Fridge query

[Cardo]

We have a Waeco CR50 front loading fridge. Yes, I know, inefficient, but it was one of SWMBO's demands for living on the boat.

The fridge seems to work fine (although the freezer compartment doesn't seem to stay frozen much) however whilst "stress testing" the batteries I found the red warning light is flashing. It flashes once every 4 seconds, which according to the manual means "The supply voltage is outside of the set range." The fridge is running through its cycles and the food and drinks are cold.
Last night the voltage at the batteries was 12.65V and the voltage at the 240V/12V box below the fridge was showing 12.5V. There's then approx. a metre of reasonably thick cable leading up to the compressor, however I couldn't measure the voltage at the connection to the compressor as this would require pulling out the fridge, which is a right faff.
The light was flashing this morning however once the sun came up and the solar panels started juicing the batteries and the voltage went up to 13 odd volts, the warning light stopped flashing. Now that the sun has gone down the batteries are showing 12.9V and the light is flashing again.

So, what's the deal? I think 12.5V is a decent voltage at the fridge? Surely it doesn't require more than this to work properly seeing as it's designed to run off 12V batteries... Does anyone know what the "set range" for the voltage is? The only voltages I could find in the manual were these:
Cut-off voltage 10.4 V
Cut-in voltage 11.7 V
I'm pretty confident the voltage isn't dropping from 12.9V to 11.7V so this surely can't be it?

Thoughts?

 

[David2452]

I'm pretty confident the voltage isn't dropping from 12.9V to 11.7V so this surely can't be it? Thoughts?

Possible corrosion resistance on the last terminals? Possible voltage limiter fault? Only a bit related I know but I recently had a similar issue with a customers heater, though fitted to a boat it was a vehicle one with a low voltage cut out set at 11.26v,(only showed up when I interogated the ECU) as opposed to the marine and universal version which is 10.5v, caused me a lot of head scratching as it was reputed to be a proper marine kit and only 8 months old.

 

[William_H]

Try a heavy piece of wire from the +ve of the battery to the terminal at the 12v/240v box. If this stops the flashing then you have a wiring loss. Do the same with the negative supply from battery to fridge -ve terminal. As said watch for corrosion on the fridge terminal itself. Make sure the fridge is actually running when doing this.
Adjust the thermostat to get more freezing. If it is at max cold and compressor is running all the time you have a problem.
Of course with UK recent weather who needs a fridge?
good luck olewill

 

[Cardo]

So I've pulled the fridge out and checked the voltage at the contacts on the compressor unit. This came back to the same as the 12/240 box at the bottom. So around a 0.1v drop from the batteries, which I think is acceptable. When I just tested it the voltage at the compressor was 12.6v, the fridge seemed to be running fine and yet the red light is flashing once every 4 seconds. I checked for corrosion and there wasn't anything obvious.

Try a heavy piece of wire from the +ve of the battery to the terminal at the 12v/240v box. If this stops the flashing then you have a wiring loss. Do the same with the negative supply from battery to fridge -ve terminal. As said watch for corrosion on the fridge terminal itself. Make sure the fridge is actually running when doing this.
Adjust the thermostat to get more freezing. If it is at max cold and compressor is running all the time you have a problem.
Of course with UK recent weather who needs a fridge?
good luck olewill

It doesn't appear to be a wiring loss from the readings I'm getting on the voltmeter, but I'll give this a go and see what happens.

Ice-cream was pretty much frozen this morning, so I've turned up the thermostat to see if that finishes it off.

 

[Cardo]

Possible corrosion resistance on the last terminals? Possible voltage limiter fault? Only a bit related I know but I recently had a similar issue with a customers heater, though fitted to a boat it was a vehicle one with a low voltage cut out set at 11.26v,(only showed up when I interogated the ECU) as opposed to the marine and universal version which is 10.5v, caused me a lot of head scratching as it was reputed to be a proper marine kit and only 8 months old.

Definitely a marine unit (well, I presume so, having come from MarineSuperstore). No obvious corrosion on the terminals. The voltage on the compressor side of the connections looks good to me. The fridge isn't cutting out, it seems to be running fine, but for some reason it's reporting a voltage fault. Daft thing!