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Can a Tesla jump an ICE vehicle with 12 v battery? [Update: Tesla says NO]

Discussion in 'Model 3: Battery & Charging' started by Earthpower, Dec 7, 2019.

  1. Earthpower

    Earthpower Member

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    I didn't find anything about this. The jump would be using cables to the Tesla 12 volt battery. I'm thinking it's not a good idea, but it would be nice to help if needed. .
     
  2. TydalForce

    TydalForce Member

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    I can’t remember where I saw this to cite it, but no. I think the battery isn’t powerful enough
     
    • Disagree x 1
  3. eprosenx

    eprosenx Active Member

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    So the Tesla battery would really not be optimized for starting another car since it would not have a lot of “cold cranking amps”. It is likely a relatively small battery that is optimized for “deep cycle” rather than “starting amps”.

    With that being said, it is interesting to me. I could see pairing your car with another dead ICE vehicle for a while in order to recharge their battery. Basically using your 12v battery, but more importantly using your high voltage DC to low voltage DC (12v) converter to pump 12v into their battery to charge it.

    I wonder how many amps the Tesla 12v converter can put out?

    It would be really fun to go around jumping ICE vehicles. :)

    I have never even seen the 12v battery in the Model 3. Looking at the size and specs on it would tell us a lot.
     
  4. aerodyne

    aerodyne Active Member

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    #4 aerodyne, Dec 7, 2019
    Last edited: Dec 7, 2019
    A starting battery has a different design of the lead plates than AGM's as used in Teslas.

    Not sure how this would work on a newer car, but for a pre-refresh MS, one could pop off the Nose cone and hook up some cables to the posts there. However, I would not start the ICE car with the cables connected.

    The traction battery, once it senses the 12V is at a low SoC, will provide over 14V to the 12V system. This is about as much as a ICE alternator...but at a much lower amperage. My guess is 20 A. So, leaving it connected for 20 min would add about 7 A/H to ICE batt.
     
  5. Saghost

    Saghost Well-Known Member

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    A Tesla will be fine for charging up the battery of another car to get the other car started, if they have a fully functional battery that's just drained. You really, really don't want to have the other car still connected when they try to crank the engine - the voltage drop and possible spike could do all sorts of bad things to the Tesla's computers.
     
  6. TydalForce

    TydalForce Member

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    Oh I found it; Tesla’s doc on jump starting .

    Do It Yourself - Model 3


    Caution: Model 3 cannot be used to jump start another vehicle. Doing so can result in damage.
     
    • Funny x 1
  7. KenC

    KenC Active Member

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    Just carry one of those inexpensive lithium power bank car starters.
     
    • Like x 1
  8. Akikiki

    Akikiki A'-Lo-HA ! y'all

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    Here's the test. If you did jump another car with your Tesla, and something/anything happened to your car, do you think Tesla would fix your for free? If you have the slightest of doubt (and I do), then your answer should be NO, Don't take the risk.

    And don't throw in the "even if", Yes, even if.
     

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