Self launching on batteries means carrying around a fair bit of dead battery weight for the entire flight. Electric sustainers (can't take off but can stay up) are pretty interesting because gliders take hardly any power to fly level. Example:
All this electric vehicle technology works really well for electric glider winches. You can get a whole lot of peak power off of a battery so you don't need a huge electric power feed.
I hope they get adopted by Formula E. A bank of ultra-capacitors in front of the main battery should make the cars lighter with stronger regenerative braking.
* http://front-electric-sustainer.com
All this electric vehicle technology works really well for electric glider winches. You can get a whole lot of peak power off of a battery so you don't need a huge electric power feed.