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    Solar charging two batteries

    I own a 1989 2302 Trophy since new. My neighborhood dock space does not have electric so I installed (3 )15 watt solar panels on a removable mount to keep my 2 batteries charged. I normally switch to which battery I want to charge by disconnecting the controller-to-battery alligator clips battery from #1 to #2 battery and vice versa as needed. My question is can I install a permanently mounted three way switch to choose the battery I want to charge or even better can I wire to both and charge simultaneously? I'm guessing 45 watts is putting out roughly 4 amps.
    Attached Files

    #2
    im answering this question base on the assumption that you have 1 battery in 2 separate banks...yes you can, but it would be much better to use an automatic combiner relay and never have to worry about switching them.... the 45 watts of solar will give closer to 2 amps and not 4.... IF you have 2 batteries in the same bank, there is no need for anything other than the panel wires and the batteries to get them both to charge at the same time.

    BUT... the problem you need to address is the 45watts of solar power may require a charge controller for the longevity of the batteries.
    15watts wont hurt the batteries, but 45watts will continue to charge them, which will very likely overcharge/overheat them.

    the following has been copied and pasted from the Mr Solar website


    When do I need a charge controller and why?

    The safest way to figure out if you need a charge controller is to take Battery Amp Hour Capacity and divide this by the Solar Panel max. power amp rating. If the quotient is above 200, you don't need a controller. If the number is less than 200 than you need a controller.

    For example if you have a 100 amp hour battery and a 10 watt panel, you take 100 and divide it by .6 (600mA) and you get 166.6. Since this is less than 200 you need a charge controller. If you have a five-watt panel in the above example you take 100 divided by .3 (300mA) and you come up with 333.3. Since this is larger than 200 you do not need a charge controller. However you still need a blocking diode, to prevent the battery from discharging to the panel at night. So as a general rule of thumb you don't need a charge controller unless you have more than five watts of solar for every 100-amp hours of battery capacity


    NU LIBERTE'
    Salem, OR

    1989 Bayliner 2556 Convertible
    5.7 OMC Cobra - 15.5x11 prop
    N2K equipped throughout..
    2014 Ram 3500 crew cab, 6.7 Cummins
    2007 M-3705 SLC weekend warrior, 5th wheel
    '04 Polaris Sportsman 700 -- '05 Polaris Sportsman 500 HO
    Heavy Equipment Repair and Specialty Welding

    Comment


      #3
      Thanks for the quick response, Centerline2. I do have a charge controller in conjunction with the solar panels. the 3 panels are daisy chained into the controller and two alligator clips from the controller clip to the battery. When you refer to a "combiner" I assume you are referring to an automatic charging relay (ACR)? Is the ACR dedicated for the solar charging circuit? Do I consider replacing the Blue Sea "1, 2, Both, Off" switch with a new battery switch/ACR system? If so, since the solar charge controller would be permanently installed (the boat would never be started when the solar panels are installed) , can the engine stator/alternator damage the solar controller when running? I was considering a more simplistic approach of cutting the alligator clips installing additional conductors to the leads and permanently attaching a (+) pos and (-) neg to each battery.

      Comment


        #4
        If you purchase the Blue Sea ACR package, it comes with the relay plus a new switch to replace your MBSS (1,2 Both). The new switch is used to turn your batteries off, or to manually combine them if needed.

        The ACR combines your batteries whenever a charge source is present and fully charges both banks. It will combine them with the solar panels, a shore powered charger, or when your engine is running. The device extends the life of your batteries as it ensures the banks are fully charged. One of the best additions you can make to your electrical system.
        Terry
        1999 Bayliner 3388
        Twin Cummins 4BTA
        Fisherman, Cruiser, Boaticus-enthusiasticus-maximus
        Member Royal Victoria Yacht Club

        Comment


          #5
          TenMile.is correct... the solar charge leads and the shore power charge leads would connect directly to the.battery that gets drawn from the most often... the acr does the rest.
          in this manner it makes no difference what position the mbss is in, the batteries will always be connected to an active charge source even if the battery switch is shut off...

          FYI... there are several brands of the AUTOMATIC COMBINER RELAY, but blue sea has a copyright on the term "automatic CHARGE relay" for their product, which is very little.differnt than other brands of the.same device... the blue sea acr is a time proven device and it works best with the mated on/off/combine switch and NOT the on/off/1/2 switch...
          ..


