12v Power For Trailer While Towing

[jeepin95]

We are less than 2 full weeks into our new 22 Lariat Powerboost and most of that we have been camping...and driving s8ce we are over 2k miles now. Prior to the PB we towed our little Jayco with a 2015 Grand Cherokee EcoDiesel that I loved. The small fridge is 120v/12v/LP capable and we always run it at least 24 hours on 120v from home before leaving, switch to 12V while driving, then back to 120 or LP once getting to camp. We never lost more than 15% SOC according to my Victron shunt even on an 8 hour trip.

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?

My other option is to plug on if we stop for breaks but that seems like overkill too.

Thanks

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[EricR]

We are less than 2 full weeks into our new 22 Lariat Powerboost and most of that we have been camping...and driving s8ce we are over 2k miles now. Prior to the PB we towed our little Jayco with a 2015 Grand Cherokee EcoDiesel that I loved. The small fridge is 120v/12v/LP capable and we always run it at least 24 hours on 120v from home before leaving, switch to 12V while driving, then back to 120 or LP once getting to camp. We never lost more than 15% SOC according to my Victron shunt even on an 8 hour trip.

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?

My other option is to plug on if we stop for breaks but that seems like overkill too.

Thanks

Why do you not want to use the ProPower while driving?

 

[JEB]

We are less than 2 full weeks into our new 22 Lariat Powerboost and most of that we have been camping...and driving s8ce we are over 2k miles now. Prior to the PB we towed our little Jayco with a 2015 Grand Cherokee EcoDiesel that I loved. The small fridge is 120v/12v/LP capable and we always run it at least 24 hours on 120v from home before leaving, switch to 12V while driving, then back to 120 or LP once getting to camp. We never lost more than 15% SOC according to my Victron shunt even on an 8 hour trip.

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?

My other option is to plug on if we stop for breaks but that seems like overkill too.

Thanks

If you’re only interested in using the 12v pin on the 7-way, then no. There isn’t much you can do to increase the current. The length is too long and gauge of the wire used in the F150 is not sufficient to provide more than a trickle charge at the 12v pin. You will need to provide a supplemental power source to do what you want. One option is to install a DC/DC converter but it will require running new wire from your starting battery to your trailer’s battery box—a lot of work.

Another option that I thought of trying is to use the Pro Power in an unconventional way. Plug a battery charger that can provide 10-20a into one of the 120v outlets in the bed and then run a charging cable to the trailer’s battery box. Use ring terminals with an SAE connector on the battery so you can keep the box closed. You might already have one of these installed if you have a port to plug in portable solar panels. Using a battery charger in this way avoids using the heavy 30a cord set and the trailer’s converter to power up the entire electrical system if all you want to do is keep your battery charged. You still might not fully keep up with the fridge’s draw but it will help.

 

[UGADawg96]

If you’re only interested in using the 12v pin on the 7-way, then no. There isn’t much you can do to increase the current. The length is too long and gauge of the wire used in the F150 is not sufficient to provide more than a trickle charge at the 12v pin. You will need to provide a supplemental power source to do what you want. One option is to install a DC/DC converter but it will require running new wire from your starting battery to your trailer’s battery box—a lot of work.

Another option that I thought of trying is to use the Pro Power in an unconventional way. Plug a battery charger that can provide 10-20a into one of the 120v outlets in the bed and then run a charging cable to the trailer’s battery box. Use ring terminals with an SAE connector on the battery so you can keep the box closed. You might already have one of these installed if you have a port to plug in portable solar panels. Using a battery charger in this way avoids using the heavy 30a cord set and the trailer’s converter to power up the entire electrical system if all you want to do is keep your battery charged. You still might not fully keep up with the fridge’s draw but it will help.

I was thinking about installing a NOCO on our trailer for when in storage and I think it could be used with Pro Power by the OP in this manner as you describe.

https://www.f150gen14.com/forum/threads/question.11490/post-234842

 

[{tpc}]

Interesting. My fridge is 12V only. I run two 12v battery's in parallel on the trailer. This allows me to turn the fridge on about 12 hours prior to a trip. Now I know from at least the panel in the trailer that once my batteries on the trailer are low (there are 4 leds, so I consider 1 or 2 leds to be low), I will start the truck if we aren't already driving, to keep them up. Once started the panel in the trailer reads full.

Now I have always heard this about the gauge of wire in the truck to no be sufficient for running things like the fridge or power tongue jack. Yet I've never had an issue with the fridge not keeping up (longest trip being 9 hours to tennesee), or the tongue jack not working (when the main trailer battery was low or dead).

