Dometic RM2553 fridge not working on DC

Submitted: Saturday, May 03, 2014 at 07:43
ThreadID: 107590 Views:6127 Replies:6 FollowUps:3
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Hi all
We have just bought a caravan (got rid of camper trailer). It has a Dometic RM 2553 fridge in it . It seems to work well on gas and 240v but not on 12v (DC).
Does it only work on 12v when driving and attached to car battery???
We have solar to charge batteries in caravan so don't understand why it doesnt get cold using it on 12 volt when stationary. ( Not good when driving either).

Can anyone enlighten me on these fridges please? We want to do more off road so would like to know if fridge is meant to work on 12v when camping.

Thanks
Linda
P.S we took camper trailer back to manufacturers and sold it back to them, spent 10 nights sleeping in car and now have a jayco sterling outback pop top which we love except the fridge.
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Reply By: Sand Man (SA) - Saturday, May 03, 2014 at 08:20

Saturday, May 03, 2014 at 08:20
Hi Linda,

The high current draw of these fridges would result in dead batteries in a short period of time, if running on 12 volts.

The chances are, the fridge is not wired to the caravan batteries due to the reason above and will only run on 12v when connected to the vehicle. The 12v option is only to keep the fridge running while traveling and preferably with the engine running. Stopping for a short period of time, say an hour or so, should be OK but you run the risk of flattening the vehicle battery if left in this state for a long period.

When camping, the fridge should be running on gas, or 240v if at a caravan park with power facilities.

Some folk ditch their 3 way fridges in favour of a 240/12v compressor fridge, which are much more efficient and consume much less power.
A compressor fridge will draw somewhere around 2.5-4.5 amps maximum and will cycle on and off, depending on the temperature setting selected.
A 3 way fridge may draw around 8-15 amps constantly when running on 12 volts.
Bill


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Follow Up By: Member - bbuzz (NSW) - Saturday, May 03, 2014 at 10:07

Saturday, May 03, 2014 at 10:07
But you can run them on gas!

Stay longer when free camping and don't need as much support ie solar panels and extra battery.

bill
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Follow Up By: Nomadic Navara - Monday, May 05, 2014 at 21:02

Monday, May 05, 2014 at 21:02
You should never connect a Dometic absorption fridge to a house battery. They draw 15 A when running on 12 V. Have a look in your handbook for the fridge on how they should be wired, you will see that Dometic direct that they should be connected to the starting battery through a relay contact that is activated when the ignition is switched on. I have seen a smaller fridge flatten a Falcon battery to the point that it would not start the motor in 40 minutes.


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Reply By: Shaker - Saturday, May 03, 2014 at 09:49

Saturday, May 03, 2014 at 09:49
Jayco or one of their dealers would be able to give you a definitive answer.
AnswerID: 531721

Reply By: Member - Peter&Lynore - Saturday, May 03, 2014 at 10:25

Saturday, May 03, 2014 at 10:25
Hi Linda we had similar problem with ours until worked it out. The fridge will work off your car when moving , yes also stationary if still attached to car, which is no good for your battery, when stopped for a period of time or free camping you must switch it over to Gas ,some times it can take a short time for the gas to come through the line , then when you are about to leave turn gas off and switch it back to 24 v , we turn gas off start car then switch it over to make sure it is going , don't know if this is right way but it's the way we know it's going on 24v.
Peter
AnswerID: 531724

Reply By: Dust-Devil - Saturday, May 03, 2014 at 13:48

Saturday, May 03, 2014 at 13:48
Linda

We had a Jayco BASESTATION for 5 years which had the 'problem' you have described.

I tried numerous 'fixes' for it over 4 years which all ended up as failures to get that bastard fridge to run off the caravan 12V battery when travelling.

That was until, I was going through all the documentation that came with the BASESTATION (purchased new) one rain affected day and came to the pamphlet/directions on the 'Magic Black Power Box'. This is the box that receives 240V power and distributes 12V to everything that needs it and manages the caravan battery charging.

On reaching the back of the subject document a inserted addendum page fell out which reads as follows:


"BATTERY
1) Battery switch MUST only be ON when using the
battery or during charging.
2)Battery will require 'topping up' with charge when
left in storage. (Approx. every 2-3 months).
3) When charging from 240v, the converter will only
'trickle charge' battery & will require several days
to charge properly.
4) Battery does not run your l2V refrigerator. The
refrigerator is connected to your car auxiliary power
only.
5) Your power converter will charge at 5A for (ST20
converter) and 10A (ST35converter).
6) Your power converter fault light will illuminate in
event of over loading, short circuit, over voltage,
over temperature and reverse connected battery.
The power supply will shut down until fault is
rectified.
7)Battery will be unusable if your power level falls
below fair.
8) Calculate your battery usage @ 1.3 amps p/hr. for
each light and 2 amps p/hr. for a water pump."


Now that will explain exactly the situation you find yourself in.

Follow these directions and as long as the wiring in the van is correct and a 100%, all should be good.

regards

DD

If you have anymore queries contact me on ken_3149@yahoo.com
AnswerID: 531737

Reply By: Member - cherrywipe - Saturday, May 03, 2014 at 15:03

Saturday, May 03, 2014 at 15:03
Hi Linda,
Some years back We bought a van and had similar problem,fridge worked on 240 volt and gas,not on 12 v. Closer investigation the thing had never had a 12v thermostat fitted.
Cheers Cherry.
AnswerID: 531744

Reply By: Member - Boobook - Saturday, May 03, 2014 at 19:30

Saturday, May 03, 2014 at 19:30
You don't have any problems with your fridge, you just need to understand how it should be used and need to make sure it is wired correctly.

3 way, ie 240v, gas and 12 v fridges will work well if.

1)you are using 240v
2)you are using gas and it is level.
3)You are DRIVING and your alternator is working ok at 13.8V or more.

Your fridge will not work at all or very well on 12v if

a)you are not actually driving and your alternator is not charging.
b)you have inadequate wiring which includes 6mm auto cable
c)you connect your fridge circuit to the caravan / camper circuit.

You must ensure your fridge is wired separately to your battery charge circuit and it will not work off your 12v battery in your camper for 2 reasons. 1) it draws 10 to 12amps and will make your battery flat in about 5 hours, and 2)it needs 13.8v not 12v to cool things.

Your vehicle is probably not wired correctly for your fridge. You need 6B&S -- NOT 6mm auto cable, wired to the reverse plug of the trailer plug and it should be ok - IF your trailer also has heavy duty cable.

Also a fan helps and insulation. You can make it work well. Mine froze food on 12V while driving after I replaced all the wiring with 6B&S. Before that it never got below about 12 degrees.


AnswerID: 531770

Follow Up By: Member - Wozikev - Monday, May 05, 2014 at 17:53

Monday, May 05, 2014 at 17:53
X 2 for that !!! Quick rule of thumb - Your fridge will run best on 240v or gas and 12v will maintain what you've got as you travel. Never attempt to run the fridge from a 12v battery as it will flatten it in 2-3 hours. If you're going to be stopped for more than an hour, flick the fridge onto gas. I run a dedicated 8 B&S (twin) wire from the car through Anderson plugs to the fridge and a duplicate wire to the Redarc BMS alongside the 2 x 120 ah AGM batteries in the van. These batteries take care of lighting etc. It all works a treat. Remember, with 12v over distance there is no substitute for nice heavy wiring.

Cheers .......................... Kev.
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FollowupID: 815079

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