What is the expected battery working time for 63.5 Watt Hours?

Thats not really measurable! What I do is not what you do for usage. Maybe I’m a light user to what you do, or it could be the other way around!

No one can really give you that hard an answer. The best you can do is use a load resistor across the battery and plot out the discharge of the battery and then compare the same with an another battery as the control, using a scientific method. But we really don’t need to as the milli Amp hours (mAh) is that measure! So a battery with 5800 mAh at 10.95 V will be the same as another one (within the defined tolerance).

Its when you start comparing different batteries things can get messy. They could be using a different level of load to make they battery look better, the temp of the room where the battery is tested or the voltage could be different! And lastly each battery will have slight differences so some will be better than others. Just like cars rolling off an assembly line some will be plus or minus in some variable.

To be clear I don’t work for iFixit nor do I get any monetary gain in helping people here in the blog!