Based on the description on their site, the controller includes a built-in battery: "8.39 Wh Li-ion battery, 35+ hours of gameplay… "
That was disappointing for me. Specially condidering the Steam Frame’s controllers make use of AA batteries: “One replaceable AA battery per controller, 40hr battery life”
AA Batteries might not be as convenient to use, but being able to replace them is a great advantage. All my Xbox360 controllers still work fine, but none of my PS3’ Dualshock 3s.
The official docking station could be used to recharge (rechargables) AA batteries so the functionality could remain the same.


Nowadays you can get AA-shaped lithium cells. Anyways I hope free battery is easy to replace after 2 years.
According to reports it is. Not as easy as a hot-swapable one, but close. You just have to remove the back panel, pop it out and put the new one. No adhesive involved.
Amazing. This should become industry standard.