12v Battery Status

Is this what you were looking for? I haven't tried this btw.

http://www.elearnaid.com/12vo1topraub.html

Prius battery test procedure for 2004 to 2008 Prius Cars

Here is a battery test you can perform on a Prius battery that is easy to do. It will not always detect a weak battery that does not allow you to park you car for long before it is drained down by the security system.

However, this test requires no tools, is easy to do and will give you some idea of the state of your battery. You can also perform this test after the car has been parked for a while to see how well the battery holds up under the drain from the security system.

* Do this test after you have driven the car for at least 30 minutes. This will give the battery a chance to be fully charged.
* Put the transmission in Park.
* Turn off the car.
* Engage the parking brake
* Push in the power button.
* Push Display button. top button to left of screen - "DISPLAY" will now appear in the upper left corner of your screen.)

* Push on the upper left(1) and lower left display(2) of the display just inside the box. (see picture) Do this three times. Keep trying till the screen changes. If the word "Display" in the upper left hand corner of the screen goes away hit the display switch again.
* Push on Menu in upper right of display screen.
* Push on Display Check
* Push on Vehicle Signal Check
* You will see the 12 volt voltage displayed. In accessory mode the voltage should be 12.6
* With no electrical accessories on including lights the voltage should be fluctuate between 12.6 and 11.9. The lower the voltage, the less of a charge your battery currently has. If the voltage is low do not proceed as the load test might totally discharge your battery. (If you see a voltage around 13.8 you are seeing voltage from the high voltage battery being converted to around 13.8 in an attempt to recharge your battery. This normally does not occur till after you start the engine but might occur earlier if the battery is very drained.)
* You can also test the battery by turning on the headlights, rear window heater and the heater fan. For a new battery the voltage would be around 11.3. If the voltage drops below 10.2 it should definitely be replaced. For voltages in between the lower the voltage, the lower current charge of your battery.
* Note: If in doubt disconnect the 12 volt battery completely (start with the negative post to avoid shorting the battery) and hook it up to a battery tester.



For the Prius you can not buy off the shelf parts to make this battery work. So we recommend you save time and trouble and also get our installation kit which includes all the parts you need and installation instructions.



You will need a vise large crescent wrench or a vise grip, a 10MM wrench, a 10mm socket, 12mm wrench or socket, a socket extender, some tape, and a 1/2 inch wrench or 1/2 inch deep socket. You have to follow the normal precautions of disconnecting the negative battery connector first and connecting it last or your can short the positive connector to any exposed metal in the car. If you follow the instructions, that come with the installation kit, you will not short out the battery but you may want to buy the kit and have your battery professionally installed.

 

Why are you worried about your 12V battery? Are there symtoms you are seeing?