Okay, I looked up the power requirements for my MX-P50M 45 watt amplifier. It calls for 8A @ 13.8 volts to put out full power. Now, I have a 12V to 13.8V boost converter (designed for powering automobile accessories at full power with the engine turned off). What sort of battery should I get to power the Bitx40 and the amplifier together, for any reasonably long period of operation (like Field Day, where I would allow the battery to charge overnight while I was sleeping)?