Battery wear

so i accidentally left my laptop on battery while i went to bed. when i woke up 5 hours later the batery was all drained. I started up the laptop, and it says wear at 7.9%, while previously it was at 4.1% after the last time i discharged it fully. I usually doesnt let it go below around 30%, but there have been 3 times now that i let it drain to 0.

1st drain 2.1% wear
2nd drain 4.1% wear
3rd drain 7.9% wear

so is there something wrong with the battery? i mean letting it drain is a normal using condition right? the laptop, a p150em is only 2 months old. any chance the battery may be defective? thanks

 

letting the battery drain completely puts unecessary strain on it, so i wouldnt wait till its at 0, better just go to like 15-20%. either that or just use it however u feel like and get a new battery once the current one is worn out

Sent from my Galaxy Nexus using Tapatalk 2

 

You shouldn't drain a lithium ion battery all the way. It isn't like a nickel cadmium or other kind of battery where draining it fully is better for it lasting longer.

 

i try not to, i usually dont go below 30%, but today i thought i plugged it in and went to bed, when i woke up i realized i forgot to plug it in and the battery was drained.

 

If you forgot to plug it in, windows shuts down by default at 7%, and then the battery shouldn't drain at all, at least not overnight. And you should only lose a fraction of a % of battery capacity with each full drain (well drain to 5-10%).