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Ask HN: Should I unplug my laptop charger at 100%?

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Re: Ask HN: Should I unplug my laptop charger at 100%?

#61

Lenovo at one time (they still might, I'm not sure) included a piece of software that allowed the user to optimize charging for battery life. Basically, it would stop the battery from reaching 100% of a charge. Great idea, except that if you forgot to turn this feature off and had to leave, you might leave the house with just 60% battery life.

The Sony VAIO laptops also have this feature. Sad thing is there is no option for enabling this on Linux.

Re: Ask HN: Should I unplug my laptop charger at 100%?

#62
Your battery's life is all about charge/discharge cycles. Say your battery has roughly ~1000 such cycles. Once you've exhausted the cycles, your battery is typically running on bonus power. Whatever performance you get after this is extra and cannot be relied upon.

Thus, the longer you can preserve your cycles, the longer your battery will survive.

You can also read this thread: http://www.reddit.com/r/askscience/comments/1snzg1/is_it_act...

Re: Ask HN: Should I unplug my laptop charger at 100%?

#63

> For proper maintenance of a lithium-based battery, it’s important to keep the electrons in it moving occasionally. Apple does not recommend leaving your portable plugged in all the time. An ideal use would be a commuter who uses her notebook on the train, then plugs it in at the office to charge. This keeps the battery juices flowing. If on the other hand, you use a desktop computer at work, and save a notebook for…

The fact that Apple no longer has this statements on their website makes me think it's no longer true for their batteries (if it ever was).

Re: Ask HN: Should I unplug my laptop charger at 100%?

#64
There seem to be 2 main ways people use laptops in my unscientific "asking of my friends" survey: Plugged in for long periods, or unplugged for long periods. It seems like the vendors should have solved for both of those.

From the previous answers to this item, it would seem that most vendors focused on long life unplugged (6 hours! 10 hours! So long, you'll forget where you last put the cord!) and "you'll have to buy a new battery... and they aren't cheap" if you stay plugged in.

While part of me finds that hard to believe, another part wonders if this is just a part of the wonderous circle of (battery) life. Luckily, the conspiracy part left the building, or he would have said that the evil vendors do this on purpose to keep a steady cash flow.

Sorry, didn't mean to evoke this earworm: https://www.youtube.com/watch?v=8zLx_JtcQVI

Re: Ask HN: Should I unplug my laptop charger at 100%?

#65

Lenovo at one time (they still might, I'm not sure) included a piece of software that allowed the user to optimize charging for battery life. Basically, it would stop the battery from reaching 100% of a charge. Great idea, except that if you forgot to turn this feature off and had to leave, you might leave the house with just 60% battery life.

Yeah, I have this on my Yoga 2 Pro. The utility is called Energy Manager - and the setting is "Conservation mode".

https://forums.lenovo.com/t5/image/serverpage/image-id/34801...

Re: Ask HN: Should I unplug my laptop charger at 100%?

#66
post #54

I know that this was an issue on my ThinkPad W700 with Linux installed. In Windows, the Lenovo drivers would automatically manage the charging level to preserve battery life, but in Linux it would overheat when plugged in for extended periods of time, and I suspect that it was "over-charging". Within a year, the battery had about 50% capacity, and a replacement battery degraded as quickly. My current ThinkPad w540 do…

I'm pretty sure that the charging logic is built into the battery or other dedicated charging circuit hardware. Almost positive that while the OS can say "don't give power to the battery", it can't say "give power to the battery even though the battery says no". Not a great source, but this agrees: http://computer.howstuffworks.com/laptop-battery-overcharged...

Re: Ask HN: Should I unplug my laptop charger at 100%?

#67
> I have talked to numerous people and there is no set consensus on whether I should be unplugging my laptop charger when it is fully charged.

Hi Zatkin,

General advice: please study the materials hosted at the following great "Battery University" website: http://batteryuniversity.com/

The charge and discharge protocols which are best for battery life and capacity depend on the kind of battery.

Certain batteries benefit from being cycled, like NiMh and NiCad. It's not that important for lithium, IIRC.

Some batteries benefit from priming: treating the battery in a certain way when it is brand new, so it lasts longer and performs better over its lifetime.

(I could use a refresher myself; I'm going to study the materials on that website.)

Re: Ask HN: Should I unplug my laptop charger at 100%?

#68

> For proper maintenance of a lithium-based battery, it’s important to keep the electrons in it moving occasionally. Apple does not recommend leaving your portable plugged in all the time. An ideal use would be a commuter who uses her notebook on the train, then plugs it in at the office to charge. This keeps the battery juices flowing. If on the other hand, you use a desktop computer at work, and save a notebook for…

The fact that Apple no longer has this statements on their website makes me think it's no longer true for their batteries (if it ever was).

They do have some advice on "long-term" storage here, which is roughly along those lines:

https://www.apple.com/batteries/maximizing-performance/

They don't say what "long-term" is, but monthly seems reasonable to me.

Re: Ask HN: Should I unplug my laptop charger at 100%?

#69
post #58

Source: I have a master's degree in mechanical engineering in hybrid vehicle powertrains, and a big part of my research was battery technology. I spent some time working with the folks at National Semiconductor learning this, so I have several primary sources. Disclaimer: my knowledge of the field is from ca 2010. 1) Lots of deep discharge cycles do negatively affect battery life. Try not to jump between 0% and 100%…

I read batteries wear off when plugged in in hot conditions, which is often the case for a running laptop. Can you confirm?

Re: Ask HN: Should I unplug my laptop charger at 100%?

#70

All my questions have been answered via this link: http://batteryuniversity.com/learn/article/how_to_prolong_li...

Yeah, that's a great starting spot for putting these crazy myths to bed.

A lot of a people seem confused about two concepts in the article: ideal storage and depth of discharge. These are two separate concerns. If you try to maintain the ideal storage charge while it's in-use (say 40%), you're going to end up wearing your battery by putting it through unnecessarily deep discharge cycles.

Unless you want to plug and unplug every few minutes, you should probably just leave it plugged in.

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