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Thread: Chevy Bolt cell specs?

              
   
   
  1. #11
    Senior Member T Rush's Avatar
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    yeah, that Dr Kelly guy said you would have to de-solder a long circuit board that runs along the outside of the module, then there are plastic rivets that hold the busbars on to the sides of the case with the tabs welded.....so it looks like if you freed the tabs(however way) and took that circuit board off...then there are only long thru bolts to undue on the module ends, and the whole thing would maybe just fall apart after that.....I think it would be easier than cracking open a bunch of Leaf cans or glued up Tesla modules



    guessing no ones done it yet because they just haven't found a wiped out Bolt to take the battery from....but you can buy brand new replacement 30 cell Bolt modules for about $3000 or so...or you could buy a really nice vintage GSXR-750 for a bout that(hint hint) so I can give it a go on some used Bolt modules before someone else buys em all up
    Last edited by T Rush; 26 March 2018 at 1001.

  2. #12
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    Quote Originally Posted by T Rush View Post
    yeah? so you like the Bolt?
    Love the car. Only wish Elon would let us buy juice at his Superchargers. Out here in the middle of nowhere, the DC fast chargers are few and far between. Not a thing 360 days a year. Can get anywhere in Virginia. But that once a year to Rochester, will be a leisurely two days, thanks to huge holes in the charging infrastructure.

  3. #13
    Senior Member Ted Dillard's Avatar
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    Just noticed this thread - I don't spend much time on here anymore, so forgive me if I'm repeating what someone's already said here or elsewhere.

    From what I've seen/read, the Volt packs are capable of nearly 20C peak. I think the Leaf modules are easier to work with which is why (I think) a few people here have used them, but curiously, a hybrid battery needs to be capable of faster charge/discharge because of the nature of it's use. Anyway, I'm not at all sure that the Bolt is running the same cells as the Volt. In any case, I'm not at all sure, either, if you can pull the cells out of the modules easily, or if the modules would be too bulky for your build.

    The place I've heard is great to do business with, and I've had limited contact with them myself, are these guys: http://hybridautocenter.com/HAC4/ind...cks&Itemid=195 Very responsive to questions to a point, and give a fair amount of information on the site.

    All that said, pretty much the most compact, usable and dense packs out there are the Zero batteries, which you can buy from Zero.

    *edit: I see they now have a dedicated battery site: https://evbatterycenter.com/HAC4/
    Power in Flux: The History of Electric Motorcycles
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  4. #14
    Senior Member T Rush's Avatar
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    well if I was able to figure this out:
    Quote Originally Posted by T Rush View Post
    if we would use a 'ballpark' price for a 7.6v 55ah Leaf module of $50 to $100 and 8Żlbs each, and say we do a 10 pack battery
    ... thats 85lbs 76v 55ah $500~$1000
    but if a 30 cell module of these is $999 on eBay; then each cell is $33 for 3.8v 55ah and 3lbs, but you need twice as many at 20s
    ... thats 60lbs 76v 55ah $666
    so its safely in the lower third of the price ballpark, and almost a third of the weight savings
    [for reference:]
    [a used eBay 18650 Tesla 20s20p cell pack of 400 might weigh alittle less @ maybe 50 lbs but cost twice as much at $1400]
    [the eBay SPIM08HP cell pack of 140 in 20s7p for the same ~ 72v 55ah would be @ 90 lbs and still $1400 specs link ]
    [then with the 2.4v eBay Lithium Titanate 11ah cells you would need 30s5p to do that same battery with 150 of these cells for the same $1400 but @ 122 lbs]
    ...I really hope that someone else was too
    as now the the guy in the video says they are all sold(got an email back from him last night)

    it would just be so sad if no one tried to disassemble the modules(as who knows when we'll see another set, and at what price) and they just end up in a golfcart

    might not of even had to break these modules down if you did a larger bike
    ... like I could have fit two of them in my BMW for 74v 160ah 17" x 13.5" x 10" @ 130lbs $1700
    compared to a 18650 pack made out of used Tesla cells at that capacity would have only saved maybe 20lbs but been over $1000 more(not counting shipping), plus you would of had to disassemble and rebuild it

    anyone here jump on these?
    (he even lowered the eBay price before they sold yesterday)
    Last edited by T Rush; 08 April 2018 at 0942.

