Originally Posted by XRider
First you need to find out what voltage the gps requires, I have one that uses +5VDC and another that uses +12VDC. It will be printed on the GPS at the jack where the charger plugs in.
If it runs on 12 volts you can connect the car charger for the GPS at the capacitor, this is where the power will be the cleanest. However since the power from the bike will be charging batteries in the GPS and not powering the unit itself it's really not much of an issue.
You don't have to install a battery on the bike to make this work but it will only charge when the engine is running. You may need to put a couple of diodes in line otherwise when the bike is off the cap might suck the GPS batteries dry. The diodes will keep the current from flowing back into the bike harness. An inline fuse wouldn't hurt ether.
Perfect! That's exactly what I need to know. The wiring for the GPS already has a fuse inline, I shouldn't have much trouble getting a diode.