I'm intrigued to find out how glider pilots maintain attitude in clouds. Presumably they don't have enough battery power to run a gyro for an AI?
I wrote earlier...
So what instrumentation do I have for IMC in my glider: ASI, Altimeter, VSI(2), OAT, T&S, Horizon, compass, radio, alternate pitot and backup batteries.
Typically for IMC use the Horizon or T&S will be on for less than one hour per flight so the battery issue is not a big one. One of the CAA's proposals for transponders required them on at all times. With flights often exceeding 5/6 hours that's the difference; it's also an additional electrical load not a substitute..