We have a Dometic RPD145 fridge/freezer in our motorhome and until recently it would not cut out until voltage dropped to <10.6 volts which is the voltage specified in the manual. Recently it started cutting out at 11.7 volts which is the voltage cut in according to the manual. Is this easily fixed by replacing the electronic module attached to the compressor or is it a bigger problem than this ? It works very well if you keep the voltage up to it . Any solutions please.

Hi dingojim,
Some info here but all fridges present with differing problems.
Whilst I am ok with most things mechanical, I can't resolve too much in the way of electrical s.
My fridge is cutting out at any setting under two on the thermostat dial at the moment running on gas or 240 volts. I reckon its the thermostat, but can cope till it presents worse issues.
There are lists of service agent around that repair fridges depending which state you are in.

Update your profile to include a state and some one may be able to help locate a repairer for you locally.


viewtopic.php?f=6&t=13940&hilit=dometic+fridg

Thanks Dieseltojo for your reply. I have had the thermostat replaced just a few days ago as it was suspect but the problem is the fridge is cutting out at 11.7v when it should not cut out on low voltage until v drops below 10.6v. There is a fault in one of those 18 cent components which cost $$$$$ to replace methinks. Cheers. Dingojim.

HI
I cannot locate any such model "Dometic" fridge
Is it an Australian 3way model???
10.6v is a very low voltage cutout point. & the batteries will not last long if taken down to that very often
11.6 V is also bad for batterries but you may have some voltage drop so the actual batteries are not going that low.
But until we canfind more information on that model, any suggestions would just be guesing
PeterQ

Hi oldtrack123 and thanks for your reply. The fridge is a Dometic Waeco RPD 145. There is another model RPD 185 and they are both 12v only, not 3 way, and they have a compressor unit. I had a new thermostat fitted a few days ago in Mt Isa so there is not a problem with that. The instruction manual states that low voltage cut out is 10.6 volts and cut in voltage is 11.7 volts. The fridge unit would still run on 10.8 volts up until a few weeks ago when it started cutting out at 11.5 - 11.6 volts. The upper and lower voltages are controlled by the electronic module attached to the side of the compressor and as it appears to be a solid state module is not repairable but would need replacing ?? Probable cause of malfunction could be some of the roads travelled recently which shake the fillings out of your back teeth. The VDO electronic speedo on the Mercedes has stopped functioning as a result of the shake, rattle and roll roads so that's nearly $400 dollars of my fun money gone when I get to a major city. We are currently touring Far North/ far West/central west Qld which is back of the black stump for anything except the necessities. In reply to your valued advice re low battery voltage I have 3x 120 a/hr deep cycle batteries, new 3 months ago, and 2x 100 watt solar panels through a good charge controller which is putting out 11 -12 amps. now the sun is getting a bit higher and as the days draw out a bit. We have the fridge @ 6 amps and an Engel @ 6 amps which are the only big current draws as all lighting is LED. This = 12 amps plus, say, 2 amps for lights, etc. being an absolute max of 150 A/day. Input from the solar is currently 80 A/ day with the deficit being supplied by genny through 25 A smart charger also new 3 months ago. The weak spot in the system is the solar panels which at 5 years old have lost a bit of sting. I will upgrade to 2x 120 or 150 amp panels in the near future, more fun money gone. I understand that deep cycle batteries can be discharged to 80% regularly and 50% occasionally without any adverse effect on the battery therefore I can discharge my batteries to 10.6 v, (80% of 12v ) without damage to the batteries can I not ? Please tell me if I am using the wrong way of calculating anything. I appreciate your, and other forumites help. Cheers, Dingojim.

Hi Jim
Yes, the Waecos do have an inbuilt voltage cutout system
IT'S prime purpose is to protect the WAeco itselve from the effects of under voltage
It is usually internally adjustable internally[by changing a resistor] up from 10.6V which is the lowest setting.
THe battery capacity does not work as a % of 12V
10.6 V is considered a completely discharged battery
IF the batterries are wet lead acid[even deep cycle]
They may already be very sick, if you have taken them down to near 10.6V often
For standard wet cell lead acid batteries it is best to not go below 50>60% DISCHARGE
That is12.06V >11.9V
I think you have misread the discharge info on wet lead acid deep cycle batteries
Those figures refer to taking down to a 80% SOC [only using 20% 0f the capacity]for longest life
with occassinal DOWN to 50% SOC [using only 50% of capapacity ON AN OCCCASSIONALl basis [down to12.06V


PeterQ

Hi Jim,
As Peter has said it’s not good if you let the lead acid battery drop much below 50 to 60% SOC. Usually a battery stated Amp/Hour full capacity cannot be delivered unless the volts drop to 10.6V but that is not the way you normally use the battery unless you are prepared to only expect a short life from the battery.

Really the solar capacity you have even if performing perfectly is not enough and at the price of panels these days is not a big cost.

On the fridge low voltage cut off have you measured the volts at the fridge as it may not be the same as at the battery, you may be getting a voltage drop somewhere!

If the low voltage cut out is not working correctly then can you bypass the cut out and consider fitting a simple low voltage cut out like this:
http://www.ebay.com.au/itm/12vdc-Low-Vo ... 51a5fd8e68

JR