  5. #15
    Senior Member Ted Dillard's Avatar
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    Honestly, what you care most about, especially for the tight build you're talking about, is density (the Tesla packs aren't particularly dense due to the cylindrical cells) and power delivery (or C rate). Unlike a car, space and power are critical on a bike. (The Tesla packs deliver lots of power, but it's because they're so big.) Thus, the Volt packs.

    It's almost like the old thing "We do fast, good and cheap. Pick two." With batteries, for a bike in particular, it's power, space and price, though there are other considerations. See these "star charts" for an idea of what I mean: https://evmc2.wordpress.com/2012/02/...ttery-roundup/ and https://evmc2.wordpress.com/2015/01/...-radar-charts/

    ...those show energy density by weight and volume, power density by weight and volume, and finally price.
    Power in Flux: The History of Electric Motorcycles
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  6. #16
    Senior Member T Rush's Avatar
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    yeah, covered that in the OP...check the quotes(and click the links) for more information on what little is known about the new battery chemistry they are using
    ...seems they were able to improve both energy density and power density...as for the price, seems I demonstrated that these were selling way below traditional market value today(for those high densities)

    I know when I contacted the seller a week ago, he'd only sold one of the smaller 24cell modules, then the rest seemed to be still up for grabs until yesterday...so I don't know if another eBay seller just cleaned him out to resell at current higher market price that other older types of battery/modules/cells are selling for...but I wouldn't be surprised

  7. #17
    Senior Member Ted Dillard's Avatar
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    Went back and read the OP, and I think you're missing the point. The LG cells are not a different chemistry, they're all NCM. There's a crap-ton of information about the chemistry they're using. You might consider going back and reading Bottled Lightning, https://amzn.to/2GGKck1 and/or Powerhouse https://amzn.to/2GKI1rv to get a little background on the development of that chemistry and those cells.

    And be careful. You seem to be confusing the cells with the pack. The Zero pack, for example, is a series of NCM pouches configured in an intensely dense pack. The Sony cells I use are crazy powerful, but the pack itself is not particularly dense, because of the cell configuration.



    Beyond that I can't really figure out what you're trying to say.
    Last edited by Ted Dillard; 08 April 2018 at 1553.
    Power in Flux: The History of Electric Motorcycles
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  8. #18
    Senior Member T Rush's Avatar
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    Quote Originally Posted by Ted Dillard View Post
    ...

    Beyond that I can't really figure out what you're trying to say.
    oh, I was saying they were cheap(at the price these were offered on eBay)
    ...about the price of Leaf modules; but with power, energy, weight, and size of pack made from 18650 cells [edit]or other types costing and weighing more[/edit]

    so let me ask you about "c rate" as people were only able to speculate how these might stack up
    ...a few of the things I read about the Chevy Bolt said they 'might' be capable of very good 'fast charge' rates....at least there were some clues from Chevy that the Bolt battery pack was designed to utilize 100kw DC charging, but they just opted out of that because the 'fast charge' infrastructure in place now maxes out at 50kw

    so my question is: does charge rate capability directly relate to discharge rate ?
    ...to ask it another way: is 'C rate' rating the same for charge and discharge?

    thanks
    (sorry, I'm sure you cringe everytime you try to read one of my posts)
    Last edited by T Rush; 08 April 2018 at 1605. Reason: added a bit, but marked where

  9. #19
    Senior Member Ted Dillard's Avatar
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    Pretty much. It's kind of a confusing thing, because the engineering terminology is pretty sloppy (from a writer's standpoint )

    See this post: https://evmc2.wordpress.com/2013/08/...-and-c-rating/

    But basically you're looking at the rate current can flow into, or out of a cell.
    Power in Flux: The History of Electric Motorcycles
    www.powerinflux.com

  10. #20
    Senior Member T Rush's Avatar
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    ok, great, that helps, thanks

    but for battery packs this size(in a car) is 100kw anything to write home about? as far as 'c rate'?
    ...like is that enough to tell if a battery has a good 'c rate'?(in this case with the Bolt)


    Quote Originally Posted by Ted Dillard View Post
    from a writer's standpoint
    yeah my Wife is a writer too....two weeks ago we were having a 'discussion' about some minor miss communication we had, and she actually said to me: "its like English isn't your first language" to which I replied: "ya think?" and then she said: "oh right, I forgot, its not"

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