On Thu, 19 Mar 2009 08:39:35 -0400, "Stormin Mormon"
wrote:

My Dad showed me how to do this, when I was a boy. Take a
flash light bulb (PR-4 is good, the old screw in 112 is
better, more close to the proper voltage). Then, take about
six or seven inch long piece of #10 or #12 solid wire. Wrap
one end of the wire around the bulb. Curve the rest of the
wire, so it looks like a letter C, or G.

Touch one end of the battery to the lead spot, on the bulb.
Touch the other end of the wire to the other end of the
battery. If the bulb lights, the battery is OK. Works for
AAAA through D cells. Have to bend the wire a bit, for
different sizes.

After using this for a while, you can also roughly guess the
battery state. New, used, weak, dead. By how bright the
light is.
Note that this kind of tester was required back in those days because
old carbon zinc batteries required a load to be properly tested.
Their open circuit voltage was misleading. However, with alkaline
batteries, you can get a pretty good idea of their state by looking at
the open circuit voltage. Your method works with either situation,
though. (I didn't see the OP's original question, so this response
may have nothing to do with it. Your response just brought back
memories of letting the batteries rest a while so I could get a few
more minutes of listening out of my transistor radio while sleeping
out in the back yard on a summer night).