I just noticed a few days ago that Windows 7 hardly refreshes the battery charge (or current capacity, expressed in percentage) as the battery is discharging or charging. I had it jump from 100% to 80% then to 20%; today it really bit me as it jumped directly from 96% to 0% - as in Windows didn't even had the chance to notice the battery was almost dead, so the laptop ran out of power (I forgot to plug it in to AC).
What is the problem here? The BIOS has no option even remotely about the battery and the diagnostic options only have memory and HDD tests; the log is totally empty. I'll give HP a call, but I'm not looking forward to it, as the customer service is horrible, at least in my country.
The laptop is a HP Pavilion dv5-1101en.
Edit: It's currently charging and it did something similar: the charge jumped from 2% to 7%, then it started increasing steadily as one would expect.