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Solar charge controller QRM mitigation?

Discussion in 'General Technical Questions and Answers' started by KB7KJY, Oct 10, 2019.

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  1. K0UO

    K0UO Platinum Subscriber Platinum Subscriber QRZ Page

    1800 watts, that's 18, 100 watt panels, even the top of the semi truck enclosed trail doesn't have enough room for all that! It's a massive amount of cables and worrying even if you're using 200 watt panels.
    I boondock in AZ and there is a guy I see every winter in the desert and has about 4000 watts and he's pulling a 24 foot trailer behind with solar panels on both sides and on top that fold out the batteries are stuffed in between the solar panels I think he's running a 96 volt system.
    There's probably a half a million people in South Arizona boondocking in the winter time so it's much different than your situation, we have plenty of qrm from Neighbors!!!
    I'm only running about 300 watts of solar and in the winter time in AZ or in the mountains in the summer I rarely use my generator. It's a lot easier getting a 30 amp controller to be quiet then it is such a large system using 1800 watts of panel, what are you trying to do run your air conditioners?
    Last edited: Oct 12, 2019
  2. KB7KJY

    KB7KJY Ham Member QRZ Page

    Thank you for your suggestion. I would be all over building my own if the sole scope of my project was The solar system. I have enough experience with that sort of thing that I would be comfortable with the project if I had time.

    I am almost building from scratch so I have body work, insulation, windows, interior finish, cabinets, plumbing & tankage, DC and AC systems and furniture.

    Pretty much everything other than the basic shell and drive train. We did cut the roof of the shell off and raised it 10" and re-sided.
  3. KB7KJY

    KB7KJY Ham Member QRZ Page

    Thanks for the input.
    No 100 watt panels here. 18 - 100 watt panels would be ridiculous. I have 6 - 300 watt panels that will fit nicely on the roof. When I started laying it out I found that I actually have room for two more. I have the panels on hand to do it but I don't think that I need it.

    My panels are flat mounted. I will never see nameplate output. I considered this when deciding what to put up on the roof.

    I put 300 watts of solar on my 5er and it greatly reduced my generator run time. I am supporting 10.8cu.ft. residential refrigerators so my power consumption is somewhat higher than if I were running a propane refrigerator.

  4. KF5LJW

    KF5LJW Ham Member QRZ Page

    OK I missed the 24 volt part, at least that gets you down to single 80-Amp Controller. Assuming those L-16's are Trojan you can get away with running C/5 charge current.

    But I can tell you your hands are full with QRM using Midnite Solar Classic series. What I can tell you is the noise is radiated out on the wiring to the panels, not so much to the batteries. Most folks make the same mistake and put the filters in the battery wiring, and of course it does no good because the noise is on the panel wiring.

    My best advice is sell the Midnite solar controller and get a MorningStar TriStar and all your noise problems goes away. In addition I would not rule out your 24 to 12 volt converter is noising things up.

    K0UO likes this.
  5. KB7KJY

    KB7KJY Ham Member QRZ Page

    The charge controller that I am looking at is the Midnite Classic. It is a quality product. No China no name here. IIRC: the Classic is FCC class B certified. My understanding is that testing for that cert is just looking at noise above 30mhz. That is my understanding. Not a statement of fact. I would like to hear from anyone who has knowledge on the particulars.

    Thank you.
  6. K0UO

    K0UO Platinum Subscriber Platinum Subscriber QRZ Page

    I posted a link to another post where a group of us had actually tested a number of units it's worth reading.
    Just because the original product was FCC certified when they were tested it, does not mean the components are going to be noise-free. The manufacturers have to deal with what they receive from China and we all know there's a lot of junk coming out of China, it's a day-to-day battle for the US manufacturers.
  7. K0UO

    K0UO Platinum Subscriber Platinum Subscriber QRZ Page

    The most typical size used for residential installations is 65 inches by 39 inches that run 270 to 300 watts. So you have six on your roof , 37 foot RV by about 7 foot wide.
    On my coach I have two AC units numerous vents, 4 skylights and a ladder mount. I'd like to see a photograph of how you did this!
  8. KB7KJY

    KB7KJY Ham Member QRZ Page

    Thanks for the input.

    The main reason for me to lean towards the Midnite Classic is the ability to limit charge current to the batteries while making full output available to your loads.

    Do you know of a morgin
    I have been looking at Trojan and Crown for my batteries.

    Again, my leaning towards the Midnite is the charge current limiting feature. That gives the ability to have full output available to loads while protecting your batteries from excessive charge current. If this were a stationary install it would be simple. Given that I may be in Seattle for Thanksgiving and Phoenix for Easter. I will be in a broad variety of conditions.

    It's a compromise game. Solving one problem creates another.

    Do I give up a key feature of the Midnite to achieve low noise and look for a different solution for being over paneled? Or do I stick with the Midnite and look for a solution to the noise that it creates?
  9. KB7KJY

    KB7KJY Ham Member QRZ Page

    That is pretty close to the dimensions of my 300 watt panels.

    My roof is a blank canvas. Roof vents and plumbing vents will be arranged to accommodate solar. I have no roof a/c's. I am running mini-splits for a/c.

    My 5er is a different story. As a factory "sticks and staples" RV the roof is crowded. I had planned on putting two 300 watt panels on it. When I tackled the install I found that I could only fit one panel without serious surgery.
    K0UO likes this.
  10. KB7KJY

    KB7KJY Ham Member QRZ Page

    I am a little slow tonight.. Long day....

    I found the link but did not see any discussion of various controllers. Am I missing something?


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