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Paralleling Multiple Batteries

Discussion in 'Electronics & Electrics' started by HSV_Enigma, May 12, 2020.

  1. HSV_Enigma

    HSV_Enigma Member

    Joined:
    Jul 21, 2003
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    Location:
    Adelaide
    Hi All,
    Just after some opinions, if I have multiple (10+) 12v lead acid batteries that get charged from a single 24v charge / discharge source, is it better to have or leave out the blue link in the middle of the image?

    I figure having the link in would help equalise the charge and discharge for the individual batteries, but it could also have the opposite effect and pick on a weaker or stronger cell.

    Batteries.png
    Thoughts?
     
  2. CQGLHyperion

    CQGLHyperion Member

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    Leave out, but also have a 2 pole CB for each string.

    You want to easily disconnect a string in case it develops a fault. If you use the blue line method, it will be more difficult to do that.
     
  3. sTeeLzor

    sTeeLzor Member

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    I wouldnt run the blue line.
     
  4. bryn

    bryn Member

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    also, you have the + & - feed wires coming off the same "bank"- flick one of them to the bank at the other end (ie diagonally opposite in this picture).
     
  5. Peter H

    Peter H Member

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    +1 to diagonally opposite corner wiring for charging AND for loads.
    You could "blue line" but use with fuses say 10-30 amp depends on battery size, so if there is a fault fuse will blow. Check current on blue wire every so often when charging, ideally it should always be near zero.
    Or - consider using an active battery equalizer. Search HA02 on eBay or AliExpress. You'd need 2 and then no need for the "blue line". I have them on a 48V bank and over time it does work.
     
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  6. sTeeLzor

    sTeeLzor Member

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    With the diagonally opposite. What's the real world effect here?

    Considering it you are looking at differences of microhoms of impedance ehich you get over terminations anyway so it shouldn't really be unbalanced? Is there something else I'm missing
     
  7. Peter H

    Peter H Member

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    Yes, the effect of high currents causing voltage drops. If you charge or draw 10's or 100's of amps it will make a big difference to the life of your batteries. And at lower currents the effect will still occur. The ones closest to the connection point will die first, because they are being worked the hardest both on charge and discharge. And it's exactly due to the mohm's of resistance from the 3 interconnect cables/terminations going to the other battery strings. Ideally you connect all batteries to one point/busbar using the exact same size/distance cables, but diagonal opposite corners is a reasonable compromise.

    See here.
    http://www.smartgauge.co.uk/batt_con.html
     
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  8. OP
    OP
    HSV_Enigma

    HSV_Enigma Member

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    That was what I was looking for thanks, I think I will run them in a star without the blue wire as suggested on that site.

    I think I might look into the HA02 equialiser too. Thanks for all the replies everyone.
     
  9. aXis

    aXis Member

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    I've used the HA02's before, they are good but expensive to scale up.

    I think you'd need 3 per column though (one between each adjacent set), or three total and put the blue wires between each set.
     

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