I love vaping,,...but just not that much to cut into my PSP. Of course this is far from being a mod. But, you can easily use any or most devices as a power supply if you have a Passthru by getting a Female USB cable and wedging it to the power source of the device, like so......
I usually use this for my 360 controller. I figured, why lug around more equipment than I have to? I carry my cellphone with me all the time, so why not use that as my power source? So, I carry this female usb cable where ever I go to leach on any availble (and suitable) power source such as the phone, PSP, and so on when I'm in a bind for power.