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What is the exact group size/battery size of the 12v Lead Acid battery?

Discussion in 'Model S: Battery & Charging' started by islandbayy, May 2, 2013.

  1. islandbayy

    islandbayy Active Member

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    Hello, my MS is still in production, so still waiting. I was wondering if someone had the exact spec/group size of the 12v aux battery. I plan on ordering a Lithium Drop In replacement for it.

    I import products from China, and a couple of my off the beaten path suppliers are testing some drop in replacement Lithium Starting/Deep cycle batteries for Auto, Cycle and Marine use, and would like to switch to one of those, and if it works good, I am going to start importing them.
    They charge Much quicker, more energy dense, are not "damaged" like lead acid is by discharges etc...

    Thanks All!
     
  2. SCW-Greg

    SCW-Greg Active Member

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    Interesting idea. I don't know the answer at all here, but with the brain trust behind JB and crew, you'd think they would have thought of this already.

    I suspect there's some underlying performance adv. with the battery in place now. (Old school jump starting, etc.)?
     
  3. islandbayy

    islandbayy Active Member

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    You can do that with the drop in lithium replacements. Only thing I was told, is not to use a pulsing desulfator. So my capacitive battery chargers I build that pulsate at 120hz will not work, or those smart chargers. As for jumping from another battery, perfectly fine, or so I'm told.
     
  4. Johan

    Johan Took a TSLA bear test. Came back negative.

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    #4 Johan, May 2, 2013
    Last edited: May 2, 2013
    This is interesting and I would also be interested to know why they chose to go with the traditional PbA 12 V battery. Perhaps they didn't want to introduce more "first time ever" features than necessary on a car that already has so much new and partly untested technology? A regular 12V battery can be replaced anywhere in the world and is at least a very proven and well developed technology. Also, some of the peripherals/electronics/lights/fluid pumps/locks etc. etc. that draw from the 12V battery are not designed in-house by Tesla and have been developed for use with lead-acid 12V batteries. However, I wouldn't think that for example the rear tailgate motor or the windows washerfluid pump would be able to tell if the power came from a 12V LiIon battery instead? Maybe it's just that if Tesla had trouble with any of these parts the supplier would complain that the problem was because the battery was not a "regular one"?
     
  5. GSP

    GSP Member

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    The Model S has been observed to charge its PbA battery at well over 15 V, perhaps to "condition" the battery. See the 12 V issues thread. I don't think that other cars do this. I would try out the Li starter battery on a conventional car until more is known about compatibility with the Model S unique charging algorithms.

    GSP
     
  6. islandbayy

    islandbayy Active Member

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    Yah, I have plenty of vehicles to test on (I own a power sports dealership). Everything from Forklifts, mopeds, cycles, EV Conversions etc... I still need the size of the MS battery. As these batteries arn't cheap (Start at around $400ish) I only want to purchase one to test out.
     
  7. curt_toolman

    curt_toolman Member

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    did you ever figure out the battery size?
     
  8. islandbayy

    islandbayy Active Member

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    No, at the moment, at least while under warranty, I'm not going to touch it/change it.
     
  9. tom66

    tom66 Member

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    How will a lithium ion battery cope with being charged by a lead-acid charger? I suspect the MS will keep the battery float charged at about 13.8V continuously, it won't behave like a CC/CV charger like a li-ion cell expects.
     
  10. gavine

    gavine Petrol Head turned EV Enthusiast

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    Plus, presumably, the accessory battery is kept at a 100% SOC as much as possible by the car and this is very bad for Lithium-Ion batteries.
     
  11. TonyWilliams

    TonyWilliams Active Member

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    That's easy to fix... Use four cells at well under 4v each to make 12.7v static / 14 volts charging.
     

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