I was on a run down to Valkaria a few weeks ago, went to start with the group to go home and the entire main bus went offline as soon as a blade turned over.   No problem, went to the second buss, started, flew home.   Traced one of the four Odyssey batteries (2 main buss, 2 secondary buss) had just completely failed.  I was a little upset until I checked the date code of 2008.  I got another from Amazon for $116 and everything is good to go.

I can't say enough about the dual buss design in my Legacy.  I've saved myself at least three times from having to be stuck somewhere:
1) Main alternator failure (diodes)
2) Standby alternator failure (did not require the second buss to operate)
3) main battery failure twice.

The Odyssey batteries are giving good service in the 4-6 year range but when they fail, they fail fully and without notice.

Paul