Full disclosure this doesn't have to do with flashlights but this sub forum seems to be the best spot to answer my question. I've got a mechanical decoy that runs off of 4 double AAs in a harness (see image). I want to build something that will allow me to get a longer run time than burning through AA's or using rechargeable batteries. The connection looks to be similar to that of a 9volt battery. I was wondering if someone knew the correct battery I could run without burning out the motor on this thing or over powering it. There isnt much room inside the decoy so I wouldn't be opposed to running a length of wire to a battery box on the ground. My first thought was somehow connecting a power bank for a cell phone via a usb to the decoy. I just don't know how to do it. I'm not sure if it this adapter is in series to get more volts or if its just in parallel to get more run time. Is there such a thing as a usb to 9volt connection?