Disappointed, January 5, 2011

I get 3-4 hours on a full charge if I use it 100% during that time. If I am not using the computer I have left it running for 8 hours and it still had juice left.

I was skeptical of purchasing a replacement battery from a 3rd party but in the end wasn't willing to pay Dell $150 for a 9-cell 85WHr M1530 battery that will hold a 5% charge the day after the 1-yr warranty runs out.This is the only battery I could find that actually matches the battery produced by Dell. Both are 9 cell, and the 7800mAh is the equivalent of the 85WHr Dell offers. Most other batteries offered by 3rd parties don't have the equivalent of 85WHr/7800mAh. So far this battery is giving at least 3-4 hours of life with my battery saving preferences. I've had it for a month - I'll be sure to post back to update how it is performing overtime. Note - I'm much more careful with it now, I leave the original battery in when I'm working at my desk using AC power and only fully charge the new battery when I need to go portable.

The battery arrived in a timely fashion. Once it has been charged up it only stays charged for abour 1hr. This is better than my previous dell battery when it was dying. My new battery does not compare to the dell battery with it's ability to stay charged for 2 plus hours. I just hope it either improves or does not decrease in holding 1hour charge. Not sure if I would buy it again, but it does have a 1yr warranty.