Funny thing I discovered today. My Sony cd player in my truck has a usb slot on it and while it won't power a passthrough (said usb overload right on my player), it will charge my VK's on the go with the usb charger from V4L. I was so happy to find this out I had to pass this on lol. I have been vaping VK full time since August and just tried this today! Now I really don't need to order the pcc and can order more batteries!!