I just recently purchased a 12 cell extended battery for a Compaq F700 laptop running Vista. The battery lasts exactly what I'd expect (a little over double the standard battery). However, it is extremely slow to recharge. Since it's new, I should note this is the first time it has been completely discharged to 0%. At the rate it is going it will take 48 hours to charge to 100%!! The standard battery I had before only took about an hour to charge, thus I'd expect this one to only take a couple hours. What is going on here? Will the charging rate speed up in the future, since this is the first time it has been fully charged? I have heard some mixed advice about having to calibrate the battery... is that what is going on here?
I should also note that I am completely unconcerned with working lifetime of the battery (if I get a year I'll be happy), but a 48 hour recharge is completely unacceptable, and I would be more than willing to shorten battery life for a rapid recharge.
Thanks for the links. Interestingly enough the battery check software doesn't detect a battery, but does see the charge level so unfortunately that didn't give me any information. Although I'm trying it, I'm not sure calibration is going to help in this case, since it's already been discharged and recharged once. That procedure seems directed at correcting batteries that are reporting an incorrect charge level. What controls the recharge rate of a lithium ion laptop battery?
Never discharge lithium ion battery to 0 percent, they can undercharge and get damaged. Li ion battery has no memory effect so it is better to keep them in normal cycle use (no discharge below 7-8%), not deep cycle (discharge to 0 and recharge to full).