I use a Garmin GPS. A Zumo 660 for a number of years and now a more recent 390. Tom-Tom GPS power requirements will almost certainly be similar. I have 12-volt electrics on my Rapide and I move my GPS unit on my more modern bikes that are all 12-volt.Not being well up on electrics what do I need to do to make a tom-tom work on the bike I have ordered a waterproof case and bracket for handlebars, I hope to connect by way of a USB connector may be bolted onto the crash bar run through a fuse link (what size) back to the battery. (do I need a step-down unit from the GPS to the USB or can a simple USB be used). My tom-tom fits in the car via a cigarette lighter plug which has the usual bulky push in adaptor on one end of the wire. I could just use a cigarette lighter adapter placed near the battery if there were a better way and what will I need for the job.
- If your supply lead plugs into a 12 Volt supply socket then you can assume that any voltage reduction will be in either the supply lead, GPS mount or unit itself.
- The 12-volt car plugs are quite bulky you will find installation easier if you use the smaller DIN type, sometimes called a BMW type. Sockets are available with a plastic plug or spring-loaded flap for weather protection. Adapters are available to convert from DIN to the larger car type if you use your GPS in a car.
- I've found mounting the socket on the handlebars or headstock is the most convenient option. I've run a short wire from the headlight switch inside the headlight. This becomes live when I select the first position on the Miller headlight switch.
- The excess length from the socket to GPS supply socket is coiled and zip tied. Not an ideal solution unless you are able to shorten the supply lead but this works OK for me as I may need the extra length if I use the GPS in my car.
- If you decide to shorten the supply lead make sure you shorten it outbye of anything in the line that could be a voltage reducer. (This most important to avoid zapping your unit.)
- If your motorcycle is 6-volt you can buy a unit that steps 6-volts up to 12-volt.
P.S. I wouldn't advise using any USB connections as power supply.