I use and recommend a Cermark power panel. It allows me to charge and/or load test either my Rx or Tx pack at 300mah. Great for topping off mid-day at the field.
It also has a glow driver and glow charger. I prefer a single cell glow starter that I can keep in my pocket. I mounted the 12v battery inside the field box and I can charge the battery through the same banana plug females that the electric starter plugs into. You must make sure the panel is off to do the main battery charging or you smoke the panel. Either way, you can mount the battery and pretty much forget about it. Electric fuel pumps are nice and they can be purchased pretty cheap. I'd try to build as complete a field box as you can. It's the one thing you won't crash and will be with you for a while...The panel will cost about $100.00