Here is my setup:
- 12x 540W JA solar panels
- 1x Victron Multiplus II 48V 10kVA Inverter
- 1x Victron Color Control GX
- 1x Victron 250/100 MPPT
- 1x "no name brand" 10kWh Lithium Battery with some type of built-in Battery Management System (BMS)
This setup powers my home, it uses grid / solar / battery as inputs.
My system was installed by a Contractor in September 2022. Since then, I have had 3 MPPT failures. I wasn't present when the first and third MPPTs failed, but I was present when the second failed. When the MPPTs died they were no longer visible on the color control GX. When the second MPPT failed this is what happened:
- The MPPT stopped working and was no longer visible on the system (needless to say the solar input stopped working with it). The Contractor's electrician came out to "investigate" and decided that all he had to do was "reboot" the MPPT. So he pulled out the cable from the positive battery input terminal on the MPPT and reconnected it (with a small arc). The device came back online and started feeding power from the solar array, this was short-lived. About 60 seconds after reconnecting the MPPT battery terminal there was a significant explosion with a lot of smoke coming out of the MPPT. I believe this was a large capacitor failure.
Aside from the 3 MPPT failures the system also has these issues:
- Inverter battery % reading and the BMS battery % reading varies as the battery discharges. So when the batter is 100% charged the inverter and BMS readings are similar, but as the battery discharges the variance increases significantly to a point where the color GX shows 40% battery and the BMS shows 10%.
- I am South African and we have loadshedding which means the grid goes off 2 - 4 hours at a time a few times a day. Ok so when the grid goes off sometimes the color control GX restarts itself and power to our home is lost until it is completed its reboot at which point power is restored. This happens randomly and the battery is always 100% charged when this happens. When this happens, an alarm relay is triggered ("relay 1 function" on the VRM logs). Interestingly when the third MPPT died the same relay was triggered.
That is a very long story. So the question is, why would the MPPTs keep failing? What is the Contractor doing wrong?
