I made a small addition to the title to reflect the above.
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@plonkster it looks like the problem lies in Venus OS. I did a firmware update on a Multiplus II at another site. This time I switched off the AC input to the Multiplus II, and I also set the charge voltage limit in DVCC to 50V. This site has a SmartSolar 150/85 connected to 3.4kWp worth of panels.
This is what happened for a few seconds around the time of the firmware update:
As you can see the 50V charge voltage limit was ignored and the solar charger ran at full tilt for a short while.
Have the correct charge settings been set in the MPPT?
I do this with all my MPPTās even if the GX has the control. That way if the GX stops doing its job they MPPTās wonāt overshoot.
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Yes, I always set the Multiplus II and any MPPTs to a charge voltage of 52V before I bring any batteries near it. I wonder why that is not the default from the factory?
Next time before I do a remote firmware update on a Multiplus II I will set both the MPPT and DVCC charge voltage limits to 48V to see what happens.
The BMS bit is set in the network mode, which means when it stops getting external voltage setpoints it drops its charge voltage to 48V, and raises error #67.
It is still a good idea to set good settings on the MPPT, just in case it does somehow come up in standalone mode (that could happen if you lost BMS comms and some helpful tech resets the BMS bit on the charge controllers after restarting the Multi), but in this context it should not happen.
Sorry, I still need to look into this again. As I saidā¦ found the wrong bug and it got fixed. Now I have to go back to the dev and tell him itās still an issueā¦ well, first I have to check whether it is or isnāt.
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Please let me know if there is anything I can do to assist. Both sites are on VRM, so if you think there will be anything useful in the logs I can send you the VRM IDs and the exact timestamps to look at.
I switched off the MP2 for a short while tonight, and this is what happened after I switched it back on:
Notice the 56V effective charge voltage for about a minute.
Perhaps the firmware update is a red herring, and there is something going wrong with the charge voltage immediately after the MP2 is switched on. All my devices are set to a 52V charge voltage, so I do not know where this 56V is coming from.