Howdy all, I saw this on ebay: http://www.ebay.com/itm/Rapid-3-Por...624?pt=LH_DefaultDomain_2&hash=item2a4e666830 and I am wondering if they are effective or if they mess up charging of the batteries in any way. I'd like to use the high power inverter in my van to charge more than one battery at once and I am hoping to do it without using more than one AC adapter but NOT at the expense of the batteries life or charging time. Ideas? BTW there are several eBay seller that have versions of the same thing. I picked that one at random. Thanks!