Waeco/mobitronic rectifier through an inverter

Submitted: Wednesday, Jun 20, 2018 at 17:56
ThreadID: 136875 Views:3664 Replies:5 FollowUps:9
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I have a Waeco CDF35, it doesn't seem to like voltage drop anymore. I thought if I run it through the supplied 240V rectifier through an inverter it might work. Any thoughts or opinions would be appreciated.
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Reply By: RMD - Wednesday, Jun 20, 2018 at 18:15

Wednesday, Jun 20, 2018 at 18:15
Maybe the wire in the lead has fractured some of the strands and/or the plug is lose on the 12v pins. Either way there will be a voltage loss while amp are flowing. I had to forcibly squeeze the plug with multi grips to close the connector so it clamps very firmly onto the fridge input pins. Even supplied with a power supply may make mo difference. I ended upmaking a new 12 lead with decent connector and thicker wire to ensure a good supply and connection integrity. Hope you solve it.
AnswerID: 619707

Follow Up By: Enormous Racing - Wednesday, Jun 20, 2018 at 18:25

Wednesday, Jun 20, 2018 at 18:25
The fridge works if the car is running or through the rectifier plugged into mains power. It will also work using a 12V socket straight off the battery. My Engel will work in the back of the car for days, so I don't think it's wiring. I am running a healthy 105ah deep cycle battery.
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Follow Up By: RMD - Wednesday, Jun 20, 2018 at 22:33

Wednesday, Jun 20, 2018 at 22:33
Have you measured the voltage at the fridge plug while running on the various methods of powering it? a couple of fine wires into the 12v socket on the power cable will show what is actually happening with a multimeter reading the volts.


If ok on the inverter setup and direct to the battery too, you may have eliminated some of the voltage drop present in other cables which do the supply to the fridge lead. I would definitely suspect the wiring in that case. Losing too much voltage will make the Waeco stop.
If the Waeco lead has a ciggy plug, I would inspect that first, along with the wiring to the ciggy base unit, they are not the most reliable way of providing power to a fridge, even one which uses 3 or 4 amps. Most only provide a point contact for the amps to flow through.
An Engel uses less power than a Waeco, around 1/2 the amount so with the Engel the voltage drop probably isn't an issue.
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Follow Up By: Member - DOZER - Thursday, Jun 21, 2018 at 10:35

Thursday, Jun 21, 2018 at 10:35
Had tesame with my bushman...turned out to be where the lead plugs into the fridge, do yourself a favour and buy 2 anderson plugs, 1 for the lead and 1 for the fridge, couple up the wires, plug in and away you go
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Follow Up By: Enormous Racing - Tuesday, Jul 03, 2018 at 19:19

Tuesday, Jul 03, 2018 at 19:19
I have done all sorts since I posted this. It is all pointing towards the poly fuse which was supposed to have been replaced about 6 years ago by a Waeco repairer. I took it there twice, I'm certain he said he had replaced it with a higher amp fuse, maybe he didn't. It has never run reliably since.
I am getting readings at the fridge of 12.3V when running depending on the length of the wire I am using. Sometimes the fridge is failing at 12.3V, but other times it is working at 11.8V. I'm at the point where it's not worth spending any more money on it, just use it when I have access to 240V.
I'd like to be able to unsolder the poly fuse, bridge it and turn the fridge off when the voltage is too low myself, I would rarely ever let the battery get that low anyway.

Thanks for the advice.

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Reply By: Notso - Wednesday, Jun 20, 2018 at 22:26

Wednesday, Jun 20, 2018 at 22:26
So under what conditions doesn't it work! Is it when you battery voltage drops below 12 volts or so.

If so I would be looking for a high resistance in the circuit somewhere. Maybe a fuse has developed resistance, maybe a loose wire, poor connection etc. This could only show up when the system voltage drops.

What type of plug are you using?
AnswerID: 619712

Follow Up By: Enormous Racing - Tuesday, Jul 03, 2018 at 19:23

Tuesday, Jul 03, 2018 at 19:23
I am using the standard plug. I have borrowed mates plugs, same result. I have used twin core wire with terminals direct to the fridge from the battery. That works fine, but as I add more length to the wire, the red light starts to glow a little. Add a bit more length to the wire and the fridge cuts out.
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FollowupID: 892243

Reply By: brianc - Thursday, Jun 21, 2018 at 09:55

Thursday, Jun 21, 2018 at 09:55
Bro in law got caught with the cut out voltage not set on his Waeco - check the manual how to setup / reset for Hi Med and Low volts.
AnswerID: 619718

Follow Up By: Enormous Racing - Tuesday, Jul 03, 2018 at 19:24

Tuesday, Jul 03, 2018 at 19:24
This fridge only has a switch for Low & High cut out. There is no way I know of for adjusting or setting this.
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Follow Up By: Allan B (Sunshine Coast) - Wednesday, Jul 04, 2018 at 14:06

Wednesday, Jul 04, 2018 at 14:06
.
That switch IS the setting that brianc was referring to. If set on "High" then the fridge will cut out at a higher voltage. Set it on LOW.
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Allan

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Reply By: Member - DOZER - Thursday, Jun 21, 2018 at 10:36

Thursday, Jun 21, 2018 at 10:36
the fridge plug is the usual culpret, ebay for anderson plugs
AnswerID: 619722

Reply By: Motherhen - Friday, Jun 22, 2018 at 23:23

Friday, Jun 22, 2018 at 23:23
We tried a Mobitronic on our caravan fridge, just so we had the option to run if direct from 240 volt, but it caused a voltage drop from the 12 v so had to disconnect the Mobitronic and wired the fridge back to the battery.

If you are getting a power loss, to my reasoning you would only add another power reduction with the inverter.

Can you run the Waeco direct from the battery on 12 volt?
Motherhen

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AnswerID: 619761

Follow Up By: Enormous Racing - Tuesday, Jul 03, 2018 at 19:28

Tuesday, Jul 03, 2018 at 19:28
I just don't think there is a power reduction problem. I do understand that an inverter and the rectifier will use more power than just fridge on its own. I'm certain it is a problem with the fridge circuitry, so the rectifier would supply the correct amount of power to get around the poly fuse issue.
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Follow Up By: Allan B (Sunshine Coast) - Tuesday, Jul 03, 2018 at 20:14

Tuesday, Jul 03, 2018 at 20:14
.
If it "works OK through a 12v socket directly off the battery" then you have a volt-drop problem with your installed socket. Face up to it.

The fact that your Engel works on that socket does not determine that the voltage is sufficient for the Waeco which has selectable low-volt cutout settings. Consult your User Guide or download it.



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Allan

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