[Astro_Bot]

I know it's only 7AH, but I'm only planning on running the telescope from it, and I'm looking for portability more than anything; any bigger and it starts to get unwieldy. What are your thoughts on this?

7Ah is a bit small, IMHO. To preserve battery life, you shouldn't go beyond 50% depth-of-discharge, even for a deep cycle battery. Deep cycle battery life is rated in number of charge-discharge cycles (e.g. 600 cycles) but that assumes a limited discharge depth (usually <50%) and going below that has a disproportionate effect on life. So, if, say, you want to run an 10" GoTo dob, that draws say 1A average at 12V (that's a guess - I think they draw less than that, actually) and you want to last a 6-hour session, then you should have a capacity of 12Ah. Some of us add a 30% safety margin to account for age and temperature effects on performance, but I suppose that's optional. First, you need to know the average current draw of the system - someone else will have to help you there as I don't have one.

We could get into discharge rate vs capacity vs temperature vs final voltage, but for now, just take the minimum "headline" battery capacity needed as being 2 x session-time x average current draw.

I've also been looking at the Calibre 12V Battery box from Super Cheap Auto, to put the battery in. Does anyone have any experience with this, and its suitability? (http://www.supercheapauto.com.au/onl...id=12358#Cross)

I have that very same box, but it's way too big for a 7Ah battery (I have a 60Ah in mine).

Finally, a bit of a noob question. What is the best way for me to recharge the battery when it gets low? Are there adapters that I can get that I just plug into the wall to charge the battery? If so, any suggestions on where I can get these and what the best one is?

CTEK chargers are the bees knees, but expensive. Any (at least) 3-stage "12V lead acid" charger should do the job, but the more stages, the better the battery preservation (in general, and up to a limit, of course). Importantly, you need to match the charger's current supply rating to the Ah rating of the battery as there are limits - the charger and battery will both have information that you should match together. Some chargers have modes for AGM, Gel and Wet batteries, and these will vary the supply voltage for different charging stages - Gel and Wet are usually similar, but AGM is different. Make sure your charger is suited to charging AGM batteries (if that's what you have).