Mppt 150/70 MC4 (two different solar panells groups)

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buryck asked Aug 23 2020 at 10:16 AM

Mppt 150/70 MC4 (two different solar panells groups)

Hi, i'm planning on buying a EasySolar 24/3000 150/70 MC4, but i have 2x160w solar panels and 2x350w solar panels. Each group will be conected in series, but my question is: can i connect each group separetly to the two mc4 conector sets on the mppt controller, or would there be a bottleneck?

Do i have to buy a sepparate mppt for the 2x160w group?

Thank you.

MPPT SmartSolar EasySolar All-in-One

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Answer 1 · 2020-08-23T10:42:52Z

Matthias Lange - DE answered · Aug 23 2020 at 10:42 AM

Connecting different panels to one MPPT will not work well.
You have to use a separate MPPT for the 160Wp panels.

Answer 2 · 2020-08-23T13:32:10Z

JohnC answered · Aug 23 2020 at 1:32 PM

Hi @buryck

It'll work, but depends on panel specs how well. If the Vmp of the panels are fairly close then it should be ok. What are they?

3

buryck commented · Aug 23 2020 at 3:10 PM

The 160w panels: Voc - 22.9V / Isc - 8.37A / Vmp - 20.2V / Imp - 7.92A

The 350w panels: Voc - 40.73V / Isc - 10.79A / Vmp - 34.07V / Imp - 10.27A

I was tinking one way is to connect the two 160w panels in series, then connect them with the other 350W panels in parallel, and have (160w+160w) + 350w + 350W.

But is it possible to connect them in series with the 350w panels???

Thank you

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JohnC ♦ buryck commented · Aug 24 2020 at 1:19 PM

@buryck

They're not a good match. Your first option leaves you still with a fair mismatch of Vmp, and a quite low one at that too, which may well be much lower in poor light, and then not sufficiently above Vbat to keep charging.

Putting them in series (your 2nd question) would reduce all panels to 160W, so you'd lose more than you'd gain.

I don't think there's any real danger testing any of this, but there's no doubt that the 2x 350W panels would really be best in series, and would cover all weather conditions at your batt V.

How best you add in the other 2 is for you to test.

A 3rd option is to have the 350's in series and add in the series'd 160's alongside. The single mppt will still track them as a combo, and you should still see a gain, but it may not be much.

Edit/: If you're testing give the mppt at least 10 minutes to retrack, or power it down to force a retrack.

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buryck JohnC ♦ commented · Aug 24 2020 at 3:50 PM

Thank you for the answer :)

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Answer 3 · 2020-08-24T01:42:57Z

misullivan answered · Aug 24 2020 at 1:42 AM

You cannot do this.. well you can if you want to lower the power and risk a fire/electronic damage.

The MC4s on the easysolar are just paralleled.. so you’ll be connecting two differing voltages together... you cannot connect them in series (160+350x2) either as this would overload the smaller panels.

You need another MPPT for the differing spec panels.

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Mppt 150/70 MC4 (two different solar panells groups)

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