question

vsheetz avatar image
vsheetz asked

Three 500w strings - convert from one controller to three?

On a motorhome with each string with varying shading throughout the day from air conditioners and such on the roof. Each string is five 100w panels. Currently Midnight Solar Classic 150.

Any advantage to changing to 3 Victron controllers?

MPPT Controllers
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4 Answers
wkirby avatar image
wkirby answered ·

There might be a small improvement in certain conditions, but I don't think it's worth the cost to change just for that purpose.
I once had four strings which suffered varied shading going into my Classic 150 and it worked well for me.

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Paul B avatar image
Paul B answered ·

I would think you may get a little bit more, like 5% maybe 10% max but it may not be worth the change.

shading is always a issue when on one controller in some way but on 3 its much easier to control and to maximize the panels

But the only way to know for sure is to give it a go.


I have never done it and tested it so my answer is a gut feeling reply.


The theory of MPPT says it should make no difference.


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boekel avatar image boekel ♦ commented ·

He / she has 3 strings, as soon as one string is partly shaded it has different properties than the other two strings, MPPT is good but not magic.

But I agree, the real gains might not be very high, so I'd only try it when there is a shortage of power, and other solutions (less shading, different panels) aren't possible.

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ben avatar image
ben answered ·

A few years ago someone ran some controlled tests on a setup like this (just two strings, though) with shading one or the other. The results were that it didn't make enough of a difference to be worth the trouble.

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vsheetz avatar image
vsheetz answered ·

Thanks everyone.

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