Battery charging

[Rayray04]

Hello I have a 2019 cougar 369BHS,, seems as tho when I’m hooked up to truck my batteries aren’t been charged. All my lights on camper works together with trailer brakes , I was under the impression the truck charging system would do both - truck and camper

[JRTJH]

Nowhere have you listed what brand or model truck you have, so anything suggested in a "best guess" based on generalities....

Most truck have a "under hood fuse" that controls the trailer charge line output. On some trucks, that fuse is shipped "in a package in the glove compartment" and is not installed until delivery to the customer. Some dealerships don't remember to install the fuse, so your truck may not have the "charge circuit activated"....

Given that, even if the fuse is installed, you've got about 30' of 12/14 gauge wire from the voltage regulator on the truck back to the two plugs (one behind the 7 way and one at the 7 way) plus 8-10' of 12/14 gauge wire from the 7 way plug to the battery cable circuit breaker.

So, the very best you can expect from your tow vehicle is little more than a "trickle charger output" through the nearly 40' of relatively small wire. Also, remember, your tow vehicle voltage regulator is wired to recharge your truck starting battery and when that battery is fully recharged (usually 20-30 minutes after starting the engine) then the voltage from the alternator will drop to a "maintain voltage" and that further reduces the "charge capacity" to the trailer batteries....

Essentially, don't count on much charging capacity from your tow vehicle. Even with a full day's towing (8-10 hours) you'll seldom see a significant charge on a multiple battery trailer system.

[Rayray04]

Thank you,, thought I had a problem but that makes sense