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Old 06-09-2012, 11:24 AM   #1
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Can you connect different voltage PV panels?

I have one 240w 36v solar panel running through a Morningstar 45 MPPT controller. I have just acquired a 130w 17v panel that I would like to add to my 36v panel. Does anyone see a problem with this?

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Old 06-09-2012, 03:58 PM   #2
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Hmm....dont think that you can mix two different voltage panels. It would be like connecting a 6 volt and a 12 volt battery together.

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Old 06-09-2012, 04:31 PM   #3
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Morningstar or one of their dealers should have the answer for that.
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Old 06-09-2012, 04:39 PM   #4
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I think you would have to get another controller for that one panel, and then you could connect the outputs together at the battery bank.

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Old 06-09-2012, 07:08 PM   #5
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Originally Posted by FlyingDiver View Post
I think you would have to get another controller for that one panel, and then you could connect the outputs together at the battery bank.

Two answers: Answer 1: Ditto (Joe got it)

Answer 2... You would need protective diodes to make sure the higher voltage panel did not back current the lower voltage, and the lower voltage panel would never actually output current save for the very odd case where it is in full sun and the higher voltage panel is not.

Suggestion: use Joe's suggestion (2nd controller) and hook it to the CHASSIS battery.
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Old 06-10-2012, 08:51 AM   #6
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You can wire them in series. You have to make sure the controller can handle the higher voltage, which it probably can. You would have the current capacity of the smaller amperage panel.
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Old 08-16-2012, 06:11 PM   #7
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There is a good discussion on Solar Electric Power Discussion Forum by Northern Arizona Wind & Sun
I have two panels with a similar difference in voltage and for the lower voltage panel I went with a separate PWM Steca controller, and it plays well with the Morningstar MPPT. One of the Morningstar Sunsaver PWM would also be a very good choice, (I got a real steal on the Steca)
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Old 08-17-2012, 10:59 AM   #8
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I say yes, if in series, and the controller will allow it and probably will as it's MPPT. Consider this - I have a 24 volt battery bank, and get this by series wiring 4 6 volt battery's. At each interconnection the voltage is different, being 6,12 18, and 24 volts, and each stage does not know if the stages prior to it is from 1,2, or however many battery's, it only knows the voltage. Same thing with panels, you wire them the same as battery's! Say you use the higher voltage leading into the lower voltage panel, the lower voltage does not know how many panels, or of what voltage is prior to it, and adds it's voltage. Done. It may not be the best producing string overall, but it can be done. I'd do it, and test the results because electrically, it's fine! IMHO Ed

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