Well, the passthrough is different than the regular battery - it has an inline battery off of a usb plug and then the wire to an empty batt casing where you put the atty/cart, etc. BUT... there is a mod to this that is esp. good if you're working off an batt pack or even a wall plug/car plug - basically - eliminate the inline battery. And you can, depending on out put, get a full 5 volt 'mod' from it. You still are tethered but some people use the kensington power pack - the size of a credit card - in their shirt pocket and they're hooked up all techie like with the wire, etc.
Fortunately you can get passthroughs for $11 china, $15 rockymountainvapor when they have them in. 20-25 bucks other places.
If you really want to mod - here's an idea - check out the bartleby - the one I linked to - still worth getting before Jay retires at 100 made. He's around 70 now. But get a nice metal case for that or figure a way to put a juice dispenser onto it and put it in a prism shaped case with a 3ml bottle encased ;-)
