Q: Does seeder cause excessive battery drain?
A: Seeder 1.2.7 introduced an RNG service power-saving mode. The process automatically suspends whenever the screen is off. The code is actually in the rngd native binary, so suspend/resume events happen independently of the UI; you can see it in action by attaching to the running process with strace. This means that battery drain while the screen is off is highly unlikely.
While the screen is on, the RNG service simply polls a file descriptor every second, and, when needed, injects a small amount of random data into /dev/random (and calls an ioctl). It's unlikely that this would present enough load to trigger a CPU governor state change at 10mhz (let alone 200mhz), so it shouldn't impact battery life. Having said that, I have received sporadic reports that it does reduce battery life on some devices. They may be coincidental (other software installed at the same time), or due to extra device use while testing. Or, they may be real