Battery

<div class='quotetop'>QUOTE(Locust43 @ Sep 7 2006, 12:45 AM) [snapback]315604[/snapback]</div>

The lights, radio, nav, door locks, power windows, AC fan and other accessories are all 12 volt. It would pretty expensive to make those all run off of 270 volts.

 

The 12V battery powers most (all?) of the electronics, including the computer. Most significantly, since the computer has to boot up before the car can start, you need the 12V battery to start the car.

Jim

EDIT: You guys (pcflorida and efusco) are just too fast for me! That's what I get for using a dialup connection.

 

It's worth clarifying that as soon as the hybrid battery is online (in READY mode), all the 12V battery is doing is being trickle-charged from the converter; all 12V system power is coming from the converter, so ultimately the HV battery is providing all the power. This is much like a conventional car, where all the power comes from the alternator (although that does rely more on the battery for smoothing).

But the 12V battery needs to be there to boot the system (because the HV battery is isolated for safety when the car is off) and it provides all the power when the car is in OFF, ACC and IG-ON modes (for central locking, alarm, radio, windows, ventilation, brakes, lights etc.) Only the electric motors and the A/C compressor run directly off the HV system.

Interestingly, I have heard it suggested that all the lights in a Prius last longer than in a normal car, because the 12V system is so much better regulated than in a traditional car. Does anyone reckon this is true in practice?

 

<div class='quotetop'>QUOTE(KMO @ Sep 7 2006, 05:44 AM) [snapback]315651[/snapback]</div>

Right, I tend to think of the 12V battery like the CMOS battery on your motherboard.

 

Not sure why you needed to reply to a 16 year-old thread when the very next post answered the very same question to which you replied.