Re: NiCad batteries and the memory effect

[brian whatcott <inet@INTELLISYS.NET>]

At 11:25 6/8/99 -0600, you wrote:
> I've been told that deep discharging reduces the memory effect of NiCad
> rechargeable batteries; however the new rechargeable million-candle-power
> spotlight we just bought says _not_ to deep discharge it, and that the
> battery will last many more cycles if it is recharged immediately after
> shallow use.
>
> Questions:
> 1. What causes the memory effect in the first place?
> 2. Why does deep discharging reduce the memory effect?
> 3. Why does Lectro-Sci (maker of the Night Tracker spotlight) say not to
> deep discharge their NiCads?
>
> Thanks in advance,
> Larry Smith

There have been several threads on technical newgroups bearing
on this topic. The idea of memory effect has been rather overdone,
 apparently.
Repeated discharge to an IDENTICAL end point voltage has
been associated by NASA with a memory effect, it is said.

  A more pernicious usage is overcharging, and overheating
which drives off some electrolyte, some folks claim.
 In the name of avoiding memory effect, people deep discharge the
cell pack, ensuring that the usual recharge time does not overheat
 the pack. A better solution is a smart nicad charger.

 All the same, this topic can generate as much heat as a
dumb charger.

brian whatcott <inet@intellisys.net>
Altus OK