Speed Twin And Usb

Just wire it straight to the battery, it’s only live when the Tomtom is clipped onto the cradle.

 

No, the cradle probably does the 12v to 5v conversion, in which case that circuitry will draw a little current even when nothing is connected. Whether that is enough to be a problem I don't know. Before wiring it in direct I'd certainly get a sensitive multimeter on it to make sure of any current draw.

EDIT: I just checked the mount for my TomTom Rider 550 and it outputs 5 Volts, so it does contain the circuitry for converting from 12V. I didn't check the current draw as that would require bodging some wiring.

 

It is enough to be a problem. I used to have my cradle connected straight to the battery. Even without the device in it would draw enough current from the battery to deplete it in a few days.

 

The cradle for my Garmin satnav has been hard-wired to the battery on my Tiger for around three years now. The battery has never been affected by it even after two or three weeks of not using the bike.

 

Power from USB socket will be enough. My TomTom Rider 550 has a USB socket which charges and runs the satnav when plugged in there. I also have the car windscreen mount for it, which just takes a standard USB lead in the back to power device.

The problem with using a USB socket when mounting on the bike is it won't be waterproof, and probably not rated for the vibrations.

I helped a mate do this a couple of days ago on his Moto Guzzi. We cut the wire to the existing USB power connector, then soldered back together with the power cable that connects to the TomTom mount. We used individual heat shrink sleeving over the Ground and 12V joints, and more over the whole bundle.