Gordon
I get a bit confused about this.
When you say "completely discharged" do you mean 0V terminal voltage or
just  <1V ? The problem I have is that to discharge a series bank of cells
completely will mean that some of them will be reverse biased - which I
believe is not a good thing to do. On the other hand I have had very
limited success in recovering Nicads from this condition.
Voltage depression seems to be my most common problem where the battery
fully (?) charges to a lower voltage than when new, which results in
equipment with battery charge monitors (e.g. cellphones) reporting the
battery as low capacity almost immediately.

Thanks,
Richard P





What you are referring to is called memory effect. NiCd Batteries have a
problem with retaining the min max voltages applied.

Example: if you discharge the batteries to the 70% point and then recharge
them every time you use the device that the battery is used in. The battery
will begin to retain this pattern.

The trick to using a NiCd battery is to completely discharge the battery
about every 3rd or 4th cycle. Then recharge the battery under high current,
back to the battery voltage rating, and trickle charge until fully charged.
Even a very bad battery can be restored if charged to battery voltage under
high current then discharged. Repeat until battery is restored. 5 - 10
cycles will bring a NicD back to life and will be usable for many years to
come, if properly discharged and charged. If the battery goes dry then it
is
useless.

I personally have restored hundreds of NiCd using this technique.

Gordon Varney



> >     I am attempting to plan a periodic battery recharge schedule
> >     and would appreciate comments regarding the best way to keep
> >     the phones ready and in good battery condition for extended
> >     periods of (hopefully) no emergency usage.
> >
> > I would be very tempted to get some of those "emergency" battery packs
> > that allow most cell phones to be run on "standard" alkaline batteries.
> >
> > NiCds suck; especially old NiCds.  I have several old laptops computers
> > that are perfectly usable other than having completely unusable
> batteries.
> >
> > BillW

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