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

#1

Post by zatkin » Mon, May 04, 2015, 6:08 PM UTC

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.

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

#2

Post by cjbprime » Mon, May 04, 2015, 6:10 PM UTC

No. Your battery degrades each time there's a cycle of charge->use. If you're lucky, you can do that a few thousand times before you lose much of your battery's capacity. If you leave it plugged in, you aren't losing cycles, so you should do that.

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

#3

Post by rajeshmr » Mon, May 04, 2015, 6:13 PM UTC

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.

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

#4

Post by ars » Mon, May 04, 2015, 6:18 PM UTC

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%.

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

#5

Post by ars » Mon, May 04, 2015, 6:18 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.

Not 10%! That's terrible for a Lithium battery. Charge it when it gets to 40%.

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

#6

Post by IkmoIkmo » Mon, May 04, 2015, 6:19 PM UTC

It depends and usually it's a good idea to check with the manufacturer.

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

#7

Post by ars » Mon, May 04, 2015, 6:19 PM UTC

cjbprime wrote: post #2

No. Your battery degrades each time there's a cycle of charge->use. If you're lucky, you can do that a few thousand times before you lose much of your battery's capacity. If you leave it plugged in, you aren't losing cycles, so you should do that.

A cycle from say 70% to 80% doesn't wear it out much at all.

The problem with leaving it at 100% is that just sitting at full charge wears it out, it's better to just keep it within 40%-80% than to leave it fully charged.

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

#8

Post by jerf » Mon, May 04, 2015, 6:19 PM UTC

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.)

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

#9

Post by kvakvs » Mon, May 04, 2015, 6:22 PM UTC

Its best to consult with your laptop/charger/battery manual.

If anything goes wrong, new battery costs like $20. Feel sorry for battery prices for Macbook users, but then their charger is smart enough to help battery survive longer.

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

#10

Post by toomuchtodo » Mon, May 04, 2015, 6:22 PM UTC

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%.

Is there a way to modify the max charge level on apple laptop products?