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12v battery died 250 miles from SC making me pay for 150 mile towing

Discussion in 'Model S' started by Lhagin, Dec 20, 2015.

  1. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    Tesla uses deep cycle AGM batteries, but the total number of equivalent cycles caused by the vampire drain still sucks the life out of most Tesla 12V batteries in a year or two. The amount of vampire drain in the Tesla Model S is obscene.

    See Power drain while idle (Vampire Load) and Near annual replacement of 12V battery is typical according to Tesla Service Tech for a lot of discussion on this subject.
     
  2. CHG-ON

    CHG-ON Still in love after all these miles

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    Of course, now after reading all this, I'm paranoid.

    I have a typical lead acid charge pack that I used to use to jump my Acura when it sat too long. Would that work to breathe life back into my 12V if it keels over during my Christmas trip with my sister? I would rather go out and buy a whole new damn car than deal with the drama that would ensue if we got stranded somewhere!:scared:
     
  3. Cottonwood

    Cottonwood Roadster#433, Model S#S37

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    See this thread for how to get access to the "jumper" lugs under the front nose cone: Procedure for exposing the nose cone charging lugs for the 12V battery

    In most situations, a "jump pack" on those lugs should get you going. The 12V system should last for the next driving cycle in in the vast majority of cases, and be good for a autonomous restart for a few hours after some "on" time to recharge, in many cases.

    Just like an ICE, once you have a weak 12V battery, it should be replaced as soon as is reasonable. Keep that jump pack handy until the 12V battery is replaced.
     
  4. Andyw2100

    Andyw2100 Supporting Member

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    In that thread the nosecone is removed using a plastic card. Some time ago someone posted a recommendation for a specific and relatively inexpensive pry tool to use for removing the nosecone. I wound up buying it and promptly placing it in the trunk organizer in the lower portion of my trunk. This is a picture of and link to that pry tool:

    Pry tool.jpg

    Amazon.com: Steck Manufacturing 21730 Easy Pry: Automotive
     
  5. Cowby

    Cowby Member

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    Are y'all sure it's Ken....I thought Kevin is the Service Manager and Ken is a Service Advisor?
     
  6. jcaspar

    jcaspar Member

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    #86 jcaspar, Dec 23, 2015
    Last edited: Dec 23, 2015
    In the one experience where I almost needed a tow (had message car was shutting down) Tesla offered to bring a loaner to my location and pick up my car to bring to the service center 100 miles away. Never have seen anything like that from any other manufacturer, European or Japanese. Ends up the car was fine and I went on with my road trip after 20 minutes.

    All this got me nervous that my 25 month old 12v might not be up to a long road trip we have scheduled next week. Removed the nose cone just now (easy) and put it on my charger. 13.7v 100% charged after sitting overnight without being plugged in. I guess I am ok.
     
  7. Andyw2100

    Andyw2100 Supporting Member

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    So, the item above is kind of "an ounce of prevention" type of product, and also one that can charge the battery (according to the reviews on Amazon, provided it is not completely dead--not sure if that applies in our case with the traction pack) as long as the unit itself is plugged in. So if you were stranded at the side of the road, you would not be able to use it in the way you would use something like the following:

    Amazon.com: Anker PowerCore Jump Starter 600 (High 600A Peak Current Car Battery Jump Starter and 15000mAh Portable Charger with Built-in Flashlight and Safety Protection) Perfect for 5L Gas and 3L Diesel Engines: Automotive

    So if I'm really interested in making sure we're not stranded, do I need both? The CTEK for general 12V battery health, and the Anker if I want to be able to start a dead battery without a power source available?
     
  8. Kandiru

    Kandiru Member

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    I wonder what Optima Red or Yellow Top would fit in a Model S?

    I swear by these, my generator and lawnmower have been running
    15 years on twice yearly charging on these. Every car with a dead
    battery in our household gets an Optima.
     
