Asking for a neighbour MIXING PANELS?

[Wjm1964]

Hi guys, I'm fighting the virus and it's clearly fizzled my brain. My friend & neighbour has a small 400w solar system, two 200W 12v panels but they differ in specs. 1 panel had a Voc of 27V Isc 9.66A Vmp 22.6v Imp 8.85a. The other panel has a Voc of 23V Vmp 19.2 Imp 10.42A.
She currently has them wired in series going to a victron MPPT 100/30 charge controller and has about 5 12v 100ah lifepo4 batteries but I think she has 2 in parallel at any time. She knows that going 24v is probably a better option but is using a 12v inverter.
She wants to add another panel & has been offered a 250w with Voc 37.7v isc 8.79a Vmp 30.4v Imp 8.23A
Thing is can she add this additional panel to the 2 she has with her controller or will she need to 2S 1P to keep within controller specs or will she need to go with a 24v battery/ inverter set up?

I apologise in advance if this is blatantly obvious but my brain is not finding its gears.

Thanks for any input.

 

[Quattrohead]

All 3 in series will be around 87v, should be fine.

 

[Wjm1964]

Many many thanks. I was very confused about wattage max with a victron MPPT 100/30. Google says 400w - 440w max depending on sources..

 

[sunshine_eggo]

Hi guys, I'm fighting the virus and it's clearly fizzled my brain. My friend & neighbour has a small 400w solar system, two 200W 12v panels but they differ in specs. 1 panel had a Voc of 27V Isc 9.66A Vmp 22.6v Imp 8.85a. The other panel has a Voc of 23V Vmp 19.2 Imp 10.42A.
She currently has them wired in series going to a victron MPPT 100/30 charge controller and has about 5 12v 100ah lifepo4 batteries but I think she has 2 in parallel at any time. She knows that going 24v is probably a better option but is using a 12v inverter.
She wants to add another panel & has been offered a 250w with Voc 37.7v isc 8.79a Vmp 30.4v Imp 8.23A
Thing is can she add this additional panel to the 2 she has with her controller or will she need to 2S 1P to keep within controller specs or will she need to go with a 24v battery/ inverter set up?

I apologise in advance if this is blatantly obvious but my brain is not finding its gears.

Thanks for any input.

Panel 1 and Panel 2 in parallel are not a particularly good combo due to the discrepancy in Voc/Vmp. There's likely a 15-20% penalty, but it's better than putting them in series.

Panel 1 has an Imp of 8.85A (-7%)
Panel 2 has an Imp of 10.42A (-21%)
Panel 3 has an Imp of 8.23A

Panel #3 will force Panels 1 and 2 to operate at no more than 8.23A

This will case Panel 1 to perform at -7% below rated, e.g., a 200W panel will perform like a 186W panel.
This will cause Panel 2 to perform at -21% below rated, e.g., a 100W panel will perform like a 158W panel.

So adding the 250W panel reduces the performance of your other panels by 56W.

This will only matter in peak solar conditions

87Voc is good down to about -12°C/10°F

Rules to observe:
Panels in series will operate at the lowest current panel in the string.
Panels in parallel should have very similar Vmp and will tend to operate closer to the Vmp of the lower panel when panel power is similar.

 

[Wjm1964]

Panel 1 and Panel 2 in parallel are not a particularly good combo due to the discrepancy in Voc/Vmp. There's likely a 15-20% penalty, but it's better than putting them in series.

Panel 1 has an Imp of 8.85A (-7%)
Panel 2 has an Imp of 10.42A (-21%)
Panel 3 has an Imp of 8.23A

Panel #3 will force Panels 1 and 2 to operate at no more than 8.23A

This will case Panel 1 to perform at -7% below rated, e.g., a 200W panel will perform like a 186W panel.
This will cause Panel 2 to perform at -21% below rated, e.g., a 100W panel will perform like a 158W panel.

So adding the 250W panel reduces the performance of your other panels by 56W.

This will only matter in peak solar conditions

87Voc is good down to about -12°C/10°F

Rules to observe:
Panels in series will operate at the lowest current panel in the string.
Panels in parallel should have very similar Vmp and will tend to operate closer to the Vmp of the lower panel when panel power is similar.

Can't thank you guys enough, I will convey the info. Many thanks ?