I bought a laptop from ebay, as I expected the battery was shot. So I decided to rebuild it myself with new lithium cells. I bought the cells online with presolderded tabs and carefully rebuilt the pack. The battery now lasts for just over an hour instead of the 20 minutes of the former cells. But I believe the laptop should last for three hours on this pack. I have done all the calculations but would like for someone to look over them and tell me whether they are right.
The battery pack is made up of 4 cells totaling 14.8 volts, 2000mah a piece.
Inside linux when the battery is fully charged it shows battery capacity as 13000mW. When I unplug the power the current usage is anywhere from 9500mW to 14000mW.
The way I see it 13000mW is 13Whr's, am I correct? If that is the case then the capacity should be 14.8 X 2amp = 30Whr's. And that my laptop is pulling around 10 watts when running.
I suspect there is some circuitry that did not get reset when I put in the new cells. What I really want to know though is if my math is correct.
Thank you for any input you have,
Fourthbean