question

mterman avatar image
mterman asked

Multiplus II turning off, than on again

Does anybody have any idea how can I debug this behavior?

The batteries are Pylontech, they are connected to Cerbo GX vie BMC Can as per manual. Everything is working on that part. Also, MPPT is behaving normally.

When I connect the Multiplus II to the Cerbo GX via Ve.bus, Inverter goes from inverting to off, then back to inverting, then back to off ...

If it's not connected to the Cerbo stays on, and keeps inverting.

It is now connected to Cerbo via MK3 dongle, and that used to work as expected. The inverter was shown in the console, and on VRM. I could see the AC consumption ...
After the update of the Cerbo to the v3.00, this stopped working. I can see the inverter in the device list, but I can't see the AC usage in VRM or overview pages...


Multiplus-IIcerbo gxDVCC
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7 Answers
luphi avatar image
luphi answered ·

make sure to have both running the latest version which are 3.10 for the Cerbo and v506 for the Multi. have you tried a different cable?

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lifeingalicia avatar image
lifeingalicia answered ·

.....After the update of the Cerbo to the v3.00....

I think 3.1 is the latest

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aaront avatar image
aaront answered ·

Make sure the ethernet cable is not running with the battery cables

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luphi avatar image
luphi answered ·

Make sure, to not terminate the VE.bus

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janvi avatar image
janvi answered ·

Had your described on / off failure caused from a loose DC wire at the Multiplus. The loose wire was already very hot. After cooling down, the MP2 starts again and heats up until disconnection. For this reason: Always double check all terminal screws and use proper crimping pliers.



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janvi avatar image
janvi answered ·

Did you check the PE connection for your MP2 ? Missing PE may cause common mode errors from occasionally static dischargings.

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mterman avatar image
mterman answered ·

Hello, me again. I still haven't resolved this problem.

Does anybody know could this problem happen because of Cerbo's lack of PE connection?

Cerbo GX doesn't have a point to connect PE to, no grounding lug or anything. I suppose that for the internal GND Cerbo is using negative of the power supply input. My Cerbo is powered directly from the batteries. Multiplus II has a PE lug connection and that is connected to the system PE bus. My batteries are not grounded, meaning the negative pole is not bound to PE. Batteries are pylon-tech, they also have separate PE lug, it is also connected to the system PE bus.

Could the problem be that the Cerbos and Multiplus GNS connections are not the same GND?
Here is the diagram of the Ve.Bus pinout I found:
13877-1602788734429.png




13877-1602788734429.png (27.6 KiB)
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