The issue with gliders isn't as simple as just needing an additional battery. Other things that need to be resolved include:
- A risk assessment for the pilot due to the restriction on where a device can be installed (likely to be transmitting very close to the pilots body)
- Finding a suitable location to install the device in a way that it's accessible to the pilot (glider instrument panels are much smaller than most powered aircraft)
- Cost of installation and ongoing maintenance/certification versus value of the airframe
- Resolution of interoperability issues (many gliders don't have a radio, so how can they be told which unique code to squark and who/what/how are colision warnings resolved?)
- Overcoming the problem of where a battery can be fitted (particularly of the size needed to run a transponder for the 8 hours that some gliders are airborne for)
I'm sure these, and many other, problems are affecting the GA community too (particularly microlights, homebuilds, ULM's, paragliders and balloonists). All this in the name of safety improvement in an environment with an already low accident rate. Let's face it folks, the real purpose behind this is to enable UAV surveilance to be introduced more widely, to provide the CAA with a platform for charging ALL aviation and to justify the continued existence of an organsation that is losing its existing responsibilities to EASA. Choose which theory appeals!