MAH Readings?

[BrianG]

Do you mean how do you determine how much is left?

Just charge them up. Whatever the pack rating is, minus what you put back in is how much you used. So, if you have a 5Ah pack, and you charged 3500mAh back in, you had roughly 1500mAh left.

Lithium voltage discharge curves are non-linear. They are generally pretty flat (~3.7v depending on load) over the majority of the cycle with a sharp curve up to 4.2v at full charge and a sharp curve down to ~3v when they deplete. So, just using voltage is not accurate.