Not charging from tow vehicle

[rockfordroo]

Maybe this will help. Seems to be related to newer F150's:

https://www.heartlandowners.org/show...y-while-towing

[18CrewDually]

The original post for this thread has a Ranger, NOT an F150.

[rockfordroo]

Originally Posted by 05CrewDually

The original post for this thread has a Ranger, NOT an F150.

Yeah, but fella10 has an F150 with a problem - see post #17. I feel obligated to help him out (we both have the same TT).

[Luv70sFords]

As the original poster, I say help the guy out! I'll spend some time with a meter on mine this weekend.

[fella10]

Originally Posted by rockfordroo

Maybe this will help. Seems to be related to newer F150's:

https://www.heartlandowners.org/show...y-while-towing

thanks rock, I'll pursue this, may even print the first post on that link and take to my dealer...... again thanks

[Luv70sFords]

Pooneil and others, thank you for your help. As an experiment on my way home, I ran my fridge on propane and monitored my voltage. I saw a good 13.5 with the TV running, so now I know I've got a good circuit. The wiring to the rear of the truck is done in either 10 or 12 guage wires so I'm guessing it's simply a matter of too much draw combined with voltage drop over the long distance.

So new question, but mostly out of curiosity, why does this fridge even have a 12v function? Seems useless at this point. I suppose if I had a huge solar array and dual 6v batteries, but....

[rockfordroo]

The 12 volts runs the "brains" of the fridge. The propane or the 120 VAC heating element make the heat that runs the ammonia cycle, depending on which one you've chosen.

If the brains ran on 120VAC, your fridge wouldn't run going down the road or in a campground with no 120VAC (boondocking).

[pgandw]

Originally Posted by rockfordroo

The 12 volts runs the "brains" of the fridge. The propane or the 120 VAC heating element make the heat that runs the ammonia cycle, depending on which one you've chosen.

If the brains ran on 120VAC, your fridge wouldn't run going down the road or in a campground with no 120VAC (boondocking).

There may be no "brains" to the fridge. The bigger RV fridges in the High Wall pop-up models have a DC control board, controls inside the camper, and thermostatic control that cycles the cooling unit. They have some brains.

Standard A-Frames and PUPs have smaller, continuous run fridges. There is NO DC control board. The controls are mounted in the exterior fridge access compartment. Most have a DC switch, an AC switch, and a knob (household dimmer) to adjust AC cooling. Behind the lower vent are the propane controls - propane on-off switch/valve, a knob/valve to regulate propane flow, and an ignitor button. The mode and amount of cooling is manually selected, and the propane flame has to be manually lit by holding down the propane on/off valve and pushing the ignitor button.

These fridges draw about 6 amps when running on DC (the weakest mode), which when combined with running lights on may overload the tow vehicle connection.

With the fridge on DC, and running lights on, you should see at least 13.2 volts across the camper battery with tow vehicle running above idle (ideally 13.6 to 13.7 volts, 13.2V is trickle charge). If less, the camper battery is supplying some of the power, and the tow vehicle is not recharging the camper battery due to voltage drops in the wiring. If I'm charging with the engine above idle, but only seeing about 12.6 to 12.8 volts at idle, that is probably acceptable.

Fred W
2014 Rockwood A122 A-frame
2008 Hyundai Entourage minivan

[Pooneil]

The 12V mode for cooling can be thought of as a "sustainer" mode while traveling in case the propane doesn't stay lit. Or more appropriately, "better than nothing" mode. For extended use, it should only be switched on when the house battery is disconnected and the TV has a relay to cut off the charge line when the motor is shut off. Otherwise dead batteries are a risk.

As to "why," I guess it's an aspirational feature like many other things about RV design.

[rockfordroo]

Originally Posted by pgandw

There may be no "brains" to the fridge. The bigger RV fridges in the High Wall pop-up models have a DC control board, controls inside the camper, and thermostatic control that cycles the cooling unit. They have some brains.

Standard A-Frames and PUPs have smaller, continuous run fridges. There is NO DC control board. The controls are mounted in the exterior fridge access compartment. Most have a DC switch, an AC switch, and a knob (household dimmer) to adjust AC cooling. Behind the lower vent are the propane controls - propane on-off switch/valve, a knob/valve to regulate propane flow, and an ignitor button. The mode and amount of cooling is manually selected, and the propane flame has to be manually lit by holding down the propane on/off valve and pushing the ignitor button.

