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12 Volt Battery?

Discussion in 'Gen 3 Prius Main Forum' started by radmangto, May 18, 2012.

  1. radmangto

    radmangto Junior Member

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    We plan to take a several day jaunt to St Augustine from SW Fla. Using one of our previous cars, I would not have any concern using our 12v powered Coleman refrig box. Many of you probably have them. Great for traveling. ;)

    Well, with a few months old P3 2011, I am hesitant to use this frig with the posts on how fragile the onboard 12v battery is. :(

    Should I be concerned? :confused: I don't even know if the 12v plug recepticles are powered by the 12v battery or the traction battery .....??? Crazy hybrid stuff .... :>))

    Regards,
    Radmangto
     
  2. NiHaoMike

    NiHaoMike Member

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    They're powered from the main battery through the DC/DC converter except in accessory mode. So it will be fine unless you leave it in accessory mode for too long.
     
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  3. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    Correct, if you leave it in Ready, it does not matter how 'fragile' the 12 volt battery is.
     
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  4. szgabor

    szgabor Active Member

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    You can do this easily, but make SURE the car is in Ready mode .... ... otherwise you will damage the 12V battery ... the 12V plugs are independently fused 10A ... so give or take 120W max I would say 100W stuff can run on them .. but again ONLY if your car is in Ready mode. It is NOT powered directly by the 12V battery.

    If the car is turned off no power to those plugs period. If you put the car ACC mode there is power but THEN YOU can deplete the traction battery (ICE WILL not come up) which could be very very damaging. (if this is not the case someone will correct me I am sure)

    In short, while you are travelling (car is moving) NO problem how to use it when "parked" is the issue.

    Directly connecting to the battery is not advisable but possible ... by spec it will be charged by an inverter up to 14.5-14.8 V and max 4.6A so you have less 'power' there I can not remember exactly what the fuse there ... there is one. though.
     
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  5. Danny Hamilton

    Danny Hamilton Active Member

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    In ACC mode, you will deplete the 12V accessory battery, not the High Voltage (HV) traction battery. This is still bad because it will reduce the life of the 12V battery, and require you to recharge it or jump start from some other battery to get the car started.

    In READY mode, the Prius will run the Internal Combustion Engine (ICE) as needed to keep both batteries (12V and HV) charged, so as long as you don't draw enough current to blow the fuses you'll be fine.

    I'm not certain what happens in IG-ON mode. I suspect that this mode allows you to draw current from the HV battery, but does not use the ICE to keep the battery charged up. If this is true, and you drain the HV battery too far, you will be unable to start the car even with a jump. You'll need to charge up the HV battery manually which is typically done by special equipment at the dealership. If I am incorrect about my assumptions for IG-ON then you will drain your 12V (see ACC mode).
    When parked, the only way you should consider using it is with the car still in READY mode and the car in PARK. Do not attempt to use it in ACC or IG-ON mode. As long as you do this, your main concern will be blowing a fuse if the device draws too much current.
     
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  6. adamace1

    adamace1 Senior Member

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    If there is no ready light you can't use the HV battery.
     
  7. szgabor

    szgabor Active Member

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    I honestly still not totally sure what ACC will do ... but yes do NOT use anything plugged in .... it WILL damage at least the 12V battery ....
     
  8. Danny Hamilton

    Danny Hamilton Active Member

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    This is what I used to think, but then I read somewhere that you can use the Air Conditioning while in IG-ON? Doesn't the compressor use the HV battery?
     
  9. qbee42

    qbee42 My other car is a boat

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    Yes. IG-ON is just like Ready, except you can't shift into gear and the ICE will not start.

    The current draw in IG-ON is fairly high. It was never intended to be a mode for sitting around running accessories. It is similar to turning the key on a regular car, but not engaging the starter.

    Tom
     
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  10. Danny Hamilton

    Danny Hamilton Active Member

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    That's what I was thinking, so:

    1) extensive use of accessories in ACC mode can lead to drained 12V, shortening it's life and requiring recharge or jump start.

    2) extensive use of accessories in IG-ON mode can lead to drained HV, requiring special equipment to recharge, typically done by the dealership.

    3) extensive use of accessories in READY mode can lead to drained gas tank, requiring the purchase of additional gasoline.
     
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