Hello,
I mainly wanted to share this little story if other people have the same issue as during my research I haven't found a lot of answer for this.
Our installation is an ESS system with 2 MultiPlus II in parallel and 2 MPPT 100/20 (48V) BlueSolar, everything connected to a CGX.
One day, out of the blue, during peak production time, we noticed our PV production got cut by half.
After looking into it a bit, we noticed a fixed yellow led on one of the MPPT (instead of a blue one when actively producing).
When looking into the MPPT details in the CGX, we could see that the battery reading where about 58V, while the battery voltage was actually 54~V (measured with a multimeter on the MPPT connection screws).
We tried to exchange the 2 MPPT, the issue following the faulty MPPT, staying in absorption, probably because it was thinking the battery was already full (with the 58V reading).
After looking quite some time in the documentation, we noticed there was a fuse behind the VE Direct connection.
We decided to have a look, and it looks like it was burnt (tested with a multimeter as well):
Luckily, we had one around, and the replacement fixed everything.
But we were a bit surprised with the MPPT not reporting any error anywhere (either with the LED or through the CGX) and the 58V reading (which, from what I gathered, is the theoreticall maximum value for a 48V system, the MPPT defaulting to it when it can't read the proper battery value?)
Is it the expected behavior of the MPPT or did we reached an edge case?
Also, how long are those fuses supposed to live? Our installation system have been running only for less than a year.
Hope it can help anyone having the same issue.
