Odd question about towed battery charging.

[Tjdave]

This may be a new one. Is there a way I tell if my previously owned towed is set up to charge the battery? My goofy set up: 2018 Tiffin 32sa I bought lightly used. PO had a Roadmaster brake set up on it. I traded the Gladiator, which I bought new, for a used Wrangler that was already set up to flat tow. Wrangler has a Stay-in-play brake system and Roadmaster baseplate. Everything works perfectly. On year two with the Wrangler. I've never had a dead battery problem after towing, even with the led light option and towing at night. Motorhome does have 12v aux power at the tow plug. I think it may have a charging system on it. Or, I could be over thinking this. Thought I'd ask.

 

[RandyB]

The best way would be to measure the battery voltage on the towed vehicle.
1. With the towed connected to the tow and both engine not running, measure and note the battery voltage with a voltmeter. It should be around 12 volts.
2. Start just the tow vehicle and again, measure the voltage at the towed battery. If it is significantly higher that step 1, it is charging from the tow. It should be around 14 volts.

 

[CaptainGizmo]

The standard configuration for a six way plug is to have 12 V constant power supply to the center pin. So what I do is I check that center pin for continuity up to the positive terminal of the battery if there’s a wire connected to it.

Another way is to remove the six way plug and see if there is a wire attached to the center pin.