TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker and becoming a Supporting Member. For more info: Support TMC
  1. TMC is currently READ ONLY.
    Click here for more info.

12v Switched?

Discussion in 'Model 3' started by GBXM3, Mar 28, 2019.

  1. Idkorcare

    Idkorcare Member

    Joined:
    Nov 3, 2019
    Messages:
    176
    Location:
    Atlanta
    nope, your still going to want a relay. We dont know exactly how much current it provides but some people even had issues triggering a relay with it, its only powering a couple Leds
     
    • Like x 1
  2. BKool

    BKool Member

    Joined:
    Sep 20, 2019
    Messages:
    9
    Location:
    Canada
    Thanks for the feedback! I will use one of the relays mentioned in previous posts then!
     
  3. eXntrc

    eXntrc Member

    Joined:
    Jan 16, 2019
    Messages:
    124
    Location:
    Houston, TX
    #123 eXntrc, Jul 17, 2020
    Last edited: Jul 17, 2020
    If that power pattern works for you, then sure you can use it. For me, I've been dealing with sleep issues for months. Some days it would take hours to sleep. Some days it wouldn't sleep at all. During this time my amplifier was getting very hot. I also have a laser wire system that generates heat and I just didn't want these systems running when I wasn't in the car. That's why I switched over to the brown wire because it cuts off as soon as I got out of the car.

    Sorry to disagree with @Idkorcare! But theoretically I think you might be OK. That brown wire is connected to a digital circuit that only supplies enough amperage to power LED lights. If you try to draw too much amperage on that wire it will trip the digital breaker (and will require a deep sleep to reset). It's not enough amperage to flip over some of the electro magnet relays people have tried, but it is enough amperage to trigger a Solid State Relay. Since remote turn-on requires very little amperage (similar to a SSR), I think you might be OK. You'll just have to try it and see. The relay will give you more safety in isolation and the ability to add more later, but if remote turn on is all you plan or need, you might be fine.

    Let us know how it goes!
     
    • Informative x 1
  4. Idkorcare

    Idkorcare Member

    Joined:
    Nov 3, 2019
    Messages:
    176
    Location:
    Atlanta
    Randomly putting a possibly excessive load on a wire like that is a good way short something out. I doubt every single thing is fused like that and even if it was you wouldnt want to do that.
     
    • Like x 1
  5. BKool

    BKool Member

    Joined:
    Sep 20, 2019
    Messages:
    9
    Location:
    Canada
    #125 BKool, Jul 17, 2020
    Last edited: Jul 17, 2020
    I have the ktp-445u Alpine amp and it's unfortunate that the remote turn on current is not provided in the instruction manual. I will most probably connect everything and then just measure roughly how much current is drawn. If less than 100mA, I might skip the relay. But as @Idkorcare mentioned, it is safer to use one since a ssr only requires on average 10mA of current to turn on. Either way, I'll keep you guys posted!
     
  6. Idkorcare

    Idkorcare Member

    Joined:
    Nov 3, 2019
    Messages:
    176
    Location:
    Atlanta
    Ask todd2fst4u in this thread, i think he has used that amp in the car before
     
    • Like x 1
  7. BKool

    BKool Member

    Joined:
    Sep 20, 2019
    Messages:
    9
    Location:
    Canada
    Hi @todd2fst4u if you used the Alpine ktp-445u in your build could you please let me know if what I quoted above would work?
     
  8. eXntrc

    eXntrc Member

    Joined:
    Jan 16, 2019
    Messages:
    124
    Location:
    Houston, TX
    There are no fuses in the Model 3 (source 1, source 2, source 3. More sources available on Google).

    Every circuit should be protected. It wouldn't be safe for Tesla to have unprotected circuits. Now I'm not suggesting to completely disregard the load limit for any circuit. However, if the load is is small (in the handfuls of mAs) then it likely will not exceed the limit. I don't agree that a relay would be required in that case. In fact, to be completely honest, I would feel much safer driving a remote-on load than I would an electromagnetic relay load on that circuit. If a relay is in fact desired, I highly recommend a Solid State relay due to the very low amperage requirements.

    Please let us know what your findings are. Keep in mind that no matter which route you go (relay or not), if you accidentally trip the breaker you can wait for the car to sleep or you can perform this procedure to reset the breaker.
     
    • Like x 1
  9. todd2fst4u

    todd2fst4u Member

    Joined:
    Oct 26, 2019
    Messages:
    180
    Location:
    Menlo Park
    The KTP-445u has signal sensing turn on that can’t be disabled. Running a remote wire to this amp is redundant.
     
    • Informative x 1
  10. BKool

    BKool Member

    Joined:
    Sep 20, 2019
    Messages:
    9
    Location:
    Canada
    Oh I did not realize this amp had auto sensing. Since it cannot be turned off the amp will remain powered as long as there is signal in the speaker wires regardless of the 12V switched (which happens when sentry is on).

    I guess I will have to proceed the following way: I will tap into the 12V switched center console LED wire and bring it all the way to the penthouse area. The 12V switched will control a relay that provides power to my amplifier. This way, I will only be providing power to my amp when the 12V switched is active.

    Let me know what you guys think of that!

    Also thank you @todd2fst4u for the info! You definitely saved a few hours of my time!
     
    • Like x 1
  11. Idkorcare

    Idkorcare Member

    Joined:
    Nov 3, 2019
    Messages:
    176
    Location:
    Atlanta
    @eXntrc The main point i was trying to make was why even bother risking trying it like that when the current limit, current load, and if the wire is even protected is unknown and its only a $5 part. Its not really practical for car manufacturers to “fuse” every circuit like that especially on lower current wiring like this. With all the unknowns your better off just going with what someone else has verified works.