  9. JenniferQ

    JenniferQ Supporting Member

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    Is the fact that it's plugged in every night not a help like when I keep an ICE car on a trickle charger? Does that big battery not keep the 12v charged at all? Seems a failure waiting to happen if not.
     
  10. dhanson865

    dhanson865 Active Member

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    #90 dhanson865, Dec 23, 2015
    Last edited: Dec 23, 2015
    Yes, you'd need two devices if you think you won't be in range of a 120v outlet and don't carry an extension cord.

    A jump pack might avoid the initial tow, but if you can reach the 120v and have time to wait you are better off charging the existing 12v battery before you take off.

    If you have a 120v outlet and need to start the car the CTEK can work for that, it isn't designed to do so but putting in on and starting a charge you'll be supplying 14.x volts around 4 amps which should be fine for starting a Tesla if you wait a minute or two before trying.

    So you have several scenarios

    * something is so wrong with the Tesla that nothing below helps - just tow to the service center
    * Jump start won't help - get a tow to home and use CTEK overnight or for 24 hours and try again or tow to service center
    * Jump will help and 120v is in range but you are in a hurry - use CTEK or jump start pack - drive to home or service center
    * Jump will help but no 120v in range - use jump start pack to drive to home or service center or have car towed.
    * 120v in range and you aren't in a hurry - use CTEK for as long as you can 24 hours even.
    * car notifies on dash - drive to the service center or home asap and be prepared for one of the above

    it's all overlapping circular logic if you have all the tools in the world you get to decide which to use and see what works. Obviously not worth the hassle if you are near a service center and the car is under warranty but well worth the trouble if you live in a rural area or just prefer to be self sufficient for any reason.
     
  11. eidetic

    eidetic New Member

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    I picked up the 400A version of that Anker for $49 on Black Friday but haven't tried it on anything yet. A Tesla sounds no worse than the battery-killing drain of a dome light left on overnight by a preschooler in my Lexus hybrid! I've had to replace that 12V battery every 2 years like clockwork. It always frustrated me that there wasn't some mechanism to tap the high voltage battery in an emergency. Anyway, the Anker's Li-ion battery definitely makes it much more portable than even the smallest traditional jump starter.
     
  12. Andyw2100

    Andyw2100 Supporting Member

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    Thanks for the detailed response.

    You hit the nail on the head with that last sentence. I'm over 200 miles from the nearest service center, so it probably makes sense for me to buy both those units (or units like them) and have as many options available to me as possible.

    Thanks!
     
  13. Spyder14

    Spyder14 Member

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    This issue seems to remain a big issue for me--I have asked all of my contacts @ Tesla (DES, Product Specialist, etc) to give me an answer here: in the event where the 12v is dying, will a modern 12v trickle charge or back-up system as mentioned above, help extend the life of the 12v until it needs to be replaced? Will an occasional 12v triple charge prolong it's life?
     
  14. Stuart1

    Stuart1 Member

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    My Roadster did not have a 12v battery. The 12v was just supplied by stepping down part of the main battery. Even if you ran the main battery down to 0 miles it still worked because there was a separate section of the battery used. I worked just fine. Later Roadsters went with the 12v lead acid battery. I would think that if they wanted a separate low voltage battery they could use a lithium pack which would have much longer life and be more reliable then a lead acid battery (and be lighter also).
     
  15. dhanson865

    dhanson865 Active Member

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    #95 dhanson865, Jan 24, 2016
    Last edited: Jan 24, 2016
    You can definitely do that but its more expensive than lead acid. There are several Lithium variants that work fine as a 12v replacement.

    The only one on amazon is Amazon.com: Braille Battery ML7S 12 Volt Lithium Battery: Automotive at $400 and it's only 6ah. Too small for a Tesla.

    You'll see most lithium 12v car replacement batteries much larger than that and all well above $400. Even if Tesla gets a discount or spends the R&D to make their own it will be more than double the cost of lead acid.

