Outback 60 with Partially Shaded Panels

[sailinglegend]

Originally Posted by noelex 77

All solar panels have bypass diodes. As the name suggests these function to bypass the current around the shaded cells (with some losses).

Yes, but only a few panels have Bypass Diodes that bypass the WHOLE panel. If you don't do that they offer a large resistance to other panels in series. You can add extra Bypass Diodes to bypass panels wired in series.

As has been suggested many times here do some tests on your panels on your boat layout to see if Series or Parallel is best for you - and do post your results.

You could spend a week doing this job properly!!!!!

[noelex 77]

Originally Posted by mitiempo

For a 36 cell panel there are usually 2 bypass diodes. Still adds up to a loss if multiple panels are in series. Parallel doesn't have any issues with current from one panel passing a shaded panel.

Yes some do, but most good panels have more. The Popular Kyocera panels for example have 8 in the most common sizes from 50-140w.

I think parallel is best, but it not correct, when wired in series, to think that the array will produce no current when one panel is shaded.

If one panel is totally shaded parallel connection does not lose any voltage with the current passing through the shaded panel like a series connection does as you point out. However, with partial shading series connection can contribute voltage to the output whereas parallel connection often cannot contribute anything.

The theoretical mathematical modelling of series and parallel connection is complex. It has defeated me anyway .

[noelex 77]

Originally Posted by sailinglegend

You can add extra Bypass Diodes to bypass panels wired in series.

Yes, this should be done if going to wire your panels in series. You only need one diode per panel and they are less than $1 each.

[Morrissey]

I have 7 Suniva 260W panels, in parallel, going into 2 Outback 80 controllers. The panels are 30 V, but output is 12V. Interestingly the Outback 80 is rated at 80 A at a range of output voltages. My system is 12 V, but had it been 24 V then I would only have needed one Outback.

The combination of horizontal panels and shading means that you never get near nameplate capacity though. Even on a powerboat there is still some panel shading as I do not routinely lower radio antennas.

[Sasky306]

Originally Posted by Hkalan

Hello,

Parallel is by far the best.

I use a Morningstar TS-60 MPPT with a combiner box I made that breaks the + and - to isolate any panel.

Attachment 85246
Attachment 85247
Attachment 85248

This is by far the best, cleanest combiner box I have ever seen. Did you make the entire thing yourself? I install solar systems on RVs and I am always looking for cost effective solutions to improve the installation. What type of breakers did you use for this? What did you mount them to? How big is the box? What is the max size wire that will fit in the ?breaker? leaving the combiner box to go down to the charge controller? Great work!

[twinboat]

Dulcesuenos said:
We have 6 panels paralleled together, no combiner box, to one controller, and very pleased with it .

How do you fit all of the wires in the controller?

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[Dulcesuenos]

Only two wires from the panels going to the controller. The panels negative wires connect, into one via 3 "Y"s same with the positive wires. Even when one side is shaded we still got good voltage and amperage out of a cheap schneider 40 controller, maybe not the best way to do it bit it worked well, and was recommended by the solar panel company .

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