Good Sam Club Open Roads Forum: JC refrigeration AC or DC upgrade?
Open Roads Forum Already a member? Login here.   If not, Register Today!  |  Help

Newest  |  Active  |  Popular  |  RVing FAQ Forum Rules  |  Forum Posting Help and Support  |  Contact  

Search:   Advanced Search

Search only in Do It Yourself Modifications a...

Open Roads Forum  >  Do It Yourself Modifications and Upgrades (DIY)

 > JC refrigeration AC or DC upgrade?

Reply to Topic  |  Subscribe  |  Print Topic  |  Post New Topic  | 
Page of 4  
Next
woodtrucker

riner, va

Full Member

Joined: 06/22/2012

View Profile



Good Sam RV Club Member

Offline
Posted: 01/30/21 11:45am Link  |  Quote  |  Print  |  Notify Moderator

Just wondering if any of you could tell me whether I should buy the AC or DC conversion for my dometic rm2652.

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?
If so, I'll go the 12V route.
Thanks,
Scott


2007.5 6.7 liter, Suncoast M3GA-68-5 Comp, mega cab,1 ton, srw, 4x4, Factory EB,3.73s
mods-EGR Delete (brand unknown), DPF delete, CCV-delete, FS-2500 bypass filter, H&S Black Maxx Tuner
2003 keystone cougar 281 EFS-31ft

enblethen

Moses Lake, WA

Senior Member

Joined: 01/05/2005

View Profile






Posted: 01/30/21 11:52am Link  |  Quote  |  Print  |  Notify Moderator

Why not just run on propane?


Bud
USAF Retired
Pace Arrow

2003 Chev Ice Road Tracker


rdhetrick

Texas

Senior Member

Joined: 08/30/2012

View Profile



Good Sam RV Club Member

Offline
Posted: 01/30/21 01:10pm Link  |  Quote  |  Print  |  Notify Moderator

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.


Rob
2006 Mandalay 40E Full Time
2015 Jeep Grand Cherokee

rdhetrick

Texas

Senior Member

Joined: 08/30/2012

View Profile



Good Sam RV Club Member

Offline
Posted: 01/30/21 01:12pm Link  |  Quote  |  Print  |  Notify Moderator

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.

Lwiddis

June Lake area, California

Senior Member

Joined: 08/12/2016

View Profile



Good Sam RV Club Member

Offline
Posted: 01/30/21 01:25pm Link  |  Quote  |  Print  |  Notify Moderator

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.


Winnebago 2101DS TT & 2020 Chevy Silverado 1500 LTZ Z71, 300 watt solar-parallel & MPPT, Trojan T-125s. TALL flag pole. Prefer boondocking, USFS, COE, BLM, NPS, TVA, state camps. Bicyclist14 yr. Army vet-11B40 then 11A - (MOS 1542 & 1560) IOBC & IOAC grad


NRALIFR

Truck Camping Out West

Senior Member

Joined: 11/27/2005

View Profile



Posted: 01/30/21 01:27pm Link  |  Quote  |  Print  |  Notify Moderator

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.

[emoticon][emoticon]


2001 Lance 1121 on a 2016 F450


enblethen

Moses Lake, WA

Senior Member

Joined: 01/05/2005

View Profile






Posted: 01/30/21 01:59pm Link  |  Quote  |  Print  |  Notify Moderator

Why convert is my question!

rdhetrick

Texas

Senior Member

Joined: 08/30/2012

View Profile



Good Sam RV Club Member

Offline
Posted: 01/30/21 02:15pm Link  |  Quote  |  Print  |  Notify Moderator

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!

theoldwizard1

SE MI

Senior Member

Joined: 09/07/2010

View Profile


Offline
Posted: 01/30/21 02:39pm Link  |  Quote  |  Print  |  Notify Moderator

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.

theoldwizard1

SE MI

Senior Member

Joined: 09/07/2010

View Profile


Offline
Posted: 01/30/21 02:47pm Link  |  Quote  |  Print  |  Notify Moderator

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 !

Reply to Topic  |  Subscribe  |  Print Topic  |  Post New Topic  | 
Page of 4  
Next

Open Roads Forum  >  Do It Yourself Modifications and Upgrades (DIY)

 > JC refrigeration AC or DC upgrade?
Search:   Advanced Search

Search only in Do It Yourself Modifications a...


New posts No new posts
Closed, new posts Closed, no new posts
Moved, new posts Moved, no new posts

Adjust text size:




© 2021 CWI, Inc. © 2021 Good Sam Enterprises, LLC. All Rights Reserved.