The 12v fridge is new to me as of 2020, but second f150 for it, and both trucks did the same thing.

As for the power jack, I've had one since my first f150 in 2018, and the worst case is letting the truck idle while connected to the trailer for about 20 min, before I could run the jack, but that was with a known bad battery on my first trailer, not the current one. On the current one, connecting the truck adds a noticeable sound and effort difference to how the jack operates.

Maybe the OP has a older 12v fridge that isn't as efficient. They might also benefit from the additional trailer battery.

My real question is why not run it on LP? It would save on the PB battery soc, and I don't think they use that much LP to really matter. Of course there is the issue of gas pumps and tunnels and such, but those could be mitigated by stopping beforehand and switching, and how often is that really a problem?

 

[UGADawg96]

My real question is why not run it on LP? It would save on the PB battery soc, and I don't think they use that much LP to really matter. Of course there is the issue of gas pumps and tunnels and such, but those could be mitigated by stopping beforehand and switching, and how often is that really a problem?

I've thought about this as well since we have a gas/electric fridge (not 12v) and haven't yet felt comfortable running the LP while driving. Maybe I shouldn't worry about it so we can have a cold fridge when we arrive. Otherwise, it takes almost 12 hours to cool ours, so we usually use a cooler for driving and the first day/night at camp.

 

[Buyer2021]

The small fridge is 120v/12v/LP capable

Interesting. My fridge is 12V only.

Note that the 12VDC current-demand (amps) of these two different refrigerators is likely very different.

The OP's (and @UGADawg96), being electric/LP capable is doubtless an adsorption technology reefer which uses heat-input to function (heat-input causes a fluid to go through a phase-change to generate 'coolth'); when running in 12VDC mode the electric resistance heating element draws a relatively high current. It's not at all uncommon for this type of reefer to underperform due to insufficient current from many tow-vehicle electrical systems (vehicle chassis wiring often being the limiting factor as mentioned). When running in 120VAC (shore-power) mode this is not an issue (and one reason some folks with PB's have set up their rigs to utilize the 120VAC capability of that truck to power their RV as if on shore-power when underway).

In contrast, @{tpc} 12VDC only reefer is likely either a compressor or solid-state 'cold-plate' technology. Those technologies demand much less current from the 12VDC system. This usually allows them to perform quite well when powered via the typical vehicle 7-pin connector.

 

[Blackout150]

I have a propane/electric fridge. I have been towing trailers for about 15 years. Always run LP when driving. Never have had an issue. Don’t have 12v so there is really no other choice.

 

[{tpc}]

I've thought about this as well since we have a gas/electric fridge (not 12v) and haven't yet felt comfortable running the LP while driving. Maybe I shouldn't worry about it so we can have a cold fridge when we arrive. Otherwise, it takes almost 12 hours to cool ours, so we usually use a cooler for driving and the first day/night at camp.

Honestly, when I had this type of fridge I almost exclusively used LP because it performed so much better. On 120vac is could take upwards of a full night to become useable, but on LP only a couple of hours.

Thankfully, I never had to negotiate tunnels and when fueling up, it was on the opposite side of the vehicle. So for me it ran all the time.

My wife wouldn’t be able to handle living out of a cooler for as much as these trailers cost with all the creature comforts lol.

Note that the 12VDC current-demand (amps) of these two different refrigerators is likely very different.

The OP's (and @UGADawg96), being electric/LP capable is doubtless an adsorption technology reefer which uses heat-input to function (heat-input causes a fluid to go through a phase-change to generate 'coolth'); when running in 12VDC mode the electric resistance heating element draws a relatively high current. It's not at all uncommon for this type of reefer to underperform due to insufficient current from many tow-vehicle electrical systems (vehicle chassis wiring often being the limiting factor as mentioned). When running in 120VAC (shore-power) mode this is not an issue (and one reason some folks with PB's have set up their rigs to utilize the 120VAC capability of that truck to power their RV as if on shore-power when underway).

In contrast, @tpc's 12VDC only reefer is likely either a compressor or solid-state 'cold-plate' technology. Those technologies demand much less current from the 12VDC system. This usually allows them to perform quite well when powered via the typical vehicle 7-pin connector.

Great explanation! Mine is a compressor style, this I know for sure.

 

[JEB]

Note that the 12VDC current-demand (amps) of these two different refrigerators is likely very different.

