From: joec@fid.morgan.com (Joe Collins)
Subject: Rechargable Batteries
Organization: None
Distribution: na
Date: Mon, 11 Jan 1993 20:56:09 GMT

In article <1993Jan4.150614.6635@kodak.kodak.com> marulli@kodak.kodak.com (Dave x71244/RDCS/2-205-KO) writes:
>I am looking for a 'cheap' source for NiCad batteries.  Does anyone know
>of perhaps a mail order place or a chain store that has them cheaper than 
>Radio Shack. ($9.75/9V, $5.75/2 pack of D-cells, etc)
RS has them on sale periodically....In addition their blue/white D-cells
are rumored to be a C-cell in a bigger wrapper.

>With all the kid's toys, I was as given a battery charger for Christmas. Now
>I'm looking at a second mortgage in order to stock up on all the batteries
>I will need, especially if I want spares!
>
>Also, does anyone have hints about uses of NiCads? For example, one toy
>will not run on known good rechargables. The truck won't even start. Radio
>Shack tells me that it's because the NiCads are .25V lower than standard
>batteries and the truck must need the full voltage (4x1.5V) I have a problem
>with this because the truck simply slows down with weak standard batteries
>but still starts up. In addition, my Mom's point and shoot 35MM camera has
>a 'No NiCad' symbol in the battery compartment.  Could there be a connection?

Due to the cemistry involved, Ni-cads cells put out 1.2Volt instead of 1.5 in
the standard cells. Anything that uses multiple cells (i.e. a battery) may have
a problem:
6 standards @ 1.5 volts each is 9 volts     (6x1.5)
6 Nicads    @ 1.2 volts each is 7.2 volts   (6x1.2)
Thats why nicads are not always appropiate.	

NOTE: a cell denotes a single chemical unit while a battery denotes a
      collection of cells to make higher voltages. For example, a 9 volt
      battery is collect of individual cells wired in series.

I have been using Nicads for years (and am using them right now in my walkman).
They do work well under the right circumstances. I first became aware of them
when I received a radio scanner as a present. The alkalines lasted one week.
I then bought rechargeables and they lasted 9 months (recharging as needed).
The economics became instantly obvious.

To keep them longer, only charge them when you are ready to use them and
adhere to the cell charge times, i.e. don't undercharge or overcharge
them. Charged cells/batteries lose 1-2%/day of their charge when idle, i.e. 
on the shelf.

After I use a ni-cad cell and it appears dead, I deep-discharge it further by
connecting the cell to a light rated for 1.5 volts until the light goes out. 
I leave it connected for a few hours more after the light goes out.
This allows the nicad to be fully discharged before recharging it. This 
should make for a longer lasting cell.

Whats not good is to recharge it before its discharged. Nicads are said
to 'remember' this and thus the NEXT time, it will run down sooner.
Thats why I deep-discharge them before recharging them.

Car batteries are a different chemistry altogether and they should be
left charged when not in use (by design). Certain video batteries may use
the same chemistry. Read the instructions of any device that uses rechargeable
batteries to determine what type of battery it is - The hint is the info
on recharging.

Rechargeables will eventually wear out as do most items in life - its called
the 2nd law of Thermodynamics (i.e. entropy). Sorry about that....

>
>What about mixing NiCads and standard? Rumor has it that I will weaken
>both types of batteries very rapidly. True?
I wouldn't....

>Anything anyone knows would be a help.  Thanks!

Hope that helps.....