2011 Prius went haywire, 12V battery???

yep, more than likely, although, i would test it first. dealer battery is a good one. since you're not going to install it, why not talk to dh and make a decision? it's also possible that you can purchase a smart charger and recharge it.

 

Yes....over a LONG period of time.
They do go off after a few minutes but that ensures that the battery is never fully charged when it is parked........which is not good.
If I had automatic lights, I would do that too.
Alas, my C has manual lights so I have to remember to turn them on when it gets dark.

I suggest that you discuss your "plan of action" with the hubby BEFORE you commit to spending $300+ dollars.
It probably IS the battery but he might want to change it himself and save $100.

 

While the headlights normally turn off automatically, this can be inadvertently defeated or overridden. In particular, if for any reason you turn them off, don't turn them back on again after the ignition is shut down, because this overrides the auto-off.

Also, don't leave the map lights on.

To check that all lights are out, lock the car.

 

it's a tough call without testing the battery. certainly a new battery is best, but the old one may be fine. be careful with the battery charger, these batteries do not like high amperage. below 4 if i'm not mistaken. try to remember, these are not run of the mill cars.

 

As bisco said, be careful how you charge that battery. Set the charger at 4 Amps and use the jump post in the fuse box under the hood. Red cable goes on jump post, black cable goes on the strut nut behind the fuse box. Set the charger on AGM mode. If the charger you are using does NOT have a AGM setting AND or a setting for 4 Amps, my suggestion would be to NOT use that charger. However, if you must use the charger use the lowest amperage setting you have access to that is NOT more than 4 Amps. The battery should charge up overnight. However, charging it may not solve the problem. I would test the voltage with a digital volt meter. If the battery does not read the proper voltage after charging, I would suspect a bad battery.



You really DON'T want to pay the dealer to put this battery in. The battery is NOT cheap. $200 for sure. Get the OEM battery from Toyota, or purchase a Exide brand battery if you can locate one locally. I do not recommend the Optima Yellow Top for the battery. They are not what they use to be as far as quality is concerned. Below is the battery I recommend. Your hubby can easily change the battery with a small handful of tools.



Be careful if you attempt to charge and or "jump" the Prius. Accidentally reversing the polarity of the cables even for a split second WILL cause THOUSANDS of dollars of damage to your Prius.

Best of luck to you,
Ron (dorunron)

 

I had a similar issue with a dead battery and when trying to start the car I hear this loud hum noise. The electrical system was in limbo (half on half off). The only way I could stop the noise was to disconnect the battery. To my surprise when I installed a new battery the instrument panel lit up like a Christmas Tree and the engine started without pushing the ON/OFF button! Charging the battery could do the same thing so I would check the car frequently if you decide to use a charger.