Tuesday, 4 August 2009

Repairing my Black and Decker A12 battery

My mobile drilling machine gave up on me :-(. The battery simply stopped working and refusing to charge. I really loved the machine, but a new accu costed me roughly 40EUR almost the same price as a new drilling machine!

So why not DIY instead ;-). First I opened up the battery with revealed me 10 small batteries interconnected which each other. They are normal NiCd battery cells, with a base voltage of roughly 1.2V. I hooked up the multimeter and 3 individual batteries turned out to be dead.

Hunting for replacements was kind of a challenge. But 'the' wiki revealed it are type C NiCd Battery. Buying those is a bit more interesting, if you are interested in batched like 1000+ it's a easy search. But only a few is a bit more interesting. eurobatteries.com brought me to rescue. A actually had to buy 4/5 type C NiCd batteries (I love standards ;-)).

So opened the accu and soldered 3 new ones in, please mind the metal strips are very sharp!
Accu open

Assemble it all:
Protection active

And we got a working battery again :-)!
Working again!

I have to admin it the costs where roughly half the price of a new one and it requires some soldering skills (and equipment) to get it assembled, but -as always- it fun todo!

6 comments:

  1. How many mAh where those batteries?

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  2. Every battery (cell) is 1400mAh

    Full details on battery: EUR 079 NI-CD 4/5SC1400mAh 1.2V

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  3. Hi Rick, I've the same problem with the same battery type (a12). I'm going to disassemble it tomorrow.
    I read that the C type batterie could be replaced with AA and a size adaptor. what do you think about it?
    And how can i find dead battery with multimeter? there's a voltage limit to declare a battery dead?
    Putting batteris in series, can i replace only some batteries and not all.
    That's for your reply
    Stefano

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  4. > I read that the C type batterie could be replaced with AA and a size adaptor. what do you think about it?

    The charger will not like this and the capacity will be severely affected.

    > And how can i find dead battery with multimeter? there's a voltage limit to declare a battery dead?

    Mine showed 0.3V after 'charging', but I guess anything below 1.0V after charging can be marked dead.

    > Putting batteris in series, can i replace only some batteries and not all.

    You have to replace them with the same specification batteries, than you are safe just repairing individuals.

    Do NOT change the battery configuration as your charger is not designed to change different configurations of batteries, causing serve damage to your equipment or yourself.

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  5. Hi,

    I know that this is a old topic, but I am just wondering how hard was to solder the battery and how safe is it? Did you use a massive soldering iron?
    Thanks

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  6. Just a simple soldering iron with enough flux will do the trick. Safe has to be your own judgement, use protective (goggles/gear) while doing the repairs for example.

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