Want to power AC Frig while towing.

[Garbman]

I recently purchase a 2018 Bullet Crossfire. It has a two way power (gas/AC) Dometic DM2652 RBX refrigerator. I would like to find a way to power it while the trailer is in tow.



Some things I think I know:


-The Crossfire has a converter but no inverter.
-Only have one GP 24 12v deep cycle battery (will be upgrading to two GP 24s rated at 201 AH each)
- there is a hidden compartment with ample space near the power center for possible install of an inverter.
- There is space under the Frig with access to its wiring available as a possible install point for a dedicated inverter.
- Tag on Frig states electrical specs as 120 volt, 2.7 amp, 1500 BTU/HR, 440 watt.
- 12 V DC available at frig, but only for lighting pilot when using gas.



Options I am thinking about:


1- Installing a dedicated 500 W inverter (with auto switch) under the Frig, just to power only the frig while in trans. Would use trailer batteries and TV alternator to power inverter. this compartment also has the AC feed to the exterior 110 AC outlet. I would likely also connect it to this inverter for emergency use of wired tools while on the road.



2- Installing a 2000/3000 inverter (with auto switch) in compartment under the power center. Would intercept shore power and run through auto switch, then to power center and take 12 V DC feed from trailer battery to Inverter and inverter to auto switch and auto switch to load center. this would power whole AC side of system from the inverter. I would only use this for running the frig during transit or occasionally use it to run an AC corded tool like a drill, impact wrench, or small tool wall charger.



3- replacing the converter/charger with an inverter/charger similar to option 2 above.


Thoughts?????

[sourdough]

[QUOTE=Garbman;444641]I recently purchase a 2018 Bullet Crossfire. It has a two way power (gas/AC) Dometic DM2652 RBX refrigerator. I would like to find a way to power it while the trailer is in tow.


Why would you go to all that trouble when you can simply run the fridge on LP while traveling? Most everyone does it, simple, easy and made for it.

[travelin texans]

[QUOTE=sourdough;444646]

Originally Posted by Garbman

I recently purchase a 2018 Bullet Crossfire. It has a two way power (gas/AC) Dometic DM2652 RBX refrigerator. I would like to find a way to power it while the trailer is in tow.


Why would you go to all that trouble when you can simply run the fridge on LP while traveling? Most everyone does it, simple, easy and made for it.

Absolutely!
Set the fridge control to "auto" then it will switch on it's own when shore power is removed just as it was designed to do.

[JRTJH]

I agree with the above !!!

That said, here's why:

The electric element is 330 watts @120 VAC. That's 2.75 amps when on shore power.

That same 330 watts @12 VDC is 27.5 amps.

Attempting to run your refrigerator on an inverter to change your battery voltage to 120 VAC to power that 330 watt resistive heater will be an extremely inefficient way to tow. You'll likely wind up with a dead trailer battery if you tow for 8-10 hours with a tow vehicle that's only capable of recharging your trailer battery at 6 or 7 amps. That's roughly a 20 amp drain on your trailer battery the whole time the refrigerator is on the inverter.

[flybouy]

Many discussions on running LP fridge while underway. Most of us "old geezers " have been doing it for many, many decades.

[spicercars]

LP all the way. I have been doing it for years without any problems.

[Javi]

Addendum to the posts above...

if you are going to replace the series 24 battery, you might want to consider a series 27...

Most of the battery boxes or mounting areas in the modern RV's are made to accommodate a series 27 and the "27" will carry the load a lot better..

[Garbman]

First thanks for all the help/replies. I guess I will just use the LP and keep an eye out for flames following me.


As for the battery upgrade . . . . the battery box can only accommodate one GP 27 or two GP 24s. I have only started looking, but the ones I looked at had 219 amp/hr rating on GP 27 and 209 on GP 24. I assume if they are connected in parallel that gives me 418 amp/hr vs 219. Correct?


Can someone direct me to a wiring diagram for a selector switch setup. I have the switch on order. It has not arrived yet.

[Javi]

Originally Posted by Garbman

First thanks for all the help/replies. I guess I will just use the LP and keep an eye out for flames following me.


As for the battery upgrade . . . . the battery box can only accommodate one GP 27 or two GP 24s. I have only started looking, but the ones I looked at had 219 amp/hr rating on GP 27 and 209 on GP 24. I assume if they are connected in parallel that gives me 418 amp/hr vs 219. Correct?


