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Using 2 charge controllers in parallel with 2 separate arrays Genius or Dud?

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  • Using 2 charge controllers in parallel with 2 separate arrays Genius or Dud?

    Today I was looking over several RV solar forums for equipment installation tips. Found some good ideas and even learned more on shunt locations, Found a neat post where the person made full size cardboard and foam mock up and moved the placement around to get the best fit - everything was to scale and had the pictures of the parts on the mock ups. They must have been an engineer. I also ran across several set ups with multiple solar controllers tied to separate panel arrays that faced different directions.

    So I searched on running two separate arrays with two separate controllers tied to one battery bank.

    So I thought I would get your expert input here

    I have and existing 160 watt Go Power solar panel through a GP-PWM-30 controller.. It covers all the battery types but Lithium. Battle Born said it would be fine set on AGM for their battery's, just not able to 100% charge. It has been doing fine so far with my 2 12v interstate deep cycle battery's (lead/acid)


    As I posted before I just purchased 2 - 190 watt GP panels and a GP-PWM-30-UL which does have a lithium charge profile.


    I was going to tie in all 3 panels in parallel through the new controller, but understand there would be a 20% loss in capacity due to the mix match in panels. This was discussed in a previous post.

    I am now thinking to leave the existing controller and 160 watt panel alone and add the two new 190 watt panels through the new separate controller and tie to the battery's in parallel with the other controller. In this configuration the charging amperage add without loss - correct? One controller wold be set to AGM and the other to Lithium when I get my new battery's.



    Would this be the better solution (separate panels and controllers) to maximize what I have. Makes install of the new panels fairly easy not having to mess with the existing wiring?



    Thoughts on this?

    Thanks

    Keith



    2018 Reflection 150 Series 220RK 5th whee, Star White 2022 F350 King Ranch CC Long bed (HAL) (CCC 4062lbs), B&W 25K OEM Companion,. SteadyFast system, Trailer reverse lights, rear receiver spare tire holder, storage tube, sumo springs, Victron MultiPlus 12/120/3000, Solar, Custom 6K axles upgrade, and other modifications.

  • #2
    Yoda ,
    I already gave you my .02 on this topic: sell the 160W panel and the controller. Get two more 190W panels (for a total of four) so you can have two series-parallel pairs. Get the right sized Victron SmartSolar controller ("cry once") and don't look back...

    Howard
    Forum moderators are not GD employees--we are volunteers and owners presumably just like yourself. Unless specifically mentioned otherwise, we have nothing to gain should you choose to purchase a product or engage a service we discuss on this forum.

    2017 Ford F-350 DRW, '19 315RLTSPlus

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    • #3
      Originally posted by howson View Post
      Yoda ,
      I already gave you my .02 on this topic: sell the 160W panel and the controller. Get two more 190W panels (for a total of four) so you can have two series-parallel pairs. Get the right sized Victron SmartSolar controller ("cry once") and don't look back...

      Howard
      Yep, you are correct that would be the best way to go. I was trying to simplify and work with what I have (budget), but you make a good point. Unfortunately the market around here is dead as far as used solar parts(winter?). Don't know why? I even checked with my dealer if they could do a bit of a horse trade on my existing system for a third new 190W panel and doing the roof and wiring to controller install. No go and they said good luck on selling used . Looked around and what was out there was not selling.

      Until I read today (watched a few to many U-Tube vids, and a lot of reading), I did not understand I could even do what I am thinking.

      If I read and understand correctly this solves the solar loss problem of the mixed panels, except for max charge on Lithium one controller would have. I guess what I am asking is there a down side to this. And yes I know there is a better way - I just need to win the free Victron give away one of the dealers is having and my problem will be solved, except for space.

      Thanks again my friend - I am slowly learning here.
      Keith
      2018 Reflection 150 Series 220RK 5th whee, Star White 2022 F350 King Ranch CC Long bed (HAL) (CCC 4062lbs), B&W 25K OEM Companion,. SteadyFast system, Trailer reverse lights, rear receiver spare tire holder, storage tube, sumo springs, Victron MultiPlus 12/120/3000, Solar, Custom 6K axles upgrade, and other modifications.

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      • #4
        Yoda You could do parallel, but normally its done when you have more panels than your controller can handle (rather than going with a new controller large enough to run all the panels). The problem is I would think the charge profiles would need to be the same (basically the same controller). Otherwise you are going to have them charging at different voltages, and one will be leading the other. I second Howards advice, pitch what you have (sell it if you can) and chalk it up to a lesson learned. I know that may sound harsh (and expensive), but trust me when I tell you that you want it to be as solid and trouble free as possible when on the road. Murphy's Law states its going to act up in the middle of nowhere when boondocking with no cell service to figure out what is wrong.
        Forum moderators are not GD employees--we are volunteers and owners presumably just like yourself. Unless specifically mentioned otherwise, we have nothing to gain should you choose to purchase a product or engage a service we discuss on this forum.

