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HP Forum Archive 15

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Paul Harvey on batteries
Message #1 Posted by db (martinez, ca.) on 13 May 2005, 12:00 a.m.

I was hoping that someone would comment on old Pablo's "news" show last week where he said that you can get some more life out of dead rechargeable batteries by banging the negative ends together a few times. Maybe i'm the only one here with this insidious radio vice.

Anyway; do you think this works? I hope it does, or i'll have to rethink everything else i learned from him.

      
Re: Paul Harvey on batteries
Message #2 Posted by John Limpert on 13 May 2005, 2:35 a.m.,
in response to message #1 by db (martinez, ca.)

I can't think of a reason why it would affect the batteries, for good or bad. All of the battery reconditioners that I've seen rely on charging and discharging the battery in a way that is designed to fix electrochemical problems inside the cells.

      
Re: Paul Harvey on batteries
Message #3 Posted by James M. Prange (Michigan) on 13 May 2005, 6:58 a.m.,
in response to message #1 by db (martinez, ca.)

Maybe it shakes some electrons down to the negative end, where they belong?

      
Re: Paul Harvey on batteries
Message #4 Posted by I, Claudius on 13 May 2005, 10:01 a.m.,
in response to message #1 by db (martinez, ca.)

It would do well to examine the source. While well-meaning, Paul Harvey is simply a radio commentator, an entertainer. He is by no means an engineer, or even a tinkerer. He makes his living with his mouth, not with any talent for technology. This particular claim of his is simply not substantiated by any evidence.

      
Re: Paul Harvey on batteries
Message #5 Posted by Ron on 13 May 2005, 11:41 a.m.,
in response to message #1 by db (martinez, ca.)

Try it and report back...

12345

      
Re: Paul Harvey on batteries
Message #6 Posted by Dave Shaffer on 13 May 2005, 1:29 p.m.,
in response to message #1 by db (martinez, ca.)

I suppose there's a small chance that just "banging" the batteries might help - regardless of polarity or direction, however. (I do like the suggestion that the electrons just need to be knocked back to the negative end!!)

Although you think of a battery as an electro-chemical system, there are also some mechanical factors involved. As the battery compounds are charged/discharged, they expand and contract slightly as their chemical state changes. This is what causes your car battery to go dead - some of the lead plates basically fall apart and short things out.

Think also of battery leakage. While chemically driven, there certainly are mechanical changes. Many batteries swell up as they die and leak.

I don't know about NiMH or NiCads, but I suppose there might be mechanical changes in them, too. So, a good bang might break up something that has gone wrong, such as dislodging a minor short circuit.

As Ron suggested, try it and see what happens!

            
Re: Paul Harvey on batteries
Message #7 Posted by Paul Brogger on 13 May 2005, 2:10 p.m.,
in response to message #6 by Dave Shaffer

I heartily recommend Steve's article -- non-leaking NiCds may be dramatically improved by the "zap" method.

But banging the negative ends together? I'd have to say:

Good Day?

                  
Re: Paul Harvey on batteries
Message #8 Posted by Hans-Erik Lehndal on 16 May 2005, 2:20 a.m.,
in response to message #7 by Paul Brogger

I read an article back in the 70īs about zapping life back to NiCd cells by using a (huge) capacitor, I think it was in Popular Electronics. While the idea seemed nice enough, I never succeeded in my revival efforts. Perhaps a bit of faith is needed too?

      
Re: Paul Harvey on batteries
Message #9 Posted by Les Bell [Sydney] on 13 May 2005, 8:03 p.m.,
in response to message #1 by db (martinez, ca.)

There is a theory that, over time, NiCad cells develop conductive "whiskers" of some crystalline substance (not familiar with the chemistry, sorry) and that these whiskers progressively short out the cells, reducing their capacity.

The whiskers are fairly brittle, and the theory says that a mechanical shock can break them and restore the cell to higher capacity. (The same theory also explains "zapping" cells with a charged-up capacitor). Obviously, it doesn't matter what end of the cell you bang against another; it's the g's that do the trick.

Does it work? I tried it once - if memory serves correctly, on a battery pack for an iCom portable radio. I slammed the pack hard against a brick wall. It seemed to work, but some time later I had the battery rebuilt with new cells, so obviously the fix wasn't permanent or some other effect was at work.

Best,

--- Les
[http://www.lesbell.com.au]


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