          NU LIBERTE'
          Salem, OR

          1989 Bayliner 2556 Convertible
          5.7 OMC Cobra - 15.5x11 prop
          N2K equipped throughout..
          2014 Ram 3500 crew cab, 6.7 Cummins
          2007 M-3705 SLC weekend warrior, 5th wheel
          '04 Polaris Sportsman 700 -- '05 Polaris Sportsman 500 HO
          Heavy Equipment Repair and Specialty Welding

          Comment


            #6
            Thank you , TenMile and Centerline2. I'll get the Blue Sea Battery Switch/ACR kit.

            Comment


              #7
              Still confused...
              I sent an inquiry to Blue Sea Systems tech support describing my system and what I wanted to do. Their reply and schematic is attached. It does not address how the other two sources of charging are wired into the system. It also appears to utilize my existing standard battery switch ( BSS 9002e). Where do I wire the solar controller and the 120v on-board charger?
              Attached Files

              Comment


              • Centerline2
                Centerline2 commented
                Editing a comment
                its not as confusing as it seems to you at the moment.... the engine will charge the system once the acr kit is installed as shown..... ALL other charge sources will connect to the battery in the same manner that the shore power charger does. no need to worry about multiple charge sources interacting with each other, as they all take care of themselves as they see other charge sources activated.... its as simple as that.

              #8
              Centerline2
              Do I keep my current battery switch and just add the ACR as shown or do I need to buy the battery switch that Blue Sea packages with their "Add A Battery" kits? Also ( sorry for belaboring this!) do I just cut the 2 alligator clips off the solar controller output and split the single (+) pos to 2 conductors to each pos terminal of the batteries and ground the (-) neg wire from the controller output? Thanks for all your help!

              Comment


              • Centerline2
                Centerline2 commented
                Editing a comment
                its better to replace the current mbss with the blue sea model. then you can have 2 banks (like you have) and there is never a need to switch from one bank to the other for charging or usage and with a simple twist of the switch in the dark when you cant see the position numbers,, you can either combine the banks or shut them completely off... there is no need for the A/B or 1/2 positions and it cleans up the wiring a little bit ..

                the beauty of the acr and mated switch is the fact that it is the most dependable way for one to have 2 fully active battery banks "on" and working. yet isolated from one another, and still have them both being charged by a single (or multiple) source(s)

                the blue sea mbss is a DTDP (dual throw dual pole switch) so both circuits are always isolated from on another, and yet both circuits will turn fully on or off with a single click of the switch.... or they can be combined together with another click of the switch..... in actual practice, unless you have an electrical problem and need to combine the banks, you will only ever need or use the on/off positions, and when the switch is off, BOTH banks are STILL being charged (as long as there is an active charge source)....

                a regular mbss ONLY allows 1 circuit to be on at a time, UNLESS its in the combine position... and then the circuits are NOT isolated from one another... and unless you have a dual leg charger, a regular mbss will only allow for charging one bank at a time (unless you turn the switch to combine)
                YES.. you could install the ACR without the mated switch to have it charge both banks, but then still, the active service needed to run the boat will ONLY be drawn from one bank or the other (unless combined and NOT isolated)

                if you are adding the ACR, you will eventually see the purpose for the mated blue sea mbss, so either now or later you will be installing it. I feel its best to do it now and be done with it. one its all installed, you never have to wonder if the batteries are charged or which one has the best charge in it, or what bank is currently being drawn from... install it and forget about it, and let it take care of the batteries better than you ever could with a regular mbss...

                Ive installed many of these "ACR kits" and NEVER has there been any negative feedback in any form when installed correctly the first time.

              #9
              I just took another look at the diagram you posted for wiring an acr... I can see how you would continue to be confused. that diagram shows how the acr would connect to a regular MBSS.... the blue sea model will have 1 more post to allow the engine and house loads to be seperate and isolated from each other....


              NU LIBERTE'
              Salem, OR

              1989 Bayliner 2556 Convertible
              5.7 OMC Cobra - 15.5x11 prop
              N2K equipped throughout..
              2014 Ram 3500 crew cab, 6.7 Cummins
              2007 M-3705 SLC weekend warrior, 5th wheel
              '04 Polaris Sportsman 700 -- '05 Polaris Sportsman 500 HO
              Heavy Equipment Repair and Specialty Welding

              Comment


                #10
                Yep...that's what I thought. Going the new switch/ACR route. No reason not to. The cost of the ACR alone is 99 bucks. The cost with the switch.....$105! Go figure.
                Again, thank you for you patience, CL2.

                Comment

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