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60KWh battery for the Bolt... ¿maybe to big for base model 3?

Discussion in 'Model 3' started by coco81, Jan 11, 2016.

  1. coco81

    coco81 Member

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    I've just read this article:

    Chevrolet Bolt EV Specs Revealed: 60 kWh, 0-60 In 7 Seconds

    And it seems that the Bolt has a 60KWh battery pack for "more than 200 miles"... but the Model S 60 with same energy capacity have 208 miles EPA ¿what's wrong here? ¿Much more efficient Tesla technology? ¿better aero?

    If such a big and heavy car as Model S makes 208 miles with 60 KWh... a smaller car should make at least ¿20% more?

    Maybe I'm missing something but I think 50 KWh in a 20% smaller car will be enough for 200 miles range and 60KWh should give at least 230-240 miles range.
     
  2. benfrank3

    benfrank3 Member

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    208 is more than 200. They haven't released the number yet because it's not significantly over 200. You can be sure their number will be in that ballpark, or they may release an even higher number but it won't be real world. In the cold you use twice as much juice per mile.
     
  3. Ryan H

    Ryan H Member

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    Maybe it will be real world 200 miles, so something like 240-250 EPA range, which would be more than 208 EPA of the Model S.
     
  4. ety

    ety Member

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    It's likely mostly due to aerodynamics. Using the i3 as another example of a tall and stuby hatchback Ev, it has a drag coefficient of .29 compared to .24 for the model S. Plus Tesla can throw a lot more money into higher quality components to stretch out the range.
     
  5. GregRF

    GregRF Squirrel Power

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    The S is also very aerodynamic. The bolt? Not so much.
     
  6. Grendal

    Grendal Active Member

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    I consider the Bolt to have a positive effect on Tesla. Tesla will now have to make the Model 3 with a 60 kWh pack minimum. It will then trump the Bolt in efficiency, aerodynamics, and most importantly the ability to Supercharge. Fundamentally, Tesla can't let GM trump them on the size of the battery pack.

    Alright Tesla - Show me the Money!
     
  7. Cobbler

    Cobbler Member

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    Why? If the M3 weighs less or has much better aerodynamics, it doesn't need to have the same capacity to achieve identical performance.
     
  8. ecarfan

    ecarfan Well-Known Member

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    (humor on) I assume you are a male and therefore think bigger is always better (/humor)
    In my opinion, Tesla certainly does not have to put a battery of at least 60kWh in the Model 3 if a slightly smaller battery can give the Model 3 a real world range value of over 200 miles.
    The Model 3 is very likely to have a significantly lower CD and possibly be more efficient in its energy usage than the Bolt and therefore may well go over 200 miles with a battery less than 60kWh. Since the announced target base price for the 3 is at least US$2.5K less than the Bolt base price, as long as the base 3 has at least the same real world range it will be perceived to be superior on that basis.
    Of course, it also seems very likely that the 3 will have an optional higher capacity battery that will offer much greater range than the Bolt. At this point there are no indications from GM that the Bolt will go into production with a higher capacity battery option. Again, another win for the Model 3.
     
  9. ImEric

    ImEric Member

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    I totally agree with this notion. If Tesla can achieve the same EPA/real-world mileage as the 60KWh Bolt with a 45-50 KWh Tesla 3, that's just another in a long line of feathers for Tesla's cap. A bonus would be that Elon would be justified in continuing his favorite rant about how the big auto makers aren't truly serious about vehicle electrification. That said, I hope there's a 90 KWh variant :).
     
  10. JeffS

    JeffS Member

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    Simple math if the efficiency of the motors, COD, aerodynamics and rolling resistance are held relatively constant to what is achieved with the Model S, the Spark EV, the Leaf the Volt. Here's my take. Could get interesting.

    I was an early adopter on the Volt. It had a 16kWh pack. Of that, the earliest models allowed 9.9 usable. They held the bottom 18% and the top 18% as untouchable to manage battery life. As the model years progressed, they dropped that to 17 on each side, and eventually 15% on each side. So in the latest models - 11.2kWh usable.

