Fridge power consumption

[Matthewbalzan]

Another issue I have been observing... I have a dometic crx65 fridge installed in my boat. Recently I checked with suppliers and directly with dometic that since I never keep it constantly on ( i switch off main switches every time I get off the boat), the compressor will take anywhere between 12 and 24 to stabilise and cut off (also my ambient temperature is always 30+ degrees). However, I have also noticed that although it is listed to use 5.5amps, I am finding the fridge frequently consuming between 6 and 6.5 amps. Is this normal in the scenario I explained or does the fridge need some maintenance? Thanks

 

[vyv_cox]

My fridge has the Danfoss 35c compressor, almost certainly the same as yours. It draws 4 amps at the start of the cooling cycle, 3 amps towards the end. In Greek temperatures, seawater cooled, it invariably runs for 1/3 of the time, off for 2/3.

 

[Matthewbalzan]

My fridge has the Danfoss 35c compressor, almost certainly the same as yours. It draws 4 amps at the start of the cooling cycle, 3 amps towards the end. In Greek temperatures, seawater cooled, it invariably runs for 1/3 of the time, off for 2/3.

I got to notice this as the compressor was always on, hence I contacted the maker who explained it needs more than 12 hours to shut off the first time ( i never use it that long continuously), but the amps it's using I feel it is too high for a 2 year old fridge...plus keeping me worried if I should keep it on overnight

 

[vyv_cox]

I got to notice this as the compressor was always on, hence I contacted the maker who explained it needs more than 12 hours to shut off the first time ( i never use it that long continuously), but the amps it's using I feel it is too high for a 2 year old fridge...plus keeping me worried if I should keep it on overnight

I have never timed it to first shutdown but it is nowhere near 12 hours. Under an hour I would guess. I turn mine on in May and off in October in a normal season in Greece. It runs off 3 x 110 Ah batteries which with 125 watts of solar panel in midsummer keep fully charged.

 

[Matthewbalzan]

That's what dometic said about first shutdown. I am very hesitant leaving electrical current on when not on boat... My only concern is if this amp load for the fridge is acceptable... So to compensate it by switching off other loads periodically

 

[ChromeDome]

Can't you "real life" test the first run claim?

These fridges normally have a battery protection feature (adjustable) to prevent them from draining the battery below a set voltage. Could be your safeguard if you leave it on.

Edit: Apparently not adjustable on your model, but the feature is there:



Must say however that leaving a battery with only 10,4 volt would prevent almost anything from working. At 10,5v batteries normally are completely discharged - as in 0% left.

 

[rogerthebodger]

I have a Danfoss 35c compressed fridge in South African summer with a front opening door

I have 80mm of insulation but I did hav a gap in the insulation and I found mine would run continuous in summer.

Once I filled the gap I would run with a 50% duty cycle measured with a timer that measured the time the compressor was running.

Mine is also water cooled. The key is the thickness of insulation providing all other factors re correct.

I did have a stainless steel inner door and I replaced it with HDPE and that also reduced the duty cycle on time

 

[Daverw]

Being water cooled is a big plus on power usage

 

[Matthewbalzan]

Can't you "real life" test the first run claim?

These fridges normally have a battery protection feature (adjustable) to prevent them from draining the battery below a set voltage. Could be your safeguard if you leave it on.

Edit: Apparently not adjustable on your model, but the feature is there:

View attachment 160925

Must say however that leaving a battery with only 10,4 volt would prevent almost anything from working. At 10,5v batteries normally are completely discharged - as in 0% left.

Yes I have this feature as I damaged my previous battery that way...I had a voltage drop problem which until I found out about caused battery to loose charge .. that's when I started noticing the compressor running time and the amp load of the fridge... i don't know if anyone has had the same load from a similar fridge

 

[B27]

Can't you "real life" test the first run claim?

These fridges normally have a battery protection feature (adjustable) to prevent them from draining the battery below a set voltage. Could be your safeguard if you leave it on.

Edit: Apparently not adjustable on your model, but the feature is there:

View attachment 160925

Must say however that leaving a battery with only 10,4 volt would prevent almost anything from working. At 10,5v batteries normally are completely discharged - as in 0% left.

The one I bought was struggling to run much due to voltage drop in wiring.
The main culprit turned out to be the 2.5m lead the fridge came with.
I shortened that, and cleaned and tidied the yacht wiring, now it's all good.

10.4V with a 3A current draw is quite different from 10.4V idle and rested.

But you are right to draw attention to this. Mine is adjustable, but it's not ideal.
It does the job. Before fridge, last year we went out in August and couldn't keep milk usable for a whole day. With fridge we're sorted for several days.

 

[Matthewbalzan]

I have a 4mm2 wire from fusebox to fridge which are about 1 metre away from each other. Size of wire is as dometic recommends re the distance and was installed by factory as the boat is only 2 years old. What I did was thicken the wire from main switch to fusebox which is about 3 metres away as it was only 6mm2 and had voltage drop. Added a 16mm2 wire and resolved the voltage drop issue.

The fridge is cooling well I have no issue with that, only the slightly higher current load is concerning me as according to manual it ahould run ar max 5.5amp and sometimes is reaching between 6-6.5amp

 

[geem]

Being water cooled is a big plus on power usage

Only when the water is cool. Here in the Caribbean summer the air temperature is 30/31degC during the day and about 27/28degC at night. The sea temperature is 30degC. Water cooled in no more efficient in this summer envirnonment. In the UK, water cooled will always be more efficient.
If you are in the Med and experiencing 40+ degC, water cooled will be the way to go. It will also keep the rejected heat from the condenser out of the cabin