Re: Memory effect in PbA and in NiCd

[Ken Olum <kdo cosmos5 phy tufts edu>]

Most people say that lead-acid batteries do not have memory.  I've
also heard the claim that flooded NiCd batteries don't have memory,
unlike the AA cells.

Putting NiCd batteries in parallel is very different from lead-acid
ones, because in a lead-acid system if some batteries are more charged
than others they want to have higher voltages, so current comes
preferentially from the ones that are charged, while charging current
goes preferentially to those that are discharged.  NiCd batteries
don't have this property, and I think in some places in the
charge-discharge curve charged batteries have lower voltages than
discharged ones.  This raises the possibility of current flowing
spontaneously from the less charged battery to the more charged one.

   Date: Tue, 5 Jan 1999 07:59:39 -0500
   From: "Max Hall" <maxo iname com>

   - The second pack will be disconnected when not in use.

This doesn't sound like a very good idea.  If you're going to have the
other batteries anyway, it's probably better to just leave them always
in parallel.

                                Ken