2014 Roller 746 12v / Control Panel issue..

[lovespend]

Hi folks.

First outing in a new to us MoHo - as you might expect, finding some niggles and issues along the way.

The control panel does not recognise any voltage in the starter battery. (Starter bat is fine)
The control panel reads full voltage capacity in leisure battery.

The fridge wouldn’t work when we put it in 12v mode and started driving (display flashing).

When driving the control panel does NOT show the ‘coupled’ light for 12v systems.

Fridge fine on EHU.

On EHU the control panel shows the ‘EHU’ light, but ALSO the ‘coupled’ light now comes on.



Can anyone offer any explanation… and how we might get the fridge going when we’re driving ! ?

Many thanks folks.

 

[GeoffnDee]

There may be a supply fuse near the starter battery positive terminal that needs replacing .
It would also be worth checking the 12v habitation fuse board for a faulty fuse (it may be under the dinette seating)

 

[lovespend]

Thank-you
I’ve done all the fuses I can find .. under the passenger seat incl the big one I can see that are right next to leisure pos. and on (what I think is) the incoming from alternator.

 

[lovespend]

Thank-you
I’ve done all the fuses I can find .. under the passenger seat incl the big one I can see that are right next to leisure pos. and on (what I think is) the incoming from alternator.

All 12v fuses check out (visually)

 

[lovespend]

Just have to wait til we get home and get the trusty multi meter out!

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[GeoffnDee]

Could it be that the battery coupled light comes on when on EHU as both starter and leisure batteries are being charged by the mains charger ? I think that it could be the starter battery supply to the fridge/PSU that is faulty/missing.

 

[DandG5515]

On my older rollerteam, you can remove the outside bottom fridge vent and access the mains and 12volt supply to the fridge. The 12 volt supply is 3 wires, negative, fat positive run from leisure battery thin positive wire D+ from alternator. The D + signal has to be their to allow the fridge to work on 12v. Maybe worth downloading installation instructions off internet to check with muiltimeter.

I have seen in the past (as the motorhome is new to you) that “barry the bodger” has cut the D+ signal to the fridge in disconnect the split charge relay to install an upgraded B2B battery charger. Just a possibility but maybe connected with the control panel not measuring the cab battery. Sorry I couldn’t be any more help.

 

[lovespend]

On my older rollerteam, you can remove the outside bottom fridge vent and access the mains and 12volt supply to the fridge. The 12 volt supply is 3 wires, negative, fat positive run from leisure battery thin positive wire D+ from alternator. The D + signal has to be their to allow the fridge to work on 12v. Maybe worth downloading installation instructions off internet to check with muiltimeter.

I have seen in the past (as the motorhome is new to you) that “barry the bodger” has cut the D+ signal to the fridge in disconnect the split charge relay to install an upgraded B2B battery charger. Just a possibility but maybe connected with the control panel not measuring the cab battery. Sorry I couldn’t be any more help.

Thanks will have look. Maybe the lack of ‘coupled’
Light on control panel has nothing to do with the fridge issue.

 

[lovespend]

On my older rollerteam, you can remove the outside bottom fridge vent and access the mains and 12volt supply to the fridge. The 12 volt supply is 3 wires, negative, fat positive run from leisure battery thin positive wire D+ from alternator. The D + signal has to be their to allow the fridge to work on 12v. Maybe worth downloading installation instructions off internet to check with muiltimeter.

I have seen in the past (as the motorhome is new to you) that “barry the bodger” has cut the D+ signal to the fridge in disconnect the split charge relay to install an upgraded B2B battery charger. Just a possibility but maybe connected with the control panel not measuring the cab battery. Sorry I couldn’t be any more help.

Do you know where the split charger is likely to be located - it’s the one bit I’ve not been able to locate yet. Cheers

 

[lovespend]

Could it be that the battery coupled light comes on when on EHU as both starter and leisure batteries are being charged by the mains charger ? I think that it could be the starter battery supply to the fridge/PSU that is faulty/missing.

Yep this could be the case and it may not be linked to the fridge issue. (Or even an error!) what fun!

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[GeoffnDee]

I think your 12v habitation fuse box/PSU may be a Nordelettronica NE196 unit , if so , if you remove its cover the B1 and B2 battery connections are there and can be checked to confirm if power from both the leisure and starter batteries are getting to the PSU to enable the correct control panel and fridge operation.

 

[DandG5515]

Do you know where the split charger is likely to be located - it’s the one bit I’ve not been able to locate yet. Cheers

Sorry no I've never looked for it in our van I am guessing yours is a fiat were as ours is a transit so unlikely to be in same place.

 

[autorouter]

Do you know where the split charger is likely to be located - it’s the one bit I’ve not been able to locate yet.

If it's the NE196 distribution/fusebox as GeoffnDee says, then the split charge relay is built into that NE196 box. If you remove the cover and find the B1 and B2 connections, then the split charge relay will be a small black rectangular box on the circuit board between the B1 and B2 terminals. I don't remember the details of exactly how to disable it, as will be required if you fit a B2B charger for the new battery.

 

[lovespend]

Hi All
Thanks so much for the help. With the help of this thread and another one from back in 2021 I solved it.
Making a note here for anyone that follows…

Big old fuse-box behind passenger seat turns out to be main PSU for the Moho 12v systems. Opened it up and using the schematic from the instructions identified the 12v in from Starter Battery.
No volts incoming.
Located starter battery (in a Ducato this is under the carpet and in a trap door in the floor in front of the passenger seat)
Continuity check between PSU and starter battery reveals problem. Big ol 50amp fuse ON the starter battery terminal had gone.
Replace fuse, continuity check OK.
Panel now showing correct volts for starter battery.
Panel shows ‘coupled’ when engine running.
Fridge operates on 12v when engine running.

 

[lovespend]

There may be a supply fuse near the starter battery positive terminal that needs replacing .
It would also be worth checking the 12v habitation fuse board for a faulty fuse (it may be under the dinette seating)

Nailed it first go! TY

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[Jim Schush]

We have exactly the same symptoms on our 2018 Dethleffs, exactly the same issue, 12v indicator for the starter battery not registering ( battery fine) and fridge not working on 12v.
Like you I have checked all the fuses on both the Schaudt control unit and also the cab battery but they all seem fine?
Could you identify from the photo which fuse you changed.
I checked the fuses using the multimeter and they all showed 0 . I might be doing something wrong so I might need to check them again.
We fitted a new fridge control unit last year but then the 12v starter gauge still worked.
Any help would be appreciated.