Hi All. I've only been getting a little over 1 hour, maybe 1.5 hours on my Cosmos with the wireless adapter and the 21w battery. I queried this with HTC and they asked me to send the battery back to be checked. I'll hopefully ship it tomorrow. At the moment they are not selling just the battery (21w) so I ordered another Cosmos attachment kit which has the battery as well as the cables. Should be here soon. It will be interesting to see if that gives the same play time?