I feel for you guys !
We have power in our small clubhouse now and everyone charges out of a wall outlets. It spoils you FAST... It makes it tough to go to another field and have to figure the same battery/generator problems out. My buddy and I keep trying to decide if we want to splurge on a small Honda generator to charge the big 6 cell packs some of our planes use.
Its fun flying electric no matter how you charge but some ways are easier than others.
We have one member that always used to charge off his car battery.. Twice he ran it down to the point he couldn't start his car ! And everyone else had already left the field..... Then he had to run an extension cord to his vehicle and charge his car battery with his small airplane battery charger !