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  1. #1
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    Which batteries?

    Hi,

    I put some fully charged 2500mah uniross batteries in my fenix torch and after one 30 min run on full beam they are dead. Is this run time normal and if not what batteries should I use?

    I am also about to fit a horn (6V 1.5A) and would the same happen with this batteries - again which ones should I use?

    Thanks

    Daven

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    If the 2500mAh batteries are AA NIMH then you'll need 5 of them to power your horn and they should run it for about 1hr 40 mins.

    I don't know what the runtime on your torch should be, but you said batteries and judging by the capacity I guess it's 2 x AA NIMH.

    If it is try changing the batteries, if one of the batteries is a bit tired it will effect the overall result.

    If the batteries are a bit elderly, some new ones might perform a lot better.

    Finally, if all your batteries seem to be underperforming, suspect your charger.

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  3. #3
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    they are NIMH. for the horn I was going to put 6 in.

    might try charging them again. Is there a way to see how much charge is left in a battery?

    Thanks

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    Measuring the voltage with a voltmeter or multimeter should give you a rough idea.

    IIRC cell voltage shouldn't go below 1v for NIMH fully discharged and should probably be somewhere ITRO 1.4V when fully charged, depending on cell make, condition and type/quality of charger.

    This isn't the same as measuring the voltage under load, a healthy looking cell can sag when under load.

    Hope this is of some help....

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  5. #5
    Senior Member kf5nd's Avatar
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    you might have ONE that has gone soft on you. Check with voltmeter after the group of them has apparently gone dead. You might find that most of the are good, but one is near 0 volts

  6. #6
    Senior Member bhkyte's Avatar
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    You could try fully discharging them and recharging them several times. This is suppose to be less usefull for NIMH batteries rather than older NICAD, but I have had good results occasionally with this. I dont think this is the problem as usually this occures if the batteries have not been used for a while, but it might be worth a try.

    good luck

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    thanks all, I don't think I have used them for a while so perhaps the charge / discharge could work.

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    You can learn a bit about battery performance by going to the sites of major manufacturers, such as:

    Panasonic

    from where you can download general articles on the batteries and exemplary specific data sheets. The batteries lose their capacity over their lifetime and capacities for marginal manufacturers are often inflated. Battery capacity usually drops with an increase in the discharge current.

    When combining individual cells, it is advisable to use identical cells from the same manufacturer. As my consumption of rechargeable and some specialized cells is high, I lower my costs by periodically ordering batteries in large quantity over the internet.

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    Making a Pilom Triple LED Headlight ? I have parts available :)
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