MAH Readings?
 

How do you manage how many Mah is left in your battery?

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.

Yeah, just thought there was some other way and reading them so you can keep track of them during long storage etc.

Plug in a voltage checker to the balance taps to read the individual cell voltages- you will see how much charge has floated away over time, but its better to just chuck them on the charger every now & then.

my Flightpower balancer has an electrical "fuel gauge" built in and you can hook up the battery to the balancer and it gives you a ball park reading of the remaining power