Multiplus2 with microgrid firmware and setting goes to inverter mode

Q&A and troubleshooting
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1

All, i (tried) to move my single-phase installation:

3 systems, one with 1x , other 2 with 2x MP-II 48/3000/35-32,
all controlled by VenusOS 3.72 on Rasp3,
all with their own DC MPPT and Battery systems,
MP2’s connected via Ve.CAN and MK3-to-USB (the 2 dual-MP2s are VE.Bus interconnected as in spec)
all MP-IIs running Firmware 2629-v561.S97,
configured and cabled as described, all with black start enabled.
to microgrid mode in order achieve combined power.

While one of the 2-MP2 systems come up in Microgrid mode while standalone,
the 1-MP2 system never starts microgrid operation, but moves to ‘inverting’ mode
when moving the switch from “0” to “I” (forward position) or when switching from
“Off” to “On” using remote console.
(i did not dare to reconfigure and re-cable the 3rd system yet …)

Visible as well on the LED indicators, the 1xMP2 lits ‘inverter’ while the 2xMP2 system
lits “mains on” .
Accordingly, there is power measurable at AC-Out on both 2xMP2 and 1xMP2, while
only the 2xMP2 system asserts 230V on AC-in (where the microgrid AC ‘bus’ is connected to)

There is no error or notification shown on any of the Venus systems.

When using VeConfigure3 to check the config of 1xMP2, it correctly shows microgrid
operation enabled.

I am at end of troublehsooting … any idea, if there is additional debug, etc i could turn
on to find the reason for that single-MP2 system to not even turn on power on AC-in
(let alone join the dual-MP2 system’s microgrid) ?

One more question aside: in that 2xMP2 parallel configuration, the 2 Multiplus-es
shall also NOT connect their AC-Out-1 to each other (no load, of course), correct ?

Help greatly appreciated - thanks !

2

Hi, Microgrids are very advanced systems they are really not intended for DIY use. You really need to contact your supplier for help.
The community is not intended as a support site because for one system it is very difficult to diagnose issues from the internet, now we have multiple interconnected systems, so it is just too far beyond what most can help with and minor install and config issues can cause big problems.

Follow the manual strictly:
NO other AC generation sources - no gensets, no PV inverters, no grid. 100% off grid with no other systems generating mains.

NO loads, generation or connections on AC OUT. The inverters must only see themselves and the loads on AC IN.

Make sure every inverter has the right firmware and has been configured for microgrid.

Every system must be fully independent, not sharing a GX or Pi, I am not sure PI’s or uncertified batteries are even supported at the moment given the strict requirements for the system. We will struggle to escalate for any system that doesn’t carefully tick all the boxes.

3

Hello Nick !

Thanks for quick answer - the problem was a hub connector assembly, which created a solid short on that Bank’s AC-in.
I dare to say that IF there was a proper errormessage issued, WHY the MP2 goes to ‘Inverter’ mode although microgrid
operation is enabled, we could have spared this thread (and some manhours).

Nevertheless, you did not answer my question, if there is an option to turn on verbose
debugging or logging for the Multiplus … because right at this time, i have one of the
3 systems reporting “AC-Input: Not available” on the ‘Systems overview’ page, although
the inverter shows “Assisting” as the operation mode and the BMS shows that there
is Watts drawn from it, as much as there is by the 2nd 2xMP2 system (and double as is drawn
from the single-MP2 bank) - measured at the AC-in of the 3 Banks - so that is as expected.
Since it is night right now and the measurements are taken independently from Rasperry
or other Victron equipment, it would also be great, if the system tells me how it comes to
the conclusion that there is no ‘AC input’ , although its in microgrid mode, ‘Assissting’
and really delivering power to the grid … ???

Please if you have contact , check with the developers if they plan to implement
something to dig deeper into the Multiplus’ status and operations - that would be a great help
(not only for microgrid operations, i think) …

Thanks again & best regards,
Martin

4

Hi, unfortunately no ability to extend logging. NS logs are about all that’s available beyond the realtime monitor in veconfigure.
I did pass this link along and a previous case already made me ask about error descriptions as microgrids can be confusing.

5

Hi @ataelim

Thanks for the post and apologies for the troubles.

Nick forwarded on this thread for my attention, I appreciate the feedback and will see if anything can be done to improve error code diagnostics for situations like this.

6

Thanks, Guy, for taking this input !

For the actual topic, i can say that i found the correct setting to prevent “AC-Input: Not available”:
(on gui-v2): Settings - System Setup - AC System:

  • AC Input 1 = “Grid”
  • AC Input 2 = “not available”
  • Position of AC loads = “Input & Output”
  • Monitor Grid failure = “Disabled”

… since i migrated from 3 separate ‘island’ Banks to microgrid, the former setting of
AC Input was “Generator” (because i never fed power to the public grid). This and the
enabled mode of Grid failure monitor has led to the “AC-Input: Not available” alarm.
Internestingly, this alarm did not prevent the bank to ‘assist’ (contribute) to powering
the microgrid, but it refused to display the power flowing from the bank to the microgrid
in the GUI and mqtt reporting.

=> there might be some discrepancy between the VenusOS code and the Multiplus firmware …

thanks again for your input and willingness to investigate and possibly improve !
best regards, Martin