Charging 3 batteries with 1 charger

Discussion in 'The Projects Forum' started by joeander, Sep 2, 2009.

  1. joeander

    Thread Starter New Member

    Sep 2, 2009
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    I am working on an electric motorcycle using a 36 volt golf cart battery and three 12v truck batteries (new). I need to charge them similtaniously with one 12 volt charger. Will the enclosed circuit work?
     
  2. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    Are those black symbols with an arrow and a bar intended to be diodes? If so, what is their purpose? Also, the three attached to the negative terminal are backward. That circuit will not work.

    If you mean that symbol as just a connector of convenience, then your connections will make a dead short. That will cause a lot of heat and likely much worse.

    John
     
  3. joeander

    Thread Starter New Member

    Sep 2, 2009
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    The arrows are diodes to keep the current from back feeding the charger and to keep the charger from shorting the batteries.
     
  4. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    OK, but how does any single battery charge through the diode on its negative terminal? If you reverse that diode, then you short the battery.

    You can do what you plan to do by charging each battery independently for a short period, then the next, and so forth. That can be done automatically, and the total charge time will be about the same as you expect from the system you have drawn.

    John
     
  5. jj_alukkas

    Well-Known Member

    Jan 8, 2009
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    As said before, You have messed up with the diodes. Use only 3 diodes, one per battery and connect them as

    charger ----->|----(+) Battery 1
    " ----->|----(+) Battery 2
    " ----->|----(+) Battery 3

    Use Diodes with sufficient current ratings.
     
  6. SgtWookie

    Expert

    Jul 17, 2007
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    You'll need to remove the crossover jumpers between the batteries before charging; otherwise you'll have a problem.
     
  7. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
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    Joseph,

    Some people might get a charge out of the resulting explosion, but the batteries won't. Look at the center battery. Connecting the negatives poles together effectively connects the positive of the center battery to its own negative, usw.

    John
     
  8. jj_alukkas

    Well-Known Member

    Jan 8, 2009
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    Removing all other connections and connecting -ve's altogether and +ve through a diode would cause no problem
     
  9. mkbutan

    Senior Member

    Sep 30, 2008
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    remove the connectors from in between the battery's
    and remove diode's from -ve line from the battery's
    the only affect will be the delay in charging time
    ie.- if 12v battery charges the battery in 1 hr. then it may take three time's the required time
    and also depend on the current ratting of the charger
     
  10. Bernard

    AAC Fanatic!

    Aug 7, 2008
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    I would not wish to unstrap my battery pack every time they needed charging, so would add a 3PDT SW. Using diodes may messup chargers voltage detection function, so could add another SW-DPST.
     
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