Ask HN: Should I unplug my laptop charger at 100%? • Hacker News Board

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

#91

Post by piyush_soni » Mon, May 04, 2015, 7:04 PM UTC

basch wrote: post #82

bkanber wrote: 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%…

>plug in and let charge to 90%, unplug and use for a couple of hours, plug back in at 50% or so, rinse and repeat. or set your power drivers to do it for you.

Time to write an app to do that (possibly only for rooted phones), someone?

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

#92

Post by basch » Mon, May 04, 2015, 7:04 PM UTC

rajeshmr wrote: post #3

AFAIK only macbooks have been designed to bypass battery ( once the charge is 100% ) and directly run on connected power. For other notebooks its best to unplug charger at 100% and connect charger at around 10% to get a longer lifetime of the battery.

10+ year old lenovos run when the battery is yanked. as do toshibas and dells.

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

#93

Post by 0xdeadbeefbabe » Mon, May 04, 2015, 7:05 PM UTC

toxicFork wrote: post #13

jerf wrote: post #8

As I sit and look at the replies already coming in, may I just add an enormous [citation needed] to the entire discussion? A question brought on by too many conflicting anecdotes can not be resolved by throwing another unsourced anecdote on the pile. (Incidentally, I'm at least a bit curious myself as to the answer, and have my own pile of conflicting anecdotes I've read.)

This is my favorite technology superstition, some citation would help many people sleep easier it seems.

I would easily fall asleep given the right citation.

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

#94

Post by basch » Mon, May 04, 2015, 7:05 PM UTC

jotm wrote: post #83

ars wrote: post #4

You should unplug it before it reaches 100% unless you know you'll need the full charge. Letting the battery sit at 100% wears it out more than sitting at 40-80%.

Have manufacturers never considered this? If leaving them at 80% was better, they would've configured the adapters to do just that. Unless they really wanted to sell extra batteries, of course...

it is an option in some power drivers.

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

#95

Post by JimmaDaRustla » Mon, May 04, 2015, 7:06 PM UTC

bkanber wrote: 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%…

The only concerns I have with this advice is the heat generated by constantly draining/charging the battery will degrade the life, plus constantly cycling will degrade the battery in other ways as well.

If a charger could be tweaked to charge the battery slowly and not overcharge it, that'd be the ultimate solution.

SOC is relative to the application, but it is possible many applications nowadays purposely operate within a specific SOC and not exactly 0-100%. We need an Apple battery engineer in here to confirm ;)

Edit: You already acknowledged this elsewhere.

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

#96

Post by bkanber » Mon, May 04, 2015, 7:07 PM UTC

raphinou wrote: post #69

bkanber wrote: 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?

Long term battery degradation happens when its membranes degrade. There are hundreds of variables involved. Temperature IS a variable. But I'm reluctant to outright confirm what you're saying because it may be misleading. Avoiding plugging in when hot could help in some situations, but it won't help in all, so it's not a categorical rule.

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

#97

Post by JimmaDaRustla » Mon, May 04, 2015, 7:08 PM UTC

piyush_soni wrote: post #91

basch wrote: post #82

Earlier quoted context omitted.

>plug in and let charge to 90%, unplug and use for a couple of hours, plug back in at 50% or so, rinse and repeat. or set your power drivers to do it for you.

Time to write an app to do that (possibly only for rooted phones), someone?

That's assuming that devices don't already operate in this range of SOC within device...which I wouldn't believe to be true.

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

#98

Post by istvan__ » Mon, May 04, 2015, 7:08 PM UTC

Generally speaking the best for the modern batteries in our laptops is to be charged between 20 - 80 %. I think Apple fiddles with the 100% and it is not the actual 100%. I am not able to find a credible source to confirm this. Ideally you would want to remove the charger when your battery is around 80% and reconnect it when it hits 20%. This can be done with some of the PC vendors easily.

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

#99

Post by matznerd » Mon, May 04, 2015, 7:09 PM UTC

webnrrd2k wrote: post #45

I hate to sound like an ass, but I think I need to say something anyway... Is this the kind of question we want at HN? It's been done to death elsewhere, and is easily answered with a quick search. I know there can be a fine line between a good, thought-provoking question and a useless one, and, to me at least, this seems too far on the "useless question" side of things. It's about basic hardware maintenance, and I'm…

Really? Because there doesn't' seem to be a definitive answer here and lots of conflicting information...

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

#100

Post by Osiris » Mon, May 04, 2015, 7:09 PM UTC

I wrote a program that monitors battery state for Windows [1], and after a lot of research I concur with the other opinions posted here that leaving a lithium ion battery at 100% for long periods of time is not a good idea.

The software I wrote has configurable alerts so a user can get an alert then it's reached a certain change level (like 90%) and then again when it drops below a certain level. Users have specifically ask for that so they can unplug without over-charging.

[1] https://batterybarpro.com