If the drive batteries fail can you still drive the car gas engine only?

Discussion in 'Gen 2 Prius Main Forum' started by plumabob, Jun 25, 2009.

  1. plumabob

    plumabob New Member

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  2. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    As the traction battery starts the engine, you could never turn it on ever again, so it is not practical to consider it.

    Why did you want to know?
     
  3. donee

    donee New Member

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    Hi Pluma...,

    No. The transmission is in effect an electric torque converter, and the battery provides the leveling action (to use a plumbing term) between the generated electricty and the drive motor. If the battery fails, it could go high resistance, and and this might allow the voltage to be too spikey coming out of the generator. So, the Prius computers will just shut everything down. In effect the battery keeps the pipe from banging when the valves are turned off and on. And avoid breaking the pipes, the system is disabled if the battery developes a fault - to continue withthe plumbing analogy.

    That being said, it rarely happens on cars on 100K miles. Its much more probable for a sticky throttle body and or running out of gas to cause the engine not to run. In which case its best to pull over the side of the road and NOT use the battery to cruise along.
     
  4. auricchio

    auricchio Member

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    Actually, it's even a bit more extreme than what donee says.

    The motor/generator is used to rotate the power-split device (PSD, aka transmission) to control power to the wheels. Since there are no gears nor clutch, electrical power is absolutely necessary for the vehicle to operate.

    When the car is stopped and the engine continues to idle, the MG rotates the PSD "in reverse" so that the engine can continue turning, but no torque gets to the wheels.

    DISCLAIMER: There are many here on PC who know this stuff way better than I.
     
  5. V8Cobrakid

    V8Cobrakid Green Handyman

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    you guys pretty much covered it. in simple answers.. NO.. you can't drive the car with a failed battery. it is required to start the car, and rotate the car. and yes.. if it's tooo out of spec, the car will probably not turn on... (assuming that part)
     
  6. plumabob

    plumabob New Member

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    The reason I asked is that say you had an older prius and the Drive batteries went bad and you couldn't afford replacement at that time. I thought it would be nice just to use the gas engine until you could afford to do so. Doesn't sound like such a bad idea to me but if it is not possible then thats all it will remain...an idea.

    Thanks!
     
  7. qbee42

    qbee42 My other car is a boat

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    It falls into the same category as driving a normal car with a failed automatic transmission. From a cost standpoint it could be handy if you are cash strapped, but it's not going to work.

    Tom
     
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