We just concluded a 1200 mile trip to West Yellowstone and back and it's evedent that the truck alternator is not charging the coach batteries underway. We only have the residential fridge running while underway, but during a day's drive the coach batteries still do not charge. When I got home yesterday, the inverter battery voltage read 11.6. I have almost 14 volts at the 7 pin connector in the truck bed when its engine is running. I have traced the wire to the 4 square box on the pin box, and then to the battery box terminal strip. The rotary switch is definitely on, as all 12V devices work.
Our batteries are 5 1/2 years old. (Diehard Platinum group 31 marine), I'm wondering if they're the problem. They will properly charge in the coach connected to shore power, as well as a portable automotive charger. Any thoughts for help?
Thanks,
Jim
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We had an identical experience recently on a 1,100 mile trip. Batteries were dead when we arrived at our first destination (Las Cruces, NM, 100+ degrees), with only the residential refrigerator running while enroute. Fridge was off upon arrival, but fortunately the fridge stayed cool enough that food wasn’t spoiled. Had to plug in at campgrounds to extend the slides. Batteries were fully charged when departed for next stop (Santa Fe, NM) but again were dead when arrived. When we returned home I removed the two 12V batteries and had them tested. One wouldn’t hold a charge and the other was weak. Yesterday I completed conversion to two 6V Interstate wet cell batteries cabled in series, including sanding and repainting the floor and underside of the entire front storage bay (already rusting on 2015 36RL). Also secured to the floor a one piece rubber mat to keep majority of dust and dirt from entering the bay, primarily due to all the openings in the floor for the generator prep (don’t have a generator and don’t boondock). Batteries are fully charged with no changes to the inverter for charging purposes and ready for our next trip. I also suspect you have battery problems.
While checking connections for tightness, be sure to check the connections for the battery disconnect switch also. Ours were barely finger snug and the nuts were loosening and probably getting looser with every bump while going down the road. We purchased our 2012 36RL in 2014. Lots of things to inspect and correct.
Chris & Maria
I had that problem last year, was going from PA to VA and the batteries were dying... I checked all connections, all seamed ok...
I had to plug into shore power to get the jacks to work.
When I got home, I did a load test that proved my 2 year old, “upgraded” batteries did not last very long... Replaced them with Lifeline, AGM’s.
Well, update
Took the two coach batteries (Sears Diehard Platinum Marine Group 31 ) 5 1/2 years old to a battery wholesaler in Tigard, OR., assuming I'm going to follow Joe's advice to buy two Lifeline AFM's. Both gents there separately load tested both batteries and found them "better than the published specs ". That begs the question, why in the world won't my F350 at least trickle charge while underwqay. The truck is fused for 25A and the fuse is of course still good. These two batteries load tested way better than good even for new batteries. I'm mistified.
Jim
A few comments FWIW! We have the same year and model as you do, without the residential fridge. Our 2 original house batteries packed it in this year, they wouldn't hold a charge for very long, even after I have rewired at that breaker block to the disconnect switch so when I throw the disconnect switch to off everything is disconnected.
I would follow the suggestions above, and have a second load check done, I had one done in the past that didn't reveal a battery problem. Another suggestion: If you have or know someone that has a clamp meter that measures DC amps, use it at various places to see if you are getting a good number of amps from the truck to the RV and from the RV entry to the batts. I bought one back at the time we were RVing in Mexico to determine and minimize DC amp draw when we had to boondock and live on 15 amp service.
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These are AGM batteries, so a hydrometer is not applicable. The wire size is #10 in the truck up to the plug in the truck bed, and #6 until it gets to the bus bar terminations in the battery compartment.
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