5th Wheel Batteries being drawn down by my RAM 3500

[bubbajames]

After replacing my 5th wheel batteries with smart Li batteries with bluetooth, I can see the charging status. Taking my 35ft 5th wheel out for 4 hours of driving. My 2 100ah Li batteries were down 50%. The only draw is a fridge. I went to my local Camping World and they verified I have a chargeline on my 7 pin off my truck. But the draw only occurs when I am driving. My truck as you can see is a 2018 RAM3500 with 54K miles. I have two batteries in the truck. The console shows 14amps (13 when lights are on). A fridge amp draw is really minute and certainly no justification for 100amps drawn over 4 hours for just a fridge. Could it be my truck batteries are 7 years old and they are pulling from my house batteries? What else could it be?

 

[danielmid]

You should get a dc to dc charger installed between the truck and trailer to isolate and charge the lithium correctly. The lithium will pull charge from your batteries/alternator faster than you can charge them without one.

 

[18CrewDually]

After replacing my 5th wheel batteries with smart Li batteries with bluetooth, I can see the charging status. Taking my 35ft 5th wheel out for 4 hours of driving. My 2 100ah Li batteries were down 50%. The only draw is a fridge. I went to my local Camping World and they verified I have a chargeline on my 7 pin off my truck. But the draw only occurs when I am driving. My truck as you can see is a 2018 RAM3500 with 54K miles. I have two batteries in the truck. The console shows 14amps (13 when lights are on). A fridge amp draw is really minute and certainly no justification for 100amps drawn over 4 hours for just a fridge. Could it be my truck batteries are 7 years old and they are pulling from my house batteries? What else could it be?

What fridge do you have? Is it a 12v fridge OR is it a residential fridge running off an Inverter?
An inverter draws power from the coach batteries just being on, which in turn will draw down the truck if the 7way plug is connected.

 

[zrock]

If your truck was pulling juice from your batterie's then you would be having electrical issues and low battery issues on the truck when the trailer is not connected. Im guessing when you are not traveling the trailer is plugged into shore power?

 

[stevenP]

First off if your trucks batteries are the OE, you are very lucky. In my last two diesel RAMs the OE batteries lasted basically 5 years. They still started the truck, but very slowly. As for the charge system, obviously the RAMs charging system is set up for non lithium batteries, so it will never top them off anyway.

In my last large fifth wheel the fridge was a residential type, and it was pulling 120vac, thru an inverter, which is terribly inefficient. That set up sucked juice like no tomorrow. It would kill two (parallel) 72 sized AGM batteries in like 5 hours. So I tried it once, and never used it again.