I have an interesting case of battery death and resurrection here... well, sort of. I have an android phone (sony ericsson xperia x10 mini pro, cca 2 years old), and a netbook (acer aspire one, can't say which exactly since the labels are all faded, also about 2 - 2.5 years old).
They each started having similar battery related symptoms at about the same time.
The phone was working well for the 2 years, battery lasted about 3-5 days depending on the usage. Last Friday morning it was all charged up, left it to charge over night, and it showed 100% charge. A few hours later, however, it showed critical battery and died less than 12 hours after being fully charged, and that was with almost no usage at all. For the next few days, I had to charge it twice per day and I already started contemplating getting a new phone, but miraculously, today when I charged it, it seems like it got back to its normal battery time. That was this morning, it has been a whole day, and the battery has only discharged slightly, same as before. So my trusty xperia can live on
The second case, my netbook is even worse. Last Thursday I took it to the library to study, and it was fully charged. Usually the battery on it lasts for about 4-5 hours. I was using it for about 1.5 hours and it showed low battery already. I ignored that and suspended it. On Friday I turned it on from suspend, but the battery was completely dead, so it hibernated. Then i plugged it in and left it alone for the weekend. Yesterday I tried turning it on, but it showed no life signs so I left it to charge overnight. Today still no change. I can turn it on when plugged in, but the battery constantly shows 0%, and if I plug it out, insta-death.
I noticed that when i plug it in, the orange light glows for a few seconds and then starts blinking as it usually does when battery is low and unplugged, and no matter how long I leave it like that, still no charge. And when I boot windows, the battery icon says "Battery present, not charging." Linux just says 0% battery.
Also interesting is that at the same time the netbook and phone started doing this, I got a cold.
So I'm thinking it seems highly unlikely that this is coincidence, perhaps there is some environmental factor to this? I don't know much about hardware or batteries, but maybe humidity, temperature or something else could have caused this?
And is there any way to revive the netbook battery? Since the phone returned to normal, I am not giving up yet.