Actually, half capacity for a liquid electrolyte battery is 12.2 volts.
But in any case, based upon your description, they do seem to be
pretty bad off.

Doug
s/v Callista

"Wayne.B" wrote in message
...
On Sat, 2 Oct 2004 20:43:04 -0400, "John C. French"
wrote:
Could these new electronics
be draining the battery even when powered off, or could it just be time to
replace the battery? The battery never reads over 12.4 volts, even when
charging, and after a long day of fishing, the battery level will be down
to
as low as 9 volts.

======================================

Sounds like it's time to replace. Batteries, even deep cycle
batteries, should never be discharged below 11.5 volts (half power).
Discharging them lower than that will severly shorten their life.