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Charging a battery?

  1. Apr 24, 2012 #1
    I have a battery. I can go get a screwdriver from the garage and open it to see the specs on it, but was for an electric bike. I don't have the AC adapter charger any more. Can I charge it with a universal AC adapter I have, just wired together? The AC adapter has two holes in the tip, and I was able to determine which hole was positive and which was negative by using a voltmeter. The universal AC adapter is variable voltage with several settings from about 2V to 12V. The old AC adapter charger for this battery output 24V. I'll go open this battery up and see the specs on it. I would really like to charge it.

    Also, (this is secondary), I'd like to attach my inverter for my car to this battery. Any tips or advice?

    Okay, I opened up the case of the battery and it's two 12 volt lead-acid rechargeable batteries in series, which would effectively be 24V (I think - it is 24V maybe I meant parallel).

    And thanks Jehan, that is what I'm looking for. Now if I can just connect it to my inverter I have for my car..

    And if anyone else has any more tips, advice, or direction, please feel more than welcome. The more knowledge that I can get, the better.
    Last edited: Apr 25, 2012
  2. jcsd
  3. Apr 24, 2012 #2
  4. Apr 24, 2012 #3
    Okay, I'm wondering what is the max safe amperage I can trickle charge this battery with? Again it's two 12V lead acid batteries in parallel.
  5. Apr 25, 2012 #4


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    Staff: Mentor

    Do the batteries have an ampere-hour rating printed on their label? If not, hop online and do some browsing to find similar looking electric cycle battery and tell us what its ampere-hour rating is.

    If the combo is 24V then the two batteries are in series.

    If all else fails, charge at 0.2A and record the voltage every few hours to gauge how the charging is progressing. If this is an old battery, it's possible that the condition of at least one of the pair inside might have deteriorated to make that one unusable. Can you monitor the voltage across each as you charge them in series? Pb-acid cells can have a relatively short useful life, anyway.
  6. Apr 25, 2012 #5


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    Staff: Mentor

    What do you power from the inverter?
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