Multiplus shuts down when VE bus is connected to cerbo gx

DIY
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1

I have a 3 phase system with 3 times multiplus 2 type 48volts 4k5.

It has run on AGM batteries before without problems. I have now installed a new 48volt battery with Sodium ion cells and I can’t get it working. As soon as I connect the ve bus to the cerbo it shuts down.

In have exchanged the rj45 cables for new ones and have one cable to the cerbo modified for pin 7

Still the same problem. Software version is all updated to the newest versions on GX (3.70) and Multiplus(557).

Battery is at 59VDC

2

Hi can you explain a bit more about how everything is wired, what batteries are you using and how they are connected?

Also 59v batttery is really high, your almost on the 60v multiplus limit, no room left

3

Does it start if you disconnect the GX?
You positive you didn’t connect it to the wrong type of RJ45 port?

4

Hello Marc, thanks for asking. My system consists of 3 Multiplus-2 units in a 3-phase configuration.

It is connected to a 16 cell sodium ion battery with a standalone JK-BMS. Yes the output voltage from the battery is high compared to a Li-ion battery, but is quite normal for a Sodium cell battery. In the beginning when the cells were not fully charged, about 48 Volts, the behavior was the same.
The battery is wired via a DC-Bus to a Victron MPPT 450/100.

The Cerbo GX is also directly connected to the DC-bus.

I will send you some pictures of my system later today.

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5

Hello Nick, thanks for your support. I have read some threads on this subject so I dubbel checked. I am sure I have connected the first of the daisy chained MP2 to the VEbus socket. These are located underneath the Ethernet socket.

Yes, as soon as I disconnect the VEbus connection, the MP2 starts.

What I think is strange is that when I connect my MPPT450/100 it is not visible in the GX configuration. It is visible local via bluetooth.

Maybe my Cerbo GX bus connection is defect?

6

There have been issues requiring pin 7 on the vebus cable to be cut.

1 Like
7

I have disabled pin 7 but with no effect. It does not solve the problem.

9

Maybe you have some stray conflicting settings and it’s worthwhile resetting everything and starting clean.

10

Problem solved by replacing Cerbo GX. I have ordered a new Cerbo GX and now the system is behaving normal. The only thing I do not understand is why I do not see my MPPT450/100 in VRM. Could it be that the VE-bus of the MPPT is also gone defective?

11

MPPT’s are vedirect. Check the cable is seated correctly as they can be fiddly.

12

RS450 is CAN or VE-Direct. If you connected it to VE-Bus → you found your reason for the shutdowns or maybe a broken port.

13

Oke, thank you then I have learned my lesson. I will try to connect it to VE can this evening and see what it does.

14

Please remember to terminate the can bus as per the docs.

15

Thank you all. My ESS sytem is up and running.

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