question

pwacquiez avatar image
pwacquiez asked

Ground fault to DC (negative) on the new MultiPlus II 15000/48

Hello everyone,


It has been 2 years since my single-phase installation on an isolated site worked well with an MP2 48/10000, two MPPT250/100, CERBO...

I bought the MP2 15000 to get more single phase power (and in the hope that the latest model would be a bit quieter). I received it yesterday and installed it. When I wanted to restart my installation, the earth guardian on the direct current side (DOLD IL 5881) immediately indicated an earth fault on the negative.

Indeed, when I disconnect the earth cable from the Multiplus 15000, the tester indicates:

- 48v between the + and the mass of the MP2

- 0 v between - and MP2 ground


Otherwise, the MP2 15000 works, but it is of course too dangerous to use it as is.


What do you think ?



Multiplus-IIfeature requestfault
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4 Answers
Duivert NL avatar image
Duivert NL answered ·

sorry off topic:

but your AC connections on the multi are badly crimped and have dangerously open copper connections

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pwacquiez avatar image
pwacquiez answered ·

I suppose that the fault comes from a tin solder which makes contact between the negative and the ground or a screw passed through a negative cable inside. but it is guaranteed so I am not going to open it. it’s tedious to take it back to the supplier (~75kg), put the new one back, rewire it…

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sharpener avatar image
sharpener answered ·

Here is a list of what to test before sending a unit back. Although intended for distributors it might contain some clues.

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pwacquiez avatar image
pwacquiez answered ·

I found the problem.

There is a metal bracket behind the negative battery connection. it is in contact with one of the tin points on the electronic card.

I took a picture of the problem with a mirror and added a red arrow.

I slipped a piece of plastic to insulate it.


I don't understand why Victron did not insulate this metal support which is on ground.


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Duivert NL avatar image Duivert NL commented ·
Hi i suggest you send your conclusion and pictures to victron, thats clearly a fabrication error, could be al faulty fabricated batch of multiplus 2 15k’s
1 Like 1 ·
Justin Cook avatar image Justin Cook ♦♦ commented ·

Unrelated, but please note that neither the Blue Sea battery switch nor any of those surface-mount breakers in your install are suitable for a 48vNom system.

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pwacquiez avatar image pwacquiez Justin Cook ♦♦ commented ·

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Where is the problem please ?

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Justin Cook avatar image Justin Cook ♦♦ pwacquiez commented ·
48v maximum, for use on up to 36vNom systems. Your system is running between 54 and 60v, and neither the switch nor the breakers are suitable for that voltage.
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pwacquiez avatar image pwacquiez Justin Cook ♦♦ commented ·

However, Victron shows these elements in this schematic system which includes 40-59v batteries:

https://www.victronenergy.fr/upload/documents/3-Phase-Quattro-system-with-Cerbo-GX-Touch-50-BYD-LVL-Smart-solar-MPPT's.pdf


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Related Resources

MultiPlus-II Product page 

MultiPlus-II Manual

Multiplus-II GX Online Manual

MultiPlus-II 230V Datasheet 

VE.Bus Error codes

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