Anyone ever use these super chargers?

[j3gq_imp]

I suppose you call them super-chargers for a reason - super for a lot of juice. This may mean a lot of power drawn from the main battery. Watch for max current rating of your "home-grown" ( ? ) harness, and the cables it's connected to. Also make sure this thing "really" switches off completely and reliably when you are not charging your phone. Now you might think, what's he talking about, it's nano-amps - right ?
It may be up to 2A on the secondary side (or even 2x 2A for two iPhones ? I don't know), and if built badly 3 Amps (or 2x 3A ?) on the primary side. So don't guess, and make sure.