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Which battery starts Prius engine?

Discussion in 'Gen 4 Prius Technical Discussion' started by davran, Feb 28, 2021.

  1. davran

    davran Member

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    2019 Prius
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    Base AWD-e
    Good morning all,

    I have a '19 awd-e and now a '13 V.

    I keep reading that the 12v battery starts a Prius engine, but I've also read that the 12v battery only runs the lights and such, and the traction battery starts the engine, as there's not a traditional starter.

    If the latter is correct (traction battery starts engine), is that for all generations of Prius?

    Thanks,
     
  2. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    Three
    In all versions of the Prius, the motor called M/G1 spins the engine to start it. It is a AC motor powered by the inverter which is powered by the high voltage battery.

    However...

    If the 12 volt battery cannot start the computers and power the fuel injection and engine electrics (the spark plugs need to fire, etc) your Prius won't start.

    There are relays to allow the HV Battery to work, and the computers need to test things to even allow all that power out.
     
  3. davran

    davran Member

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    Base AWD-e
    Thank you for the clarification.