One for every solar panel connected to the Huawei inverter. Provides rapid shutdown compliance and also performs the MPPT algorithm per-panel (good for partially shaded arrays).
Gauranteed to work. I have not tested every optimizer but the ones I’ve tested have worked and have just a few KWH of usage. Not gauranteeing how many KWH has been pushed through them but I do gaurantee they will be perfectly operational when they arrive.
User Manual:SUN2000-375W-USP0 Smart PV Optimizer User Manual