RE: NiCd Battery Storage

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Mccauley, Daniel H by way of Terry Fritz <twftesla-at-qwest-dot-net>" <daniel.h.mccauley-at-lmco-dot-com>



The problem is that you CANNOT do this without damaging the NiCd cells if it
is in a pack configuration (more than one cell.)
It can only be properly done when the NiCd cells are individual.  If you try
to discharge a pack like this, you will get what is called cell-reversal
(because not all cells with discharge the same way) and this will damage the
NiCd cells within the pack.

You are talking about 9 volt (probably a 9.6 volt nicad - no such thing as a
9 volt) since NiCd cells are nominally 1.2V and since this is a 9.6 volt
battery it is comprised of 8 cells.  I would store this fully charged, and
every so often top it off.  My main hobby is portable recreational lighting
systems so I have a great deal of experience in dealing with batteries
etc...  Your only concern here is that you don't want the battery to
discharge less than (1.0V per cell - 8.0 volts for the 9.6V pack) otherwise
you risk deep discharge damage which is caused by cell-reversal)

Dan


To the list,

I read that NiCd batterys should be stored uncharged.  Is this still true
for older nicads that have been charged and discharged a number of times?
What about storing a newer battery that has seen only one or two
charge/discharge cycles?

What would be a good proceedure for discharging a battery pack?, discharge
until the output voltage drops off then stop, or continue discharging until
current flow is minimal?

BTW, I use 9 volt nicads for portable operation of a SSTC pulse generator,
and to run a MOSFET driver circuit.

Gary