Ever since I got my first set of mismatched panels, seeing then react to different conditions convinced me they would interfere with a MPPT controllers ability to track. With the TS-MPPT-60 I could log a series of test with the three different panels I have, 220w mono, 230w poly and 250w poly. They will have to be in series, I don't have the branch connectors or wire for parallel yet. It wont be tomorrow, I was lucky to have the sun for a few simulated flat mounted test today before the weather came up. I'd need a few days of nice clear sky between 11:00 and 1:00 for the test. Start with a individual log for each panel as a basis. Then a log of the mono paired with each poly, the poly with the other poly and all three in series. Each log can have just about any info needed and is easily turned into charts. Any interest or boring?

Hi Jim,There is never too much data! Go for it.

I'm interested but I'd be glued to the experiment if you could do it in parallel. AFAIK, that is the situation that confuses the MPPT function.

With panel voltages varying so much, (even with matched panels), due to partial shading and such, I'm not convinced it will pose a problem for the mppt controller. But I guess we're about to find out.As Captain Picard would say... make it so.

I'll start working on it then. One road block for parallel is finding 3-1 branch connectors rated for over 30a. I can find 2-1 rated for 50a but not 3-1. Then I realized that if I did find a 3 to 1 rated high enough that there are no MC4 connectors that will handle 2 AWG wire. Bus bars are looking better and better all the time.

Yup, bus bar. Have any old load centers hanging around? Otherwise 8 place panel mount bus bars are around $10 at Home Depot. I used a couple shorter ones to make my combiner box.

Interest in mismatched panel test? | Good Sam Community

37 Replies

CA_Traveler
Explorer III
May 17, 2015
Sounds interesting. Please post the panels make/model.
BBFD
Explorer
May 17, 2015
Given our crappy weather don't expect to hear from Jim until at least June! Seriously, I am interested as I have 2 150 watt mono panels now for my new TH that will be delivered this week. I am somewhat concerned that I don't have enough real estate for 2 more of the same panels I want to add. Thus I may have to go with smaller 100 watt poly panels from Solar Blvd due to spacing and shade issues from 3 vent covers and the AC. Curious to see the results.
westend
Explorer
May 17, 2015
Yup, bus bar. Have any old load centers hanging around? Otherwise 8 place panel mount bus bars are around $10 at Home Depot. I used a couple shorter ones to make my combiner box.
JiminDenver
Explorer II
May 17, 2015
I'll start working on it then. One road block for parallel is finding 3-1 branch connectors rated for over 30a. I can find 2-1 rated for 50a but not 3-1. Then I realized that if I did find a 3 to 1 rated high enough that there are no MC4 connectors that will handle 2 AWG wire. Bus bars are looking better and better all the time.
jrnymn7
Explorer
May 17, 2015
With panel voltages varying so much, (even with matched panels), due to partial shading and such, I'm not convinced it will pose a problem for the mppt controller. But I guess we're about to find out.

As Captain Picard would say... make it so.
westend
Explorer
May 17, 2015
I'm interested but I'd be glued to the experiment if you could do it in parallel. AFAIK, that is the situation that confuses the MPPT function.
pianotuna
Nomad III
May 17, 2015
Hi Jim,

There is never too much data! Go for it.

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Interest in mismatched panel test?

37 Replies

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