question

flythesun avatar image
flythesun asked

Switching PV-Panel from one MPPT to another

Hi there!

I was just about to link two MPPTs to one single PV Panel. Since I had some doubt that this will work - I searched the forum an found my exact setup: Two MPPTs + one PV Panel

Conclusion: doesn't work!

Now I was thinking about another approach: how about switching that panel from one MPPT to the other? Will that work?

Is the MPPT fine with the "full load coming in at once" if I switch during sunshine?

Thanks for any thoughts


P.S.: pls excuse my english (german guy)

MPPT Controllers
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3 Answers
wkirby avatar image
wkirby answered ·

Yes, you could switch the PV panel over from one MPPT to the other. It is not recommended though. Better to have the PV connected as a permanent installation.

Make certain that your switch is DC rated above the current and especially the Voltage. An improperly rated switch will create a DC arc and then it would light a fire.

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flythesun avatar image flythesun commented ·

Because of what aspects did you mention the "It is not recommended though." ?

Because of voltage peaks? Will the back and forth switching blow the diodes of the panel and/or of the MPPT in the long run? Any other risks that come to your mind?

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klim8skeptic avatar image
klim8skeptic answered ·

This would be no different to what happens when a cloud passes over your PV panel (or shade from a tree / overpass / tunnel on a mobile system).

PV panels are pretty cheap, why not have 1 for each system?

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flythesun avatar image flythesun commented ·
A second panel will not fit onto my car's roof...
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klim8skeptic avatar image klim8skeptic ♦ flythesun commented ·
Fair enough, small roof.


I now count 3 batteries? Car, plus 2 connected to 2 mppts?

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flythesun avatar image flythesun commented ·
Yes - right you are!
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klim8skeptic avatar image klim8skeptic ♦ flythesun commented ·

Victron actually make a PWM charge controller that can charge 2 batteries.


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flythesun avatar image flythesun klim8skeptic ♦ commented ·
Thanks for the hint! I'll check on that one.
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flythesun avatar image flythesun flythesun commented ·

"...is only suitable for lead-acid, and LiFePO4 batteries..."
That eliminates it.

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kevgermany avatar image kevgermany ♦♦ flythesun commented ·
What batteries do you have?
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flythesun avatar image flythesun kevgermany ♦♦ commented ·

Yeah, I see your point. I have Gel-Batteries which can be set in the settings of the mentioned charge controller. I found it in the manual ;-)

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kevgermany avatar image kevgermany ♦♦ flythesun commented ·
So no problem.
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flythesun avatar image
flythesun answered ·

@WKirby :

Hi Kirby - I see, you're still around...
Would you mind checking for my four little question to your answer?
Would be very much appreciated.

Thank you!

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