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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 Funds for M3 secured. Contingent on wife aproval.

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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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