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Ni-Cad batteries

Discussion in 'd.i.y.' started by a.palfreyman, Sep 17, 2022.

  1. a.palfreyman

    a.palfreyman pfm Member

    My Dewalt 18V drill batteries are getting tired. About 3yrs ago I opened them up to find 2-3 duff cells in each of the two packs. I recharged these low cells separately using a current limited psu and cycled the packs a couple of times which improved things, but fear they are as bad now if not worse.
    Just spotted this:
    https://itstillruns.com/refurbish-18v-dewalt-battery-6225112.html
    This suggests that a 3 second burst from a 12V car battery charger can revive poor cells. Seems a bit risky to me, but I'm tempted as I have nothing to loose. Oh, I'd not remove the cells. I'd just 'burst' charge them in-situ. Any thoughts?
     
  2. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    I can't see it making much difference. You would need to do it to individual cells also if going to try it.

    When conductive "whiskers" form internally which can cause a cell to malfunction it was not unknown to try and cure this by getting a 10000uF or so smoothing cap and charging it to say 70V and then discharging across the cell to try and vaporise the whisker.
     
    a.palfreyman likes this.
  3. Mynamemynaim

    Mynamemynaim 38yrs a Naim owner

    As mentioned in a previous thread
    Scrap the NiCd cells and replace with Lipo cells
    You will increase the capacity (Amp hours) considerably and you can charge them faster too
     
  4. a.palfreyman

    a.palfreyman pfm Member

    Aren't lipos a bit funny though? I'd read that these typically have a circuit which monitors charge/discharge rates to stop them catching fire...
     
  5. Puggie

    Puggie pfm Member

    This works if its the dendrite whiskers causing discharge. We used to freeze them overnight then give them very short (sub second) charges at upto 90A off a big power supply until the cell warmed up a bit. Your car battery will do similar. You are limping them on at best.

    I have a similar DeWalt in the garage, I replaced it with a beast of a Hitachi drill, but I would like to make an adapter to to git the Hitachi packs to the dealt. There is a guy that does adapters for most packs onto ryobi cordless tools, so I'm sure you could make/3d print something for a dewalt.
     
  6. Puggie

    Puggie pfm Member

    LiPo batteries are awesome, they just demand a bit more respect than nicads. Use a proper dedicated charger and they are fine. Most powertools just want to see the right number of volts to work. The Parksidebatteries for their stuff from Lidl is surprisingly good for the money.

    Like this:
    https://www.ebay.co.uk/itm/25554873...d=link&campid=5338728743&toolid=20001&mkevt=1
    But someone may do one that takes a better value pack than dewalts.
     
    Mynamemynaim likes this.
  7. Mynamemynaim

    Mynamemynaim 38yrs a Naim owner

    Lipo batteries are fine if treated with respect
    as other's have said

    It's easy enough to strip out and throw away the nicad batteries and replace them

    Alternatively...if someone makes a converter for a Parkside or similar...then all the better
     
  8. a.palfreyman

    a.palfreyman pfm Member

    Thanks chaps,
    I'll look into this.
    Car battery charger has reinvigorated 1 cell. Just pressed the clips to ends of cell after removing most of card. 4 more cells from same pack no difference after about 6 pulses each. Unless I can couple some caps to give about 10mF and charge to 60V off my bench PSU as suggested by Jez...:confused:
     
  9. a.palfreyman

    a.palfreyman pfm Member

    2 off 3.6AH Ni-MH XRP packs from ebay for £25.
    :)
     
  10. Loz828

    Loz828 pfm Member

    Why bother mucking around with dying battery packs? You can make $50 or more an hour cutting lawns and then just buy a new one, and if you are handy enough to even attempt to restore an old battery pack then you could charge $100 an hour for misc handyman repairs/jobs for people who don't know how to (all cash work of course), then you can buy new Makita LXT tools/batteries and dump the Dewalt NiCd stuff.
     
  11. a.palfreyman

    a.palfreyman pfm Member

    Nice thought Loz, but I don't use this for work, only DIY. Plus I'm a tight g1t...
     
    Mynamemynaim likes this.
  12. a.palfreyman

    a.palfreyman pfm Member

    Oh, and I should add that as a professional engineer (metallurgist) of over 30 years standing, I can only DREAM of $50 (£40) an hour...
     
    Snufkin likes this.
  13. Pete MB&D

    Pete MB&D Pete Maddex, the one and only!

    I bought some cheap 12V makita ones of ebay and they work perfectly, I also have a couple of the 7.2V stick ones for my old 90deg drill again faultless.

    Pete
     
  14. martin clark

    martin clark pinko bodger

    Last time one of my old cordless drills had its battery die, a 14.4v nominal jobbie - instead I just soldered a cheap pair of c.15A croc leads to the battery terminals - about £6 then from amazon (and recycled the battery)

    And now use it for odd jobs on the cars, clipped to the SLA terminals instead; good heavens does it develop a torque it was never capable of, off Nimh C-cells. & I don't care if this burns it out, I'll repeat with some other junkbox freebie likewise when it does!
     
  15. Pete MB&D

    Pete MB&D Pete Maddex, the one and only!

    When I did my decking I used my small blue Bosch mains drill for some screw a it had mountains of torque compared to my 12v makita drills, but the impact driver was easier to use much less strain on your wrist.


    Pete
     
  16. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    Maybe the world is not ready for the technical marvel of power tools with virtually limitless power that don't even need a battery... just a simple mains cable:rolleyes:
     
    a.palfreyman and Richard Lines like this.
  17. James Evans

    James Evans Bedroom Bodger

    I thought mains cables made no difference? ;) (runs and hides...)
     
  18. a.palfreyman

    a.palfreyman pfm Member

    Seems @martin clark agrees as he's gone halfway house with his leaded battery power ;)
     

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