Hi Community,
I nearly did a mistake setting up my system by forgetting the temperature coefficient in the calculation. Luckily, I recognized it early enough but now I have to deal with less PV cables… My plan was to install 12 JA solar JAM60S20 in two strings (6 in a row) on a MPPT 250/85 MC4. Considering the temp. coefficient this is not gonna work at low temperatures. Now I need to split the strings to avoid over voltage but I am limited to 2 Strings (4 cables) because the basement wall ist closed and sealed already. Is it possible to go with 3 strings via 2? Meaning by this: 4 modules in a row are going directly to the first MC4 port of the MPPT. The other 8 Modules are combined to 2x 4 in a row on the roof connected by Y-connectors and fed to the MPPT via the second string. At the MPPT, both strings would have equal voltage but the second string will carry the double current (max 24A). Could that work? Should make no difference if parallel strings are combined inside or outside the MPPT as long as the max input of the MC4 terminal of 30A isn’t exceeded, right?
Looking forward to your expert answers!
Beset regards
rer.nat.
