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JamesI, Handyman
Category: Appliance
Satisfied Customers: 2160
Experience:  I have repaired and maintained numerous items over the years, from fridges to freezers, radios to TV's.
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Hi, Were on holidays on our boat, first day, and the Waeco

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We're on holidays on our boat, first day, and the Waeco Coolmatic has stopped working.
I have a voltmeter and I have measured 11.8V going into the Fridge
It's a CoolMatic MDC65 with a Danfoss unit 101N0220, Compressor is BD35F
It was working earlier today ... had it on mains.
The Error Code LED blinks onece every 4 secs ... book says the Voltage is out of range... but it's not
Any ideas?
When you tested the voltage did you test this under load, or disconenct the lead and test the voltage?
Customer: replied 3 years ago.
I did not disconnect the lead.
I measured the voltage at the connector to the fridge, between the AC / DC converter EPS100 and the fridge.

Can you please check what your getting at the AC end, and at least that rules out the inverter?

Customer: replied 3 years ago.
Have just pulled in to where we can connect with 220v and it works on 220 so inverter is fine

Reading the manual you need 11.7V of more for the switch on voltage, you have a reading of 11.8V so this should be sufficent all being it very close to the cut off.

Its going to look to pull around 15A at 12V so good chance is the battery voltage will drop bellow 11.7V on startup.

I was initally wondering if the inverter was trying to take DC and pass it through as AC, but it looks like it runs on DC, it also appears its not needing to do anything other than pass through the 12V so there isnt a transformer at fault.

I would say the issue is the battery, if you can pick up another 12V or borrow one from another boat plug that in directly, check the voltage to see if that is above 11.8V and if the fridge starts..

Secondly if that still doesnt start put the two batteries in series and plug it into the fridge and see if that allows the fridge to power up on 24V.

It could be simply your volt meter being 0.2V out, or the tollerance of the fridge not being 11.7V but 11.8V for it to start, and as the battery has aged the voltage has dropped.

The other thing you may notice is that once the fridge cools on mains, the fridge will start working again on the original battery as its not needing to pull as much current on startup.

Let me know how you get on trying with another battery (borrowed or otherwise)

Customer: replied 3 years ago.
Hi James
We're on a boat. So swapping batteries is difficult.
However we took it for a short journey and found that the fridge works when the engine is running.
The alternator runs at 13.8V.
When we stopped it would not start even with the battery showing 12.2V
But I think you might be right in suspecting the battery.
It might be collapsing when/if the fridge is trying to draw 15A
Do you think it might behave differently if I change the fridge setting to 4, down from 6?
We'll test again after a few hours of charging.

Hi Gerry,

Changing the temp control wont change the current being drawn, as its either ON (drawing ~15A) or on Stanby.

The temp control would just affect how often the fridge starts up to cool it.

My suggestion is set it to 6 when on mains, then set it to 4 when on battery, and you might find for short periods of time it can keep it cool via 12V, but if its set at 6 it means its going to be running for longer to get the temp under control.

Another approach is seeing if the light stops flashing when you set it 1, and starts flashing when you turn it up, as this will certinly indicate if its the voltage dropping when under load (if flashing only once you turn it past 1) or if the battery is completly knackered and not even producing the voltage required under no load.



Good evening Gerry,

I have contacted the Waeco technical department, and their view is that this fault is most likly caused by the battery.

Do you require any further assistance, if not I would appreciate it if you could rate my answer in order for the case to be closed down.

Otherwise reply back and I will happily look to assist you further in anything you need clarified.

JamesI and other Appliance Specialists are ready to help you
Hi Gerry, if you need anything else please let me know, otherwise I would really appreciate it if you could log in and rate my response so I can close the case.
Many thanks
Customer: replied 3 years ago.

Thanks for all your help James,

We're now back from the holidays and managed to keep things cool by switching the fridge on when the motor was running.. it held it when we stopped, so I guess it was the "switch-on current" .ie. we need a new battery.


Gerry Joyce

PS Clicking on rating image does not seem to do anything