I have a powered quest mount for sale if you are interested. It has a ram ball on it now and can easily be mounted. The battery will last for close to 20 hours as long as the back light is not on. With the mount you can also run a wire if you wanted to hear the thing talk to you, I tried it once but did not like hearing it ***** at me if I missed a turn. If you want it you can have for $30 including shipping. here is a pic.
