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  • charging battery bank

    Hi all,
    maybe a silly question but!

    can I charge my bank of 6 x 12v batteries wired to 24 volts with a standard 12v battery charger please, it can be ramped up to 16 amps

    all the best Derek

  • #2
    Originally posted by Alpaca-Meadow View Post
    Hi all,
    maybe a silly question but!

    can I charge my bank of 6 x 12v batteries wired to 24 volts with a standard 12v battery charger please, it can be ramped up to 16 amps

    all the best Derek
    A 12volt charger can charge each of those 6 batteries individually but not wired together as a 24volt system.

    You need to find a charger that can do a 24volt system and have the ability to adjust for battery types like FLA and AGM depending on what battery you have as well as having enough amps to do your large system.
    Last edited by SunEagle; 10-16-2014, 04:19 PM. Reason: added amps

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    • #3
      Sure you can. 1 battery at a time.
      MSEE, PE

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      • #4
        I think this might be interesting:

        http://www.geniuschargers.com/G26000/specs

        12 and 24v charging. However at 24v, it will only supply 13A.

        There are plenty of modes you can choose with this versatile charger, so one must choose carefully. In addition to flooded and agm, it will do EQ, and also charge calcium-calcium properly. In the case of EQ or calcium-calcium mode, you should know what you are doing.

        It is primarily an automotive charger, although a VERY good one, but assumes that after charge you are going to put the battery back in the vehicle to let it finish a long float. Otherwise, it does what a lot of smart charger do and *monitor* for the voltage to fall after absorb, and do it's thing. That may not be ideal for a daily charge setup.

        However, if you are primarily doing solar, with this as a backup, or used as a battery-balancing / recovery tool, it could be quite handy for your situation.

        The one thing we are trusting is that you KNOW you need 16A. Is that true? In other words, what is the capacity size of the batteries you are using? Without knowing that, you may be wasting money on a charger that is too little, or too large for your needs.

        --Mod Note to PNjunction: In case your are wondering why your post took so long to show up, some posts containing URLs (not sure just what the criterion is) get diverted for Moderator approval.

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        • #5
          system not working correctly

          Dear All,

          I cant understand that after all the work and expense I can not get the system to work. All I am running is a 75 watt brooder heater, 24 / 7 I now have the 4 205 watt panels wired and producing 48 - 50 volts the 8 110amp batteries wired in a bank of 24 volts with a 40amp mppt controller(tacer 4210RN which will take a 1000watts at 24v and a 150 watt inverter!

          why are the batteries not making it until the morning? the controller has a red light every morning and the batteries are showing 24.4 volts??

          what is wrong anyone Please Help, we are lucky at the moment having a warm spell here in south of England with temps at night at 14, but that will change very soon and the chicks will need the help

          any help much appreciated Derek

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          • #6
            Originally posted by Alpaca-Meadow View Post
            I cant understand that after all the work and expense I can not get the system to work. All I am running is a 75 watt brooder heater, 24 / 7 I now have the 4 205 watt panels wired and producing 48 - 50 volts the 8 110amp batteries wired in a bank of 24 volts with a 40amp mppt controller(tacer 4210RN which will take a 1000watts at 24v and a 150 watt inverter!

            why are the batteries not making it until the morning? the controller has a red light every morning and the batteries are showing 24.4 volts??

            what is wrong anyone Please Help, we are lucky at the moment having a warm spell here in south of England with temps at night at 14, but that will change very soon and the chicks will need the help

            any help much appreciated Derek
            Derek for us ole hands we spot the problem in a few seconds, and your experience fits around 90% of all such that come here. Story goes something like this. I bought all this stuff and it will not work. The problem is likely you did not design the system to do what you intended it to do.

            Your Brooder Heater uses 75 watts x 24 hours = 1800 watt hours. To generate that much energy from solar depends on a few variables. One is which controller type you use of being PWM or MPPT. If you were to use PWM requires the panels to generate 3600 watt hours, or 2700 watt hours if using MPPT. To generate that much energy we next need to know your location and time of year use to determine how many Sun Hours you get in a day. If you run the system all year long we have to use worse case winter hours. Depending on location you may receive as little as 1 Sun Hour up to 3 or 4 hours in winter (3 is about average). We have no clue where you are or if you have clear view of the horizon to the east, west and south. Once we have sun hours and shading issues we can them find the panel wattage. For example if you get a generous 3 Sun Hours and use MPPT it will take 2700 watt hours / 3 Sun Hours = 900 watts. If you use PWM then 3600 wh / 3 sh = 1200 watts.

            As for battery you need to have a minimum 5 day reserve capacity. This is needed to make the battery last more than a year and cover you for a couple of cloudy day spells. Battery is pretty easy to figure once you know your daily watt hour usage. AH = WH/ Battery Voltage. So 5 days x 1800 wh = 9000 watt hours. So for a 24 volt battery you need 9000 wh / 24 volts = 375 AH. Sounds like you are OK on battery capacity other than you used the wrong batteries. If you needed 400 AH you should have bought 400 AH batteries. Parallel is going to shorten battery life significantly.

