question

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jmarc asked

Why are some MPPTs in Stand Alone when DVCC is active

We have the following set-up:

Cerbo GX v2.89

Batteries: 2 x MG Energy masters V1.30 with Combined Master app (phyton3)

8 x MPPT250/100 Ve can V3.1 networked via can

3 x quattro on Ve.bus paralleled v497

1x quatro Via MK3 usb link v430

DVCC is set-up to follow MG Combined master charge reference

2 / 8 MPPT are in External control like they should

5 / 8 MPPT report being in Stand alone mode and do not follow BMS

1 / 8 MPPT does not appear to communicate. Still investigating

7 out of the 8 Unit are being reported by the Cerbo and are visible via VRM.

Why are 5 units not in external mode like they should. What can we/should we do to have them go to that mode?

MPPT Controllerscerbo gxDVCC
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3 Answers
jmarc avatar image
jmarc answered ·

Hi Corey,

thanks for the comment but those are not drop in batteries. The masters are Active masters providing current and voltage control limits to the Cerbo. The MPPT's should all be in External control. I do not know why some are and some are not. First thought is communication (VE.CAN) but Cerbo does receive the status for all of them but one. It is my understanding that the MPPT will revert to Standalone in case of network loss. But why do not they reconnect back? A review of the Network status in the Cerbo does not indicate any major issue:

1658785809071.png


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jmarc answered ·

We have resolved the problem at this stage but it raises more questions...

In short to resolve the issue we had to return all the stand alone MPPT's to default factory settings. Rebooting the unit. Removing power from the PV and the Batteries did not resolve the issue.

What we noticed was that after we reset all the Stand alone unit to Factory Default in the new MPPT section "Network Operation" Menu the status of one of the unit was "Group Master":

1658893635501.png 1658893693635.png


Why this unit decide to be the group Master. What group? Master of What?? not sure. All the other MPPT's are in Slave mode so they must be obeying the Master. I cannot find any information on this subject. Anyone with info please share.

But bottom line:

1) We do not know why 5 units were in Stand Alone mode. Could it be that DVCC was not yet set when the MPPT first came online? But it is clear from the VRM history that the unit were in Standalone mode from day one.
2) The two units that were in Slave mode are in fact new units we replaced and we did the software upgrade. They were in fact online when DVCC was already activated.

Why do we have to go to the extreme Factory reset to enable the mode?

Some documentation on the subject would be appreciated.


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jmarc answered ·

Update:

System is still being commissioned. So every night we shut it down. This morning, when we arrived we switched ON the MPPT solar panel Input first.

This did awake the Cerbo and it correctly displayed that all 7 MPPT's had Error #67 Missing BMS. All the outputs were in Float.

We then turned ON the Battery. Error #67 disappeared to be replaced by Error #66 Incompatible Devices. The documentation indicates this means that different devices have different charge algorithm...

1658981033936.pngBUT Why??? Yesterday they were fine all working happily. Only thing we did is shutdown the battery at the end of the day and open the PV panel power to the MPPT. and reverse the process this morning.

All 7 MPPT's are the same type. All upgraded to latest version. All reset to factory default yesterday

When I check the Network Status with Cerbo, today

  • 3 of them have decided to be Group Master
  • 4 are Slaves

They all say

  • BMS controlled "YES"
  • Externally Controlled
  • All seem to operate normally

Using the Reset BMS does not change the the Fault status nor the Mode:

1658981221365.png

Error #66 does not appear in the VRM log


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1658981221365.png (75.6 KiB)
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