On 8/26/2011 7:47 PM, Smitty Two wrote:
In ,
Tony wrote:

On 8/26/2011 10:41 AM, Smitty Two wrote:
In m,
"Steve wrote:

The old nicads
developed a "memory" if partially discharged then charged, and you could
only get them to charge up say 70%.

Complete nonsense, and one of the internet's most persistent fallacious
rumors.

It's true, and the so called rumor was out before the internet was
around. Newer Ni-Cads, yes they found a cure for it. Also true that
they could often be brought back to life after a few charge discharge
cycles. I have first hand experience with 500 to 1000 of them, I _know_
it was true. And the 70% is putting it mildly, I dealt with ones that
were down to about 10% capacity until being discharged and recharged
which brought them back to about 90% capacity. I did however always
hate the term "memory" to describe the problem.

I've rehashed this so many times I hate to do it again, but here goes:

1. Non-rechargeable cells were (are) nominally 1.5 volts. A standard
gadget often used 2 such cells, providing 3 volts.

2. Rechargeable (nicads) were (are) 1.2 volts. A two-cell gadget was
thus supplied with 2.4 volts.

3. The gadgets were NOT re-engineered for the lower voltage.

4. The "memory" effect lowered the voltage by about 5%, period.

5. Do the math: 0.95 x 2.4 = 2.28 volts.

6. Most 3 volt gadgets were more or less designed to stop working
somewhere in the 2.3-2.5 volt range, so a battery with less voltage
remaining was essentially "dead."

7. The nicads therefore had virtually zero headroom, and a tiny drop in
capacity due to anything less than absolute perfect charge/discharge
curves put them under the bottom edge of performance minimums for many
gadgets.

8. Therefore, this was NEVER a "memory effect" problem, it was ALWAYS a
lack of proper engineering changes to account for the lower nominal
voltage of rechargeables.

9. The fake "memory effect" went away when the engineers woke up and
redesigned stuff to run well on 2.4 volts, and down to a reasonable
discharge level of 2 or less.

LOL! So why did the batteries hold a charge better when charged as
recommended?