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affects on MS's 12V Deep Cycle battery with aftermarket audio amps?

Discussion in 'Model S: User Interface' started by yobigd20, Nov 4, 2014.

  1. yobigd20

    yobigd20 Well-Known Member

    Oct 28, 2012
    Skaneateles, NY
    To the audio experts out there, I've been holding back on doing any custom audio work like adding another larger sub and amp primarily due to unknowns to me of the affects on their 12V deep cycle battery.

    We all know that when the 12V battery goes, the car shuts down. This is the major reason why I've been holding off. I've done custom systems (nothing complicated, basic [amp+speakers]+headunit+[cap+amp+subs]) on ICE cars before without worry. But I've used capacitors to protect those 12V battery for the sub amp. I know A&E's does audio upgrades, and Reus audio does audio upgrades, and theres system's like NVX's BOOST for added amp+sub. If I recall Dr Taras' MS was done by A&E's (I think) and I think they added a cap. Can't recall. So I know knowledge is out there now about this....

    Basically, I want to know how powerful of an amp we can use while staying 'safe' and not causing a big drain on the 12V battery. Clearly I am going to use a class D amp. but can something like JL Audio HD1200.1 safely be used without a cap? or should a cap be used and is that ok with the 12V deep cycle battery? [and if so, what caps to use] That HD1200.1 looks pretty sweet, but it's 1000W RMS and I think requires 100amp fuse. that seems rather large to me to use without a cap, especially if the MS is sensitive to 12V issues, hence my hesitation to 'experiment' without getting advice from the real pro's that know what they are doign w\ regards to aftermarket audio on EVs, specifically w\ the MS.

    The other question I have is with regards to the line out converter. I have the upgraded sound studio package. I know that I need to use something like Audio Control LC2i 2-channel line output converter and hook that up to the car's sound studio amp. The question I have is which line out's did you use? speakers or sub out? and did you split the out so that the speakers(orsub) still works? (does splitting the output affect quality on the factory speaker?). fyi I plan on keeping the stock sub and just complimenting it with a larger one, hence the need to still use the existing sub line out.
  2. supratachophobia

    supratachophobia Active Member

    Sep 24, 2014
    Columbus, Ohio
    I don't know if this will help or not, but consider this. If you have the basic audio system, I would assume you are good adding an amp up to what the premium audio system adds without any adverse affects whatsoever (is that 500 watts?). Now how much past that can you go? Again, this is all speculation, but there is a 200amp circuit between the high voltage battery and the 12v battery. Adding an amp that is only pulling another 15/30 amps shouldn't be much of an issue, especially if there are options you may not have that rely on the 12v system (blanks in the fuse box). But going up to 60amp is where I would strongly consider not going. That is almost a full 1/3 of the 200amp circuit and would be pushing it, regardless of how many options you didn't get. Coincidently, I have the LC2i that I didn't use because I have a newer car and I don't have the premium audio. Let me know if you need it. And check out regarding where you will need to splice into the harness, that guy already did the work for all of us.
  3. Cottonwood

    Cottonwood Roadster#433, Model S#S37

    Feb 27, 2009
    As long as you are not going to run the Audio for long periods of time with the car off, it's not a big deal. Whenever the car is on, the 12V system is powered by a DC-DC converter that feeds the 12V system from the large High Voltage (HV) battery. Even when the car is off, whenever the 12V battery droops far enough, the HV system wakes up, charges the 12V battery and then goes back to sleep, so it is better than an ICE with the engine off.

    With Class-D Amps, and the size of the MS interior, even with very inefficient sub-woofers and at deafening audio levels, the most you are going to pull from the 12V system on average, is 100's or Watts or 10's of Amps. That is well within the capabilities of the MS 12V system. I think the DC-DC converter is 150 Amps at 12V; that is like having a 150 Amp alternator in an ICE. Others will have to recommend the best place to tap into the 12V system for your power. I think there are some high current feeds in the area of the Frunk, just in front of the passenger seat for first responder disconnect. As for adding some caps near the amps, it won't hurt, but a good quality amp should have them built in.

    Good Luck!
  4. Drtadakichi

    Drtadakichi Member

    Nov 6, 2014
    United States
    The DCDC will keep up with whatever draw you put on it, the problem you run into, is you will cause the battery to run through its cycles faster. The battery runs through all its lifetime cycles which is why they are needing to be replaced. The big question is, will digging into the electrical system void any warranties you will get on 12v battery replacements due to unanticipated strain on the system?

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