Battery powered amps

Anybody have experience with battery powered amps? I am specifically intrigued by the Red Wine Audio products. They have a pair of 70 watt mono blocks that run totally on battery power. Six Moons has reviewed these (and RWA's 30 watters) very favorably. At 70 watts, they should be capable of driving a fairly wide range of speakers and in reading up on the technology they seem to be fairly low maintenance. Of course, recharging is an issue, but it looks like these amps will go 6-12 hours on a single charge. That would satisfy 95% of my listening requirements. Considering how much time, effort and expense that we audiophiles spend trying to tame the AC powering our equipment, battery power is very intriguing since it removes that evil altogether. It looks like RWA also has a tubed battery powered pre-amp/DAC in the works as well. Cool stuff, but I would be interested in real world experiences.