Warning about Victron MPPT 100 20
UPDATE March 2024: There was a Firmware update for Victron MPPT 100/20 this month. Unfortunately, it seems it did not solve the problem. There is however a Beta Firmware available (V1.64) which is supposed to fix the issue. More infos here and here
A big Thanks to all forum members that continue to contribute to the identification and reporting of these issues at the Victron Forums.
Many users with Victron 100/20 report that strange behaviour Victron 100/20 with variable cloudiness
It seems to be a well-known phenomenon that the Victron 100/20s go down once every 10 minutes and the voltage drops (The behavior every 10 min is normal - that is the MPPT looking for the new maximum power point). If this happens at a moment when the cloud cover is changing rapidly (April weather), the Victron hangs at 3-4W charging power. Often it manages to recover at the next 10min interval. But sometimes it takes much longer... which is really annoying! What leads to success much faster is to deactivate the charger in the APP and activate it again.
The behavior from your lower diagram is not normal - I also have this on my 100/20 and am almost desperate. I have also already contacted Victron support - but there no one really took me seriously and they said that I should buy a Cerbo GX to it (bullshit). My charge controller is also not defective - I have already replaced it and the new one shows exactly the same behavior. I have tried forever around and could not solve the problem directly. Then I made a workaround with Homeassistant: If the PV voltage (in my case) greater than 73V (open circuit voltage) and the MPPT is in "bulk" and produces a power of less than 5W, then I switch a relay that disconnects the PV input from the Victron for 15 sec. and then reconnects - then it immediately continues normally. Too bad that Victron does not take you seriously. I assume that it is a firmware bug - but for 6 months there was no update (have v161 on it). With a friend these problems do not occur with the 150/35.