Busardo is correct. The cable charges the battery. Then battery powers the mod. There is no REAL pass through that supplies power by bypassing the battery. But you can cape on it while it is charging so what happens is you pull from the battery while the cable is pushing power into it. I hope I explained it right. Does this help?
sent from my Limited Edition Monkey Island™ Talking Voodoo Doll Head named Murray®
The only 'real' APV passthru that I can think of off hand (which isn't thinking too hard) is the one for the Provari. It doesn't involve the battery at all... in fact you have to remove the battery to even use it. There are probably others, but it's late.. and I'm tired... and my buddy just got back from Belgium & dropped off some super rare beers that I haven't partaken in, but I'm still drooling over the fact that they're in my possession at all. Westy 12.. oh yes, Westy 12.