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48 Volt battery bank wiring

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  • #16

    Re: 48 Volt battery bank wiring

    Re: 48 Volt battery bank wiring

    Here is Edward's "keyturbocars" thread where he did a bunch of research and testing a setup to recover Lifeline AGM batteries:

    Sulfated Lifeline Concorde AGM Batteries

    If the batteries in series (and parallel) are terribly mismatched (i.e., good battery in series with sulphated battery) could cause the unbalanced charging where one battery is charging at "low voltage" and the other at "high voltage"...

    Charging/recovering batteries separately may help... Also matching batteries by capacity ("high" capacity in one string, "low" capacity in a second series string) may help too.

    -Bill
    20x BP 4175B panels (replacement) + Xantrex GT 3.3 inverter for 3kW Grid Tied system + Honda eu2000i Inverter/Generator for emergency backup.

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    • #17

      Re: 48 Volt battery bank wiring

      Re: 48 Volt battery bank wiring

      I agree with Bill. Handling each battery separately is a good idea. I did it and it did help my situation. Even so, my batteries were so far gone to begin with that the situation is still not great. Things are better though.

      If your battery bank is newer and in better condition then mine, then trying to equalize each battery separately according to Lifeline's procedure might give you good results.

      Edward
      On-grid with RE backup power. HY-2000 2kW wind turbine charging 48V 600Ah Concorde Lifeline battery bank. Wind power diversion heats water in an auxilliary 80 gal hot water heater. 2.1kW Evergreen solar panels & TS-MPPT-45. XW6048 inverter, Onan 6kW 6DJE diesel generator, and Yanmar YDG3700 diesel gen as backup.

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      • #18

        Re: 48 Volt battery bank wiring

        Re: 48 Volt battery bank wiring

        Last I checked the resting voltage they were within .01 to .10 of each other. (Actually my batteries never "rest"). Just checked (7:25 PM).. Neg side parallel batteries at 12.75v, .07 to .10 higher than all other batteries with about a 150w to 200w load.

        I bought the first two batteries March '10 and the last string of four in Oct '10.
        (By the way, two of the strings had discharged batteries (12.5 - 12.7). I wasn't happy to have paid that kinda money for new batteries and then have to spend several days charging them before I could use them).

        All in all, I'm pretty happy with these little Lifeline batteries..

        I have another small 4-battery-12v-system of Costco wet cell batteries. Little bit higher in total amp hours than the Lifelines but of course, they just can't take much of a load for very long compared to the lifelines
        OB Flexware 500, 3648 inverter, two FM60 cc, eighteen Kyocera 135sx panels, sixteen Lifeline 105Ah 12v AGM batteries - off grid. (grid power available) 6800w diesel gen

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        • #19

          Re: 48 Volt battery bank wiring

          Re: 48 Volt battery bank wiring

          Your batteries were (and are) in much better shape than mine were. If memory serves me right, I think some of my batteries were reading as low as 11.5V when I took them out of the boxes. They sat for 2 YEARS before I bought them. Other batteries were higher, but they were all over the place. They were all very low!

          I thought I was getting a good deal paying around 1/3 price (getting 3 for the price of 1)!. In reality I was paying a lot for scrap lead! UGH! It is amazing at how well they have come around all things considering, but they are definitely NOT what they should be. One day I plan to do it right. For now, they are sufficient for what I need.

          In the future, I'd like to get a couple strings of the 6V Lifeline GPL-6CT (oversized golf cart size) that are rated at 300A/H each. This time, I'm going to make sure that they are factory fresh and all from the same lot. And I'm going to treat them like they are made from GOLD!

          Live and learn!

          Edward
          On-grid with RE backup power. HY-2000 2kW wind turbine charging 48V 600Ah Concorde Lifeline battery bank. Wind power diversion heats water in an auxilliary 80 gal hot water heater. 2.1kW Evergreen solar panels & TS-MPPT-45. XW6048 inverter, Onan 6kW 6DJE diesel generator, and Yanmar YDG3700 diesel gen as backup.

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          • #20

            Re: 48 Volt battery bank wiring

            Re: 48 Volt battery bank wiring

            Originally posted by n3qik View Post
            I would go with this:
            Greetings. After much experimentation and blown fuses, I have concluded that there is no other practical way to wire a 48 volt bank of 12V batteries than that shown by n3qik's most excellent diagram. Perhaps I should refer this to David Small, the author of the interconnection article?
            Cheers.
            Stand-alone system: 6 X Kyocera KD210, AirX 48V, Outback FM 60 controller, 2 X Outback FX3048 Inverters, FW-X-240 transformer, 20 X Sterling HA 140Ah 12V AGM batteries @ 48V.

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            • #21

              Re: 48 Volt battery bank wiring

              Re: 48 Volt battery bank wiring

              Thanks and you can show David the drawing.

              Originally posted by JCOrd View Post
              Greetings. After much experimentation and blown fuses,
              The blown fuses statement reinforces why I had each string fused. But moving forward, please be safe. Batteries as you have found out, can be a source of some nice fireworks.
              Ken
              Telford,Pa
              Old Homepage: http://home.comcast.net/~n3qik
              Updated 6-7-2009

              Updated Homepage: http://home.comcast.net/~n3qik/site/?/home/
              Updated 12-3-2011

              Home Automation: http://n3qik.homeip.net:5800 Password = guest
              Software/hardware is 100% complete. At least for today. Tomorrow is a different story.
              Updated 2-17-2012

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              • #22

                Re: 48 Volt battery bank wiring

                Re: 48 Volt battery bank wiring

                I am not a fan of cross trapping batteries of different strings. I prefer to keep each string as standalone.

                Crosstrapping makes it harder to detect a battery going bad. It also has a greater chance of taking out more good batteries as the bad battery starts raising the charge voltage on other batteries. You can juggle batteries around sometimes to match up series connected voltage per battery and current for each string.

                I have ten strings of four series 12v batteries (forty batteries).

                I have 100 amp shunts on negative lead on each of the strings and monitor each batteries voltage regularly. I have a common 500 amp shunt for a trimetric monitor.

                I have two parallel strings per cart (about 550 lbs per cart) with 350 amp Anderson connector for each of the five carts. Carts are on casters so it is easy to pull the Anderson connector and roll a single cart out for service.

                Each cart is 27" long, 24" high, and 15" deep so doesn't take up too much room from wall. Welded all five together, mostly from salvaged bed frame angle iron.

                Been running this config for about 15 years. The fifth cart at far right was a later add on and not matched for wire length but I don't have much voltage variance due to low current per string using 2/0 interconnects.
                Attached Files

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