MPPT 150/100 VE.Can stops charging the battery for some unknown reason.
In my setup running stable Venus OS v3.70 I have DC-side excess energy export to the grid enabled. Today I noticed that the MPPT charger simply stopped working. First thing I did was reboot the Cerbo GX, and at first glance that seemed to help. But as soon as the charger switched to “External Control” state, it stopped working again.
My configuration has been stable for quite a while and basically unchanged, so this really got me thinking. It turns out that disabling DVCC fixes the problem immediately. The MPPT starts working again and DC-side export to the grid functions correctly.
Interestingly, I already had this issue once on one of the 3.70 beta versions. I even mentioned it in the main 3.70 beta thread. Back then, reverting to 3.67 solved the problem. The system ran for a few days on the older stable firmware without any issues. Then when a new 3.70 beta was released, I started testing again. Everything had been working fine — until now.
To make things even more confusing: re-enabling DVCC a few minutes later did not cause the issue to come back.
Where should I start looking for the root cause?
Unfortunately, I can’t roll back to 3.67 anymore for testing, because installing 3.7 wiped my local 3.67 firmware copy from the Cerbo.
You can download and reflash the device with 3.67.
Worth checking if your battery set CCL to 0 at the time.
DVCC is effectively enforcing what the battery is asking for, so if it is shutting MPPT’s down it is because that is what it is interpreting the battery wants.
The behaviour can vary depending on the pack, this isn’t a DIY BMS is it?
My system is not controlled by the battery BMS, so the BMS definitely wouldn’t be able to enforce or override anything. I’m using DVCC only to manually limit the maximum battery charge current to 100A.
Also — what’s the simplest way to install Venus OS v3.67 on the Cerbo GX? Can I upload the OS image to some specific directory via SSH and downgrade that way?
Unfortunately, I don’t have a microSD card on hand, so I can’t follow the standard recovery procedure. I’d also prefer not to wipe any settings — I just want to reboot the Cerbo on the older firmware version.
EDIT:
OK, the issue has just happened again.
The MPPT has practically stopped working. Meanwhile, the PV inverters connected on the AC side are producing very nicely the whole time. The panels are on the same roof and facing the same direction.
After disabling DVCC and rebooting the Cerbo GX, the MPPT starts working properly again.
That’s the PV side. Send the battery end please.
That is a low PV voltage. If it is getting very marginal in places to the battery voltage +5V cutoff that will lead to the mppt stopping charge, can’t see specific values from the image.
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