RE: field charging lipos
Recently picked up a Wal-Mart 122 AMP Deep Cycle Marine Battery $81 w/ core credit, $9 more without . Made by Johnson Controls- a well respected company) and the plastic tub( $8) . They even put it in the vehicle and told me it's store policy not to accept a tip( which I offered). Have it behind my seat on the floor of my Odyssey and don't plan to move it as it is damn heavy- Johnson Controls sez 61 lbs. - it feels heavier.
So far, so good. I use a TP 820CD . I've charged two 10S bricks(5300 5S Gens Ace) , one brick at a time @ 2 AMP; once home and in the garage , attach my "Battery Tender" . After roughly 14-16 hrs., the charge was complete for that amount of usage.
I also fly e-UKIE Stunt and have charged four individual 5S 3300 Gens Ace @ 1AMP.
Haven't measured the limit of the battery just yet because after 4 flights in this heat, I wanna go for ice cream , a cold drink or just get home.
Down the road, I hope to wire it to my vehicle's altenator.