jkwilson wrote:
Rustofer wrote:
Another thing that could be happening is that your alternator is pushing out current based on the needs of your starting battery, which gets replenished quickly. It's frustrating that today's trucks come with high-capacity alternators that basically do almost nothing because the sophisticated controls tell it the starting battery is fully charged. I've wondered if a way around this would be to wire the trailer connection directly to the starting battery with an isolator that opens when the truck is not running. Hmmm . . .
That’s not really how an electrical system works. The trailer charge line will draw current from the vehicle electrical system and that draw will cause the voltage to drop and the charging system will increase output. The trailer batteries are in parallel with the starting battery, so they are all one electrical system.
Not exactly. The remote/trailer battery will receive the full voltage the tow vehicle provides but the tow vehicle in many applications and in all modern (factory install) cases uses a battery isolator to protect from discharge of heavy loads and rapid discharge of the remote/trailer. True they are installed in parallel but it is one sided. No matter the state of charge/discharge of the trailer battery the tow vehicle battery is isolated from loads/discharge originating from the remote/trailer battery