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E Z Peaces

wrote:
The advantage of my 8 day to charge setup is it's impossible to harm
the batteries. I'll always have fully charged batteries on hand. The
price of the setup is ridiculously low.

When you said a person who set his timer for 2 hours a day would always
have a fresh set of batteries, I assumed you meant to keep them fresh by
charging every day.

Two hours a day, every day.

Well, if a smart charger is smart enough to go into trickle charge,
and stay there, then just how is it that my trickle charger which
trickles considerably less can somehow become dumb and harm
the battery?

Panasonic says a timer should terminate the C/20 - C/30 trickle. I
think a top-off trickle is foolish. Sometimes an automatic charger can
shut off before a cell is fully charged. So what? If sometimes I have
to swap batteries after running a device 9 hours instead of 10, I won't
notice. I will notice if I put charged cells on the shelf and they're
dead two weeks later because trickle charging has damaged them.

How do you decide when to recharge? Did it work before hybrids were
available?

It actually was/is more useful with batteries that have a high self
discharge rate. The batteries are topped off each day.

Before I bought my first NiMH, I read that their self-discharge was
higher than NiCd. I've been pleasantly surprised.

Panasonic says heat won't hurt NiMH until they reach a temperature where
they vent. I've never seen them nearly that hot. Panasonic says the
cumulative effect of overcharging will damage cells. That's why I like
a charger that senses the voltage drop when a cell is charged.

Again, all this is only pertaining to chargers that charge at a higher
rate. Chargers less than C/10 don't apply. Mine is C/15 at absolute
max, but in reality is more like C/50 once charged.

My first experience with a NiCd was using a Wahl soldering iron about
1973. On a ship's mast, it was a great advantage to be able to solder
without an electrical cord. The Wahl unit was intended to be kept in
its charger so it would always be charged. In a few weeks, the battery
was shorted. At the time, I thought the current was too high for
extended charging.

My second experience was with walkie-talkies in 1975. The old ones used
several alkalines. The new ones used NiCd battery packs. The
walkie-talkies were kept in chargers designed to fast charge and switch
to a trickle. Before long, these batteries would short. Back to alkalines.

I started using AA NiCds in 1981. They were supposed to be good for 500
charges. I'd read that the capacity would gradually diminish. Instead,
the self-discharge increased while the capacity showed little change.
My first set shorted completely within 100 charges.

In 1986, I made a regulated charger for a cordless drill. I thought
that would make the cells last longer. They went bad very quickly.

In my experience with AA NiCds, timed charging at C/10 causes cumulative
damage that increases self-discharge. In my experience with
walkie-talkies and a drill, regulated trickle charging is worse.

For me, automatic fast charging has worked much better. My chargers
measure only voltage change, and that's not foolproof. Panasonic says
an ideal charger should monitor voltage, temperature, voltage change,
temperature change, and time.