12v Power For Trailer While Towing

[UGADawg96]

Agreed. But my point remains. As installed, does it work on shore power with no batteries? If so, there is an AC/DC converter in the rig providing power so the fridge continues to work without stressing the batteries unnecessarily. Installed this way, the only difference between a DC fridge and an AC/DC fridge is where the converter is located--built into the fridge or located externally in the trailer.

The specs on those show they only take 12v, so if the existing RV inverter is already powering all the other 12v devices (lights, usb plugs, etc), then it probably also powers the fridge when connected to shore power.

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[JEB]

The specs on those show they only take 12v, so if the existing RV inverter is already powering all the other 12v devices (lights, usb plugs, etc), then it probably also powers the fridge when connected to shore power.

We're saying the same thing. The compressor itself--if it's a Danfoss--is only a DC device. But in RVs they all use a converter somewhere. Nova Kool, for example, builds the converter into the unit so it can be plugged into an outlet. Everchill and the Norcold and Furrion you cited have no built in converter so it's wired into the trailer's converter (not inverter--inverter converts DC into AC). Likely at the load center as you indicated.

 

[UGADawg96]

We're saying the same thing. The compressor itself--if it's a Danfoss--is only a DC device. But in RVs they all use a converter somewhere. Nova Kool, for example, builds the converter into the unit so it can be plugged into an outlet. Everchill and the Norcold and Furrion have no built in converter so it's wired into the trailer's converter (not inverter--inverter converts DC into AC). Likely at the load center as you indicated.

 

[{tpc}]

Interesting. I didn't know that there were 12v only fridges that large on the market. But, I suspect it's still wired in to operate as an AC unit when on shore power. There is an AC/DC converter in there somewhere so there isn't a constant draw on the batteries. Does the fridge still work if you have no batteries on the tongue? Taken them in for winter storage? That will tell you for sure.

I've had the trailer since 2020. It only operates when the 12v disconnect is switched on. I imagine the convertor would operate it if the batteries were removed and 120vac connected, which would give the appearance that it works off 120vac, but if you look at the door sticker on the fridge itself, it says 12 VDC.

In the risk of beating the horse completely dead, here is the link to their website:

wayinterglobal

In there you will find the product manual which shows the connection diagram as 12 vdc. No mention of an AC cord. Actually a further dive into the product manual says direct connection to AC is forbidden and do not connect this unit to an ac power source.

 

[JEB]

In my case power from the tow-vehicle is moot; I will not have a TV-RV 12VDC 'pin-4' connection at all

I think this thread has gotten a bit off the rails. It might be moot for you, but it is the only question the OP asked about. I think that even with a Danfoss, the F150's 12v pin is not enough to keep up. At least that's what I've observed.

 

[Buyer2021]

I think this thread has gotten a bit off the rails. It might be moot for you, but it is the only question the OP asked about.

Fair enuf, you are quite correct, Thank You, I've deleted my admittedly off-the-rails post.

 

[jeepin95]

Thanks for all the good info, we're out camping so I was finally able to get back to read through. The fridge is in a 2021 Jayco and is an small absorption fridge. I figured it was connected to undergauged wiring, we just never had an issue with our Jeep. Granted, that is a little shorter, but must have had heavier wiring also. At least until we look at another trailer I'll probably look at a 120v charger that I can run via the ProPower. The power cord for the trailer comes out mid way down the drivers side so running the heavy cord up and to the truck seems like I'm just waiting for something to go wrong

 

[JEB]

Thanks for all the good info, we're out camping so I was finally able to get back to read through. The fridge is in a 2021 Jayco and is an small absorption fridge. I figured it was connected to undergauged wiring, we just never had an issue with our Jeep. Granted, that is a little shorter, but must have had heavier wiring also. At least until we look at another trailer I'll probably look at a 120v charger that I can run via the ProPower. The power cord for the trailer comes out mid way down the drivers side so running the heavy cord up and to the truck seems like I'm just waiting for something to go wrong

A charger should help. Make sure you get one that allows you to easily disconnect the alligator clamps and use something else, like an SAE connector running to ring terminals. You’ll have a sturdier connection while moving. Some chargers won’t let you swap out the alligators and then you’ll end up cutting them off to wire in another kind of connector. There are a few options but I know the NOCO Genius line allows for different connectors. Unfortunately, they can get pricey for chargers with more than 10 amp outputs.

 

[BLoflin]

A couple of points to clarify some of the things discussed so far.

RV industry is moving to 12V only Refrigerators. Advantages, you can get a 10cf in the space allocated for a 8cf adsorption/multi-fuel. Second, there is no external vents needed (Adsorption frigs usually have an lower and upper vent, can leak with a driving rain, and the mud wasps just love to build in there). The 12V compressor units cool very quickly compared to adsorption (i.e. I can get my refrig/freezer from off and above 90 to below 32 in the freezer and below 45 in frig in about 4 to 5 hours.

Edit: Update on current draw. I was remembering wrong. Looking at my current usage thru my PowerDog EMS, which is showing the 120VAC draw it is about 1Amp, translates to about 10amp at 12V.

The issue on charging the RV battery thru the 7 pin is highly dependent on the voltage presented to the battery, not so much the current, as I believe in can provide 20 to 25 amps. But to drive current into the RV battery the voltage presented needs to be above the voltage in the battery. This even more so for Lithium RV batteries, as the voltage needed is above 14 to charge during the absorption phase. Hence the reason people install DC to DC convertors to raise the nominal 12v at the 7pin to 14.25V to present to the battery. Regular AGM batteries need slightly less voltage, but same issue.

 

[HammaMan]

Now with the PB we have noticed that the truck is not able to keep up with the 12V demands of the fridge. At the end of a 3 hour trip we were at 63% SOC. I realize I could rig up a cord holder to run off the ProPower while driving but I don't really want to do that. Is there any way to improve the power available via the 7 pin connector so that it is better able to keep up with the trailer demands when traveling?

The PB has plenty of 12v power -- The 280 amp alternator combined with the DC-DC converter has 500 amps on tap. The issue is probably voltage at the trailer. DC-DC boost device will get you up and running https://www.amazon.com/Converter-DROK-12V-120V-Adjustable-Regulator/dp/B098SVD2B8

Install at trailer. People who have issues with these are trying to do huge deltas like 12v to 80v. Just not enough amps to do that. Before I had a PB, when towing a trailer I'd use a voltage booster like this to get a real proper charge on the trailer's battery. Find a spare 60lbs worth of trailer weight and put a 400w panel on the roof with an MPPT to keep your battery happy.

Personally I'd just plug in your trailer into the PPOB and let it do its thing. You could feed your trailer 7kW worth of power and not even affect your gas mileage. Ya bought the truck for the generator function, among other things. Use it!

 

[isthatahemi]

Unplug the battery management system lead at the battery when towing. Problem solved. Voltage stays at a steady 13.7 iirc.

 

[SuperRaptor]

Since you're not going to be pulling that much juice I'd just run a normal extension cord from the propower and into the trailer for a long trip. It's always great to show up with everything topped off.

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