OCC Forums

Solar Panel Input Switch to MPPT Controller Controlled by SSB Power On

https://forum.oceancruisingclub.org/Topic6264.aspx

By simoncurrin - 7 Dec 2020

POSTED ON BEHALF OF GORDON NICHOLL

hope this makes sense to you. It has worked for my and may benifit others.

I needed to document and upgrade my wiring diagram record so thought I'd share it with you.

Phil / Simon maybe you can put it on the OCC technical page if you think it worthwhile.

Gordon and Louise
Martinique
US NY 1 300 518 300 3799
By Dick - 7 Dec 2020

Hi Gordon,
Thanks for this contribution.
I may have not understood the whole of it, but I have no doubt that another skipper, experiencing this problem, could follow your explanations and execute a remedy. Well done.
A couple of comments: I would want to flag your schematic diagram (as well as the whole write-up) as a template for every skipper doing additions to their electrical system. I am forever impressed with how quickly one (meaning me) forgets the details of electrical additions and forever grateful for discovering that I made schematics such as yours when troubleshooting is necessary.
It is a wonderful winter project that will likely pay huge dividends doing wiring schematics of one’s boat. It is much easier troubleshooting from one’s easy chair than tracking wires all over the boat.
I was also curious about the RF interference that comes from Tx’ing the SSB and the MPPTs. Do you use chokes and line isolators? And do they make a difference in the issues with which you are concerned? Or, might they make a difference?
Thanks, Dick Stevenson, s/v Alchemy
By Gordon.Nicholl - 7 Dec 2020

Dick,

Thank you for the comment. 

To clarify, the MPPT Controllers change the panel voltage and therefore the line voltage and therefore the noise is generated on the line, solar panel cable, between the MPPT Controller and the Solar Panels.  This is an inherent characteristic of the design and does not exist on an older PWM style regulator which only works on the battery side of the controller.  This has already come up as a comment from another recipient of the post that did not differentiate between the two controller styles. This refers only to MPPT Controllers. The problem does not exist on PWM controllers.

As noted in the note I have three MPPT controls on three panel arrays. Only one of the Solar Arrays has the cable near the SSB Antenna and this is the offending controller. The other two, albeit smaller, have cabling that is not near the SSB antenna system and noise from these is not a problem in my case but all three are turned off with the SSB ON.  Not everyone will have this noise, it depends on proximity of the solar panel cabling to the SSB antenna.

Yet another recipient commented that he has already a solenoid/relay between the panel and the MPPT controller to solve his noise problem but the solenoid is controlled by a manual switch, he liked the idea of an auto disconnect with the radio ON.

A third recipient likes the concept since he needs to use his I-Phone to turn off the Controller when using his SSB so that he can hear incoming signals. It is a Victon MPPT Controller and this presents another option, to turn off the controller, not just disconnect it from the 12V+ Batt. Again the problem is remembering to turn it back ON!

I do not quite understand the Tx'ing the SSB and interference on the MPPT.  The MPPT generates the noise and the noise finds it's way to the antenna where it interferes with the Rx receive.  RF chokes etc are messy compared to isolating the source of the noise, easily done in this case by the panel disconnection. I don't have any RF Chokes on the boat.

I hope this clarifies the questions raised so far.

Regards

Gordon