Power in Flux
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Thread: Chevy Bolt cell specs?

              
   
   
  1. #21
    Senior Member Ted Dillard's Avatar
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    lol

    My sympathies to her...

    Let me think on how to explain that best. But the pack size has a huge effect on the power capacity of the pack. The Tesla cells don't put out much in terms of C rate, but since it's a huge pack, you get a lot of power. That's the trick. In a car, you can get away with a lot. On a bike power/weight is king. I had a tiny RC lipo pack that could do 30C, but because it was so small, the total power it could do was the bottleneck.

    Again, for a bike, you're looking at the cell's c-rate, not the pack. So if you're comparing the Leaf cells vs. the Volt, I can tell you the volt cells can do a higher c-rate. However, you may not be able to really tear them down to the cell level effectively.

    OK, done for tonight. Cocktails coming... lol
    Last edited by Ted Dillard; 08 April 2018 at 1626.
    Power in Flux: The History of Electric Motorcycles
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  2. #22
    Senior Member T Rush's Avatar
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    thanks....I think I get (some of)it alittle better now

    guessing that taking the Bolt cells out of parallel would lower the 'C rate'...right?....maybe?

    oh darn, he's gone....I had a BloodyMary before starting this conversation but I'm sure Ted needs something now after talking with me again
    Last edited by T Rush; 08 April 2018 at 1638. Reason: converted 'conversion' to 'conversation'

  3. #23
    Senior Member Ted Dillard's Avatar
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    OK, this is one Manhattan in, but let me give it a try.

    Kind of. You're not going to change the cell C-rate. You will change the pack c-rate. Paralleling the cells adds the amps, so if you're getting, oh, say, 100A out of a cell, when you parallel it with another, you'll get 200A at the same voltage.

    Important, because you've got to make sure the conductors between paralleled banks of cells can handle the amps, as well as the final output conductors.

    Let's try an example. I've got a 3.8V Volt cell that is rated at 20ah, and maybe, oh, I dunno, 100A. (pulling that outta my butt). If you parallel that with another cell, you get 40ah, and 200A, but still at 3.8V. Series that to get the voltage you want.

    The Tesla is running tiny, 2.5ah cells at 3.4V. Parallel that to (I have no idea how much, let's say 4000 ah) and you have cells that can do only 2C, but after you parallel them, you get eleventy million C. Or something. Then series that to the voltage Tesla's running and you get eleventy million at 300V or whatever.

    Yeah, I know. Put down the Manhattan or get off the internets. lol
    Last edited by Ted Dillard; 08 April 2018 at 1659.
    Power in Flux: The History of Electric Motorcycles
    www.powerinflux.com

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  5. #24
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    My recollection is that last month someone posted a video on the Electric Motorcycle Forum that showed a fellow taking a Bolt battery pack apart. I only glanced at it for a few minutes before I decided that it looked like way too much trouble to even think about. I went back to the forum to look for the video but I couldn't find it as it was one post in a thread and I can't recall in which thread it was deposited.

    It seems like I can hardly find anything that was posted before on a forum. My searching skill are nil.
    Richard - Current bikes: 2018 16.6 kWh Zero S, 2016 BMW R1200RS, 2011 Royal Enfield 500, 2009 BMW F650GS, 2005 Triumph T-100 Bonneville, 2002 Yamaha FZ1 (FZS1000N) and a 1978 Honda Kick 'N Go Senior.

  6. #25
    Senior Member Stevo's Avatar
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    Quote Originally Posted by Richard230 View Post

    It seems like I can hardly find anything that was posted before on a forum. My searching skill are nil.
    I agree, and also agree with Ted getting upset with threads going off topic. It makes it difficult, if not impossible, to relocate important nuggets of info when you need or want them!
    Current rides: '96 Honda Ohlins VFR, '03 Cannondale C440R, '03 Cannondale Cannibal, '06 Yamaha 450 Wolverine 4x4
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  7. #26
    Senior Member Spaceweasel's Avatar
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    Quote Originally Posted by Ted Dillard View Post
    OK, this is one Manhattan in, but let me give it a try.
    Liking this just for your choice of cocktail.

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  9. #27
    Senior Member Ted Dillard's Avatar
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    We've been doing Redemption Rye, perfect, straight. Can't go wrong for those cold New England nights...

    ...went on an Old Fashioned binge for a bit, but it made me feel too much like my grandfather.

    Now what was that we were saying about going off-topic? lol
    Power in Flux: The History of Electric Motorcycles
    www.powerinflux.com

  10. #28
    Senior Member T Rush's Avatar
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    Quote Originally Posted by Spaceweasel View Post
    Liking this just for your choice of cocktail.
    oh? are you a writer too?

    (hehe, if anyone doesn't get that joke: seems like one of the requirements to be a writer is drinking Manhattans )

    anyway, I just think these are very special cells: at one point I figured that without the module and pack casings, they might only weigh in at 2.2lbs per 55ah cell
    ....now that might not set any new record or anything, but at the price they were offered on eBay for(down to $950 including shipping for 10s3p 17"x13.5"x5" @ 65lbs) I just don't think you could beat it....seems like someone should have grabbed them(me ) and without having to reconfigure the modules at all(no taking apart or much screwing around) stuck two of them on a bike for a 72v 160ah pack
    ...we can poo-poo about all kinda of things we don't know about them, but just going on what we do know, these are the newest battery options we have seen in awhile...as the the Chevy Bolt hasn't really been on the road for a year yet, so finding a recovered battery pack from a crashed car this early would be very rare

  11. #29
    Senior Member Ted Dillard's Avatar
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    You understand the difference between "power" and "energy", right?

    This is a snark-free question. Just asking because it's dead here at work and I actually went back and read the first page. Made me wonder.
    Power in Flux: The History of Electric Motorcycles
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  12. #30
    Senior Member Spaceweasel's Avatar
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    Quote Originally Posted by Ted Dillard View Post

    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.
    I always thought these were cool and informative. I'd love to see new charts for Leaf / Volt / Tesla / ?? modules. Seems like it would be a good resource for elmoto to pin in the forums. Anyone up for the task?

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