Adding another string of panels to Growatt 5K voltage question

[Dskvid]

Hello,

I currently have 6 x 370watt @ 41VOC panels up for a year now. I discovered that my 6 six panel array was not ideally located for winter and last year took 4 of these panels to different part of yard. This year I wish to leave main 6 panel array alone and add 4 new panels at my winter location. I was thinking of buying 4 X 450 watt with a VOC of 50.3. They would be on separate run and breaker but would meet up on Y cable at the Growatt 5K as it only has one MPPT. Is this ok to mix this much of swing on voltage potentials? In winter the 4 new panels will be active the 1st and longest part of the day but Im hoping to have all 10 panels in operation in the summer time. I could just add more the 370w but because I'm only able to put 4 in this location trying to get more bang for the buck.


Thanks for reading

 

[MisterSandals]

Is this ok to mix this much of swing on voltage potentials?

Yes but the higher voltage array will be clipped to that of the lower voltage array. The amps will be summed.

You'd use the Vmp and Imp to do this correctly, here is my go with Voc:

6 x 40.1V = 240.6V (370W / 40.1V = 9.2A)
4 x 50.3V = 201.2V (450W / 50.3V = 8.9A)

Output would be (if we were using correct Vmp and Imp)
(9.2A + 8.9A) x 201.2V = 3642W <---fixed, i had it wrong earlier

 

[Dskvid]

Thanks for the response .
OK so it sounds like it i get more constant power by keeping all the panels the same or at least closer, But here is what the other info is:

370W panels are VOC 41, VPM 34.2, IMP 10.82

450W panels are VOC 50.30, VPM 41.40, IMP 10.87

 

[MisterSandals]

6 x 34.2V = 205.2V (Imp = 10.82A)
4 x 41.4V = 165.6V (Imp = 10.87)

21.69A x 165.6V = 3592W

The voltage difference, leaves (205.2V - 165.6V) x 21.69A = 859W unharvested (a lot)

I could just add more the 370w

If you added 2 more to this location and configured this as 4S2P that would make 136V.
Adding 4 more panels (10 total) would be 5S2P for 170V that is a very good match for the 4x 450W panels.

 

[Dskvid]

Thanks for the math, it seems like short term benefit of have the extra wattage is quickly out weighed by the voltage and cost. lol

 

[MisterSandals]

Thanks for the math, it seems like short term benefit of have the extra wattage is quickly out weighed by the voltage and cost. lol

You could get those same panels and add an SCC to charge the batteries as a separate system.
What is your battery voltage? Guessing 48V...
4x 450W = 1800W
1800W / 58V charging = 31A

Mighty nice SCC 40% off ($218, reg $364):

Amazon.com