Quick and easy starter kit, for a 2-meter setup... CellPro 10xp with JST-XH balance board (and JST-HX extensions optional, but they make life a lot easier), 24-volt power supply from FeathermerchantRC, and 2 or 3 sets of the Hobby People 4500 5S lipo batteries. I also like the iCharge 3010B, but it is not forgiving if you mistakenly plug the balance taps in backwards.

It is not at all practical to recharge these fairly large packs on your car battery. Charge times will be slow and the car battery will be dead in a jiffy. Best to plug into an AC outlet at the field, if they're available, or into somebody's inverter generator, or eventually get your own Honda generator at Wise Sales. I have a generator and it's very handy, but my preferred solution is to have a bunch of battery sets and charge them at home the evening before going to the field.