Re: ATM Amp Hours? Power requirtements for dew heaters, etc.

["Thomas A. Moulton" <tmoulton@gte.net>]

-----Original Message-----
From: Michael P. Lindner <mikel@att.net>
To: BodyByJay@aol.com <BodyByJay@aol.com>
Cc: atm@shore.net <atm@shore.net>
Date: Tuesday, April 20, 1999 11:53 PM
Subject: Re: ATM Amp Hours? Power requirtements for dew heaters, etc.


>
>BodyByJay@aol.com wrote:
>> 
>> I am trying to figure out if the 12V converter (110VAC to 12VDC)
>
>I suspect that you will get better answers than mine, but here goes. An
>amp hour is 1 amp for 1 hour. If the "average" observing session lasts 4
>hours, and the heater is rated 2.4 amp hours, then it is drawing 2.4/4
>or .6 amps.  For what it's worth, Kendrick's web site claims you can run
>your system on a 12 amp hour battery (although he doesn't say how long
>that battery will last, so you can't compute amps). The web site also
>says that he sells a 4.5 amp inverter that'll power his stuff, and that
>typical power consumption is 60% less than the maximum, so you can do
>some estimating.
>
>Of course, the most accurate way, if you have the dew heaters already is
>to take an ohmmeter (you can get one at Sears for under $10 if you don't
>already have one), and measure the resistance, in ohms of each of the
>heaters. You can then use Ohm's law (E = IR, or Volts = Amps x Ohms) to
>find the amps. Just divide 12 volts by the resistance in ohms of EACH
>heater to find the amps for each one, and add them up. This will give
>you the MAXIMUM current the heaters can possibly draw.
>
>--
>Mike Lindner

The only way to be sure is to hook it up and measure the Current with the
cheap meter...  Heating elements tend to change resistance when they get
hot.

tom