Adding solar panels in series facing different directions.

I only have room for 2 more south facing panels but I have a ton of east west side. My question is will there be any disadvantages of putting 2 on my south facing and 3 on my east or west facing, I haven't decided which side yet any guidance on that would be appreciated as well. The panels are is series 5S currently 3P and this will make it 4P. Thanks in advance.

I have panels on both the south and east sides which is helpful in winter with the low sun angle having eastward panels but mine are in parallel into a combiner box so there is no issue. If your panels are in series I think I would do two strings with one string on the East and the other string on the south and then use a combiner box. That way when your east panels are shaded your south facing ones are putting out full power and vice versa.

Arion said:

I have panels on both the south and east sides which is helpful in winter with the low sun angle having eastward panels but mine are in parallel into a combiner box so there is no issue. If your panels are in series I think I would do two strings with one string on the East and the other string on the south and then use a combiner box. That way when your east panels are shaded your south facing ones are putting out full power and vice versa.

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How much do you get out of ur east string in comparison with your south facing ones? Based on what your saying I think I’ll put all 5 east facing and then at least I can see what strings are doing what

More panels on the south of course. I have four panels on the east which come into play more during the winter with the lower sun angle as they are mounted on a gambrel style roof with a pretty sharp angle which works real good for the lower sun during the winter. I did that to help more with the winter power production as I'm located pretty far north.

I just know that if you are in series and one of the panels are shaded that will degrade the rest of the panels in the string whereas if you are in parallel configuration only the panel that is shaded will be effected and the rest will be putting out full output. That is why if you run in series I would have one string pointing south and put all the east panels on the other string and then with the separate strings you would need a small combiner box.

Since I have never done a string in series someone else with more experience should chime in to make sure this advice is sound.

If the panels aren’t the same sun exposure as the current string (they aren’t) you need to
a) put them in a parallel connection provided proper diodes
b) use/add a second charge controller

Hello- I have 1 HQST 40a MPPT & 4 panels total:

2 Canadian Solar 400w (52.3 VOC & 9.9 ISC)

2 REC 370W (44.1 VOC & 10.55 ISC)

Due to space constraints, I will need to have 2 panels facing West and 2 panels facing South. Being they are facing different orientations, I want to lose the least amount of production. I already know due to the panel types being different, I will lose some production due to VOC dropping to lowest in series or ISC dropping to lowest in parallel. I know that the best way to do this is to have panels of the same orientation on its own MPPT.

However if I were to want to remain with just the one MPPT what is the next best way to wire these panels? Can I Just parallel all 4 panels together? Thanks for taking the time to read this. Your help is much appreciated, Happy New year!

Brandontoron,
No, you are gonna need a second SCC. Look at the specs for your scc:

HQST 40Amp MPPT Solar Charge Controller​

• Battery voltage: 12/24V
• Max PV Input Voltage: 100V(25℃)；
• Charge current: 40A
• Max. PV input power: 600w/12v; 1200w/24v

So the max PV solar panel input is 600w. And that is 40A of OUTPUT POWER TO BATTERY, not PV input.
You have 800W if one panel, and 740W of the other. Your SCC doesnt even handle a pair of them. You can't even series 2 of them without exceeding the 100v max in cold weather.

If you wired each pair in parallel:
Canadien 800w total, 52.3voc, you would lose 1/4 possible power on that hqst alone. Now they probably wouldnt really produce 800w, but might do 700 on good days.

1540W total for all of them, theoretical. At 15v to 14v lithium charge rates, thats 113 to 130A needed for a SCC!


If you had a 24v battery pack, you could do twice the watts.