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  1. #1
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    New Battery Malfunctioning....ideas?.....

    Just bought a 14.4V 5000mAh NiMH battery & smart charger from a popular online supplier. Got about a half hour run time on 32w dual beam halogen head after an hour initial charge.
    I've discharged and recharged 2 time since then, with approximately the same time to charge and the same burn time.
    Now attempting to charge for the 4th time and the battery won't charge.... At least the indicator on the charger doesn't come on when I connect the battery now. Each time I discharged the battery I ran it until the lights started to dim/turn yellow. I'm waiting for an email response from the seller..... In the meantime, does anybody have any suggestions?

  2. #2
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    You're pulling about 0.5C. How many amps is the pack rated for?

    >>Each time I discharged the battery I ran it until the lights started to dim/turn yellow<<
    Don't tell the popular online supplier that you did that as you probably ran the cells lower than 1v/cell and possibly killed a cell or put the pack out of balance

  3. #3
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    Battery specs are:

    Voltage: 14.4V (working) 17.4V ( peak)
    5000 mAh min. (72 wh)
    4.2 Amp limited by two polyswitch

  4. #4
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    Battery may be defective

    If the battery was operating properly, you should have been able to run longer. I calculate:

    32watts/14.4volts = 2.2 amp
    5000mAh/2200mA = 2.27 hours

    That's under ideal circumstances, but 2 hours should have been obtainable.

    You aren't overvolting?

    I don't think you did anything wrong by running the pack until the lights dimmed. Past that point is very bad though.

    Walt

  5. #5
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    lemme guess - the charger is a blue box about 2x3x7" and you can select the charge current of 0.8 to 1.8 A ?
    Got a multi meter ? test the final voltage of the pack... I had a charger which would indicate full charge prematurely (less than 1/2 way) I would have to reset the charger to insure a full pack.

    Measure the final voltage of the pack after charging - I think you will be well below the 17.4 peak.

  6. #6
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    same battery - same problem.

    Yep, the charger is the little blue "smart" one. I figured out the under-charge problem just this weekend. When the light turned green I unplugged the charger (from the wall) and plugged it back in. The green/red flash sequence would go and then the charger would start charging again. After a couple cycles like that, it would flash green/red when plugged in and then go to green.

    Running one 20w 12v flood and occasional 20w spot, I got tired of urban trail riding after a long day at work before the battery went. It was over two hours as opposed to 1 hour 20 minutes.

  7. #7
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    Quote Originally Posted by heatstroke
    lemme guess - the charger is a blue box about 2x3x7" and you can select the charge current of 0.8 to 1.8 A ?
    Got a multi meter ? test the final voltage of the pack... I had a charger which would indicate full charge prematurely (less than 1/2 way) I would have to reset the charger to insure a full pack.

    Measure the final voltage of the pack after charging - I think you will be well below the 17.4 peak.

    Exactly! That's the charger. I'll test with a multimeter at work tomorrow. Thanks for the advice ....I knew somebody on here would have the same setup!

    Quote Originally Posted by paulrad9
    >>Each time I discharged the battery I ran it until the lights started to dim/turn yellow<<
    Don't tell the popular online supplier that you did that as you probably ran the cells lower than 1v/cell and possibly killed a cell or put the pack out of balance
    I was concerned about that, but their site claims that the battery has "One 4.2 Amp polyswitch installed to limit max. discharging current at 8.4 A and to protect wrong polarity". Doesn't that mean I can just run it until it shuts off completely.... let the "polyswitch" do its job? The lights have gotten quite dim with no shut-off occurring.

    Quote Originally Posted by Walt Dizzy
    >>You aren't overvolting?
    Yes, 14.4V pack on a dual beam 12v halogen head.

    Thanks again guys!

  8. #8
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    I think the polyswitch will not shut off the light except when exceeding the current drain. Just run the lights till they are dim.

    My advise is to get a "GOOD" battery charger, something like one the RC folks use and can handle different battery chemistry.
    I have the multiplex LN5014, only problem is that I think lifepo4 batteries are on the way and my charger will not handle the new cells.

  9. #9
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    [QUOTE=heatstroke]I think the polyswitch will not shut off the light except when exceeding the current drain. Just run the lights till they are dim.

    Good thinking, a polyswitch is resettable fuse, it's used to protect against over current faults.
    To protect the pack from over discharging you need a protection circuit.

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