12V battery-11.9v engine off &13.7v with Hybrid battery 'only'running

13.7 seems normal for a gen 2 in Ready.

11.9 is of course, bad. (didn't you JUST have a thread on this?)

 

If you are sure this need to be a different thread than My 12V battery is 6 years old & working fine=Should I replace it before 3000 mile trip? | PriusChat

 

one of the things that is mentioned here over and over is that a "voltage reading", on it's own, is not a sure-fire way of determining the true health of a battery..................

 

Any auto parts store should be able to test the 12v battery to get a true real world capacity.
The SKS model battery is rated 325 CCA when new, but tests significantly higher when new. I would say if it is tested and shows under 275, I would get ready to replace it.

 

You are being a little dense here.

You already had one thread started to discuss your battery.
You could have and should have put the voltage readings IN THAT THREAD TO KEEP ALL OF THE DISCUSSION TOGETHER.

The first reading is the battery itself and 11.9 is a bit below half discharged. NOT GOOD.
The second reading is really not the battery but the charging system.......and 13.7 is OK.

As you suspected, you need a new battery.

 

It certainly CAN be.....if you take the conditions under which the reading was made into consideration.