MPPT update to charger panel wiring

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m-beach asked Feb 4, '21

MPPT update to charger panel wiring

I recently Upgraded to SmartSolar Charger MPPT 100/50 for my RV setup. I presently have 3- 160W (8.38A) Flex panels run in parallel to the charger (based on advice for my previous 30A PWM charge controller).

I am looking to add a 4th panel to the setup and more storage capacity. my question is wether I should add it in Parallel as well or should i rewire for series or series/parallel for this new controller? attached is previous wiring Diagram with old charge controller for reference.

Any advice would be greatly appreciated.

MPPT SmartSolar offgrid wiring

wiring-diagram-s1b.jpg (7.8 MiB)

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Rob Fijn answered · Feb 04, 2021 at 02:17 AM

Hello m-beach, my advice would be two in series and two parallel. The reason is to have the MPPT start charging with less lights, as the PV voltage is higher because of the series connection. In Parallel could be good in case of shadow. As well when the PV voltage is higher the current is less, so less loss in your existing cables and connections.

Hope this helps.
Regards, Rob

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m-beach commented · Mar 05, 2021 at 02:45 AM

Rob, I wanted to thank you for the feedback and info on the setup. The install went well and system has been charging and storing perfectly!! I edited my wiring diagram (s) to reflect the new setup

cheers!

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a6054e04-0a0d-4ede-ace3-80673f6b3715.jpeg (168.1 KiB)

Rob Fijn m-beach commented · Mar 05, 2021 at 02:11 PM

Great to hear!
Thank you for your post back onto this forum.

Wish you many beautiful trips with your RV

Regards, Rob

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Modifications Space

Node Red Space

Answer 1 · 2021-02-05T01:15:05Z

m-beach answered · Feb 05, 2021 at 01:15 AM

Rob, Thanks for feedback. I am curious about a couple of things.

1: do you mean to say 2 panels in series and another set of 2 running in parallel then run the 2 pairs all together in parallel? I didn't think that would work because there would be 12V and 24 Volt going into the same inputs. ( i am using one smart controller with only one input)

or did you mean 2 pairs of series panels (24V) run parallel to the controller in a Series-parallel set up like the attached diagram?

2. is there are recommendation of how to pair the panels for best efficiency based on position on RV relative to the sun? ie pair closest panels together or ends together/middles together

I appreciate any additional input!

9c2560f7041e5c7d17df7a0b42715652.png (378.0 KiB)

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Answer 2 · 2021-02-05T12:03:51Z

Rob Fijn answered · Feb 05, 2021 at 12:03 PM

Hello m-beach, yes, connected like your drawing of the Series - Parallel connection.
No, it does not matter where the pairs are connected in relation to your MPPT. Believe all the panels will be on the roof of your RV, so the location does not matter as you are driving around.

For series connection you can not go over the 100V, as specified for your MPPT.

Regards, Rob

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