2 cell 30whr after being all day working 12 hour day and not shutting it down and getting up next morning battery still shows over 50% charge ..4 cell 60 whr shows 65% to 70% charge switched over to 60 whr after first week of use .... 2 days without charge and being used to just close calls out, sending drop cards , badges over email...charge drops to 10% ...that's leaving it on for two days and system sleeps while not in use....so, I would say pretty good battery life ...I bought a 200 watt inverter which allows me to plug right in with the standard charger but I am finding out that was an unnecessary purchase...but might prove needed as the battery will degrade over time as they all do.