Batteries

[bazaud]

It's about time I moved out of the backyard.
I'm looking at powering my Eq6 and laptop, any suggestion on what type and size (Amp/Hr) 12 volt battery I should buy?

Have I forgotten anything else I need to power?

Thanks
Barry

[GrampianStars]

No power failure with this: :thumbsup:
http://www.ktbattery.com/crown-battery/deep-cycle/marine/supreme-battery-27dc24.html

[bazaud]

Thanks Rob.:thanx:

[Astro_Bot]

How long do you want to run for? The EQ6Pro draws 11W in sidereal tracking and 22W at maximum slew - average of about 12W. For your laptop, you'll have to figure out the power draw yourself.

Allow for typical 50% depth-of-discharge of the battery to maintain battery life (i.e. multiply capacity by a factor of 2). Many places/people, me included, also recommend a 30% (i.e. a factor of 1.3) safety margin to account for temperature variation, battery age and miscalculation.

So if your laptop draws (guess) 3 amps average at 12V, and your mount is 1 amp average, and you intend to run for 8 hours per evening, then your battery capacity in AH should be:

(3 + 1) x 8 x 2 x 1.3 = 83 AH.

The battery should be deep-cycle as they are designed for low, continuous current and deeper depth of discharge. Car batteries are designed for high instantaneous current and shallow (~5%) depth of discharge.


Dew heaters? But, personally, I wouldn't drive those from the same power source as the electronics - just an opinion.

Edit: A note of caution with regard to advertised capacity ... the battery capacity will change with current - if possible you should view the current/voltage/time curves for the battery before buying. The most indicative capacity for astronomy needs is usually the "20 hour rate", sometimes written as "C/20".

[bazaud]

Many thanks, I love IIS!!

Barry