cordless drill batteries

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  • January 5, 2012 at 7:07 pm #67212
    washtronics
    Participant

    I have heard that it is possible to revive a rechargable battery for a drill/screwdriver that does not hold its charge. Does anybody know how its done? I have a relatively new battery but after a full charge gives up on its first use.

    January 5, 2012 at 9:54 pm #366668
    iadom
    Moderator

    Re: cordless drill batteries

    There a video HERE for Ni-cad batteries.

    Several online methods involving a welder suggested. :eeek:

    January 5, 2012 at 11:38 pm #366669
    Madmac
    Participant

    Re: cordless drill batteries

    Wouldn’t try that with lithium cells though, and if its fairly new it might contain just that, lithium cells can flare quite violently if overcharged.
    I replaced the 18650 sized lithium ion cells in my 18v drill last year (five 3.7v cells in series)but then it was a £200 drill so worth doing, decent 18650’s are around a fiver each depending on amp hrs rating.
    Works perfectly again, a new complete battery pack was going to cost £90! 😯

    Eddie.

    January 6, 2012 at 7:58 pm #366670
    leavemetogetonwithit
    Participant

    Re: cordless drill batteries

    Have seen the 18650 type on ebay from China for pennies. Could be OK for cheaper drill. Or dismantle old laptop battery. These packs normally contain protection devices against thermal overload which must not be over-ridden of course.
    Mike.

    January 9, 2012 at 9:51 am #366671
    Hollytree_Technical
    Participant

    Re: cordless drill batteries

    Before I started this job I used to work as a test engineer for a local company and we used to have to revive batteries that we could no longer get replacements for, the way we did it:

    1. Take battery apart to get to the individual cells.
    2. Find the duff cells.
    3. Get hold of a large value capacitor – we used to use a 33 millifarad with a 40V rating.
    4. Charge it up to the highest voltage you safely can – we used to use a supply that kicked out 30V.
    5. Disconnect from power supply.
    6. Short it out through the duff cell.
    7. Check cell voltage and repeat the above as necessary swapping connection polarity to the battery each time – usually found that it could be done in a maximum of 4 shocks.

    Note: Don’t get your fingers across the capacitor when its fully charged as it will hurt, you may also find that you lightly arc weld the leads from the cap to the cell.

    You try this at your own risk but it worked for me.

    Jem

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