Solar Panel Direction & Charge Control Question.

[NVCYberPro]

I currently have a string of 10 - 410 watt panels facing solar south, I plan to add two more strings of 10 panels for 30 total panels. I have a single EG4-6500EX at the moment. I had originally planned to add a second one for additional load and PV inputs, as it looks over the last 3 months of use I may not need the second 6500 for power as we rarely hit 65% output on the one, however I will still need additional MPPT's for the PV arrays.

I am up in the north around 45 degrees, what I have noticed is that although the days are getting longer, the production hours on my current string is not. The sun rises far in the east (actually maybe north east) and sets far in the west (maybe north west). What it looks like is that the sun is rising and setting behind the panels and spending quite a bit of time perpendicular to the panels. Although it is still light outside I am not seeing any PV productivity during these times and I am running off of batteries while the sun is still out.

With this observation I am considering installing only 1 more string of panels towards the south and then possibly splitting the third string and add 5 panels at 135 degree to catch the morning sun and another 5 panels around 225 degrees to catch the afternoon sun.

I figure If I could catch sun longer I could get more daytime power and reduce the need for additional batteries.

Questions:

Does this type of scenario make sense or is this a harebrained idea?
If this would work, would the 5 panels at 135 degrees and the 5 panels at 225 degrees need to be on different strings? (wondering if this would be the same as shading?)
Since I would need 3 maybe 4 strings total but not really need the extra inverter power would it be best to go with separate charge controllers or should I just add the other 6500 and pair them, possible use the second 6500 just as a charge controller and maybe a backup inverter?

Thanks in advance for any advice.

 

[MichaelK]

Answer is yes and no. Yes, pointing panels in different directions works, and it's referred to as "virtual tracking". No, it is not going to work in the manner you are describing. Your EG4 has only one MPPT controller input right? I could not confirm this because right now because there appears to be a problem downloading from their site at the moment. That means that all solar strings should be of the same length (voltage). You can not have one 10-panel string paired with another 5-panel string. Secondly, all the panels in one string should be all pointed in the same direction. So, you can not have a 10-panel string with half pointed at 135 degrees, and the other 225 degrees.

You could though accomplish this, but in a different manner. You could convert your original 10-panel string to two 5-panel strings, and then add two additional 5-panel strings, one facing 135D and the other 225D.

A second alternative is to add a second MPPT controller specifically for handling the two new strings, but leave the original 10-panel string connected to the EG4. It would be important for the charging parameters of the new controller to match the EG4's controller exactly.

Thirdly, you could do as you mentioned, and add a second EG4, and connect only 5-panel strings to inverter #2. One advantage of that is that the two inverters can be paired to each other, allowing them to talk amongst themselves on how to best utilize their disparate solar inputs.

Finally, a fourth suggestion is to instead place new panels on rotating mounts like the ones I make for myself and track the sun over the course of the day. I'm finding that I can almost double solar production compared to an array that is fixed on South.

One important issue that I don't have an answer for at the moment is the total number of amps your EG4 can receive at any given moment? Could you please document that to help use better refine answers for you?

 

[NVCYberPro]

The EG4-6500EX-48 has 2 individual MPPT trackers, its my understanding that the strings on each do not need to match. Here is a snippet of the specification sheet.
Thank you

 

[NVCYberPro]

Finally, a fourth suggestion is to instead place new panels on rotating mounts like the ones I make for myself and track the sun over the course of the day. I'm finding that I can almost double solar production compared to an array that is fixed on South.

Would you mind sharing plans on how to create a tracker such as yours? (mechanical / electrical)

Thanks

 

[MichaelK]

Would you mind sharing plans on how to create a tracker such as yours? (mechanical / electrical)

There are no "plans" per say. I just custom-welded unistruts together to fit whatever panels I was ready to mount. Basically, I sunk a 8' length of 3.5" schedule 40 pipe three feet deep in concrete, with 5' sticking above ground. I slipped a 4' section of 4.0" schedule 40 pipe on top of it, with a T made with horizontal unistruts welded to the top of the 4" pipe. The solar-bearing frame is bolted to the T with hinges.

The vertical spar members are 10' lengths if full-channel 1&5/8 unistrut. Diagonal members are half-channel unistruts. I have two locking bolts about mid-way up the 4" pipe to fix the array in a specific direction. The array can be adjusted for both azimuth and declination. There is no motor. I rotate the frame by hand (hillbilly solar tracking).

The two-row design I have pictured can hold as many as 6 large grid-tie panels. So for 5-panel strings, you'd need two of them.

 

[NVCYberPro]

There are no "plans" per say. I just custom-welded unistruts together to fit whatever panels I was ready to mount. Basically, I sunk a 8' length of 3.5" schedule 40 pipe three feet deep in concrete, with 5' sticking above ground. I slipped a 4' section of 4.0" schedule 40 pipe on top of it, with a T made with horizontal unistruts welded to the top of the 4" pipe. The solar-bearing frame is bolted to the T with hinges.

The vertical spar members are 10' lengths if full-channel 1&5/8 unistrut. Diagonal members are half-channel unistruts. I have two locking bolts about mid-way up the 4" pipe to fix the array in a specific direction. The array can be adjusted for both azimuth and declination. There is no motor. I rotate the frame by hand (hillbilly solar tracking).

The two-row design I have pictured can hold as many as 6 large grid-tie panels. So for 5-panel strings, you'd need two of them.

Thank you for that explanation, I think I can see that now, the top pipe simply rotates on the 3.5" pipe. That helps alot.