Flaky Dewalt 18v battery

[Toller]

I have a Dewalt 18v battery that came with a tool at an auction. If I put it partly in my drill it works fine, but putting it in all the way breakes the connection. Sometimes if I wiggle it around it will work briefly all the way in. It works that way in 3 tools, and a new battery works normally; so it is the battery.

I have put contact cleaner on it, scratched it up with a file, and tried bending the contacts in an out; but nothing helps. The blades look pretty much like the ones on the good battery, so I can't imagine why it isn't making contact. Any suggestions?

[Jeff Wisnia]

Sounds like a "loose disconnection" inside the pack.

If you can figger out how to pen it you should be able to easily find where that is and repair it with solder or even conductive epoxy.

Jeff

[Rich Greenberg]

An internal connection is intermittant. Clip a voltmeter on the tabs and try pressing them or moving them around.

[Toller]

Yes, that is exactly what it is, right at the top so it is pushed together when partly in, but separated when in all the way. My soldering iron isn't up to the job. What is conductive epoxy?

[Jim Yanik]

"Toller" wrote in news:%sLhf.247$ [e-mail]:

Epoxy with copper or silver fillers.

Don't waste your time with it;its too resistive for the high currents in this application.Solder it or get it re-spotwelded.

Now,ordinary epoxy WOULD be useful for building up a worn part of the plastic casing.

[Jeff Wisnia]

It's a silver bearing epoxy which has amazingly high conductivity.

I just went to the kitchen fridge where SWMBO, bless her heart, lets me use one door shelf in the freezer to store my back up supplies of epoxy and seldom used adhesives. And pulled out my pack of conductive epoxy,

I bought a 0.5 oz. kit of it (Two little tubes, Parts A & B) about ten years ago, and thanks to keeping it in the freezer it's still usable when I need to make a connection that just doesn't lend itself to soldering.

The card the tubes were blister packed to says the conductivity is 0.001 ohm/cm, which is about 5 times as high as soft solder, but if the distance you span is small, you'll never notice it.

One drawback though, the stuff is damn expensive in small quantities, around $24 for a little package, like this one:

It might be cheaper for you to buy or better yet borrow a larger soldering iron.

HTH,

Jeff