Feedback on FlexBOSS21 + FlexBOSS18 Stringing Plan (47 × JA-Solar 440W)

Hello everyone,

I’m planning to install 47 JA-Solar JAM54D41 440W panels (Vmp ≈ 32.47 V, Voc ≈ 38.9 V, Imp ≈ 13.55 A).

At first, I thought a single FlexBOSS21 could handle the full array since we’d be under the 21 kW PV limit. After reviewing the MPPT current limits, I realized it isn’t possible to safely distribute all 47 panels across its 3 MPPT inputs.

To stay within spec, I’m planning to add a FlexBOSS18 and split the array like this:

• FlexBOSS21: 31 panels → 3 strings (11 / 10 / 10)

• FlexBOSS18: 16 panels → 2 strings (8 / 8)

Both inverters will be connected to three EG4 Wallmount indoor batteries wired in parallel.

Does anyone see any issues with this setup? Any suggestions for improvements or alternative approaches?

Thanks in advance,
Ray