question

pauldunn avatar image
pauldunn asked

MPPT PV panels in different orientation

Hello

Looking to finally add some PV to my Multiplus/Pylontech setup. I am planning to get 15 400w Q Cell panels.

  • 12 panels would be facing directly east
  • 3 panels would be on a dormer window roof facing directly south.

Now I know you should have a MPPT per orientation but how much difference would this actually make to performance?

Using the Victron MPPT calculator I am able to support the 15 panels with 1 SmartSolar 150/85

https://mppt.victronenergy.com/#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

It would save a decent chunk of cash not having to buy 2 charger controllers but I am willing to if its going to seriously degrade performance only having 1 controller.




MPPT Controllers
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

4 Answers
bennysnaucum avatar image
bennysnaucum answered ·

you should protect the strings against reverse currents. Otherwise, the MPP tracker should manage this without problems

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

pauldunn avatar image
pauldunn answered ·

Thanks for the advise.

So if I add something like this https://www.bimblesolar.com/mc4-blocking-diode to each of the 15 panels that will prevent reverse current issues and the charger controller wont have performance issues because of the different orientations?

1 comment
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

bennysnaucum avatar image bennysnaucum commented ·

No, these type of diode have a voltage drop of 1V, at 5A these are 5W. They get very hot and semiconductor are not a good protection. Please use PV Fuses 15A

0 Likes 0 ·
kevgermany avatar image
kevgermany answered ·

Hard to say how much degradation. MPPT will simply do its best.

You could always cable with isolators so you can experiment with 12 panels, 3 panels and 15 panels on a single controller. Then get a second controller if you lose a lot. Make sure the isolators can handle the switching under load.

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

nickdb avatar image
nickdb answered ·

Rather leave the 3 panels off and see how you go. No point handicapping the larger investment with the smaller one.

A small MPPT to cater for the other 3 panels isn't going to affect costs that much.

2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.