[Icom] Nicads

[icom@mailman.qth.net]

Jerry,

I would not consider myself an expert on batteries, but I
have and do use nicads.  Here are my experiences.

Older nicad packs do have a tendancy to develop memory
problems if they are partially charged and discharged.  This
limits the amount of charge they will take resulting in
lower voltage and shorter useful time or both.

The newer melal hydride nicads do not have a significant
tendancy to develop memory problems.

Both types of battery packs tend to discharge over time and
it does not matter if they are used or just sitting on a
shelf.  I used to leave my battery pack on trickle charge
all the time to ensure it was hot when I needed it.  Now I
understand that constant trickle charging is not good for
the batteries.

I do have one nicad pack that has just one nicad cell.  It
is rated at 1.2 volts and 5 amphours.  It is a single cell
that is kept charged with a small solar panel.  This setup
will most likely never have memory problems but it is only
good for the lowest power QRP operation.  The 1.2 volts is
converted in a small switching regulator to deliver 13.8
volts.

Three years out of a battery pack is good service.  My
experience has been that they eventually give up and die
after a few years.  The only nicads I have that have lasted
longer are some wet cells that have been maintained and
still work after 15 years of use.  The wet cells are in a
very large battery pack that is the size of a large
motorcycle battery.

Regards,
Frank Kamp
K5DKZ