Can someone direct me to a wiring diagram for a selector switch setup. I have the switch on order. It has not arrived yet.

I've never seen a battery box that would hold 2 of the 24 series but only 1 series 27.. not doubting you, just want to see pictures

[Garbman]

Just another thought, to complete the record. I also considered replacing the current refrigerator with a 3-way model of the same size. It would be a plug and play replacement, except for up sizing the 12vdc wiring to accommodate the added load and adding an auto switch.


I have put this on hold while I try getting underway with the LP. I am curious to see How long my 2 - 20# tanks last. Not crazy about needing to find swap outs for one or both of them daily.



Any hint as to how long a 6 cu ft frig will last on a 20# bottle?

[Garbman]

I took the measurements with my current setup, which does have some complications.


- it designed to have the batteries placed end to end.
- I assumed each battery would be in a separate box
- there is a junction box mounted on the end that takes up about 3" of space.
- I even looked at one 24 and one 27, and they would not fit (with the required boxes).

- could place two 27s side by side, but the samples I looked at would have only given me an additional 20 amp/hrs at a considerable additional cost.


I have not looked for a two battery box. I am sure they exist. I guess that's my next research project.

[pappy437]

Don't know for sure how long a 20# bottle will last but I bet it's a lot longer than your thinking.

[Javi]

Originally Posted by Garbman

I took the measurements with my current setup, which does have some complications.


- it designed to have the batteries placed end to end.
- I assumed each battery would be in a separate box
- there is a junction box mounted on the end that takes up about 3" of space.
- I even looked at one 24 and one 27, and they would not fit (with the required boxes).

- could place two 27s side by side, but the samples I looked at would have only given me an additional 20 amp/hrs at a considerable additional cost.


I have not looked for a two battery box. I am sure they exist. I guess that's my next research project.

The difference between a 24 and a 27 is about 1 - 13/16" in length. Other dimensions are the same.

[Blackrock]

FWIW My 5th wheel has 2 grp27 batteries and 2 30# propane tanks. On trip to Alaska I boondocked as much as I could but would tie down in an rv park about every third night. We had to run the heat almost every night plus hot water heater and the fridge. Twelve days going up and just used one and a half tanks. When boondocking I would run one Honda 2000 gen as my OL would have the TeeVee going. I filled the propane in Fairbanks and again just before heading back south.

[CedarCreekWoody]

A fridge uses very little propane. It should run several days on one tank.

[bobbecky]

Our dealer installed the battery box for two group 24 batteries when we bought our rig. A number of years later I upgraded to two group 27 batteries, so went to the dealer and bought a new battery box that would hold two group 27 batteries. This was an easy change, only had to cut a new hole in the battery compartment for the bottom vent of the new battery box. We also travel with our fridge on propane and never have an issue. There are some locations, tunnels, ferry’s, and other locations that require you to turn off the propane, but there are always signs telling you prior to arriving at these locations.

[travelin texans]

I would bet a coffee & donut that 99.99999% of the RVs you see traveling down the highway have their fridge running on LP for the trip.

[NH_Bulldog]

We run the fridge on LP when traveling and always have. It uses VERY little gas. In a typical camping season from May to October we rarely burn through a full 20 lb. tank and we are pretty transient, rarely staying in any one place more than a night or two. On a related note, we have 2 group 27 batteries and just made our own box from two.

[Garbman]

Thanks all, makes me feel a lot better about my setup. I will follow the crowd and just fire up the LP for the frig when we hit the road. If I am not using the batteries for running the frig then I do not see the need to up size the batteries. I do not plan on doing a lot of boon docking and will have a gasoline/NP/LP Generator if the need arises. Our next big trip will be Georgia to Alaska and we will want to have options available for when camp sites with hookups are unavailable.

[Javi]

Originally Posted by Garbman

Thanks all, makes me feel a lot better about my setup. I will follow the crowd and just fire up the LP for the frig when we hit the road. If I am not using the batteries for running the frig then I do not see the need to up size the batteries. I do not plan on doing a lot of boon docking and will have a gasoline/NP/LP Generator if the need arises. Our next big trip will be Georgia to Alaska and we will want to have options available for when camp sites with hookups are unavailable.

Smart move.. I would still use a 27 series battery... it seem to work better with extending the slides and landing gear when not already hooked up to shore power... actually much better..