Originally Posted by
David792
Your 4 pin connection has left and right turn/brake, taillights, and a ground. If you tap into the taillights you would only have power when the vehicle lights are on. You will also need to tap the ground in order to get your pigtail powered and grounded.
The 7 pin connection has a constant 12v power but you would also need to tap your ground. I highly advise against tapping the 7 pin harness. Your brake controller relies on a small amount of current feedback to let it know that the trailer is connected. If you start to disrupt the amperage(?) you can confuse the trailer brake controller.
If it were me, which it clearly isn't, I would wire a dedicated power and ground but you still have no control of the power going to your m/c battery. I agree with the 110v inverter. You can get them for about $25 on amazon.
but really.... your trike can go for a while without needing a tender.