Converting propane fridge to 12v compressor

[RoadTurtle]

My issues with propane accelerated this winter while snow birding. It literally became a daily challenge to keep it running. Potpourri of issues like build up on spark igniter to some unknown issue with coolant flow, to just being cantankerous.

I knew putting in the 12v compressor system would hit my battery bank a little harder. I sized my system for 5 days with no solar, and actually achieved that in one really bad rainy week. I figured going to 12v compressor (90w) would reduce me to three days if the fridge ran 24/7.

Sitting idle, my 5th wheel would go through 60ah every night, with draw from 12v and 120v systems. It never bothered me, never sought to identify the culprit. TV's, sound bars, etc etc etc.

I seem to recall sitting idle, my 12v had a constant 37w drain. Color me surprised, with the 12v compressor system turned on, but not running, I'm only seeing a 11w drain on 12v. This would imply the propane fridge was burning through 25w just sitting there, not even running. I've not made any other changes to the 5th wheel. Nothing additional has been unplugged.

The new unit, took the fridge from 50F ambient to 37F in one hour of operation. It's generally pulling 90w, while running, but I am seeing on occasional slightly higher spike. Maybe Cerbo is picking up compressor startup? I'd have thought the startup spike would be too fast for Cerbo to record.

It's a JC Refrigeration unit, installed by them. Installation took a whopping 2 hours, and out the door cost of $ 1,111. So far, I'm extremely pleased.

 

[sunshine_eggo]

JC has a good reputation, and your electrical power consumption should be 15-20% of what it was if you ran on DC/AC.

We had our big nevercold double door (12 cu ft) go out, and I didn't have ANY repair/replace options that were much less than $2K including DIY JC replacement.

I pulled it, sealed the compartment and installed a 10.1cu-ft magic chef apartment fridge for $400. It's CRAZY efficient, and the additional depth available that's not occupied by a cooling unit. The extra 8" to the side serves as a little cubby for a trash can and broom "closet".

 

[MrBond]

your electrical power consumption should be 15-20% of what it was if you ran on DC/AC.

installed a 10.1cu-ft magic chef apartment fridge for $400. It's CRAZY efficient,

Confused! You say that converting to a dc compressor should yield a 80% saving, but then install a 120v apartment fridge. Can you elaborate for this Luddite please!

 

[sunshine_eggo]

Confused! You say that converting to a dc compressor should yield a 80% saving, but then install a 120v apartment fridge. Can you elaborate for this Luddite please!

Sorry. I'm saying compressor fridge (AC or DC ) replacing absorption fridge (AC/DC/propane) running on AC or DC should yield 80-85% savings in electrical usage.

I was just describing an alternative for a significantly lower cost in my situation.

 

[RoadTurtle]

We looked at doing what you did, your unit would have been a perfect fit. however, we both like the decor of the factory nevercold. I wanted DC, because even when I'm hooked up to park power, I tend to run 120v off of park power, and DC off of battery. If I'd get off my rear, and do the software upgrade, I could run a lot more off of solar/battery.

I would typically pull 350w on electric, the new one is 90w.

I am somewhat surprised at how much energy was being used by the nevercold even when it was turned off. That seems excessive to me.

When I placed my solar panels, I left space for one more panel on each string. One of those is over the fridge vent. With less heat coming out, my plan is to place one panel over the vent. I'll switch from 3P to 2S2P. My only concern then will be temp. Since we're now snowbirds, it should never be a concern. I'll see how things go in our limited use of the 5th wheel this summer to see if it's even worth the exercise.

 

[sunshine_eggo]

We looked at doing what you did, your unit would have been a perfect fit. however, we both like the decor of the factory nevercold. I wanted DC, because even when I'm hooked up to park power, I tend to run 120v off of park power, and DC off of battery. If I'd get off my rear, and do the software upgrade, I could run a lot more off of solar/battery.

I would typically pull 350w on electric,

About the same.

the new one is 90w.

The 10cuft only pulls 60W, and I'm 99% certain the insulation is much better.

I am somewhat surprised at how much energy was being used by the nevercold even when it was turned off. That seems excessive to me.

I never noticed anything like that.

If the JC option had been closer to $1000, I probably would have gone that route, but when I was looking at $2K, it just wasn't an option. Even with the sacrifice of the decor, the smaller fridge actually feels far more usable as a fridge due to the greater depth and more modern design... 2 liter bottles in the door, someplace to actually put a full gallon of milk, etc.

 

[RoadTurtle]

If the JC option had been closer to $1000,

The actual part cost for my model was $795. I chose the installation option, 1st because it was only $250, and 2nd because they are only a hour away from me. That and right now I'm on weight restriction from surgery for several more weeks.

We looked at all the options, and putting in the same residential you chose was a very close second. If it hadn't been for the fact we bought a RV lot in AZ, which has a casida with a full size fridge in it, might have been a different decision.

I'm 90% sure I'm going to add one more panel to the roof. I'm running the fridge now, even tho the 5th wheel is just sitting idle. Watching the daily use and recharge rate. This is where we are at right now with heavy cloud cover. Yesterday I peaked out at 1050 out of 1200 right around 10:30a. Increasing 600ah battery bank is not an option I'm willing to take on. My hope for 3 days with no solar might be stretch... but the fridge is empty.

 

[MrBond]

Thanks roadturtle and sunshine. My 30yo Canadian Dodge B350 has the original 3 way in it and it just couldn't cope with Texas heat so promptly died. I need to add a very small ac for my service dog, so a 110v fridge is not a big add.