Quote:
Originally Posted by garcia1000
Don't buy old lithium ion batteries. Lithium batteries can be charged and recharged or drained completely, or hit with a hammer, or whatever, they'll do fine. But they have a natural degrading that increases with time and you can do nothing to reverse it. If you buy second-hand lithium ion batteries, it's really likely they are old and useless.
I agree with this tip, but there is something you can do to spare your own lithium ion batteries! The amount of capacity they lose per year is dependent upon two variables: temperature and % charged.
A fully charged battery in a warm/hot environment will lose a significant amount of capacity/year, and a 30-40% charged battery kept cold will only lose 2%-3% per year.
If I know I'm not going to be taking my laptop anywhere for a while, I run its battery down to 40% and store it in the fridge. Lower is better, but you don't want to take too low; you don't want static discharge bringing it completely to 0%.