Bob G. rg327_remove_comcast.net writes:

According to those in the know (not me) RECHARGABLES just do not
work...

The claim is that 8 rechargable AA's only put out a total of 9.6 v not
when freshly charge not the 12 V that the regular AA's put out... so
while the rechargables will work for 10 minutes when the voltage even
drops a hair all hell breaks loose because the scope dances all over
the sky ... instead of slewing to Jupiter or some specific target...

That's only true of badly-designed electronics. Alkalines are 1.5 V
when new, but drop to 1.0 V or lower at the end of their life, depending
on load. Any well-designed electronic device intended to operate from
alkalines ought to operate down to 1.0 volts per cell, or at least 1.1 V
per cell. Any device that doesn't operate at this voltage is leaving
a substantial amount of energy in the batteries when it shuts down or
begins to malfunction.

Rechargeable NiCd and NiMH cells drop quickly to 1.2 V per cell, and
then *remain at that voltage* until they are almost completely
discharged. Since this is above the cutoff voltage that should have
been designed in for alkalines, rechargeables work fine in almost
well-designed electronics. In the case of 8 cells in series, alkalines
supply 8-12 V, so the electronics ought to work properly on 8 V, and the
9.6 V supplied by rechargeables is well above this limit.

(There are sometimes problems with rechargeables working too well -
their lower internal resistance means they can deliver several times as
much current into a low-resistance load as an alkaline cell of the same
size. Some electronics built assuming the alkaline cell's internal
resistance is part of the circuit can be overloaded and burned out when
rechargeables are used instead (e.g. certain cheap electronic flashes
from 30 years ago). And battery packs with NiCd or NiMH cells need a
fuse or circuit breaker if there's any chance of the terminals being
shorted, while an akaline pack does not.)

Dave