1. Attachments are working again! Check out this thread for more details and to report any other bugs.

"The 12v battery starts the car" no, it doesn't.

Discussion in 'Gen 2 Prius Main Forum' started by Prius92, Aug 5, 2024 at 10:46 AM.

  1. Prius92

    Prius92 Member

    Joined:
    Sep 14, 2019
    392
    97
    0
    Location:
    Iowa
    Vehicle:
    2008 Prius
    Model:
    II
    I've gotten into a couple arguments with "hybrid experts" on reddit, and yesterday when I went to a local hybrid shop to get a new cell, ran into the same issue.

    Who came up with this BS?

    Sure, the 12v battery "turns on" the car. But the 12v battery does NOT START the car.

    It's painfully obvious if you look at the transmission. There's no separate high amperage lead set for 12 volts.

    If you look at the inverter, there is one high amp 12v connection, but this is for charging the 12v battery itself.

    The OEM 12v battery itself is only 325 cold cranking amps, which is really small for a modern car. (Yes, I know aftermarket batteries have more CCA, around 410) Now stop and think of all the extra electrical things the Prius has that most non-hybrids at the time did not. Also this 325CCA is WITH the smart key system,

    3 electric coolant pumps, about twice as many computers, a 12v operated auxiliary heater system, 12v brake accumulator, etc. Some models also had navigation which would of used a bit of power as the system is based on a DVD disc drive.

    I think the people who state "the 12v battery starts the car" have never actually studies Toyota's hybrid drive system.

    Take a look at the size of a regular car starter motor's windings and then look at the massive windings in the Prius MG1 motor which starts the car.

    [​IMG]

    [​IMG]
     
    #1 Prius92, Aug 5, 2024 at 10:46 AM
  2. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
    9,323
    1,631
    0
    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    They don't really care they're just arguing regular car talk points from click and clack tap it or what have you. No matter but yeah the motor generator access the starter because anytime the Prius is moving forward the reciprocating mass is turning as in the Pistons are going up and down that sort of thing there's a lot people don't understand about the Prius oh well certainly not worth getting in an argument in a bar about or any of that kind of crap. Let them go out and look for the starter etc etc oh well Why is the engine running when you're backing up if the transmission isn't used to back you up only the electric motors are because the battery needs to be popped off and you know whatever. It doesn't really matter what they understand. In today's climate it's not worth arguing with anybody about anything because everything can be whatever they say it is because they said so that's the world we live in now it's facts are non-existent until somebody gets killed or blown up.
     
    #2 Tombukt2, Aug 5, 2024 at 10:49 AM
    BiomedO1 likes this.
  3. dolj

    dolj Senior Member

    Joined:
    May 14, 2012
    7,694
    3,897
    0
    Location:
    Wellington, New Zealand
    Vehicle:
    2007 Prius
    Model:
    N/A
    You are arguing semantics.

    It probably would be helpful for you to differentiate in your mind the difference between starting the car and starting the gas engine.

    If you think of it like that yes, the 12 V battery starts the car and the HV battery starts the gas engine.

    It is not that big of a deal
     
    #3 dolj, Aug 5, 2024 at 11:20 AM
    Brian1954 and pasadena_commut like this.
  4. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    109,094
    49,586
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    someone on the internets was wrong?
     
    #4 bisco, Aug 5, 2024 at 1:26 PM
  5. Mendel Leisk

    Mendel Leisk Senior Member

    Joined:
    Oct 17, 2010
    55,673
    38,789
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    Well, the Prius won't start without the 12 volt, so maybe semantics? Obviously not involved in the heavy lifting, but if ain't there...

    People argue that if the Prius 12 volt battery measures low cranking amps (significantly below spec), all is good, since "it's not involved in cranking". I'd counter that even so, any 12 volt battery showing low CCA is on it's way out, regardless of it's use.
     
    #5 Mendel Leisk, Aug 5, 2024 at 2:15 PM
  6. BiomedO1

    BiomedO1 Senior Member

    Joined:
    Mar 27, 2021
    1,502
    812
    0
    Location:
    SacTown, Ca
    Vehicle:
    2021 Prius Prime
    Model:
    LE
    Don't forget about the "alternative truth":(o_O:rolleyes::D:LOL::ROFLMAO::sick:
     
    #6 BiomedO1, Aug 5, 2024 at 5:51 PM
    Last edited: Aug 5, 2024 at 9:39 PM
  7. ColoradoBoo

    ColoradoBoo Senior Member

    Joined:
    Jul 19, 2019
    971
    640
    4
    Location:
    Monument, Colorado USA
    Vehicle:
    2017 Prius
    Model:
    Two
    lol....totally true! And I tell people who love to argue and fight to get a Reddit account....seems like major brawls going on constantly!!
     
    #7 ColoradoBoo, Aug 5, 2024 at 5:53 PM
  8. highmilesgarage

    highmilesgarage Active Member

    Joined:
    Jul 28, 2022
    281
    104
    0
    Location:
    Kansas City
    Vehicle:
    2007 Prius
    Model:
    Touring
    if you post it 100x, it will become the truth..

    btw, did you ask yourself "if the car will start if there's no 12v battery"?
     
    #8 highmilesgarage, Aug 5, 2024 at 10:18 PM
(You must log in or sign up to post here.)