In article ,
AZ Nomad wrote:

On Tue, 05 Aug 2008 22:33:18 -0700, Smitty Two
wrote:
In article ,
"Worn Out Retread" wrote:

If the batteries are NiCad's, the memory effect is NOT a myth. Ask anyone
who flies radio control aircraft and uses or used to use NiCad's.

Real men fly gas.

The memory effect isn't really a myth, but it's so widely misunderstood
that is might as well be. AIUI, less than perfect charge/discharge
cycles lead to a reduction in fully-charged voltage. That reduction is
approximately 5%.

So a device that uses four 1.2 volt cells, i.e. 4.8 volts, would charge
to approximately 4.56 volts.

The problem arose because early engineers tried to substitute NiCad
cells (1.2 v) for alkaline cells (1.5 v) one for one, so they were
already working at minimum voltage. Battery operated devices were barely
above the working threshold, and losing another 5% was enough to kill
them.

After NiCads had been out for a while, engineers wised up, and started
building a more reasonable margin of safety into their products.

The myth is that memory effect destroys amp-hour capacity. It doesn't,
to any significant degree. It will cause a device to quit operating if
that device is designed to quit with a 5% reduction in voltage. That
isn't finicky batteries, that's ****ty engineering.

That makes sense. I've think I've seen the "memory effect" in devices
that operate right at the voltage a fully charged set offers: ie: 4
1.2V cells almost providing 5V to a circuit requiring 5v. I've seen
no such "memory effect" in circuits operating a motor, lamp, or
anything but a poorly designed electronic circuit.

'Zactly.