Central Electric panel showing 15.1v or zero

[Adrianlle]

I posted a couple of days ago about fridge losing power. Yesterday everything lost power- nothing worked- and the central electric screen was blank. Multimeter on lithium batteries showed 13.7v and sufficient amps.Victron Shunt showing the same. So started the engine and central electric panel showed a flashing 15.1. Switched off and start again and still flashing 15.1. So drive off and screen stopped flashing and came down in stages to 13.7. Overnight the voltage has dropped to 13.0 ( commensurate with our useage) and all stable inc fridge. Can anyone offer any explanations/solutions ? Could it be the Westfalia Shunt ? We are continuing our trip with fingers crossed! Thanks.

[iCook]

Hallo!
I again can not help you directly. I would use a "Bosch Car Service" or "professional campervan service" to analyse your electrical setup downstream from the generator / alternator to the batteries. I could not even make an educated guess.
Best regards, Wolf

[HerrmannOnTour]

Looking at the wiring diagram any defect within the shunt should not lead to power off the central electronic because it is wired to ground directly. However this only applies to the original circuits. I guess you changed at least the charging device to comply with the new batteries? Which device is it?

Do you also have pv/solar power?

BR,
Matthias

[Adrianlle]

Thanks Matthias. The set up ( which has worked since Spring last year) is 2 x 100ah Lifepo4 ; a Victron Multiplus charger/ inverter and 2 x 100w solar panels wired via a Victron mppt controller. Also a Votronic booster. Both the Booster or the Multiplus can put upto 40a i tothe batteries. The negatives from the batteries reach ground via first a Victron 500a Smart Shunt and then the original Westfalia Shunt. The Smaet Shunt shows a fairly consistent voltage and a state of charge not below 50% - so we’ll within the Lifepo acceptable minimum voltage / amperage.
I have read online that a defect in the Westfalia Shunt can cause issues with the Central electronics panel which then causes the fridge etc not to work. But that starting the engine or applying 240v via hookup will start the fridge etc. Those are exactly my symptoms. Without engine power or 240v , without warning all power systems will shut down and the Central Electronics Screen will go blank.But the Victron Shunt shows ok readings. Start the engine or hook up to 240v and all is fine again. So I am wondering how to test this theory. What if I bypass the Shunt as an experiment by moving the cable from the battery side to the ground side? But will the Central Electronics Screen and buttons then work? Any suggestions appreciated as I don’t want to be stranded without Bord batteries! Adrian

[HerrmannOnTour]

I am sorry, you are right! The batteries actually are not connected to ground of the central unit directly but to common ground of the vehicle/generator. There is the shunt in between the batteries. So this fits very well.

In my opinion it should not be an issue to bypass the shunt by simply changing the ground wire from the batteries to the opposite side of the Westfalia shunt. However it seems that sometimes the built-in shunt acts like a fuse. So I am wondering whether you had currents exceeding the specification of the shunt. Since you also have the smart shunt you would know about it.

As far as I could find out the Victron smart shunt is delivered including cables with fuse for the positive wire. This should keep you on the safe side.

BR,
Matthias

[Adrianlle]

I am sorry, you are right! The batteries actually are not connected to ground of the central unit directly but to common ground of the vehicle/generator. There is the shunt in between the batteries. So this fits very well.

In my opinion it should not be an issue to bypass the shunt by simply changing the ground wire from the batteries to the opposite side of the Westfalia shunt. However it seems that sometimes the built-in shunt acts like a fuse. So I am wondering whether you had currents exceeding the specification of the shunt. Since you also have the smart shunt you would know about it.

As far as I could find out the Victron smart shunt is delivered including cables with fuse for the positive wire. This should keep you on the safe side.

BR,
Matthias

Thanks Matthias. Yes it makes sense and I too wondered about a voltage spike affecting the Westfalia Shunt. Anyway, it’s ok at the moment ( fingers crossed for the rest of the trip) and when I’m home again I’ll do some experimenting. Adrian