Did someone say batteries in series and 12V battery ? : http://www.youtube.com/watch?v=ZxBF7WC0TQk
probably just going to purchase a small 12v battery.
Your best bet would be to go with a Sealed Lead Acid battery (SLA). They're basically the same as car batteries, just smaller and usually a little less powerful.A battery will typically have an AH rating(Ampere-Hour), the math is very straight forward. If you have a 12AH battery and you have a 12A draw, it will last for one hour. Likewise, a 1A draw will last for 12 hours.If you only need it for one hour, I'd recommend this battery. Typically around $50, but they are hearty batteries. For roughly three hours of run time, I'd recommend this battery. Anything more than that and you'll need to get a deep cycle, lead acid, battery(typically labeled as marine trolling motor batteries).If you do end up buying a larger, lead acid battery, it is imperative that you buy one with deep cycling capabilities. If you don't, you'll kill the battery for reasons beyond the scope of this discussion.For what it's worth, I worked at a battery store(Batteries Plus) for 4 years, so batteries(and making suggestions) tend to be my strong suit.
As I said earlier, in my opinion the Ah capacities of lead acid batteries are grossly exaggerated - perhaps twice what they really are.I could not open your links to the batteries.Starter batteries are specially designed to give a huge current for a few seconds until an engine starts. I presume you can get sealed starter batteries but they would not be suitable for sustained output or more than a few moderately deep discharges.I use my un-sealed lead acid batteries 24/7....R