The OP's (and @UGADawg96), being electric/LP capable is doubtless an adsorption technology reefer which uses heat-input to function (heat-input causes a fluid to go through a phase-change to generate 'coolth'); when running in 12VDC mode the electric resistance heating element draws a relatively high current. It's not at all uncommon for this type of reefer to underperform due to insufficient current from many tow-vehicle electrical systems (vehicle chassis wiring often being the limiting factor as mentioned). When running in 120VAC (shore-power) mode this is not an issue (and one reason some folks with PB's have set up their rigs to utilize the 120VAC capability of that truck to power their RV as if on shore-power when underway).

In contrast, @tpc's 12VDC only reefer is likely either a compressor or solid-state 'cold-plate' technology. Those technologies demand much less current from the 12VDC system. This usually allows them to perform quite well when powered via the typical vehicle 7-pin connector.

If it's in a trailer, I highly doubt the fridge is a Peltier-style cold plate. They don't work all that well. And I further doubt that it's just 12v if it's this is the trailer's primary fridge. It's probably an AC/DC fridge with a Danfoss compressor that runs on both 12v and 110v. They are efficient, but I have seen multiple tow vehicles have difficulties keeping up with even a Danfoss compressor using just the 12v pin. I have such a fridge--a 6 cu ft Nova Kool--and my F150 can't do it without supplemental power from the solar panels.

Propane is a good option if you have it. But you then have the problem of blow outs in the pilot light if the deflectors on the vents aren't angled properly. But propane works well for a lot of people and it's the only practical option for the thousands of Norcold fridges out there that work only on AC or propane and have no 12v option to use while traveling.

 

[Buyer2021]

I have a propane/electric fridge. I have been towing trailers for about 15 years. Always run LP when driving. Never have had an issue. Don’t have 12v so there is really no other choice.

Many folks, myself included, use LP for cooling when underway. All of my (and my parent's) many RV's have had 3-way (120VAC/12VDC/LP) adsorption reefers. They all have safety systems which cut-off the LP if the flame is extinguished and then automatically cycle to restart the flame for normal operation. I've no way of knowing if or how often that occurs when underway but I know I've never arrived at a destination without a cold reefer.

Some (likely most) blithely pull-in at fuel stops without shutting down their open-flame sources. Others, myself included, won't approach fuel-islands when another RV is present and take the time to shut off our LP at the tank before doing so ourselves. IMO while fuel-vapor ignition is unlikely, it is always unintended and the nature of those rare accidents is invariably catastrophic for all in the vicinity. Everyone has their own measures of risk tolerance and safety

 

[{tpc}]

If it's in a trailer, I highly doubt the fridge is a Peltier-style cold plate. They don't work all that well. And I further doubt that it's just 12v if it's this is the trailer's primary fridge. It's probably an AC/DC fridge with a Danfoss compressor that runs on both 12v and 110v. They are efficient, but I have seen multiple tow vehicles have difficulties keeping up with even a Danfoss compressor using just the 12v pin. I have such a fridge--a 6 cu ft Nova Kool--and my F150 can't do it without supplemental power from the solar panels.

Propane is a good option if you have it. But you then have the problem of blow outs in the pilot light if the deflectors on the vents aren't angled properly. But propane works well for a lot of people and it's the only practical option for the thousands of Norcold fridges out there that work only on AC or propane and have no 12v option to use while traveling.

Unfortunately this is trending towards the norm for trailers ie, the 12v fridge. I too thought the same thing when purchasing our latest trailer, and it was only late in the process that I realized it was 12v only.

It’s really large inside, and really nice to look at on the outside. If I could do it over, I’d have looked harder for one with the 120v/lp but those are also much smaller. My trailer actually comes with a smaller secondary fridge accessible from the outside that is…wait for it….120 vac only. Lol.

Here is the main one:

Ever Chill

 

[JEB]

Unfortunately this is trending towards the norm for trailers ie, the 12v fridge. I too thought the same thing when purchasing our latest trailer, and it was only late in the process that I realized it was 12v only.

It’s really large inside, and really nice to look at on the outside. If I could do it over, I’d have looked harder for one with the 120v/lp but those are also much smaller. My trailer actually comes with a smaller secondary fridge accessible from the outside that is…wait for it….120 vac only. Lol.

Here is the main one:

Ever Chill

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.

 

[UGADawg96]

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.

They are 12v only. Here are a couple examples:

https://furrion.com/products/8-cu-f...refrigerator?view=base&variant=37727045648567

https://norcold.com/product/polar-8dc-rv-compressor-refrigerator/

 

[JEB]

They are 12v only. Here are a couple examples:

https://furrion.com/products/8-cu-ft-furrion-arctic®-12-volt-built-in-refrigerator?view=base&variant=37727045648567

https://norcold.com/product/polar-8dc-rv-compressor-refrigerator/

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.

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