    Im just trying to keep you or anyone else from messing your car up. I use to do stuff like this professionally, so I usually recommend the safer, proven way than a “should/could” especially if they are asking somewhat basic questions. So sorry if my reply came off aggressive/ disagreeable but a few others have had issues using that wire already when it “should” be fairly straightforward.
     
    • Informative x 1
  12. eXntrc

    eXntrc Member

    Joined:
    Jan 16, 2019
    Messages:
    124
    Location:
    Houston, TX
    This is not meant to be argumentative, but I was wondering if you would mind linking to a source that supports this statement? As far as I know, the only alternative to an unfused circuit is an unsafe one. If there is a dead short, that current has to go go somewhere. I am not aware of any circuit on any modern vehicle that isn't fused. Even 5 amps on a dead short would not be safe. If you can point to something that says it's safe for manufacturers to skip fusing certain kinds of circuits or loads, I'd be happy to update my knowledge on that.

    I can appreciate that. I just want to mention that I do have significant personal experience working with the power system in the Model 3. Much of that experience is shared in this post. I have personally tapped the brown wire and I used a solid state relay to do it. I have also (unfortunately) already tripped the Model 3 "circuit breaker" in my car twice (namely 12V on VC_LEFT). And I have used the reset procedure I posted above to clear the breaker in under 5 minutes.

    Most head units will only provide 150 - 200 mA for the remote turn on wire. So no amplifier should ever require more than a couple hundred mA for remote turn on. The Data Sheet for the PC236 relay which you mentioned in post #62 has a current draw of 0.6W, which is 50 mA at 12v. While I agree that there is a difference between 50 mA and 200 mA, I also know that it's a small fraction of 1 Amp. I'm also personally pretty confident that circuit is on a breaker, so I personally wouldn't have reservations trying a direct line to remote turn-on if it were my car.

    I appreciate that you're trying to help people keep from messing up their systems. And I also don't get any enjoyment from arguing in forums. It's just not my thing. So this will be my last post on this subject.
     
    • Informative x 1
    • Love x 1
  13. spyderdawg

    spyderdawg Member

    Joined:
    Jun 29, 2018
    Messages:
    82
    Location:
    Georgia
    Did you ever get a response for this? Looking to tap this wire without a relay for a radar install if it will be ok. Thanks
     
  14. mooo

    mooo Member

    Joined:
    Dec 29, 2019
    Messages:
    6
    Location:
    here
    Nope, for the time being I'm just using the center console 12V plug for convenience's sake, very janky setup but it's safe.
     
  15. meso

    meso Member

    Joined:
    Jul 14, 2020
    Messages:
    23
    Location:
    USA
    Tapped the brown wire in VC_LEFT. Ran it to a standard SPDT relay. Fused and ran up to my Valentine One. Works perfect. Open the door, turns on with the radio/etc. close door and it shuts off. I’m also retrofitting some headlights which is all data/CAN controlled and I need an “IGN” power. So I’ll be using the relay to power some more accessories. Thanks for the info everyone.
     
    • Like x 1
  16. ftlum

    ftlum Member

    Joined:
    Jul 31, 2010
    Messages:
    118
    Please
    Please post some wiring pictures!
     
  17. spyderdawg

    spyderdawg Member

    Joined:
    Jun 29, 2018
    Messages:
    82
    Location:
    Georgia
    What are you using for power? I'm planning on using vcleft port for power and running relay to the brown wire like eXntrc. Thanks for the clarification and pics would be great if you get a chance.
     
  18. Graycie

    Graycie Member

    Joined:
    Sep 5, 2019
    Messages:
    21
    Location:
    Richmond, BC
    Read back a few pages. It’s been discussed in this thread.

    essentially, the brown wire will reduce to half voltage if there is excess power draw (eg your amp or standard relay). You need to buy a low resistance relay which the brown car cannot sense so it won’t cut the power in half. I grabbed 12v constant from the thick red wire at VCLeft. Good luck

     
  19. todd2fst4u

    todd2fst4u Member

    Joined:
    Oct 26, 2019
    Messages:
    180
    Location:
    Menlo Park
    Here are some photos of the brown wire relay setup.
    54E487C9-3910-4494-A5E8-66926EDF84B2.jpeg DC14B16C-2854-4875-8DC9-C7F51391D069.jpeg B73C1A9E-BC78-4F32-A6DD-550CFC17F786.jpeg

    This is the relay I’m using.
    Directed Electronics 8616 Relay Assembly Mini https://www.amazon.com/dp/B000CJ05WW/ref=cm_sw_r_cp_api_i_kxnhFb3A59QG1

    Pin 85- black wire- I ground this to the VCleft mounting bolt.
    Pin 86- red wire- This is wired to the center console led switch circuit brown wire.
    Pin 30- yellow wire- I wired this to the light blue center console 12v wire.
    Pin 87- brown wire- Use this to power your accessories. This is switched 12v.
    Pin 87A- orange wire- unused.
     
  20. spyderdawg

    spyderdawg Member

    Joined:
    Jun 29, 2018
    Messages:
    82
    Location:
    Georgia
    Question about my relay setup for radar detector. My power cord has a fuse built in, should I cut the fuse off to connect to the relay?
     

Share This Page

  • About Us

    Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.
  • Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.


    SUPPORT TMC