That all accords how much power you have taken out of the packs, I work on about 150Mah per flight and it all accords how much you charge at, all obvious rearly, 500Mah will take half an hour at 1amp, but the beauty of the A123's is you can charge them at way over that if you are in a hurry, I generally charge at 5amps so it takes about 6 mins to put 500Mah back in, just put the charger on the batteries whilst you re-fuel.

Mike