12V Battery

Yes, 11.6 volts is way too low. The Prius 12 V battery charging routine might take several days to bring it up to full capacity. The fact that your voltage reading when Prius made Ready was only 13.5 volts says the battery is depleted. Normal Ready voltage should be around 14.5 volts. I would take the battery back to where you purchased it and have them test, charge, and test again to demonstrate to your satisfaction that the battery is fully charged.

 

Why the new battery? Is it your first?
Why the two day delay before the install?
Where did you get the battery and where did you store it for the 2 days?

You might be fighting an electrical issue caused by 200,000 different things---one for each ownership mile, but if you're having battery issues a good place to start troubleshooting is with a 'known-good' battery which, as @AzWxGuy mentioned above might require a visit to the place that you purchased the battery from.
Or?
If this is the first new battery for your '11 you're just about due and you may have bought a battery that sat on a shelf for a while before you walked out the door with it.
Your car IS BOOTING UP - right?

You may also want to check your cabin air filter....
Your location is non specified, which is GOOD....but I'll betcha they have mieces there.

Good Luck!

 

Yes, as further clarified by ETC(SS). Good idea to check your cabin air filter and make sure you even have a cabin air filter. And while you're at it, make absolutely sure your drivers-side floor mat is properly installed and clipped in. Man, I'll betcha Toyota just hates to have to put that on every service document.

 

Automotive retailers should get into the habit of demonstrating their battery's health before handing it over to the customer. They typically have electronic load testers for this purpose; should use them routinely at point-of-sale.

 

Exactly. I always call before hand to let them know I’m coming to buy a particular battery and to have them charge it to 12.7 volts with the most recent month/year affix label. When I go pick up, I measure the 12v bat with own multimeter before paying.

Lesson, You can leave with a new battery from the store it being low on charge also. You’ll be back in square one again.

 

I bring along a Solar BA5. As often as not they offer to demo-test the battery with their tester, typically a similar, but pro-level tester. These devices test volts but more importantly: Cold Cranking Amps. Regardless of the Prius not needing cranking, the CCA test of the battery is a good measure of it's health.

A fresh battery in good shape will test well above the rated CCA, say 25~40% higher.

That they were sold a dud is one possibility. The other, as @ETC(SS) 's already pointed out: the car may be "eating" batteries. The OP will have to clarify the back story.

 

I take it you got the battery from a Toyota dealership?
You could just purchase a 4 amp battery charger and charge the battery overnight.
You can get a decent one for about $30-40.

Since it boots up the computers and the car runs, you could just take a long drive of 2 or more hours
and that would probably charge it up.

 

All things considered, I think whoever you got the battery from owes you the dealership owes you. A test, a charge, most likely a replacement. Sounds like they sold you a dud.

 

11.6 is really very low. Every reply in this thread assumes that this was accurately measured.

Mitzie, when you say you did the "car's battery self test" what does that mean?

 

I ain’t paying for a new battery that’s not up to voltage and then buy a charger for it also

 

Theres a way to check 12v on ACC.

 

Interesting. Could you be more specific?

 

I like to get a good battery, AND then give it an initial charging session. But yeah, it should not be necessity. If it's low voltage at the outset it's likely on the way out, way too long in storage. Again, an electronic load tester, check the CCA, cuts through the fog.

 

A fully operating battery from the store will not require an initial charge on your end, plug in play.

 

You should ask them why you aren't supposed to charge the Prius battery with no
more than 4 amps?
Because I would bet some one will probably put the regular charger on it, and put in 30 amps!
AGM batteries are charged at a lower amperage.