At 16:27 6/13/99 , Joel wrote:
>
>On the question of testing under load, am I wrong in assuming that an
>analog tester is actually testing under some kind of load, since it is
>causing the hand of the tester to move? Did you mean anything in addition
>to this?
>
Yes, the meter will put a "load" on the battery, but it may be miniscule
compared to the "load" created by the camera. Small batteries will often
show a relatively high voltage near the end of their life until you put
them under a load representative of what is demanded of them in use . . .
and then the voltage drops.
With my OM-4, my observations are pretty much the same as what has already
been stated . . . the battery test function on the camera body will
sometimes show the batteries good when they are really marginal and the
mirror locks up.
Most small multi-meters have incredibly high internal impedence . . . so
the meter will not change what is happening if you are looking at voltages
on test points in an operating circuit. In this case, what many demand as
a feature in a multi-meter is probably working against you. I've found my
small multi-meter is almost as useless as the battery test on the camera as
it places a near zero load on the battery.
Since I use 357's and buy them at a watch counter, I've also occasionally
encountered batteries that have likely been sitting in the store for eons .
. . past their shelf life (which is not that short) . . . and they have a
shorter life in the camera as a result. In all cases, the problem has
never been the camera, always the batteries. Unfortunately the bubble pack
the 357's come in is not date coded so I have no way of knowing how long
they've been on the store's rack. I *always* keep an extra set of
batteries in the camera bag and replace them as soon as possible when they
get used.
-- John
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