Just Installed a new 12v Aux Battery in my 2006

Does it start? Does it run right? Do all the accessories power up? Do you get and DTC's?

What I'm trying to say is I think we put too much stake in a .3V difference. I've seen numerous posts where one will say "It read 12.1" and the response will be "that's too low, it should be at least 12.4, you really need to be concerned about that battery". All the while, the person reporting the reading mentions no problems with the car.

Even if 12.1 is a little low, that doesn't mean the battery is bad and I surely wouldn't take the Prius diag mode readout as gospel. It is a basic measure but, I've never seen stats on its accuracy.