FWIW, batteries period may be the wrong technology for most users of these devices. Personally, I'd happily trade the need to have multiple battery packs with

FWIW, batteries period may be the wrong technology for most users of these devices. Personally, I'd happily trade the need to have multiple battery packs with long charging times for ultracapacitor powered tools that might not run as long, but could be recharged to full power in seconds. Cost really might not prohibitively higher since you wouldn't need so many of the battery packs anyhow, and chargers could readily be run off of either wall current or your car/truck.