In message ,
(D.M. Procida) wrote:

I've got a bunch of alkaline cells here, and I'm wondering which of them
are going to be any good at all. What should I use as a cut-off voltage
when I'm deciding? I have a multimeter, which also has a battery tester
(I guess it just puts a bit of a load on them).

From one set I get around 1.4V with the battery tester, 1.45 with the
voltmeter. But while that sounds pretty good, I know that in practice
they were useless. How much do 'rested' alkaline cells recover after
use?


IME there is no easy answer to this question, but as a rule-of-thumb
this is what I do:

A brand new alkaline will register well over 1.5V (between 1.6V and
1.7V) on a high-impedance multimeter off load.

A part-used alkaline which has been off-load for several hours and
measures less than 1.5V doesn't have much life left.

Down to about 1.4V you'll still get a reasonable amount of use from an
Alkaline in low-power devices such as clocks, remote controls and small
portable radios, but not in high-power devices such as torches or
anything with a motor.

Below 1.4V it is rarely worth re-using the cell and I dispose of them.

9V alkalines get thrown when they are down to maybe 8.5V.

For example, a Maglite which takes 2 AA batteries may begin to look a
bit dim so you change the batteries. You may find however that there is
enough life left in them to power your 2xAA tranny for a week or two of
normal use.

As others have said though, the amount of use to expect varies depending
on the actual load. These figures of course only apply to alkaline cells
and *not* to zinc-carbon or zinc-chloride batteries which have the same
nominal voltages but different characteristics. Rechargeables have both
different voltages and different discharge characteristics and there are
other experts on this group in that field.

Just my 2p.

Hwyl!

M.

--
Martin Angove: http://www.tridwr.demon.co.uk/
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