    Cheapest at 12 Volt Lithium Battery is almost $600 but at least it is 40 ah so you know it's big enough.

    advance Auto has one that is 14ah for $150, just not sure if that is enough for a Model S, might be better than the current 12v, might be similar (lead acid works OK with 50% depth of discharge, most lithium 12v replacements are good to 80% depth of discharge so you don't need as large a nameplate capacity to have the same usable capacity). I don't know enough about the vampire drain vs 12v capacity to make a judgement if that is enough.

    Oreily auto parts doesn't have any lithium 12v replacements

    Autozone is the same, nothing there.


    Overall lithium 12v replacements are a darn nice solution. I hope after the gigafactory comes on line they dedicate a corner to make 12v replacements someday. Maybe at some point they can make them with recovered cells from larger packs and toss a custom controller in there to make a drop in friendly 12v that would work in any car. If they even got it to the same price as Lead Acid it'd be a major improvement. If they could get it down to half again more expensive than a AGM Lead acid I'd buy one for every car I drive regularly.

    I'd like to see one around 20ah with pencil posts for the Prius and one around 25ah to 30ah with standard sae posts for general US car use.

    But I'm not holding my breath. Apparently most of those cells are put to more valuable use in larger packs for the main pack in an EV or for powerwall type battery backup/load shifting uses. Until those markets are saturated the first run cells won't be cheap and the harvested cells will take years to trickle in.
     
  16. Nismode

    Nismode Member

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    Could you go into detail as to how this works and what you're exactly connecting to what? I found that link above as well as a link to another device, and I'm confused as to how they're used.

    Amazon.com: CTEK (56-263) Comfort Connect Cig Plug: Automotive
    Amazon.com: CTEK (56-864) MUS 4.3 12 Volt Fully Automatic 8 Step Battery Charger: Automotive
     
  17. eloder

    eloder Active Member

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    My first car (a smart car) probably has similar numbers/locations to Tesla service centers. There was a limit on the free tow offered within warranty of I think 100-150 miles, and smart cars can also run into a situation where you can be at least a few hundred miles from the nearest service center.



    I'd actually be interested to know if Teslas will do this. On my Leaf, charging it will not also charge the 12v battery, as the 12v battery is only charged when the HV pack is engaged (car is fully on). It runs into the interesting problem where you can run accessory mode on the car while charging, but the 12v battery will die out after too long.
     
  18. dhanson865

    dhanson865 Active Member

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    If you have a hot always on 12v connector in your Tesla you plug the CTEK from a 120v socket to the adapter and then into the dash or wherever your 12v socket is. (with a window rolled down so you can leave the car turned off on a long charge session).

    If you don't have an always on 12v connector inside the car you have to use the alligator clips and the nose cone removal (not convenient but doable). I wouldn't want to do this for anything but an emergency it's just too much hassle.

    For the general procedure You'd make sure the car is turned off, plug the CTEK up to the wall and the car and press the mode button on the CTEK until it is lit under the snowflake symbol and let it charge the battery as long as you can. After it is fully charged the top light will be one of the green ones for stage 7 or 8. You can unplug it and put everything away.

    The hard part is getting access to the 12v bus on the Tesla. You either have to pull parts of the car to access 12v while it is off or you have to modify the car to have an always on 12v port (assuming your car doesn't have one already). Test all your ports while the car is off with a cell phone charger to see if you have one that is live while the car is off.
     
  19. qwk

    qwk Model S P2681

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    FYI, yes a trickle charge will keep the 12V on life support until you can replace it. Another thing you can do is to plug the car into a 120V supply and dial the amperage way down. Doing this will keep the main battery contractors closed, and the DC/DC will keep the 12V on life support(as long as the car is charging).
     
  20. Spyder14

    Spyder14 Member

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    After months of asking the question, thank you for a clear & concise answer! One quick follow-up question: I have NEMA 14-50 all ready so if I turn the amps down on that set-up, will I get the same result? Again, THANK YOU!
     

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