Ah, good tip! Thanks for that! So I tried doing that on the cable I had but it didn't work as I expected, I ended up trying another cable I forgot I even had that was a universal charging cable and it actually had a barrel jack (the wrong size of course) on it along with some others. It seems this cable is wired up the way you said, and with some adapters, I'm able to use it well past the 0.7A mark now! I'm getting up to around 11.3v at 1.8A@5v before it dies off my 2.1a ipad2 charger, my phone charger was able to get it up to 11.85v at around 1.95A@5v, but it died anything remotely above that. So, still unable to actually use the full 2.1A, and not really quite getting to 12v off of these 2.1A chargers, but getting closer to it. That said, you definitely would need more power than a 2.1A charger to get much above 11.5V. Would a 2.4A work? It's still a big maybe, but you're really cutting it a bit close for comfort. You will likely be on the very edge of the current protection kicking in, which is not optimal. 5v source in general is not the most optimal thing in the world - when you're going up in voltage, you always need a lot more amperage, and USB unfortunately is pretty lack-luster in that category, leading to many of these companies adapting non-standard protocols for USB charging as the above poster mentioned! This was yet another time being able to monitor input voltage on the VK was nice, as I could see the sag in the input! Essentially, you've got a built in voltage-tester on the VK, standard! Needless to say, when pulling 11.5v from these chargers, the input voltage was sagging all the way down to 4.18v! At that lower sagging voltage, you'll need even more amperage to get the desired voltage, making the 2.1A even less adequate. That doesn't spell to well for the 2.4A battery pack, unless it's truly able to deliver that current without sag. For much the same reason it's not very practical to run a unit off say, 4 double A's. Once you get up around 6-8 AA's, it's a different story. No problem there. However, charging and/or dealing with 6-8 double A's sounds like a pain to me! Anytime a device has more than 4 batteries it's just too frustrating half the time, especially if you plan to use rechargeable batteries, having to pull out and recharge 6-8 AA's, possibly in two separate sessions, as most chargers only do 2 or 4 batteries at a time, well that's just not optimal. The all-in-one USB device is definitely a nice idea for that reason, but, I have a feeling they won't be as practical until we can find some with 3-5A output. I don't think the USB connectors are rated for that much current though, so that might be a long shot, they'd have to be violating a few standards i'm sure! Not as if they aren't already though! That said, I'd like to keep all my battery packs 4 cells or under at the moment. I'm also considering pre-made packs that use different sized cells, the only thing with those is that they probably will need custom charger adapters. The nice thing about the nitecore battery/charger combo I've recommended is that charger can charge Lithiums, NIMH, or NICD, and it can also charge AA's in addition to 18650s, etc, so really, the setup I'm currently recommending is not only good for use with the VK or 18650s, but rechargables in general, so I'm hoping people might invest in it just for that reason alone. I'm a big fan of the "pre-charge" or "re-charge" style NIMH AA batteries, and I use them in all my tv remotes and appliances, they don't drain as fast when you don't use them like typical rechargables, and are great for replacing AA's. On the other hand, it can also take the 18650s which are larger, but have enough current to be practical for use with a log style vaporizer.