JC refrigeration AC or DC upgrade?

Why not just run on propane?

My Dad just got one this week, it's not installed yet so no feedback on that, but we talked it through and he went with the 12v version on his coach.

Reasoning was that when connected to shore power, the converter will provide the power, and while on the road or boondocking, he wouldn't need to run the inverter with it's losses. If by chance, the refer draws the batteries down faster than the alternator can recharge them (doubtful because I think it draws 7 or 8 Amps only when the compressor is running), he can always start up the generator.

For anyone that is planning to be mobile, I don't see a compelling reason to go with the 120v version.

enblethen wrote:
Why not just run on propane?

Because the conversion isn't an absorption refer - it's a compressor similar to a household refer.

I vote 12. If you do camp without power or there is a power outage, it will run off your batteries...for a while at least.

rdhetrick wrote:
My Dad just got one this week, it's not installed yet so no feedback on that, but we talked it through and he went with the 12v version on his coach.

Reasoning was that when connected to shore power, the converter will provide the power, and while on the road or boondocking, he wouldn't need to run the inverter with it's losses. If by chance, the refer draws the batteries down faster than the alternator can recharge them (doubtful because I think it draws 7 or 8 Amps only when the compressor is running), he can always start up the generator.

For anyone that is planning to be mobile, I don't see a compelling reason to go with the 120v version.

That’s probably what I would recommend. No DC-AC conversion loss.

Another option if the alternator can’t keep up would be a DC-DC charger. You could probably install a small (charging amps) DC charger without a wiring upgrade, and your house batteries would charge better too.

:):)

Why convert is my question!

enblethen wrote:
Why convert is my question!

In my dad's case, it is for performance reasons - his current absorption unit doesn't work great, can't get his ice cream cold enough!

rdhetrick wrote:
Because the conversion isn't an absorption refer - it's a compressor similar to a household refer.

NRALIFR wrote:
That’s probably what I would recommend. No DC-AC conversion loss.

Every 12/24VDC compressor refrigerator actually INCLUDES its own inverter ! The incoming DC voltage is converted to 3 phase AC and sent to the compressor motor. 3 phase is used because it is a much more efficient way of powering a motor.

Just to be clear, this "built in" inverter is specially designed just for this application. The AC output voltage does not have to "match" any "standard". It can be whatever voltage the inverter and motor designers choose ! Also, many (most ?) of these inverter are variable frequency meaning that the compressor motor itself runs at different speeds as the required.

If I lost you, a DC compressor refrigerator is likely more efficient than a straight up residential AC refrigerator powered by a separate inverter.

woodtrucker wrote:
We are on shore power almost always except for traveling. Would the truck charge battery enough to keep the 12VDC unit cooling while on the road?

The good news is that if the refrigerator and its contents are cold, it will likely keep them cold for a good 8 hours, if you don't open the door !

A typical 7 pin 12V battery charge connection should keep the battery from discharging and keep the refrigerator running as long as the vehicle is running.

If you are boondocking/dry camping, things are more complicated. You will likely need to re-charge your house battery. 3 way to do that :

• solar
• generator and charger
• DC-DC charger from the tow vehicle

I would also recommend a pair of 6V golf cart batteries. They store more energy than 12V batteries and may even cost less !

I’m converting because my domestic rm2562 started spewing ammonia.
Yuck. I would have gone residential route but I literally only have 55” of height.
So I opted to pull the cooling unit on the domestic.
It’s out and in the dumpster minus the control boards and fins.
So in will go the dc compressor. Sounds like even if the fridge runs batter down even in a couple hours, that would help cool on a long travel day say 8-9 hours until I get to shore power.
Boondocking is not in our future until our kids are gone and it’s just two of us.
Thanks for the info. 12vdc is what I’ll buy!