Phone Charger Phone Charger 23 of 44 Now that all the pre-assembly work is done it’s time to get this contraption wired and working. We need to start off doing some pre-wiring because once that box is epoxied to the back of the cover there will not be much room to solder. I decided to do the switches and jacks since they will be the least accessible. As you will see you have to think this out because after assembly some joints will difficult if not impossible to reach. Adapting the battery charger to the computer jack would be easy since the car plug supplied 12v to the charger. The cell phone on the other hand had a circuit built into the plug. This is the part we are after. Here is the charger before disassembly.