2018 RAM 7 pin trailer charge wire switched with ignition?

[Tuesdak]

My 2003 was a direct connection where I had to pull the 7 pin trailer plug to keep the 5er from draining the pickup's batteries overnight via the trailer battery charge wire.

Is the 2018 the same direct connection or is it now switched with the ignition?

If not any recommendations on a battery isolator for the charge wire on the 2018 RAM?

 

[Learjet]

my 2017 is hot all the time

 

[GAmes]

An easy check with a multimeter.

 

[Wiredawg]

Hot all of the time... Simplest is unplug the trailer at night.... if not, you can install a HD relay, like Hella, rated 40 amps. You can wire relay operate to connect automatically by connecting it to ignition hot source, like cigarette lighter. I still just unplug mine.

Cheers, Ron

 

[GCroyle]

Or optional find HOT WIRE connection inside the trailer and disconnect or install good switch.

I'm in the middle of complete 7 way cord R&R. Yuck you'd be surprised, mine's laced thru the frame.

 

[GAmes]

I never unhook the trailers I tow. Too much wear and tear on the receptacle for no reason. If the truck batteries are going dead you need new batteries.

 

[Cummins12V98]

"If the truck batteries are going dead you need new batteries."

So true!!!

 

[GCroyle]

I never unhook the trailers I tow. Too much wear and tear on the receptacle for no reason.

Might work for a work trailer but it don't work for my RV trailer. I've had real good service from a metal Pollak flat blade plug, no connect/disconnect issues. But a Bargman duck bill plug, not for me cut if off and chunk it.

 

[Tuesdak]

I pull near 50% out of my house batteries overnight with what I run esp. if the heater runs. So the truck batteries, that are not deep cycle, need to be disconnected. I had hoped the 4th gen would have improved on this. Not fond of pulling the plug like I did on my 2003 so I will look at a relay.

Any "easy button" place where a hot ignition wire and the trailer charge wire are in one close place?

FWIW Yes, just had the battery replaced under warranty less than 2 years old. (Weak cell dropping 2V on load test.) Yes, ONE as FCA disregards industry standards in dual battery systems to replace both of them at the same time. I was tempted to buy a second MOPAR one to match em, but, the FCA/MOPAR warranty is clearly so bad by leaving one old tests good battery to drag down the new one... I can replace both batteries with cheap ones for the cost of one dealer battery.

 

[Wiredawg]

Yes, cigarette lighter or 12vdc plug is ign hot. rev lights ign hot.

 

[GAmes]

Not fond of pulling the plug like I did on my 2003 so I will look at a relay.

If all you want to accomplish is the trailer not feeding off the truck batteries a simple diode in the truck's hot wire to the 7 pin would do the trick.

 

[juicedcummins]

I pull near 50% out of my house batteries overnight with what I run esp. if the heater runs. So the truck batteries, that are not deep cycle, need to be disconnected. I had hoped the 4th gen would have improved on this. Not fond of pulling the plug like I did on my 2003 so I will look at a relay.

Any "easy button" place where a hot ignition wire and the trailer charge wire are in one close place?

FWIW Yes, just had the battery replaced under warranty less than 2 years old. (Weak cell dropping 2V on load test.) Yes, ONE as FCA disregards industry standards in dual battery systems to replace both of them at the same time. I was tempted to buy a second MOPAR one to match em, but, the FCA/MOPAR warranty is clearly so bad by leaving one old tests good battery to drag down the new one... I can replace both batteries with cheap ones for the cost of one dealer battery.

If you are drawing the house batteries down to 50% overnight it almost sounds like a single battery. Last fall I broke down and had to sit for 16hrs before the repair shop opened on Monday am. 2 furnaces running in a 35ft fifth wheel left plugged inti tge truck only dropped batteries to 75%. This was at -10C so furnaces ran pretty steady. The house does have 2 Batteries too.

 

[Tuesdak]

If you are drawing the house batteries down to 50% overnight it almost sounds like a single battery. Last fall I broke down and had to sit for 16hrs before the repair shop opened on Monday am. 2 furnaces running in a 35ft fifth wheel left plugged inti tge truck only dropped batteries to 75%. This was at -10C so furnaces ran pretty steady. The house does have 2 Batteries too.

Simply taking the truck batteries out of the deep cycle loop. Covered the RV 6 volt x2 battery setup extensively here:

https://www.turbodieselregister.com/threads/rv-house-batteries-for-dry-camping.259757/

 

[AH64ID]

If you are drawing the house batteries down to 50% overnight it almost sounds like a single battery. Last fall I broke down and had to sit for 16hrs before the repair shop opened on Monday am. 2 furnaces running in a 35ft fifth wheel left plugged inti tge truck only dropped batteries to 75%. This was at -10C so furnaces ran pretty steady. The house does have 2 Batteries too.

Is that 75% on the 4 light OEM display, or 75% from voltage?

There is a huge difference. My OEM display will shows the batters at 2/3 or more at 12.2V, which is 50% SOC. I don't trust the OEM battery monitor at all.

I guessing OEM display since furnaces draw ~7A, so 2 would be ~14A. 10 hours of operation would take be 140AH, which is a big hit on batteries. The truck starting batteries have about 75 usable AH's. You didn't mention if you have 12V or 6V house batteries, but assuming standard 6V for ~105 usable AH. So the combined would be ~180 usable AH, which a 140 AH taken out of would put the battery bank at ~60% SOC.. assuming only 10 hours of furnace operation and no other draw.. which is unlikely at -10°C. If it's a pair of 12V standard batteries the bank would be closer to 55% SOC.