I've had my Compaq Presario 900 for around 2 years. A large portion of it's life, it's been plugged into the wall with the battery sitting dormant. I recently found out that this is bad for it *rolls eyes*. Now my battery life is horrid... well sorta. I think my battery is suffering from a rough case of Battery Memory. I charged the battery all night last night. I got up this morning and turned it on. 100% battery life. Then it gradually started dropping, as it should. Once it got to 90%-ish, it dropped to 5%... Needless to say, I was not pleased. I've updated the battery firmware and everything.
Now for the weird part... The laptop thinks the battery is completely dead *It's at 0%*. But I've been sitting here with the battery at 0% for around 30 minutes watching a video lol. The battery's obviously not dead because when I turn off all the alarms and hibernation/suspension things, it just keeps running and running like it normally would *except the laptop battery meter reads 0%*. Any advice?
I have had EXACTLY the same problem on my Presario 919EA. I also noticed that when charging it gets to about 70-80% then stops increasing, then after 20 mins approx it will jump up to 100%. Like you, when I disable the hibernation at 3%, the computer keeps going normally, except that the tray icon is saying 1% & 2 mins remaining. I have tried several full charge / discharge cycles but with no improvement.
I bought a brand new battery and it is fine (normal operational life, steady charge/discharge from 0 to 100% and down again with no sudden jumps). What I have noticed though is that when I turn on the laptop using battery power and the battery is less that about 50% charged, I get the same thing - it jumps down to 1 or 2%, but then continues working for over 1 hour. If the computer was powered on at, say, 60%, when it runs down to less that 50% it is fine, it will run down to zero as normal. It only seems to be the act of switching it on at less than 50% that causes the fault. Laptops do draw a lot of power at startup, so my guess is that this is just confusing the "smart" capability of the battery.