4 east 6 west 410w panels - wire in series, or two separate series into separate dual mppt sockets

[Fred Funk]

Hi, I have 6 west facing, and 4 east facing 410w panels. and a dual mppt inverter (solis). should theses be wired in one series string into a single string , or two strings of 6 and 4, into separate inputs ports of the solis. The solis says min input voltage 120v. the concern is whether minimum voltage requirements of the inverter will stop start up if two strings.

 

[sunshine_eggo]

Hi, I have 6 west facing, and 4 east facing 410w panels. and a dual mppt inverter (solis). should theses be wired in one series string into a single string , or two strings of 6 and 4, into separate inputs ports of the solis.

This.

All panels in a series string MUST be facing the same direction. If you put all ten of them in series, the weaker facing will restrict the stronger facing, i.e., with sun primarily on your East panels, they will put out less than your West panels at that moment.

The solis says min input voltage 120v. the concern is whether minimum voltage requirements of the inverter will stop start up if two strings.

Your voltage concern is legit. Is 4X your panel Vmp > 120V? If not, you're going to have performance problems.

 

[Hendo1337]

Definately wire them into seperate MPPTs. Your solar panels should produce a voltage north of 30V per panel, meaning even a 4 panel string shoujld get you across the 120V mark.

I hope this helps,

Hendrik

 

[cyd]

I used blocking diodes to separate my east and west PV strings. (Not to be confused with bypass diodes) The technical term is polystring and the AIO single MPPT doesn't care. Cheaper at the cost of a few percentage points in efficiency compared to a dual MPPT setup.

 

[sunsurfer]

OP, are those the solarever 410w 108 cell panels? I was looking at them since they have a low VOC compared to most panels in that wattage range. I believe they are 1/2 cell 9BB too.

Just wondering how they are doing in low light? How many watts are you getting in the morning and evening. I'm wanting to do the same thing. Put some east and put some west.

 

[cyd]

OP, are those the solarever 410w 108 cell panels? I was looking at them since they have a low VOC compared to most panels in that wattage range. I believe they are 1/2 cell 9BB too.

Just wondering how they are doing in low light? How many watts are you getting in the morning and evening. I'm wanting to do the same thing. Put some east and put some west.

It doesn't matter if panels are somewhat mismatched regarding Voc.

The important thing is that they are grouped in array(s) facing 90 to 180 degrees away from the original array.

And blocking diodes are vital.

For example my east facing array has Voc of 80v, the west facing array has a Voc of 72v. Without blocking diodes this polystring will not work efficiently.

 

[sunsurfer]

It doesn't matter if panels are somewhat mismatched regarding Voc.

The important thing is that they are grouped in array(s) facing 90 to 180 degrees away from the original array.

And blocking diodes are vital.

For example my east facing array has Voc of 80v, the west facing array has a Voc of 72v. Without blocking diodes this polystring will not work efficiently.

I run mini strings with their own SCC and currently have non with parallel strings to the same SCC. It works really well and no blocking diode needed. That may change for me but I have some diodes in my parts bins if needed.

I'm just curious on the low light performance of the specific panels OP is running if they are the solarever 108 cell panels.

I'm looking at the 100/20 (48v version) victron SCC's and want a high watt panel that has a VOC below 40v for 2S. Allot of the higher watt panels are closer to 50v VOC.

 

[cyd]

I run mini strings with their own SCC and currently have non with parallel strings to the same SCC. It works really well and no blocking diode needed. That may change for me but I have some diodes in my parts bins if needed.

I'm just curious on the low light performance of the specific panels OP is running if they are the solarever 108 cell panels.

I'm looking at the 100/20 (48v version) victron SCC's and want a high watt panel that has a VOC below 40v for 2S. Allot of the higher watt panels are closer to 50v VOC.

That's good you found a system that works. I can see the benefits of seperate SCC units. With AIO systems the user is kinda stuffed if one section of the unit fails but read on...

2s5p polystring arrays work for me as my 4kw AIO inverter is eight times (eight!) oversized for the average load. The working theory is that the electronics should last longer on a low stress life.

FWIW my AIO inverter ignores PV voltages below 55v. I've seen the inverter grind out about 800w when the unclouded sun is low in the sky and the MPPT is hanging around 60~61V. I guess the take home is that the MPPT is quite forgiving and actually works at a slightly lower PV input voltage than advertised.