Forum Discussion

CAJW's avatar
CAJW
Explorer
Jan 31, 2017

Dueling Solar Controllers?

My question for the TC collective, has anyone noticed any efficiency degradation in amp output when both rooftop and the solar suitcase panels (on separate controllers) are used concurrently, on the same battery bank?

I am just about to purchase a 150W Renogy panel to mount on the roof of my Arctic Fox and run it through a TriMetric SC2030 controller which will be connected to my existing Trimetric TM 2030 Battery Monitor. I'm doing this to supplement recharging our 2-6V LifeLine batteries as our 100W Renogy solar suitcase isn't up to the task by itself.

In talking to a Renogy Tech today, I was informed that he was afraid that when I connect my 100W solar suitcase (with separate PWM ViewStar controller), to the same battery bank as to the rooftop 150W panel, the two controllers would sense power from the other charging source and dial back the output, degrading the efficiency.

I've read where others are doing this, (Mello Mike for one), but haven't read about any reduction in charging output. Any real world experience others would like to share before I put out the dollars for the rooftop panel?

Please limit feedback from those who have both a rooftop panel and a separate panel on separate controllers. I could put additional panels on the roof and not use the 100W suitcase unit, but I'm not willing to go that route yet until I get a solid consensus it the above setup works or is the tech correct that it won't work efficiently?

Thanks for any help.
  • AnEv942's avatar
    AnEv942
    Nomad
    Jan 31, 2017
    That's also what I did, but in reverse. Added the 100w portable(with its Viewstar) to existing 130w roof panel and Morningstar prostar30. But I couldn't see how the controllers would not see the input to batteries from each other and not read as battery state and get, at minimum, confused.
    That and me reading 2 controllers which 'seemed' kinda silly.

    So I removed the portables controller and ran to a plug from existing Controller. Mine is switched so I can see individual input and combined.
    Works well.
    I agree that the batteries can have multiple charge inputs and it works fine, its just the controllers are a bit smarter than gen or truck.
  • trail-explorer's avatar
    trail-explorer
    Explorer
    Jan 31, 2017
    A battery will accept current from multiple charging sources. The chargers/controllers will not conflict with each other. WHen the battery bank can no longer accept the full amount of current available from both charging sources, one source's output in tot he battery will reduce.
  • CAJW's avatar
    CAJW
    Explorer
    Jan 31, 2017
    towpro wrote:
    I would run wire so the mobile panel so when its in use, it will also input into the Bogart Solar Controller. That controller is good for 30A.

    Thanks for the predominance of positive suggestions. I think I'll go this route as I have already invested in the 100W suitcase. Although it'll void the warranty to bypass the Viewstar Controller, the Bogart unit gets high praise so connected to my TM2030, it should work fine.
  • Geewizard's avatar
    Geewizard
    Explorer
    Jan 31, 2017
    towpro wrote:
    I would run wire so the mobile panel so when its in use, it will also input into the Bogart Solar Controller. That controller is good for 30A.


    That's what I do with my Morningstar MPPT controller and mobile panel.
  • NinerBikes's avatar
    NinerBikes
    Explorer
    Jan 31, 2017
    I'd get all the same size and brand panels, wire them parallel, and one big controller, and be done with it. Mix and match is just plain stupid engineering design. Do it right, or don't do it at all with a mismatch. I don't know, it just seems like common sense to me to do it that way.

    Would you build a multi cylinder engine with different sized bores in the engine block to make power, when they are all connected and bolted on to the same crank? Thought so.
  • towpro's avatar
    towpro
    Explorer
    Jan 31, 2017
    I would run wire so the mobile panel so when its in use, it will also input into the Bogart Solar Controller. That controller is good for 30A.
  • landyacht318's avatar
    landyacht318
    Explorer
    Jan 31, 2017
    I always find the weirdness happens with two charging sources when they are set for the same absorption and float voltages. If set for the same absorption voltage, and both are relatively accurate, then it turns into a cockfight.

    If one is set higher than the other, One just stops and the other continues.

    When they are set the same voltage starts doing a yoyo and one can hear relays shutting on and off.
  • BFL13's avatar
    BFL13
    Explorer II
    Jan 31, 2017
    They will add their amps ok at first in the morning but then it gets complicated. The ViewStar has that fixed EPSolar charging profile where it gets the battery to Absorb voltage (for AGM as set by you) then holds that for two hours then drops to 13.x (AGM setting) Float.

    The Bogart controller is different ISTR you can set voltages? So set that one as close to the ViewStar charging profile as possible for the longest period in the day where they both have the same charging voltage.

    Any time one has a higher charging voltage than the other, the lower voltage one will not put out any amps at all to the battery and you are on just the one.

    EDIT-When I did that a few years ago, I was using two LandStars on the one battery set, so the two controllers were identical. Worked great. Maybe get a second ViewStar instead of the Bogart?
  • vermilye's avatar
    vermilye
    Explorer
    Jan 31, 2017
    Why not bypass the controller on the portable panel & feed it into the input of the SC2030?

    I have 195 watts on the roof that feed a Blue Sky 30 controller & added a port to the trailer that feeds the input to the Blue Sky controller. I use the port to connect a 160 watt portable with an additional connector that bypasses the portable panel's onboard controller. A Trimetric 2025 keeps track of total in & out for the batteries.

    My reason was I wanted the Blue Sky controller to show all the solar panel current & amp hours - If you don't feed all the panels into it, you won't have accurate readings of the amount of energy collected. Also, if both panels don't go through the TriMetric 2030, that info will also not be accurate.

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