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12v battery drained by aftermarket stereo

I’m in my 4th MS and have had aftermarket stereos/amplifiers in each. Never had a problem until my 2020 LR+. I am currently on my second battery after only 2 months. I get several warning messages (simultaneously) and then the car won’t start and requires service. Each time I was told by Tesla that the 12v needed to be replaced. Has anyone else experienced this with a newer Tesla? What changed with the MS that an aftermarket stereo is now constantly draining the battery?
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Comments

  • Is it the same aftermarket stereo?
  • That doesn't sound like the stereo is the problem. It sounds more like the onboard charger for the 12v battery is not working. A few times a day (I think it used to be 4, not sure what it is now) the car partially wakes up and charges the 12v battery from the main battery. If this is not happening, then the 12v will go dead pretty quickly. Maybe this is what is happening to you?
  • Your latest installation is defective.

    Why would you blame the Tesla rather than the high school dropout who bolted a Made in China stereo into your dash?

    Have them check the electrical connections and power draw. Sounds to me like a subwoofer amplifier or the head unit is powered continuously rather than only when the car is “on”. Even that should only drain the 12v battery, and shouldn’t destroy it.
  • Thanks for the suggestion. I had my car towed into Tesla service center twice and both times they ran diagnostics. Each time they said aftermarket stereo was causing drain and charged me about $450 each time. (Aftermarket stereo voided warranty on 12v battery).
    I had everything professionally installed and they have done many Tesla’s. Definitely possible 12v isn’t charging from main battery. Definitely worth looking into.
  • Thanks for verifying adding aftermarket stuff can void warranty.
  • > @Frank99 said:
    > Your latest installation is defective.
    >
    > Why would you blame the Tesla rather than the high school dropout who bolted a Made in China stereo into your dash?
    >
    > Have them check the electrical connections and power draw. Sounds to me like a subwoofer amplifier or the head unit is powered continuously rather than only when the car is “on”. Even that should only drain the 12v battery, and shouldn’t destroy it.

    I agree, sounds like they hooked the power up straight from the 12V battery. The problem with this is that the car doesn't know about the load and it just sees the battery continuously draining for no reason. It will keep charging it, but at some point the car thinks there is something wrong with the battery and throws flags.

    Now this actually gets me wondering....I wonder if this 12V battery "failure" is actually a battery failure at all and not just the computer thinking the battery is bad and acting as if the battery is bad(kind of like the memory effect on ni-cad's). I wonder if in these scenarios you might be able to remove the 12V battery, externally charge it back up and then put it back in the car and the car would then think there was a new battery installed and be good again as long as you removed the offending power draw....I will NOT go test that theory on my vehicle however. :)
  • > @jerrykham_98166189 said: > That doesn't sound like the stereo is the problem. It sounds more like the onboard charger for the 12v battery is not working. A few times a day (I think it used to be 4, not sure what it is now) the car partially wakes up and charges”

    The most plausible answer. If you go to top installer with experience with Tesla, they likely know more than the less experienced Tesla techs.

    If the Tesla tech said the stereo was discharging the battery then he should have been able to ID and remove the connection causing the drain.

    You could have the installer double check also.
  • >>> he should have been able to ID and remove the connection
    So your asking a Tesla technician who isn't trained in aftermarket stereo installation to figure out where all the wiring has been run, where the electronics have been tapped into the car's power, look up the manufacturer's installation instructions for each piece of aftermarket gear to figure out how it should have been wired, and attempt to remedy the poor workmanship? Doesn't sound like a good way to do business to me.
  • “The most plausible answer. If you go to top installer with experience with Tesla, they likely know more than the less experienced Tesla techs. “
    ————

    Spoken like a true troll
  • I certainly hope you don’t have pack problems later on otherwise it could be traced back to the two denied warranty claims already, for parasitic draws from customer installed accessories
  • > @Frank99 said: > So your asking a Tesla technician..."

    Who said stereo is draining battery to prove it. Should be easy to demonstrate if true.
  • It is easy - you measure the power being drawn from the 12v battery. Doesn’t require trying to understand someone else’s ratsnest of wiring.
  • > @Frank99 said: > It is easy - you measure the power being drawn from the 12v battery. Doesn’t require trying to understand someone else’s ratsnest of wiring.”

    How would that prove it was the stereo doing the power draw?

    How do you prove that whatever the stereo’s power draw, it is excessive?

    If Tesla told me that, I’d have the stereo installer take a look to make sure there’s nothing wrong with stereo or the wiring.

    Tesla does have a history of issues with the 12V batteries and/or the 12V battery charging system. And the owner has not had the issue before with modified stereos and uses a Tesla experienced shop.

    Interesting that it is a 12V on a new Model S while we only see Model 3 12V battery issues, which do sound similar.
  • edited December 2020
    > @FISHEV said:
    > If Tesla told me that, I’d have the stereo installer take a look to make sure there’s nothing wrong with stereo or the wiring.


    That's where you should have started. If a configuration change predates unexpected failures, look first to the configuration change as likely cause. That change *might* not be the cause, but it *probably* is.

    You can 5-whys it or fishbone (something you should be familiar with but probably aren't) it, and that configuration change should be prominent in both.
  • > @Frank99 said:
    >>> I'm feeling cranky this morning for some reason, so I'm not going to listen to the side of my brain that's telling me to just move on.

    Such an angry little elf.

