Mppt Controller High Amps or High volts

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Mppt Controller High Amps or High volts

Postby Rainier70 » Tue Apr 30, 2019 9:11 am

I am thinking of adding a couple of panels to two that I already have.
The two that are now connected are wired parallel and send (in theory) 10 amps at 20 volts to the mppt charge controller.
I am considering connecting the two new panels in parallel also, but then connecting their end cables in series with the other two panels. So it would be a total of 40 volts at 10 amps to the controller to save on wire drop.

The controller is 40 Renogy MPPT.

Is there any advantage or disadvantage in either high voltage or high amps to an MPPT controller or does it just use the watts no matter how it is delivered?
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Re: Mppt Controller High Amps or High volts

Postby John61CT » Tue Apr 30, 2019 8:25 pm

Dunno about that SC.

But on designs designed to accept very high Voc panels like the big ones designed for stationary projects

Victron's SmartSolar line being an excellent value example,

there is a range where the MPPT algorithm having that wider range gives it a greater ability to optimize the watts delivered to the bank.

So for example, their 75/15 gets a bit better efficiency from same-wattage panels in the 35-60Voc range than if you just had regular 20-25Voc rated.

Also, one large panel with is internal diodes, may handle partial shading better than two wired in series.
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Re: Mppt Controller High Amps or High volts

Postby Shadow Catcher » Thu May 02, 2019 9:09 pm

Ours is a single high voltage panel and the only controller I could find that would deal with the voltage ten years ago was a Morningstar MPPT Sun Saver 10A, and typically we see 35V when shaded.

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Re: Mppt Controller High Amps or High volts

Postby Rainier70 » Thu May 02, 2019 10:22 pm

Thanks for the comments and answers. After doing a bunch more reading, I think that I will hook up the panels all in parallel with some larger gauge wire on the home run. Parallel connections are somewhat better at handling shading issues.

From what I have read the other method that I mentioned would have been okay too, but with the two parallel sets connected in series makes partial shading more of an issue. The actual amps and voltages wouldn't have been okay for the mppt controller as long as they are within the specs for the controller.

Either way, I am glad I researched more about the varieties of panel connections and their dos and don'ts.
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Re: Mppt Controller High Amps or High volts

Postby MtnDon » Thu May 02, 2019 10:39 pm

More than 2 panels in parallel should have each one fused. That is usually done where the wires from each are combined to a single pair that run to the CC.
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Re: Mppt Controller High Amps or High volts

Postby Rainier70 » Fri May 03, 2019 9:03 am

Thanks
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