Cerbo GX + 3Ph MultiPlus-II failing with Error 10 when incoming AC fails

Q&A and troubleshooting
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1

My setup is 3x MultiPlus-II 48/5000/70-50 for a 3-phase system, and a Cerbo GX. Software version is 3.66 on the cerbo and v558 on the MultiPlus’ses, Updated today from 3.60 and v498, but the issue is the same.

Everything works fine until the incoming AC fails. Then it switches to battery power, but after about a minute, it switches off with “#10 System time sync error”. I understand that according to VE.Bus error code list (sorry, can only put 2 links in a post…) this error is usually a ‘by product’ of other errors, but in this case, its the only error i get. After about 10 seconds the error disappears and the system powers on again. Only to fail again in the same way after 10 - 30 or so seconds. This keeps repeating.

When i disconnect the converters from the Cerbo, it works. If i connect it via an MK3 to my laptop, or the cerbo, it works. When i plug it back into the direct VE.Bus connector on the Cerbo, it fails again.

It looks identical to whats described in Lost Grid followed by VE.Bus Error 10: System time synchronisation problem - VictronEnergy , but there the work-around seems to be to use the MK3, but i was just told in Inverter Data not showing on GX Display - #12 by pwfarnell this is not supported (anymore?) and converters connected via the MK3 are seen as secondary.

The battery are 6x 4.8kWh Pylontech. When i tested it, the load on the system was about 400W, and they batteries where at 40% SoC.

Grid code is for The Netherlands.

Anyone can help me resolve this issue? i would like to use the system as a backup for the house.

Thanks!

2

The Cerbo ought to see a Mk3 plugged into a USB port the same as the built in Mk3. I would try this and see.

Else, the root of error 10 is that the inverters lose synchronisation with each other. This can be caused by loose or dirty inverter negative terminals - if the common negative is lost, then a sudden draw of battery current can block the VE-bus data = but if this were the case one would expect that to show up on the external MK3/laptop set up. Alternatively, check the VE-bus communications cables are secure, shop made, and free from interference i.e. routed next to power cables.

3

Hi Mike,

I have tried this, and a MultiPlus-II connected to via an MK3 is not the same as direct. It does show up in some screens, but not on the main one, and not in the ESS one either. From what i understand, your primairy Multiplusses MUST be connected to the on-board VE.Bus of the Cerbo, any connected via the MK3 will be secundairy.

4

The one time I tried this, the external Mk3 worked fine, but it was not an exhaustive test. This was on an old cerbo that lost it’s internal Mk3 due to a firmware update glitch. Maybe results are different if there are 2 Mk’s on one Cerbo.