These fridges draw about 6 amps when running on DC (the weakest mode), which when combined with running lights on may overload the tow vehicle connection.

With the fridge on DC, and running lights on, you should see at least 13.2 volts across the camper battery with tow vehicle running above idle (ideally 13.6 to 13.7 volts, 13.2V is trickle charge). If less, the camper battery is supplying some of the power, and the tow vehicle is not recharging the camper battery due to voltage drops in the wiring. If I'm charging with the engine above idle, but only seeing about 12.6 to 12.8 volts at idle, that is probably acceptable.

Fred W
2014 Rockwood A122 A-frame
2008 Hyundai Entourage minivan

Sorry, I didn't realize this was an A-frame - so you are correct - no brains to speak of. A-frame and PUP fridges are small enough that they can operate on 12VDC with just a thermostat turning the 12 volt heating element on and off.

I ran my Coleman fridge from my (3) Dodge Grand Caravans's 12VDC going down the road for 20 years, no problems. (I did add a green LED on the side of the fridge wired in ahead of the thermostat that told me when 12VDC was available to the fridge (my PUP had no battery so I knew it was from the TV), and a red one on the other side of the thermostat that told me when the thermostat had turned on the heating element.) I did this after I had some trouble with the 7-pin plug one time. I wasn't getting the TV 12VDC to the camper, even though the lights all worked.

[pgandw]

Did some more research. My A-Frame (2014 A122) has a Dometic RM4223 3 way fridge installed. Downloaded the manual and actually read some of it. I got surprised.

The 12V coil in the fridge is 125 watts, which is about 10.5 amps when on. If your clearance and running lights are on - and are not LEDs - they draw close to another 10 amps. If the tow vehicle wiring is not 12 gauge, and fused for 20 amps, your fridge is going to suck out of the camper battery when traveling down the road (with lights on). A voltage check at the camper battery with fridge on, and lights on and off, will reveal the truth of the voltage drops - I need to do this prior to my next trip.

The 12V DC heating coil is fixed, and has no control other than an on/off switch. So the 10.5 amp draw is continuous as long as there is power in the batteries. The same was true for the fridge in my 2000 Coleman PUP.

I could not find specs for the 120V AC heating coil.

The two ventilation grills are mounted at the minimum height difference allowed by Dometic. I wish Forest River had mounted the upper one a little higher - there is room.

The door is reversible - which I intend to do. Right now the door opens to the middle of the floor. I'm going to see if it will work opening towards the dinette.

Learning as I go
Fred W
2014 Rockwood A122 A-frame
2008 Hyundai Entourage minivan

[dalford]

It appears the 2015 F150 has a smart trailer controller that turns on the 12 volt once the trailer is connected..

Read this forum about 4 pages in gives the details..

7 pin connector trailer charger - Ford F150 Forum - Community of Ford Truck Fans

[rockfordroo]

Originally Posted by pgandw

Did some more research. My A-Frame (2014 A122) has a Dometic RM4223 3 way fridge installed. Downloaded the manual and actually read some of it. I got surprised.

The 12V coil in the fridge is 125 watts, which is about 10.5 amps when on. If your clearance and running lights are on - and are not LEDs - they draw close to another 10 amps. If the tow vehicle wiring is not 12 gauge, and fused for 20 amps, your fridge is going to suck out of the camper battery when traveling down the road (with lights on). A voltage check at the camper battery with fridge on, and lights on and off, will reveal the truth of the voltage drops - I need to do this prior to my next trip.

The 12V DC heating coil is fixed, and has no control other than an on/off switch. So the 10.5 amp draw is continuous as long as there is power in the batteries. The same was true for the fridge in my 2000 Coleman PUP.

I could not find specs for the 120V AC heating coil.

The two ventilation grills are mounted at the minimum height difference allowed by Dometic. I wish Forest River had mounted the upper one a little higher - there is room.

The door is reversible - which I intend to do. Right now the door opens to the middle of the floor. I'm going to see if it will work opening towards the dinette.

Learning as I go
Fred W
2014 Rockwood A122 A-frame
2008 Hyundai Entourage minivan

The AC element is also 125 watts. Here's the parts manual.

https://www.livinlite.com/pdf/servic...23%20Parts.pdf

Seems odd that on DC the DC heater is on all the time, but on AC, the AC heater is controlled by a thermostat.

There's a wiring diagram on the last page.