A PSA for Gen 2 Prius Owners...

If by a "car battery" you mean a standard flooded Lead/Acid battery, then yes, it will work fine – in the short term. It is not as safe for use in the cabin, nor will it last as long. But horses for courses.

 

The 12v

 

Yes, I got that, but was it flooded Pb/A or AGM?

 

AGM

 

Cool. Specific details as to which make and model.

 

I thought it AGM But it’s actually a Optima battery here’s the model number Part #: BAT N9951HEV from Napa I think the old battery was AGM

 

Most likely you need to swap out the abs master cylinder and pump. As far as the 12v, once the car is in ready mode the inverter is supplying all the 12v requirements usually at 13.5v or higher. So the 12v is very unlikely to be the problem unless its so depleted it wont ready the car. Its possible the battery is severely discharged to the point the inverter/converter can not pull it up to 13.5 but thats a severe discharge. Any auto supply can load test your battery.

 

Gen 2 Brake Booster
2007 Brake Actuator Failure | PriusChat

 

I just came across this thread. 12.6V in ready mode looks like a problem to me. That's the voltage I would expect with the car off after resting overnight. Either something is drawing some serious current to pull it down or the DC/DC converter isn't up to snuff. In ready mode it should show about 13.8 to 14.1 or so.

 

Geez! I got a Toyota true start last week for $260 with text and popped it in myself in like 15 minutes! What we're those idiots doing? Playing cards?

 

What is the 'Resting Voltage' of the 12V battery? In other words, what is the voltage measured at the battery before anything in the car is powered on? The battery needs to sit for several hours to read resting voltage.

 

These two statements can't both be true.

For the resting voltage, pop the hood before you shut off the car in the evening. Then, in the morning, before you open any doors on the car, check the voltage at the jump points under the hood. That's the resting voltage.

 

How many ways can you avoid answering the same question?

 

Immaterial. If the car is “booted up,” it is on HV power, whether from traction battery or during regeneration or charge mode.


iPhone ?

 

That's not what Ready mode means.

As @nssdiver said, it makes absolutely no difference if the engine is running. If it's in ready mode, the DC/DC converter is charging the 12V battery from the traction battery. Ready mode just means the car is ready to drive. The engine may or may not be on. The 12V charging system doesn't care. So yeah, your information has not enlightened us.

 

Several members have tried to ask you, what is the voltage of the battery before you start your Prius? They're trying to determine the baseline number, to help you understand if your battery was truly charged completely.

No matter how many ways they try to ask you, you seem to sidestep the question.

The value you have posted does not indicate a fully charged (new) battery.

If you have access to a cheap voltmeter, trying the following. Disconnect your 12 volt battery from the Prius. Don't remove it from the car, just let it sit overnight. Then first thing in the morning, measure the voltage before you reconnect it to the car. If you get anything less than 12.8 volts, then your new battery has not been fully charged.

There could be a defect with your new battery, or the place you took it to never put it through a full charging cycle. No one can tell at this point because you mention values that are different, even within the same reply