..
..
Sam Heywood
You are totally correct in your strategy, with
many "dead" ni-cad or lead-acid batteries, if
they have not been dead for too long.
The "temporary death" is caused by "branch crystals"
growing between the + and - plates, being sharp,
and actually puncturing the insulator between
+ and - plates, thus short-circuiting the battery.
Your "brief" high power surge burns off these
short circuit bridges, thus permitting the battery
to once again take a charge.
You are also correct in your "cautions" to wear
safety glasses, protective clothes, gloves, etc.
If any of these batteries rupture/explode acid or
caustic fluid will go in your eyes, nose, mouth...
all of which are not nice, not to mention possible
blindness. Also, an exceptionally heavy surge
current, if you use such, will generate significant
amounts of hydrogen and oxygen, mixed together into
a deadly cloud if there is even the slightest
spark.... Boom !
For someone who was just guessing how to re-activate
batteries, you are very clever. You are almost
intelligent, taking all the safety precautions.
Keep on truckin with those batteries.
Ross Virgin
Toronto, Canada
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On Wed, 05 Mar 2003 12:11:12 -0500, Samuel W. Heywood wrote:
> On Wed, 5 Mar 2003 08:04:32 -0700, [EMAIL PROTECTED] wrote:
>> Hi all,
>> I was given 2 very old laptops (Toshiba Satellite 1800s) that still
>> function, but the batteries won't recharge. Everything else still works
>> fine.
>> I wanted to use the laptops for a demo of an old DOS database, but it's
>> not so important that I'm eager to buy some new batteries.
>> Does anybody have a brilliant scheme to shock old batteries back to life?
>> Thanks,
>> Bob
> Shocking Ni-Cad batteries into a resurrectable condition is something
> I have done many times. I don't know if my way of doing it is the
> recommended method, but I do know that it works. Nobody ever
> recommended the method to me. It is just something I tried and I found
> out that it works. Since then I have met others who say they have made
> the same discovery on their own about how one can shock a Ni-Cad battery
> pack into a resurrectable condition.
> Here is how I do it:
> I shock the battery pack for a period of several seconds by using a
> power supply having about twice the voltage of the power-pack and capable
> of delivering at least twice the amperage of the recommended charging
> device. After doing that I hook up the battery pack to the recommended
> charging device. Then I make measurements to determine if charging
> current is flowing through the battery pack. If no charging current is
> flowing I shock the battery pack again. I repeat these procedures until
> I get the battery pack shocked back into a rechargeable condition. In
> some cases I have to increase the power of the initial shocks up to about
> 4 times the normal charging power. In most cases my efforts to resurrect
> Ni-Cad batteries are successful, but sometimes I find that they have been
> dead for too long and that their souls have already gone to heaven. I
> can't bring them back after that, not even if I convert to an alternative
> religion. In shocking Ni-Cad batteries back to life you want to take care
> to just zap the battery pack and not to fry it. If the battery pack
> starts getting very warm, then you are applying too much power for too
> much time. You should wear safety glasses and take other precautions when
> trying to shock a battery into a resurrectable condition. Too much power
> applied across the terminals of a battery can cause the battery to melt or
> even expode.
> Regards,
> Sam Heywood
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