Repairing cordless tools

[nelectric]

Does anyone have any information on testing and repairing cordless tools? I'm after expected resistance across +/- terminals on the drill itself and on the charger (unplugged of course) and any other useful pointers as to the condition of the drill. Note I am not talking about the battery because I already know how to rejuvenate the battery. It is just the drill itself and the charger that I want to test/repair.

Bit of background information - I am doing voluntary work for a charity who renovate hand tools and some power tools for subsequent use by disadvantaged people, be they in Africa or local groups in the UK. We come across different makes and types of cordless tools, usually not working, and before I came along they were just thrown away. I have learnt how to rejuvenate the batteries which in some cases makes the tool reusable, but in others, even if I sort the battery out, either the tool itself or the charger does not work. I would like to learn how to repair these parts. Any tips/advice would be appreciated.

For anyone interested, the charity details can be found at: http://www.tfsrnorthampton.org.uk/

 

[ban-all-sheds]

You'd probably find it more cost effective to get a part-time job, work the hours you'd otherwise spend fiddling with rickety old tools, and use the money you earn to buy new ones for the charity.

 

[kevplumb]

I have learnt how to rejuvenate the batteries

how

 

[electronicsuk]

I have learnt how to rejuvenate the batteries

how

I expect it involves putting a DC voltage a number of times larger than that of the stated terminal voltage across the cells for a short period of time. This can sometimes help, although in the majority of cases the battery is already well on its way to the dustbin anyway.

OP, as every tool is different, there are no specific readings to look for or set procedures to follow. As most cordless power tools are (electrically at least) quite basic, it's just a case of running through the individual elements one by one, from battery to switch/speed controller to motor. Any tools with a broken motor or variable speed control are likely to be beyond economical repair.

 

[stillp]

These "rejuvenated" batteries will almost certainly expire very soon after you've exported them to the deserving poor in the developing world. Is it likely that the hazardous substances contained in the batteries, such as cadmium, will be disposed of in an ecologically-sound way? Or is it more likely that someone will try to repair them, thus exposing himself, his family and his neighbours to carcinogenic chemicals?

By the way, I'm aware of two ways of "rejuvenating" Ni-Cad batteries, both of which are extremely dangerous and give at best temporary results.

Do the developing countries a favour, and recycle these cordless tools through the local authority waste disposal site. If you think they really need cordless tools, then follw BAS' suggestion.

 

[nelectric]

The power tools all remain in this country, typically donated to local groups. I am aware of the possibly temporary nature of the battery fixes, but then these tools will be passed on to people who otherwise have nothing. We are very careful not to export hazardous materials to Africa and these particular tools will not be sent there. We are even wary of using non-reusable and non-biodegradable materials in packing the kits we send to Africa.
As for the suggestion that I get a paid job (if only!) and buy new tools, that is not what we (TFSR) are about. We recycle unwanted items to give them a new lease of life so they do not end up as landfill. We also provide opportunities for vulnerable adults to experience a working environment. It is in many ways a worthy cause and very satisfying to be involved with.

 

[jj4091]

Unless you have what was originally a very good quality ( no names mentioned ) expensive cordless tool, which can be economically repaired & therefore never given nor thrown away, you will be wasting your time. Parts for the cheapos are never readily available & in most cases you cannot even canibalise as it is always the same part that goes in most of them. Sorry, I have to agree with the other similar observations, but I do admire your good intentions.

 

[stillp]

OK, sorry, I assumed you were sending these overseas. Presumably you remain in touch with the local groups who receive these tools so you could recover them when they expire?
I don't think that typical resistance readings would help you very much though since as already said every one will be different, particularly as regards the chargers. Most chargers now are switch mode, so a resistance reading won't mean very much - the only option will be to remove the circuit board and use standard electronic fault finding techniques.
Please bear in mind what I said about "rejuvenating" batteries. There have been several fires and at least one death (in the USA) resulting from the application of various voltages/currents to the sort of batteries used in most cordless tools.
Like jj, I applaud your good intentions (and will sort out some redundant hand tools for your charity) but I think you're wasting your time with the cordless tools.

 

[ban-all-sheds]

From my experience of trying to sell them for even a fraction of a cheap price, you could do worse than go to car boot sales and buy used-but-working cordless tools for next to nothing.

Re battery "rejuvenation" - if you can get the proprietary shaped plastic case open you'll often find that inside are standard sized cells which can be replaced with new ones.