Sol-ark 15k MPPT connection question

[mistertam]

I have 24x 400w solar panels configured like so:
2 sets of 8 panels in series. 16 panels total. Combined into 1 string
1 string of 8 panels in series. 8 panels total. 1 string


4 Total Wires coming from roof:
PV1+, PV1- (string "MP1: 1x8", 10awg)
PV2+, PV2- (combined string "MP1: 2x8", 10awg)

Using the Sol-Ark Sizing Calculator https://www.sol-ark.com/solar-panel-sizing/SolarPanelSizing.html

It looks like I need to connect the wires to the Sol-Ark using Configuration A

Can someone with better understanding of MPPTs help me double check to be sure it's not supposed to be Configuration B?

 

[Danke]

I think you need to change “Number of strings MPPT 2” to 2

 

[mistertam]

I think you need to change “Number of strings MPPT 2” to 2

Good catch. Thanks. Changed

 

[Danke]

Not supported in B. That would be all strings (24 panels) on MPPT 1

 

[mistertam]

Thank you for confirming, Danke. Always nice to have someone check my work. Config A it is.

 

[Danke]

Thank you for confirming, Danke. Always nice to have someone check my work. Config A it is.

Although you may never see 400W production per panel, you are potentially giving up 1400W by not running separate wires for all strings and using MPPT 3.

 

[mistertam]

Although you may never see 400W production per panel, you are potentially giving up 1400W by not running separate wires for all strings and using MPPT 3.

I didn't know that. After this sol-ark conversion, I'll look into re-wiring the panels. Tesla did all the wiring, so I'll need to see where they combined the 2 strings. May I ask how you calculated 1400w? Thanks.

 

[Danke]

I didn't know that. After this sol-ark conversion, I'll look into re-wiring the panels. Tesla did all the wiring, so I'll need to see where they combined the 2 strings. May I ask how you calculated 1400w? Thanks.

19,500W Max from panels, but 15K can only use or invert 15,000W.

 

[mistertam]

I get it now. I think you're right. It definitely makes sense. I'll call them and ask, but looking at the spec sheet, I tend to agree with you. Appreciate the responses. Thanks again!

 

[GregTR]

I have a similar setup. 2x8 into MPPT1 (East) 2x8 into MPPT2 (South) and 2x6 into MPPT3 (West). My panels are 440W Aptos DNA 144 half cells.

I can safely say that each MPPT can handle the 6,400W on their own, there is no 5kW limit per MPPT. This is production from the 3 MPPTs the other day.



The only thing that concerns me is that you're running 10AWG for the 2x8 strings which can theoretically carry 20+ A and I would much rather have that on 8AWG or two pairs of 10AWG. My setup has a total of 6 strings and they're all home ran to the Sol-Ark 15K on 10AWG.

But if you run separate wires you might as well run to separate MPPTs in case there is a string imbalance. We don't know your orientation/shade situation, but generally individual strings will perform better than strings in parallel, even if they're perfectly matched.

My West facing panels have some shading that does not go away until around 2:30 in the afternoon, and my Tigo optimizers aren't working yet as I'm still waiting for the CCA to be connected and provisioned. Once that works I think I will see a much better power curve out of the west than the one I have today.

 

[mistertam]

I have a similar setup. 2x8 into MPPT1 (East) 2x8 into MPPT2 (South) and 2x6 into MPPT3 (West). My panels are 440W Aptos DNA 144 half cells.

Thanks, Greg. Great info. I'm definitely more confident in setting this up with asis wiring now. My current wiring was done by Tesla when they installed the panels. It's a taller than avg 2-story, so I was hoping my 2x8 string was okay since even with my roof harness, it's not fun looking down from the edge.

All 24 of my panels are south facing with 0 shade/trees and standard 4/12 pitch roof. That is a really cool graph you have. Is that from the Sol-Ark app? So the app can customize the name of each controller and can graph each one? That's good stuff.

 

[GregTR]

That is actually a Grafana chart I custom created with data from Solar Assistant, a paid monitoring app running on raspberry pi.

Either way, you'll be more than fine with your setup as is, I would not bother with splitting up the string unless you have shade issues. I hit just over 7,200W from my south facing panels for a few minutes. Today it was overcast which can produce some weird reflections where I actually got more power than if it was just regular broad daylight.

The Sol-Ark setup is a BEAST! I am very impressed with mine so far, it is by far the best solution for whole house solar with backup on the market.