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12 V Battery measured quiescent current

Discussion in 'Gen 1 Prius Plug-in 2012-2015' started by giora, Jan 30, 2014.

  1. giora

    giora Senior Member

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    I have measured the quiescent current (standby current when car is off and locked) and found it extremely low, around 5 mA!
    These are good news for me as it means very low drain rate (calculates to about 10 Ah in 12 weeks!).
    I have also checked the followings:
    When IGN-OFF and hatch is open (interior lights on) the current is about 1200 mA.
    When locking the car the current is reduced from about 1200 mA to about 18 mA and then (a bit slower) to about 12 mA and then to about 5 mA, the whole process is taking about 30 seconds.
    Passing, with the FOB on me near a door with a smart entry will awake 1200 mA, once the lights shut off it will go through the cycle above. Same happens when I unlock the car with the FOB and not opening a door, once the passive lock is activated - it goes through the cycle above.

    In order not to reset the computers and loose all data while connecting the multimeter for these tests, I have tighten a conductive wire around the negative post, under the cable shoe when connected, connected the meter to both the post and the shoe before separating them:

    Before separation:

    battery before.jpg

    After separation:
    battery after.jpg
     
    CaliforniaBear, -Rozi-, ftl and 3 others like this.
  2. bisco

    bisco cookie crumbler

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    thanks giora, that's great info! makes me feel better about leaving my pip in the cold for 6 weeks for the second year in a row when we head to florida.:cool:
     
  3. giora

    giora Senior Member

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    bisco,
    I made an error in calculating originally (when saying 20 Ah in 6 weeks) the correct calculation (edited already) is 4 times less - 10 Ah in 12 weeks! so you can certainly rest assured in Florida!
     
  4. mrbigh

    mrbigh Prius Absolutum Dominium

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    That's a more reasonable figure..........(y)
     
  5. retired4999

    retired4999 Prius driver since 2005

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    Florida!!!!!!!!! Cold down there too! :D
     
  6. giora

    giora Senior Member

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    Israel is the place to go!!!...20 C day, 12 C night:LOL:
     
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  7. priuskitty

    priuskitty PIP FAN

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    Hey! Guess what? February thaw Saturday! Eight inches of snow though.:cry:
     
  8. retired4999

    retired4999 Prius driver since 2005

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    Sweet! :whistle:
     
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  9. Lourun

    Lourun Member

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    Going to be 45 Super Bowl Sunday here in north Jersey!
     
  10. retired4999

    retired4999 Prius driver since 2005

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    Boy you guy,s sure got lucky! Enjoy!:D
     
  11. bisco

    bisco cookie crumbler

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    they should have the superbowl in israel next year!(y)
     
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  12. -Rozi-

    -Rozi- Member

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    Don't forget about the self discharge (typically about 5% per month). Otherwise, 5mA is really battery friendly.
     
  13. CaliforniaBear

    CaliforniaBear Clearwater Blue Metallic

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    Great experiment! What is the current if the FOB is in the car, doors unlocked, after 20 minutes (ie after all circuits are in their steady state)? I generally leave my car in that condition overnight in my locked garage. I know that's not good for long term but I drive it every day.
     
  14. bisco

    bisco cookie crumbler

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    you leave your fob in the car because you drive it everyday?
     
  15. giora

    giora Senior Member

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    Didn't check this.
    I was too afraid to make further experiments (involving slamming the doors...) and loose contact (the tiny clamps...), now that I have more confidence I may try more things.
    Any good reason for putting this artificial load on the battery? even if you use it everyday?
    BTW, I believe that when charging the car, the 12 V battery is being charged as well (if required)?
    I have measured voltage overnight (at the terminal in the engine compartment) to be 12.6 V, and during charging it was 13.5 V. This 13.5 V is probably the voltage of the DC/DC inverter to the 12 V BUS?
     
  16. giora

    giora Senior Member

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    Agree.
     
  17. CaliforniaBear

    CaliforniaBear Clearwater Blue Metallic

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    Its for convenience. I can't keep the fob in my pocket because then it will be within a few inches of a computer most of the day and that's not supposed to be good. I've checked the battery voltage overnight with and without the fob in the car and it doesn't make any difference. The battery is a year old and still indicates full charge per the voltage method in the manual so I expect the current draw with the FOB in the car or out must be very similar to what you measured.
     
  18. priuskitty

    priuskitty PIP FAN

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    That's strange, key fob next to a computer. .....haven't experienced any problems so far, what problems have you encountered?

    SGH-M919 ?
     
  19. CaliforniaBear

    CaliforniaBear Clearwater Blue Metallic

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    None. Its a caution in the manual. I believe it may cause the FOB battery to run down faster as it may be trying to communicate with whatever. Of course that may be no different than leaving it in the car. I have a spare FOB battery :)
     
  20. priuskitty

    priuskitty PIP FAN

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    I have never had my fob quit on me and I have owned a prius since 2007, also I would think leaving the fob in the car would run the fob battery more than being next to a computer

    SGH-M919 ?