I'd like to run power wires from my vehicle battery, to my trailer, through my trailer lights wiring. I have two spare wires, through my trailer light wiring. These are 12 gauge wires and I'm sure that 12 gauge is not big enough to handle the load from the vehicle.
Any electrical engineers know how to run a charger through 12 gauge wire?
9/23 update - My Conclusion
Thanks to Red_5, for posting a great solution. This seems like a great product at a great price.