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

Aftermarket Sub-woofer Amplifier Installation using DC-DC +12v Power Source

Discussion in 'Model 3: Interior & Exterior' started by Jamie Sibley, Apr 18, 2019.

  1. marcmerlin

    marcmerlin Member

    Joined:
    Jan 12, 2016
    Messages:
    65
    Location:
    Cupertino, CA
    Thanks. It's a long document, what part was what actually helped?
    I'd think that if you disconnect 12V from both sides (battery and DC-DC side), the car should fully lose power and forget the old battery. Are you sure that it's not enough?
     
  2. marcmerlin

    marcmerlin Member

    Joined:
    Jan 12, 2016
    Messages:
    65
    Location:
    Cupertino, CA
    Interesting, I didn't think about those, but I am dealing with 200A, I'm not sure a few of those, even in parallel, are going to do the trick. (3000W inverter at 12V is actually 250A)
    Other people who worked on this talked about a bypass relay once the inrush is over, and honestly you need a solid piece of copper for 200A, so I'm not sure there is any way around that.
     
  3. 9-Volt

    9-Volt Member

    Joined:
    May 15, 2019
    Messages:
    318
    Location:
    Vancouver
    All of the (13) steps outlined to disconnect the high voltage power, and then the reverse to reconnect the high voltage (and 12V), were required.

    Sorry, I thought you'd already tried disconnecting the 12V and it didn't work. The guys in the shop fully disconnected the battery for 24 hours and it still wasn't enough to make the car think a new battery was being hooked up. Worked instantly after following the steps above, and no problems since, so I think the key is a disconnect/connect of the high voltage.
     
  4. marcmerlin

    marcmerlin Member

    Joined:
    Jan 12, 2016
    Messages:
    65
    Location:
    Cupertino, CA
    Did you disconnect the 12V from both sides? If you only disconnect the battery, the DC-DC will keep the car alive from the other side.
    If the DC-DC trips, or you disconnect it from under the rear seat, and then you also disconnect the battery, the car's computers have no power and absolutely nothing will work, including opening doors (so don't close the trunk unless you want to try the emergency opening procedure).
     
  5. 9-Volt

    9-Volt Member

    Joined:
    May 15, 2019
    Messages:
    318
    Location:
    Vancouver
    Not 100% sure, as my audio shop did it, but I think they had the battery out of the car and sitting on a charger. I know they also tried disconnecting the power from under the rear seat (but not sure if the battery was disconnected at that point or not).

    Obviously, your mileage may vary as to whether some or all of the steps outlined in the Tesla document linked above are required to clear the 12V error message. I just thought I'd pass along the info that worked for me--as food for thought--in case you can't clear the message and have a known good battery.
     
  6. marcmerlin

    marcmerlin Member

    Joined:
    Jan 12, 2016
    Messages:
    65
    Location:
    Cupertino, CA
    To close off that discussion on this thread too, please go to How many amps can you get from the 12V system for emergency situations? for how I made it work.
    I now have a 2000W inverter that powers on and off at the same time than the car DC-DC system, without the big current inrush that was disabling the car's DC-DC system in a way that it didn't really reset on its own.
    Turns out I didn't even need a zener diode, relying on the voltage being high enough at the inverter poles to trigger a bypass relay, was enough.
     
    • Informative x 1

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