Didn't really strike me as exceptionally low. Open circuit my Optima measures about 12.7V at the terminals and the Yeasu (from memory) usually says about 12.5V when I turn it on with the truck not running. BTW, when I say the Yeasu, that's my ham radio which reads out the voltage it sees when you turn it on. So, really, it's didn't initially seem to me as crazy low. I would expect my truck to start with the battery at about 11.8V or higher.
Just checked again. Radio reads 12.3V and at the battery terminals 12.5V with my Fluke 87 (last calibrated about 5 years ago at least).
I also figured it's been running a lot, sitting in the back of my truck, closed, in the sun without its extra insulating cover. I got a Transit Cover, which should be here today or tomorrow. That is supposed to reduce cycling quite a bit, too.
'91 Pickup - Imelda
'08 Tacoma TRD - Donna