Hi Guys, Is this thing good or a waste of money? http://www.ebay.com/itm/For-DJI-Ins...954?pt=LH_DefaultDomain_0&hash=item27fc7f8472 There are several on eBay. I don't want to waste my money or mess up my batteries. I currently have two AC adapters but I have 3 batteries. (Might get a fourth eventually.) Charging two at once on a single AC Adapter would be helpful (so long as it was less time that going one at a time on a single charger. Obviously the most ideal is a charger for each battery simultaneously but that is an extra 55 bucks for each charger. I will be charging in the field off an high capacity inverter in my van. Any feedback is appreciated!!