Hey, i was at the field the other day, when i saw what one of the members was using for power other than a battery.
This might not be a new idea, but i thought i would share.
Its one of those motomaster power packs. They guy modified it so it can plug into his power panel. It can be charged by pluging into a wall and is rated for 300amps. I have noticed regular hobby batteries arent quite as strong, and 12v car type batteries are heavy and a PITA to lug around. Im thinking of going this route once i get the money to buy them. he said he bought his for about $40 on sale.

Yes they work quite well. They are not much better than the small batteries for life though, that 300 amps is not ampere hours, it is just the max current that you can draw instantly from them. Most do not even state the ampere hours they are good for but it is not much if any more than your little motor cycle battery. They are made to deliver very high currents for a very short time; i.e. starting a car or truck, not for long low amp use. There built in charger is handy though.

If it can make it through a day or two of flying, then it will be good for what i need.  They guy said that his works better for longer when using the starter and high drain devices. It provides higher amps for longer than the hobby battery