I connect 2*40W polycristalline PV on my MPPT 75/15 to charge 7 Ah battery (for electric car). VictronConnect shows me : Power = 15W, Voltage = 19.2V, Current = 0.8A during Absorption. When I connect only one 40W module, things seem better (e.g. Power rises above 26W). Measured directly, each PV gives Voc ~21 V, Isc ~ 2,4A.
A couple of months ago, I connected 600W PV on this controller without any problem…
Any explanation ?