Before I bother the supplier for a warranty replacement I thought I should see if anyone has any ideas why my newly installed 150/45 smart solar MPPT is not performing as it should.
The PV array is 2 strings of 3 REC Twin Peak 4 modules in series, Voc of around 120v MPPT voltage of 105V, the Isc for each string has been measured under strong sun at 10.5A.
The MPPT output fluctuates wildly and falls to zero and compared to the output of the AC coupled array mounted next to it is giving very little power output. The AC array is 8.6kW so I would expect around 25% of the output power of the new DC coupled array at any given time but rarely see more than 10%.
I have checked all the connections and tested the array at the end of the cables feeding the MPPT, the Isc and Voc are as expected for the insolation.
Measuring the current using a clamp meter going into the MPPT I can see it drawing a current of around 1.5 amps (Insolation of around 200w/m2) but not indicating any power output at all on the GX or connect app, 1.5 amps being the approximate Isc measured under the light conditions at time of test.
Twice, on seperate days, the MPPT has flagged up a #28 fault code on the GX system which can be cleared by isolating the unit and re-connecting it but the output power remains very low as above.
MPPT is connected to the battery with 16mm2 cables around 1.5 long, PV cabling is a 4 core 6mm2 SWA cable (2 cores per string) connected in parallel at the DC isolator, Cable run is 12m.
If anyone has any suggestions I would be grateful otherwise I will return the unit as a warranty claim.
Thanks,
Nick
