Hi,
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 ?
Maybe but its a guess
are you are placing the two panels in parallel then maybe one is pulling down the other ones voltage. thus lower output.
try them in series so the voltage goes higher to 42 volts.
to test each panel use a DC clamp meter join one panels neg and pos and then the secound panels neg and pos and place both in good sun light measure the amps each produce.
then disconnect each panel and measure the open circuit voltage of each panel.
these should match what the panel tag says.
when disconnected from the controller, I get from the PV 2.2A current and ca 39V voltage (serie connection). And see the attached once everything is connected. It's getting worse… 0A charge current also when I connect one pv module (ca 19V). About clamp meter measures: I got quite the same values on the clamp meter and the panel before everything is getting worse ! A couple of days before, it was able to charge the battery, but never went beyond 38W (I tried serie and parallel connection).
I tried several configuration, but this controller don't charge anymore!
