Myself & Mike have had a go at the powerfail code and come up with some tweaks: basically, this upgrade patches an existing beta7a with a new kernel which is more stable at low voltages (eg: more reliable booting with engine off, after cranking, etc).

If people who've had problems in these areas would like to give it a try:

http://www2.empeg.com/upgrades/test/interim/

Thanks,
Hugo