NiCad battery care

[Larry Fisher]

Hi all,

When the battery thread came up a long while back, I didn't take the time to
add my 2.5 cents about NiCads.  I presently have a set of three of the plug
in type used in a Skil cordless screwdriver.  A Skil of the same model, that
became unusable when the direction switch malfunctioned, has now become the
battery drainer.  I screwed a drywall screw into the switch in such a way so
as to jam the switch on all the time so as soon as you plug in a battery, it
runs all the time, or until the battery runs down completely.  I leave the
battery in there for sometimes a few days, simply because I forget about it.
It should be left in there at least an hour, assuming the battery was pretty
weak in the first place.  Then place it in the charger and let it charge
well over the minimum suggested charge (usually about an hour or 2).  I let
mine sit in the charger at least a full day before using it again.  All
three batteries are in constant rotation, one in the charger, one in the
drainer, and one in use.  They wear down like carbon batteries, slowly
without cascading suddenly, like so many people have told me about.  I too,
had the same experience with NiCads when they first came out, but I was
recharging them when ever they got weak and then only for a little while,
long enough to use again for a little while.  A brainy, nerdoid, physicist,
chemist, gone psycho and smells bad kinda guy told me that NiCads must be
run completely down, and recharged completely for them to work right.  He
was right.  All three of my batteries are over 2 years old and get rotated
at least once a month. 

I had a hand held radio that hadn't been used in years.  The batteries
measured not even a tenth of a volt.  I recharged them, and found the charge
didn't last long.  I then let it totally go down by leaving the power switch
on for a few days.  I then put it on the charger for at least a day, and
cycled the batteries through this proceedure for 4 or 5 cycles (I lost
count).  It now holds a charge for an entire day of listening and a modest
amount of transmitting.  Not bad for free.

I have a small flashlight (torch for some) that has NiCads in it.  It used
to die on me in a cascading fashion.  Since I've cycle the batteries through
a few times as mentioned, it now works just as if it had carbon batteries.


My point is this.  NiCads, when used properly last forever. Here's a few
steps to follow that I've found works well for me.

Discharge them completely before recharging them.
Recharge them completely before using them.
Don't leave them on the charger for weeks at a time.  I'm told it's not a
good idea.
The more you cycle them totally through this proceedure, the better they work.

Some devices require the full voltage delivered by carbon based batteries.
NiCads are a few tenths of a volt less than carbon batteries for some reason
and may not work in some devices.

Early generation NiCads may not respond to this proceedure, or NiCads that
have been misused in the past may have developed a "whisker" in them and so
they won't recharge properly.  (that's a technical term that the above
mentioned individual refered to, I didn't ask questions for fear of hearing
a quantum megaload of boring technical recitation....... zzzzzzzzzzzz)

May your batteries never loose their charge.

Lar



                                    Larry Fisher RPT
   specialist in players, retrofits, and other complicated stuff
      phone 360-256-2999 or email larryf@pacifier.com
         http://www.pacifier.com/~larryf/ (revised 10/96)
           Beau Dahnker pianos work best under water