Instructables

Is there a way I could convert a cell phone's car charger to a charger I could use in an outlet found in my house? (How)

I dug around and found an old Motorola cell phone, and it's accompanying car charger (or adapter, whichever suits you). I want to make it into an adapter that will plug into an outlet (wall outlet, etc.). I ended up cutting the car adapter off, and stripping the wires. Just about 5-6 inside. I take an old Gameboy SP charger and cut the end off of that, just two wires. You can see where I hit a problem. Anyway, if you're about to ask what's the output voltage on the car adapter, I couldn't find it.
I just noticed... if it sounds like I have no idea what I'm doing... I have about half an idea.
Simply put:
What's the best way to do this.

Wasn't too sure if you need a part number or something, because I don't have a camera.
Car adapter: SYN7818A


Re-design5 years ago
The voltage going into the car charger from the car would be 12-13 volts dc.  That's one pos. and one neg wire.  No ground.  You need a meter to check the polarity of the wires.

The game power supply should be marked on the plastic case.  But if it's not you need a meter to check to see what the voltage is and the polarity.  It might be dc, with a pos. and a neg. wire or it might be ac, but there is no ground wire.

You have to know the voltage and polarity of the cell phone charger.  You have to know the voltage and polarity of the wall wart.  If they match the you can use them together.  If they don't match then you have to adapt them or you destroy you phone.

If you have a 12 v. dc wall wart you can attach an aux. accessory outlet that the car adapter can fit into and use it that way.  You still have to check the polarity.  There is probably a voltage regulator inside the car charger.
 I checked on the Internet and found cell phone chargers use the USB standard, which means the black wire of the USB is ground ("earth" in GB) and the red wire carries the voltage.  But what voltage?

You should buy yourself a volt-ohm meter to measure it, but www.discovercircuits.com/DJ-Circuits/phone-chrg.htm says cell phone batteries take 5 v, though I imagine you can run a bit higher.

The Gameboy charger has two wires, one must be a ground, and the other the "hot" wire.  If one is black, it is probably the ground, and would be connected to the black phone wire (if there is one).  If the phone has a red wire, connect it to the other Gameboy wire.  Plug it in for a short time to see if the phone turns on or the battery charges.

If the wiring is different, you'll have to use an ohmmeter to trace which wires of the phone plug go to the battery.




Sandisk1duo5 years ago
splice the power into a USB cable, it will be the simplest way (unless you want to go buy a $5 cellphone charger)