According to the ARRL (I believe their opinion counts<g>): "Hi Dan: Batteries may be fully changed before the start of the Field Day period. Any charging of the batteries during Field Day must be per the rules. Thanks and 73 Dan Henderson, N1ND ARRL Contest Branch Manager" So, a 100 mW solar array trickling into a BIG battery is legal, and = within the spirit of the rules. Odd, but I'm gonna call that a Bingo! Dan