Re: [APML] ST4 power requirements???

["Matthias Felsch" <mfonline@gmx.net>]

----Ursprüngliche Nachricht----
Von: "Lane, Jason R" <jason.lane@navy.mil>
An: "Discussion of Film Astrophotography" <astro-photo@seds.org>
Gesendet: Samstag, 16. April 2005 00:38
Betreff: RE: [APML] ST4 power requirements???

> Figure out how many amps the dew heater pulls and add that number to
> the 1 amp from the ST-4.  So if the Kendrick pulls less than 4 amps,
> then you'll be fine.  What's your power supply?  Is it a wall
> convertor or a battery?  If you use a car battery you'll have no
> problems for a night's session.

But I had.

My ST4 needs 12 Volt and stops working when the voltage drops
beyond 11,6 - 11,8 Volts.
My battery (36 Ah) could deliver the amps, but at the price that the voltage
dropped each time the Kendrick controller started the next
cycle for the heaters (about every 30 seconds...) by switching them on
for a little while.
In such a situation the ST4 shows 0 - 0 - 0 in the display and is
"blind" and stops guiding for several seconds.
This happened to me in a long cold night with the ST4 and two
Kendrick heaters (a 3" and a 5" refractor) being supplied by the
same battery.
Since then my ST4 had a battery of its own...

Matthias



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