[APML]: Batteries (originally AP Questions)

[Gene Horr <genehorr@swbell.net>]

The Astro-Photography Mailing List
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(Sorry, I left the original message at work <g>).

I always power accessories seperately from the mount.  Most 
mounts pull very little current and a full charge can often
run the mount for days/weeks (depending on battery size).
By doing this you are assured of at least having one good
battery for running the mount.  You can always hand guide.

Autoguiders, CCD cameras, computers, and heaters pull 
quite a bit more current and as Kent pointed out some
of these are very sensitive to voltage.

You mentioned a car battery.  You weren't too far off.
The best choice is the biggest deep cycle marine battery
you can find.  A deep cycle battery is designed to be
drained without the plates warping and shorting out a cell.
They provide the amp-hours to run a heavy load all night.

If the only accessory you are planning on using is the 
ST-4 then a lighter alternative is the Sears whellchair
gell-cell battery.  It is more expensive and requires
a special charger but is quite small and light for the
30AH it contains plus being a *true* sealed-cell battery
means both *true* no maintenance and higher safey.

Sorry, TANSTAAFL.

Gene Horr
genehorr@swbell.net