            If I had to guess with you being in England you just do not have enough Sun Hours. With 800 watt panels you would need a minimum 2.25 Sun Hours. You might get that in Summer Months, but not likely late fall , winter, and early spring. Either that or you have shading issues that block full view of the horizon eating your Sun Hours up. .
            MSEE, PE

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            • #7
              system

              Hi and thanks for getting back to me, I actually did do a design it is just the configuring that I am having trouble with.
              the solar panels are facing south ground mounted and no shadow after 09:30 am even in winter and set at the right angle. I believe in worst case we get 3.5 - 4 hours.
              agree about batteries, would I be better putting them back to 12v? I also still have the spare 205w solar panel so it would mean purchasing another of similer spec and then wire it in if this helps the controller is as you see Tracer4210Rn which I stated, so it is still not stacking up, today we have had sun all day and it has charged the batteries back up and reading 28v so why is in not lasting over night?

              thanks for you comments and help so far
              Derek

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              • #8
                Originally posted by Alpaca-Meadow View Post
                I believe in worst case we get 3.5 - 4 hours.
                You are in Englang correct? If so there is no possible way you get 3.5 to 4 sun hours in winter. In England you would be doing good to get that much in late June and Early July. Winter months down more like 1 to 2 Sun Hours if the sun comes out. As Christmas and New Year approaches I suspect by then your batteries will be completely destroyed from abuse and over discharge.
                MSEE, PE

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                • #9
                  Originally posted by Sunking View Post
                  You are in Englang correct? If so there is no possible way you get 3.5 to 4 sun hours in winter. In England you would be doing good to get that much in late June and Early July. Winter months down more like 1 to 2 Sun Hours if the sun comes out. As Christmas and New Year approaches I suspect by then your batteries will be completely destroyed from abuse and over discharge.
                  Ok your not really helping because what you say is not correct, I am not sure where you are from! anyway without sounding rude thanks for you trouble and lets leave it at that

                  Derek

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                  • #10
                    Originally posted by Alpaca-Meadow View Post
                    Ok your not really helping because what you say is not correct,
                    Well OK but you should really find the truth about England because you are in Denial. You did not say which city in England but in London is less than 1 Sun Hour (.65 hours) from November to February. Less than 2.5 Sun Hours from October to April. Check it out yourself here. Best help you will get anywhere. That means you will be dark from October to April in your location if your numbers are similar. England is not very good for solar, numbers don't lie. In England it would take a 2700 watt panel to do what you want Sir. In Tuscon AZ USA only takes 350 watts. Location means everything.

                    Enjoy.
                    MSEE, PE

                    Comment


                    • #11
                      Useful solar charging hours, are much less than the hours the sun is up over the horizon. As Sunking says, you do not have enough panels for the sun hours in winter, to maintain that load.
                      Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
                      || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
                      || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

                      solar: http://tinyurl.com/LMR-Solar
                      gen: http://tinyurl.com/LMR-Lister

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                      • #12
                        For a 1 kW DC grid tie system for an area near you - using a 20% derate which is never going to happen with a battery system - this is an absolute over the moon optimistic projection

                        Your sun hours are grossly off.

                        Requested Location southampton, UK
                        Weather Data Source (INTL) LONDON/GATWICK, UNITED KINGDOM
                        56 mi
                        Latitude 51.15° N
                        Longitude 0.18° W
                        DC System Size 1 kW
                        Module Type Standard
                        Array Type Fixed (open rack)
                        Array Tilt 20°
                        Array Azimuth 180°
                        System Losses 20%
                        Inverter Efficiency 96%
                        DC to AC Size Ratio 1.1
                        1.08 26 N/A
                        1.59 35 N/A
                        2.45 60 N/A
                        4.07 94 N/A
                        5.15 119 N/A
                        5.03 112 N/A
                        5.22 118 N/A
                        4.76 108 N/A
                        3.44 77 N/A
                        2.26 53 N/A
                        1.31 30 N/A
                        0.77 18 N/A
                        3.09 850 0
                        [SIGPIC][/SIGPIC]

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                        • #13
                          [QUOTE=russ;126742]I assume you pulled his IP address to locate him and used his area real numbers? FWIW an off grid system is at best 66% efficient. 80% is for grid tied as you noted.

                          Based on .77 sun hours he is going to need a minimum 2300 watt panel with a 95 amp MPPT controller which does not exist. Nor can his batteries take that much charge current. Hpefully now he is beginning to understand why his system failed and destroying his batteries. To do this will require a 48 volt battery system using a 60 amp MPPT charge controller and a 48 volt 200 AH AGM battery. Basically replace everything he has except panels, just a lot more of them.

                          What he has now like I said earlier is come mid September he goes dark and will not see light again until April.
                          MSEE, PE

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                          • #14
                            amount of panels

                            HI Mike,
                            thanks for that what do you suggest I have a 205wat spare if I get another as close as possible to the specification would that work, although it would put me close to he 1000watt total for the charge controler

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                            • #15
                              solar data

                              HI Russ may I ask where you got these figures from please as they don't seem quite right

                              regards Derek

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