Remember that what we do on battery power can cause the battery time to vary widely.

I'm been able to swing the battery times as much as 10 times depending on use. For example a laptop with dimmed screen and web browsing could hit 10 hours but the same laptop running the CPU at full load and screen at full brightness could not hit 1 hour.

Supply a full model so we can see what range your laptop falls into. BEWARE that batteries lose capacity over time so if over 2 years old I take off 50%.