Camper battery not charging while driving?

[TURBS]

I in fact am going to do some tests with this information.

The first was to look in my owners Manual.

Nothing about battery charging or boost as far as a duramax and allison transmission is concerned.

Turbs

[TURBS]

Then I found this.

← *Electrical-battery- Alternators- Wiring

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Free higher voltage charging for GM trucks


So i found some interesting information on the 05-08 general motors half tons. They have a Regulated Voltage Control (RVC) system which lowers your charging voltage to improve gas mileage. The RVC system reduces the alternators output voltage to 12.6-13.1 volts when in "Fuel Economy Mode", this feature is bypassed if the tow/haul feature is enabled. With the tow/haul feature enabled the system will stay in "Charge Mode" and the targeted generator output voltage will be 13.9-15.5 volts, depending on the battery state of charge and estimated battery temperature.

heres the gm tech letter

Some owners may comment that when towing or hauling a camper/trailer that their auxiliary battery for the camper/trailer battery will not stay charged. In most cases, this concern is blamed on the new Regulated Voltage Control (RVC) system. While the new RVC system does reduce the generators targeted output voltage to 12.6-13.1 volts when in "Fuel Economy Mode", this feature is bypassed if the tow/haul feature is enabled. With the tow/haul feature enabled the system will stay in "Charge Mode" and the targeted generator output voltage will be 13.9-15.5 volts, depending on the battery state of charge and estimated battery temperature.

Recommendation/Instructions:
To correct this concern while towing or hauling a camper/trailer use the Tow/Haul feature.

Note: A second way to increase the generators targeted output voltage to 13.9-14.5 volt, is to turn on the headlights.*

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.



GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.




Turbs

[Tomgky]

Thanks for the research Turbs. I know the battery on my TT went down and I plugged it in to my Yukon hit the tow haul button and let it idle for about ten minutes and the battery was good to go.

[kc5mhb]

Interesting find F1100turbo. I'm not a GM fan so I will definitely pass that on to others in my family who are GM owners. Got me wondering if the newer F Series vehicles with haul/tow mode do the same.... My 2000 F250 is 13.8 V pretty much all the time. Oh and after some searching the owners manual I seem to be a bit off on the current for that circuit which is a max on the Ford of 30 amps. Probably same on the Chevys as well.

[flaggy]

I thought I would add another thought to this thread. One year ago, we set up at a state park and left our fifth wheel unattended. We came back on July 3, and found all electricity to the camper shut down, and the food in the fridge was ruined. Our theory was lightning or a surge. For the rest of the season, I could not charge the house battery while towing. While in for warranty work, my wife mentioned the problem to the dealer service tech. He replaced two heavy duty 30 amp in line fuses in the underbelly of the fifth wheel, located under the power center. An access panel had to be removed in the basement to obtain access. I hope your problem gets resolved successfully. -Mike


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[RamblerGuy]

Originally Posted by mud yapster

I have another question;
Will the trailer when tied to shore power charge the truck battery when its plugged into the trailer plug on your truck and trruck not running?

The tow vehicle relay that supplies power to the trailer plug is only energized when the tow vehicle is running. This prevents the trailer's 12 volt system from draining the tow vehicle's battery if the trailer is left plugged into the tow vehicle when the tow vehicle is not running, as would happen if you parked in a pull-through and didn't unhook.

[boatnut]

UPDATE- Dealer installed relay. I haven't had chance to try it out. I asked the mechanic how many amps would be at the plug. He didn't kmow but said the circuit was protected by a 30 amp fuse which tells me it should have enough to keep batteries topped off.

I asked him about the "GM thing/tow haul boost" and he said he wasn't aware of that on the Fords.

Anyways, thanks for the tips and the educational posts!