        Neil Citro
        2018 Reflection 28BH Pepwave
        2019 F350 6.7L Long Bed Crew Cab

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        • #5
          Originally posted by ncitro View Post
          Yoda You could do parallel, but normally its done when you have more panels than your controller can handle (rather than going with a new controller large enough to run all the panels). The problem is I would think the charge profiles would need to be the same (basically the same controller). Otherwise you are going to have them charging at different voltages, and one will be leading the other. I second Howards advice, pitch what you have (sell it if you can) and chalk it up to a lesson learned. I know that may sound harsh (and expensive), but trust me when I tell you that you want it to be as solid and trouble free as possible when on the road. Murphy's Law states its going to act up in the middle of nowhere when boondocking with no cell service to figure out what is wrong.
          Neil you have a very good point. Thought - with two solar controllers I have a backup if one goes wrong ???? The better of the two will be in the 190 watt panels so I should get full charge. I am going to call Battle Born and Go Power tomorrow and ask about this. So far they both have been very helpful in educating me. Battle Born said I could get by fine with what I have - but maybe they just wanted to sell me batterys.

          Hopefully this will help others in the same situation. Dealer installed one system and they need to upgrade. This may be a way to salvage what the have. I say may as my thought train could be faulty....its never been wrong before right? NOT!!!

          Tomorrow is another day
          Thanks for the help I need to sleep on this - or stop searching the subject???????????
          Keith
          2018 Reflection 150 Series 220RK 5th whee, Star White 2022 F350 King Ranch CC Long bed (HAL) (CCC 4062lbs), B&W 25K OEM Companion,. SteadyFast system, Trailer reverse lights, rear receiver spare tire holder, storage tube, sumo springs, Victron MultiPlus 12/120/3000, Solar, Custom 6K axles upgrade, and other modifications.

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          • #6
            Yoda There's a difference between will work, will work well, and will work optimally. I'd think your proposal will fall between the first two. If there's one thing solar had taught me, none of the components work anywhere near the optimal level (except maybe the batteries those things are rock solid). There's loss from the way they're made, loss from shading etc. I usually figure if I'm getting half of the rating I'm doing pretty good. With all this loss I tried to build the rest of the system as solid as I could so that any losses or inefficiencies would be minimalized.
            Forum moderators are not GD employees--we are volunteers and owners presumably just like yourself. Unless specifically mentioned otherwise, we have nothing to gain should you choose to purchase a product or engage a service we discuss on this forum.

            Neil Citro
            2018 Reflection 28BH Pepwave
            2019 F350 6.7L Long Bed Crew Cab

            Comment


            • #7
              OK I talked with Go Power. The dual controllers will work with a slight improvement over the mix panels in parallel.

              However I need to eat some crow here

              You can all say I told you so

              Battle born got back to me

              Keith,

              You will want to get an MPPT solar charge controller if you have different wattage/voltage panels. If you
              have an mppt then you can connect the panels in series or parallel and this will optimize your efficiency.

              Thanks

              Jesse


              What I don't understand is how the MPPT will reduce the losses? Is it due to the fact I can wire in series?? If I do go in series will the panel wiring that is 10 gauge still be enough?

              I guess I need to do more reading and see if I can make a return to Etrailer.

              2018 Reflection 150 Series 220RK 5th whee, Star White 2022 F350 King Ranch CC Long bed (HAL) (CCC 4062lbs), B&W 25K OEM Companion,. SteadyFast system, Trailer reverse lights, rear receiver spare tire holder, storage tube, sumo springs, Victron MultiPlus 12/120/3000, Solar, Custom 6K axles upgrade, and other modifications.

              Comment


              • #8
                Originally posted by Yoda View Post
                If I do go in series will the panel wiring that is 10 gauge still be enough?
                Wire size is very dependent on the current you carry in the wires. When you wire in parallel, the current adds and the voltage stays the same. When you wire in series, the voltage adds and the current stays the same.

                This is the chart that I use for calculating wire size. It was developed for marine applications which work very well in RV's. When calculating the length of the wire run, it's the complete loop length of the run. For example, if you're powering a device that is 10 feet from the battery, you'd use 20 feet. The chart is designed for both 3% and 10% acceptable voltage drops. I try to stick with a 3% drop if possible.

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                Jim

                Jim and Ginnie
                2024 Solitude 310GK
                GDRV Technical Forum Moderator
                GDRV Rally Support Coordinator

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                • #9
                  Thanks Jim TucsonJim
                  What I still don't understand is the physics of connecting mixed panels still has not changed - the loss will still be there (other thread) so is what she is saying that the MPPT controller would maximize the seen power over the PWM's I have. I guess I need to go back over that video that compared the two in the other thread. It clearly showed the MPPT as being better. I just don't know how much.

                  I think I also need to look at the panel loss in the series connection, I did not look at that as the PWM would not handle the voltage. Check me on this - voltage in series increases, amperage does not. In parallel amperage is additive, voltage stays the same. To get the best charge rate I need the highest amperage output at the correct voltage? So what brands of MPPT controllers should I look at - I'll do a search and review the saved links I have on the systems folks put together. But first I need to go back and see what my panel outputs are again and investigate the best way to tie them together.

                  Thanks
                  Keith
                  2018 Reflection 150 Series 220RK 5th whee, Star White 2022 F350 King Ranch CC Long bed (HAL) (CCC 4062lbs), B&W 25K OEM Companion,. SteadyFast system, Trailer reverse lights, rear receiver spare tire holder, storage tube, sumo springs, Victron MultiPlus 12/120/3000, Solar, Custom 6K axles upgrade, and other modifications.

                  Comment

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