    I drove the most miles on a 2013 model year with 10.4kWh usable pack. And I regularly achieved 50+ miles per charge except during the months Dec through about mid March in Wisconsin. So I ran about 4.8 - 5 miles per kWh. Average in winter though, and I was in the high 3's.

    Volt is rated at 3.5miles/kWh. It was easy to over achieve their rating in spring, summer and fall.
    If they are putting in a 60kWh pack, and claiming 208 miles...here's an interesting bit of math.
    208miles / 3.5miles per kWh comes out to 59.42kWh. So are they planning to keep the miles/kWh rating the same, and claim they are going to use the whole pack? No zero-mile buffer and no anti-bricking safety reserve? Hmmm...

    In my opinion, 200mile range with current electric motor technology needs a 70kWh pack. Unless they're coming in at under 3,000 pounds or doing something else that's paradigm shifting...I don't see how they're going to get a fleet average of 4miles/kWh and have a buffer to support a 208 mile claim. Leaf gets about 3.8 - 4.0 miles per kWh. Tesla Model S - a little better than 3.0 miles/kWh. I'm cautiously optimistic that they've done something big in that car? What could it be?
     
  11. Lonnie123

    Lonnie123 Member

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    #11 Lonnie123, Jan 11, 2016
    Last edited: Jan 11, 2016
    I don't think there is any chance of them hitting 200 miles of EPA range with a 45kWh pack. Thats a 30% increase in efficiency, which would be stunning if achieved. I think even 50 would be quite the accomplishment honestly, and even that's a 20% increase.

    Having said that, the battery is the single biggest component they need to reduce the cost of to get it down to their target, and as such they will be doing everything they can to make use of every kWh, which will allow them to use as few as possible to get to 200 miles, which will also allow drivers that can afford it to upgrade to bigger packs for huge improvements in range and really deliver some impressive headline-making numbers
     
  12. omarsultan

    omarsultan Active Member

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    From the spec sheet, its also not clear how much of that 60kWh is available on the Bolt, much the same way the full pack is not available on the Model S.
     
  13. Lonnie123

    Lonnie123 Member

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    Do you know how much they keep in reserve on either car?
     
  14. tom66

    tom66 Member

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    On Model S, about 5~6kWh is reserved.
     
  15. Twiglett

    Twiglett Single pedal driver

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    This is the biggest reason that the early production of Model 3 will not be the smallest/cheapest battery.
    I'm betting that the real base battery size will not ship until full production starts in 2018, just to give enough time for the costs of the small battery to come down.
     
  16. Lonnie123

    Lonnie123 Member

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    #16 Lonnie123, Jan 13, 2016
    Last edited: Jan 13, 2016
    Do you mean to say that they will roll out Founders, Sigs, and then large battery capacity orders before the "base" orders roll off the line in order to buy as much time as possible to get the economies of scale up and cost down on the smallest battery packs?
     
  17. Twiglett

    Twiglett Single pedal driver

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    Personally I'm hoping for a "Builders" version instead of Founders, but yes I would assume initial shipments would all be larger battery sizes
     
  18. scottf200

    scottf200 Active Member

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    Here is what GM is doing on the Volt. Pretty conservative.

    Gen 1 2010-1015: SOC ~22% to 87% (65% of battery)
    Gen 2 2016-2017: SOC ~18% to 87% (69% of battery)
     
  19. Jeff N

    Jeff N Active Member

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    The gen 2 is officially using 14.0 out of 18.4 which is 76%. GM has not disclosed the upper and lower SOC boundaries yet and I don't think any early owners have measured it yet using OBD-II.

    GM expanded the usable range in the 2014 ELR to be at least 70% and was said to have similarly expanded the 2014 Volt but I'm not sure about those usable SOC numbers.

    I'm also not sure about the Spark EV but I believe it allows quite a larger usable percentage (over 80%).
     
  20. scottf200

    scottf200 Active Member

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    Thanks for the correction. I only recalled our local GM expert, WOT, stating they go down to ~18% SOC now. (hmm. 18+76=94%)

    Volt battery doc certainly says 14.0/18.4: https://media.gm.com/content/dam/Media/microsites/product/Volt_2016/doc/VOLT_BATTERY.pdf
     

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