lithium battery to 80% only?

#119

Post by crashmat »

kragen wrote: post #57
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.

most recent phones and laptops have batteries that require advanced tools and chemicals to remove and replace

Laptops also? I didn't realise it had gotten this bad anywhere but in Macbooks.

Re: Charging a lithium battery to 80% only?

#120

Post by BigJ1211 »

justworkout wrote: post #82
vGPU wrote: post #6

Earlier quoted context omitted.

Even my iPad has horrible background drain. My iPhone is the only device I have that I can calmly leave at 15% when I go to bed and know my alarm will still work in the morning.

I had an iPad that I bought 5? years ago and I could leave that thing in sleep mode for literal weeks at a time and I'd still have a mostly full charge. I "upgraded" to a Pro 2 years back and the first thing I noticed was it'd go from a 100% charge to 60% to even 40% overnight. All apps closed, freshly rebooted and did nothing but charge it the previous night before unplugging it. A lot of comments online say "This d…

Also using an iPad Pro that I got in 2018 (I think, the first 12.9 inch with the current look), it used to be better at it than it is now. In the beginning it would rarely drain now it drains ~20% overnight. Granted mine is older and has been heavily used. So the battery has had quite a few charging cycles by now.

It's still fine to work on though. So have no need to replace it, but it is a little annoying to find it at much less of a charge than what I would expect.

Post reply on HN