Does My 12 volt battery appear bad?

Your battery is fine. Your method of testing it may not be the best, but it’s fine. As long as there’s a load on it in READY the system will charge at a rate that’s required to compensate for the load.

 

Look into the new generation of electronic load testers. You use them with car off. If I was shopping for one it’d likely be Solar BA9 (I’m familiar with it predecessor, BA5, which I currently have and use), but there are lots of choices.

 

That's fine, though an informal test. It would be worrisome if the voltage dropped below 11.75 under the same conditions. I believe you'll start encountering sensor error messages down around 10.5 or less.

Hope this helps...

 

get a free load test at many auto parts stores

 

or buy your own TOPDON BT100 battery tester

 

Geb 3 s have a diagnostic mode you get to on the MFD. Look in your owners manual under the MFD stuff.
It shows amongst other stuff the 12 volt static reading.
I've never tried this, but it might be possible to see in all three of Prius On states. Acc, On and Ready.

 

THIS! I love my battery tester and use it all the time.

 

Call me old school but I still like the standard carbon pile load testers. It doubles as a hand warmer in the winter.

 

As far as I know these electronic load testers aren’t mislead by “surface charge”, can be used any time. They’ll obviously show higher voltage with a car fresh off a drive (or charger), but they still will get accurate read of the CCA.

At least that’s the case with my Solar BA5.

Still, it doesn’t hurt to let the car sit overnight, let voltage settle back.

 

Yes, it should be tested as a flooded. Once you shut the car off turn your headlights on for approximately 30 seconds to remove the surface charge, shut them off and begin your testing. You can check out The Car Care Nut on YouTube as he tests the battery tester you have.
Additionally you can check out Professor John Kelly from Weber University on YouTube for more information. If I remember correctly, both of them advise to remove the surface charge and in every class I ever had on battery testing I learned you needed to do it (unless you care about accurate results).

#14

 

No, because the charging algorithms programmed into the car are based on a flooded lead acid battery being installed. Again, One of John Kelly’s videos goes into good detail about this. You will however see contrary opinions on this site, and if you follow such advice you could perhaps never notice an issue. Having said that, you could also end up having problems. To me, it just makes more sense to install the correct battery to begin with.