Can't you use the cigarette lighter plug for the source??

 

You can now....Used to Gerbing didn't recommend it or even sell a plug for it due to the possibility of overheating the socket, but now they have a cigarette lighter plug available. I still wouldn't want to use it on a bike. Why would you want a cord dangling over the gas tank of your bike? Using the harness that is provided for free with the gear is simple enough. Every piece of gear comes with a new harness. I have enough harnesses that my Sportster has one, my Road King has two, my Jeep has two, and I have another couple that I can use either in my boat or with the boat battery to carry the "heat" with us..........We went to a race last year on a cold night. I carried a deep cycle battery with us. We were able to run two jacket liners on the 1/2 setting on the thermostat for about 4 hours before draining the battery.

 

Gerbing does make an adaptor that will allow you to use your cigarette lighter source.