Originally Posted by Alan Carroll
Presumably you also have a way to check the backup battery voltage during preflight to make sure it actually has a charge? (the fusible link won't let you know when its blown)
Funny you should mention that. I am right now looking around for some sort of voltage monitor for the IGN#2 battery system. Preferably it would turn on an LED. I already have some nice flashing LEDs for other warnings so I'd just add another to the row.
This one seems interesting. I ordered two and will report in due course:
If the monitored line exceeds a set upper or lower V limit, it closes a relay. I'd probably hide it under the panel, using the built in display for setting only.