    Funny how you pretend to know everything that transpired with my service appointments and audio install based on fewer than 10 sentences in my original post and an even shorter response in a second post. If you only knew a fraction of the details you would be laughing your ass off at your displayed ignorance. The intent of my original post was simply to see if others within the Tesla community have experienced any similar issues with an aftermarket stereo - not to be criticized, ridiculed, or jabbed at by a want-to-be know it all.

    >>>Just a life tip - perhaps you should have a thoughtful conversation with yourself about who you trust and why, and about where you get and accept information from.

    Thanks for the life tip. Someday I hope to reciprocate with an equally profound piece of advice. But for now all I can share is this:

    >>>”So your asking a Tesla technician who isn't trained in aftermarket stereo installation....”

    YOUR is a possessive adjective. It is always followed by a noun in a sentence. (FYI, “asking” is not a noun). YOU’RE is a contraction of two words, “you” and “are”. Here’s a good example of how they can work together:
    YOUR response to my post tells me that YOU’RE a jackass.
    See how easy it is?
  • Not unique to Tesla.
  • > @"aj.bordinko29_98441000" said:
    > I’m in my 4th MS and have had aftermarket stereos/amplifiers in each. Never had a problem until my 2020 LR+. I am currently on my second battery after only 2 months. I get several warning messages (simultaneously) and then the car won’t start and requires service. Each time I was told by Tesla that the 12v needed to be replaced. Has anyone else experienced this with a newer Tesla? What changed with the MS that an aftermarket stereo is now constantly draining the battery?

    Seems like an easy test....disconnect the aftermarket stereo for lets say a month or two, if your battery doesn't go bad then it was probably the stereo. Where exactly is the stereo getting it's power from, where is it physically connected?
  • well if your aftermarket stereo system draws more power than the battery receives in charging, then you are going to drain it. Why does it need to be replaced is not something i can answer over a forum, but my guess is whatever aftermarket load you are putting on your battery is not working out for you and you should probably stop.
  • Here's another perspective. While parked and locked, let's assume the car draws 3 amps to power the computer and other stuff. Let's say the new super-amp takes 30 amps. This means the 12v battery is charged/discharged 10 times more often than without that amp.

    The 12v battery normally charges twice a day and is designed to operate for 3 years and 2000 cycles. With the amp, it requires charging the 12v battery 20 times a day, the 2000 cycles means the 12v battery will only last 100 days.

    Obviously, I don't know the power that the amp requires, and I've just pulled the 3 amp number as a guess, and it could be far less. It does show how an add-on could dramatically shorten the life of the battery.

    The 12v charge cycling occurs whether the car is externally charging or not.
  • How big of a stereo system did you install, and how loud do you listen to it?

    It could be as simple as your drawing more power than the 12v charger can handle. The DC-DC converter can handle up to about 2400w (200A) which includes running the lights, computers, cameras etc.
  • Thank you all for your thoughts and insights. Long story, short....it seems to be an install issue. Per Tesla, there are no dc-dc converters in newer 2020 MS’s. This is the first time my stereo installer experienced this. Brought my car in for an audio “re-wire” and had them install a switch that will kill all power going to aftermarket stereo equipment (as an added precaution). Hopefully this will fix the problems. Keep you posted.
  • > @"aj.bordinko29_98441000" said:
    > Thank you all for your thoughts and insights. Long story, short....it seems to be an install issue. Per Tesla, there are no dc-dc converters in newer 2020 MS’s. This is the first time my stereo installer experienced this. Brought my car in for an audio “re-wire” and had them install a switch that will kill all power going to aftermarket stereo equipment (as an added precaution). Hopefully this will fix the problems. Keep you posted.

    Looks like your installer made some assumptions. Guess Tesla was right, who would have thought...

    Frank99 called it at least partially with his very first post. "Sounds to me like a subwoofer amplifier or the head unit is powered continuously rather than only when the car is “on”."

    Maybe you should go after the installer for the damage they caused to the 2 batteries you had to pay for.
  • @aj.bordinko29 - Sounds like a good solution. You might also consider some kind of relay that would disconnect the audio when the car is off, but that may be getting too tricky.

    On the DC-DC converter - I think whoever you spoke to at Tesla is wrong. Every EV (including non-Teslas) has a DC-DC converter to charge the 12v battery, with the exception of the original v1.0 Roadster back in 2010, which used part of the main pack as the 12v. It was not a great design as it added more wear to one part of the pack. They changed the design in the v1.5 roadster to be similar to all EVs today.

    What happens is the 12v battery powers electronics and accessories. The main pack (360V in a Model Y) has a DC to DC converter that is turned on occasionally to charge up the 12v battery. Once charged, it disconnects. I believe (but unconfirmed) that when driving, the DC-DC converter runs continuously. The loads when driving are high enough to warrant continuous operation.
  • @mbowden_98415965 @"aj.bordinko29_98441000" I Just had speakers upgrade and an 8" sub with an amp installed in 2018 Model X They finished install at 6pm. By 7:20 PM in my garage the car bricked. Totally locked. I could smell sulfur from the 12v battery. Battery is probably at end of life already 2.5-3year. Tesla mobile appointment is in a few days to hopefully replace battery. Any suggestion on how to proceed. The install was done by highly rated company although they did not seem to be very familiar with Tesla. Not sure if there is a lot different than regular car? Any help appreciated. I dont think Tesla is going to warranty battery either.
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