I'm having some strange issues with my battery. This is my 2nd one and is around 9 months old with 170 charge cycles. First battery lasted one year was replaced under warranty when it wouldn't hold charge. I've done all the things like cycle the battery, run it off battery power most of the time, etc. to try and maintain battery health for both batteries and so far neither have performed as expected. This latest battery will show 9x% health one day, then suddenly drop to 5x% out of nowhere and then shut down without even a low battery warning. It will then stay at 5x% for a few days and then suddenly spike up to 9x%. But even in the 90% range, battery life doesn't last long and the machine will shut down prematurely and without warning. Very frustrating when I'm in the middle of doing something. I don't know if there's some internal battery meter than needs to be recalibrated on the computer or if the charging circuit in the battery is whacked or what? Any suggestions to try before I have to get a 3rd battery in less than 2 years?