I'm looking to power about 10m of RGB LED strips (60 LEDs / meter) from a battery of some sort. Max current draw for the 10m run is 36A @ 5V.
My initial thought was to get a ~12V RC Car battery and run it through multiple DC/DC buck converters to get it down to 5V (probably get 8 rated at 5A or so) but I wanted to make sure I wasn't missing another, possibly cheaper, option. Runtime doesn't have to be super long... I'd be happy with anything beyond 20 minutes.
Also, note that 36A is absolute worst case scenario. Everything full white. In reality, it would probably average 1/2 - 1/4 of that... probably even less. But, obviously, I want to design for beyond max possible current to give some margin of error.
Battery needs to be rechargeable. Are there any other good (and hopefully cheap) options for providing that much power?