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12v constant in rear trunk

Discussion in 'Model S' started by Sir Guacamolaf, Jul 1, 2016.

  1. Sir Guacamolaf

    Sir Guacamolaf The good kind of fat

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    I cannot find any definitive info on how to tap into a 12v constant supply in the rear trunk. I did search and found that the rear applique taps into this power, but no steps etc. on how to get to that power source.

    Any info on how this can be achieved? I don't want to route cables from front to back through the headliner.
     
  2. LoL Rick

    LoL Rick Like Buttah

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    The link to the applique installation instructions is here EV-Appliqués - Installation

    You are looking for the section titled "Lower level trunk connections" on page 16.

    One personal tip is that I found the carpet liners much easier to remove and install by first removing the plastic section that runs across the center of the car where the trunk latches. It lifts straight up.
     
  3. mblakele

    mblakele radial cross member

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    I found it pretty easy to route a cable front to back, then jump the gap to the rear window. That leaves some cable visible but it doesn't bother me.
     
  4. Ingineer

    Ingineer Electrical Engineer

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    The Power liftgate module has a good source of +12v always on. Even if your car doesn't have the option, the connector is still there. It's located on top of and behind the right rear wheel arch and can be accessed by pulling the carpet piece out there. (must remove plastic trim to do this)
     
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  5. sacha81

    sacha81 New Member

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    Is this the connector you mentioned?

    IMG_9345.JPG
     
  6. Akikiki

    Akikiki A'-Lo-HA ! y'all

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    While I was installing the rear lighted applique, I added a small fuse box from the lift gate power cable. Tucked the fuse box to the inside right corner of the truck and used a wooden block on the outside of the fuzzy carpet and screws to secure the fuse box up. Now I have the rear applique fused and 5 spares for the next project that needs consistent power.
     
  7. HankLloydRight

    HankLloydRight Fluxing

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    Thanks for this tip... I have been looking for a 12v source for my flux capacitor currently running off of a battery.
     
  8. artsci

    artsci Sponsor

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    When WATTSUP and I were doing an applique install a few weeks ago we tested all of the wiring leading to the charge port to see if we could find a wire to tap for the charging lead into the bluetooth controller. We didn't find that but we did find an always on 12v power source, which is easily accessible. I can't remember the color code of the wire but will check and post as soon as I can confirm.
     
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  9. Ingineer

    Ingineer Electrical Engineer

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    No, the connector in question looks like this:
    [​IMG]

    It's located behind the passenger (right) rear side of the shock tower behind the carpet. If you have the powered liftgate, it goes into a black box with an additional connector. If not, it's disused and taped to the harness.
    Pin 8 is the +12v (hot always). It's a Red with Grey stripe 2mm conductor wire. It's fused by a 30A fuse (Fuse #42 located in the fusebox shown below). The ground is pin 7, a black wire, also 2mm.

    This feed can also be picked up in the large grey rectangular connector located behind the passenger kick panel in front of the passenger door on the right. Still the same Red wire with grey stripe, on pin #3.

    If the liftgate isn't in operation, it's safe to draw up to 30A on this system. If the liftgate is in operation, I'd limit my max draw to about 10A peak. Since the liftgate only operates very intermittently, it's usually fine for electric coolers, HAM equipment, etc. Note that this is not switched, so it will draw on the 12 volt AGM battery when the car is sleeping. The gateway monitors the voltage of the 12v system with a check every hour. If it detects a low AGM, it will place the car in support mode to recharge it using power from the main pack. However, since it's only checking every hour, if you have a substantial load, it could run the AGM down before the gateway notices, and you'd have to jump the car to get it going again. I recommend turning off "energy savings" and choose "always connected" if you are running anything more than small standby loads on the 12v system while the car is off. You can tell when the car enters support mode, as you hear the contactors make the "clunk clack" noise under the car.

    [​IMG]
     
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  10. Akikiki

    Akikiki A'-Lo-HA ! y'all

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    @Ingineer, wow. It amazes me that you find some of the electrical information that you do.
    How or where did you get that image of that connector? Just wondering.
    However, have you noticed/seen the small simple connector used on the puddle lights and the truck side lights?
    Do you know where we can find a source for these connectors, with or without a pigtail?
    It surely would be handy to have some of those in the goody bag.
     
  11. Ingineer

    Ingineer Electrical Engineer

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    I found that connector by searching on Mouser: http://www.mouser.com/ProductDetail/Molex/31372-1000/

    The little 2 pin lighting connectors are also easy to find. They have several parts:
    http://www.mouser.com/ProductDetail/TE-Connectivity/1-1534113-1/
    http://www.mouser.com/ProductDetail/TE-Connectivity/1534112-1/
    http://www.mouser.com/ProductDetail/TE-Connectivity/928999-6/

    Personally, since those are essentially standard .1 two pin header connectors with a fancy latch, it's much easier and cheaper just to buy the common ones.
     
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  12. Ingineer

    Ingineer Electrical Engineer

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  13. Akikiki

    Akikiki A'-Lo-HA ! y'all

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    Wow. Yes, that's what I was talking about. Thanks so very much.
     
  14. markn455

    markn455 Member

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    I am wondering how much current is available there safely..I would think the lift gate pulls a good amount.. I am looking for a 12V source that can support peak current of 5-8 amp occasional... most of the time a few hundred milliamps.
     
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  15. Ingineer

    Ingineer Electrical Engineer

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    If you simply read back a few posts, (#9) I have explained this. Does anybody read before posting anymore?
     
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  16. markn455

    markn455 Member

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    Yes I do and many of us do. Must have missed it. Apologies.
     
  17. brabusamg55

    brabusamg55 Member

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    sorry, stupid question. is the Pin 7 Ground the same as connecting to a bolt on the chassis? hate to run extra wire to chassis. if this works then will be perfect. thanks.
     
  18. Xenoilphobe

    Xenoilphobe Active Member

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    This is a great location for the Blackvue rear camera- if you chose the twin 650S single channels verses the bundled 2 channel 650 that uses 1080P for one camera and 720P for the rear... the rear one is next to useless.
     
  19. bjornb

    bjornb Member

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    I have also retrofitted a 12V output from the liftgate supply on my car:
    2017-07-07 20.12.47.jpg

    Since I also own a Mooshimeter 2 channel logging multimeter I left it in my car connected to the 12V port for the two las days and logged the voltage once every minute.

    One can see the behaviour of the 12V system here (always connected ON):
    Batterispenning_Tesla.JPG
    The green sections are when the main battery is charging, the red sections are when I am driving, and the rest is when the car is parked. One can see that the DC-DC regulates the voltage at about 13,5-13,6V when you are driving (the voltage is also regulated when main battery is charged).
    The car charges the battery when the AGM battery voltage falls to 12,2V, and one can see the bulk and absorb phases when charging.
    One can also that there is a load on the battery periodically, voltage sags/dips seen several times every hour.
     
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  20. HankLloydRight

    HankLloydRight Fluxing

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    That's cool, thanks for posting.

    The Mooshimeter is awesome!
     

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