RE: Amps
I use our 7 amp, 12v hobby type battery for several flying days before recharging. Usually it's 20 or more starts of 46 sized engines before I even consider recharging. I carry a chicken stick, just in case, but have not used it in my recent memory.
I have two glow drivers and use one until it dies, then switch to the other and charge the first one that night.
Jack