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Thread: 4680 cell lights

  1. #1

    Default 4680 cell lights

    After Tesla gets the 4680 cells going, will we see some 4680 lights? That's 1.8" wide!!

    I'm mostly joking, but not completely. 9000mAh!
    GOOD TINT!

  2. #2
    Flashaholic*
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    Default Re: 4680 cell lights

    I dunno. That's even fatter than a D cell. But, when I measure my BLF Q8, its body is fatter than 2", so I can see the 4680 being useful in a light like that. Assuming the 4680 can deliver high current.

  3. #3
    *Flashaholic* idleprocess's Avatar
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    Default Re: 4680 cell lights

    I would sure like to see what the 4680/46800 cell can do.

    I did some theorycrafting a while back:


    Spitballing, but assuming average Ah/cm™ relative to other high-density 18650/26650/21700 cells, I guesstimated 25Ah in that formfactor for high-density cells.

    The initial peak current estimate for a potential high-power cell using a similar metric (peak current per cm³) relative to other high-power 18650/26650/21700 cells was ... almost certainly unrealistic. Even scaling by the surface area:volume ratio relative to 18650 the peak current value was still seems unreasonable.

    Reality is that any 4680s produced for Tesla will be principally high-density cells. High-current versions on the same order as 18650/26650/21700 seem a bit unlikely to emerge - the low surface area:volume ratio is not conducive to heat removal.

    2C would be a good discharge rate for a high-density version, meaning that such a cell could hypothetically spit out approximately 180 watts for 30 minutes. I could certainly handle a stubby ~1D formfactor light with ~90Wh on tap - even a 1C peak discharge would be more power than most high-power cells can deliver and that level of discharge is unlikely to stress the 4680 very much. 2 in series would be spectacular.

    I've seen some sources bafflingly claim 9Ah for the 4680, but that would be a huge step backwards on density, the exact opposite of Tesla's goal with a mere 31kWH pack (960 * 3.6V * 9Ah) - merely ~2x a 21700's capacity while being ~5x times the volume. Reversing Sandy Munro's math, I get slightly more than 25Ah:
    • Model 3/Y 21700 : 75kWH pack / 4416 cells = 16.68 Wh / 3.6V = ~4.7Ah
    • Model 3/Y 4680 : 87kWk pack (16% more range = 16% more energy) / 960 cells = 90.63 Wh / 3.6V = ~25.2Ah
    I apologize that this letter is so long; I did not have time to write a short letter

  4. #4
    Flashaholic* fivemega's Avatar
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    Default Re: 4680 cell lights

    Battery holder of parallel 3x18650 has diameter of 44mm and length of 83mm which fits in this body with outside diameter of 50mm and capacity of (3x3500=10500)mAh. Capacity of single 46800 cell should be much more than 9~10 Ah

  5. #5
    Flashaholic* orbital's Avatar
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    Default Re: 4680 cell lights

    +

    Tesla was saying their new cells are specifically designed for high Amp currents.

    Would I want a 2 x 46800 light?? no , yes , no , kinda

  6. #6
    *Flashaholic* idleprocess's Avatar
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    Default Re: 4680 cell lights

    Quote Originally Posted by orbital View Post
    +

    Tesla was saying their new cells are specifically designed for high Amp currents.

    Would I want a 2 x 46800 light?? no , yes , no , kinda
    With the 4.6x reduction in cell count, they need at least that increase in absolute current per cell. But they still need good energy density for range.
    I apologize that this letter is so long; I did not have time to write a short letter

  7. #7

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    Default Re: 4680 cell lights

    I can see using a 4680(0) battery in a light but only with an on board protection circuit. A shorted battery of that size is like a hand grenade.
    I wouldn’t mind a few of them in series to replace the lead acid monster in my car though; or maybe an e-bike.
    Great spirits have always encountered violent opposition from mediocre minds.
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  8. #8
    *Flashaholic* ChrisGarrett's Avatar
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    Default Re: 4680 cell lights

    Quote Originally Posted by jabe1 View Post
    I can see using a 4680(0) battery in a light but only with an on board protection circuit. A shorted battery of that size is like a hand grenade.
    I wouldn’t mind a few of them in series to replace the lead acid monster in my car though; or maybe an e-bike.
    Who the hell needs a light with that big a cell and no true upside in current handling?

    Buy a couple of Sony 5As and call it a day with whatever light you choose.

    Chris
    Convoy: S2, S2+, M1, M2, Fenix: P1D, PD32, HL30, ET: D25C Ti, SF: 6P, ZL: SC-600, Klarus: P2A, Jetbeam: BA-20, Icon: Rogue 1, L3: L10, Xeno: E03, ShiningBeam: I-Mini, Olight: i3s, SWM: D40A, M11R, V11R, Maglite: 6Ds, MMs, Solitaires, LaCrosse BC-700, Maha C-9000, XTAR VP2, MP1S, XP1, MC1+, WP2 II, NiteCore i4, v2.

  9. #9
    *Flashaholic* idleprocess's Avatar
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    Default Re: 4680 cell lights

    Quote Originally Posted by ChrisGarrett View Post
    Who the hell needs a light with that big a cell and no true upside in current handling?

    Buy a couple of Sony 5As and call it a day with whatever light you choose.

    Chris
    Slapping an 18650 protection circuit limited to 2-3A would be dumb. However considering the likely capacity of 25Ah, limiting such a beast to mere 1C would still mean 90W of output potential.
    I apologize that this letter is so long; I did not have time to write a short letter

  10. #10

    Default Re: 4680 cell lights

    Sounds like a nice cell to make a 12 volt battery for a really bright h.i.d. spotlight or even a compact l.e.p. (light emitting plasma) light.

  11. #11
    *Flashaholic* ChrisGarrett's Avatar
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    Default Re: 4680 cell lights

    Quote Originally Posted by idleprocess View Post
    Slapping an 18650 protection circuit limited to 2-3A would be dumb. However considering the likely capacity of 25Ah, limiting such a beast to mere 1C would still mean 90W of output potential.
    I’m not saying that there aren’t applications out there, for some people, just that personal lighting apps probably aren’t that practical and as somebody who has two Emisar D4s and a 3Tronics triple, we’re already on the cusp of the ‘thermal apocalypse.’

    Chris
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  12. #12
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    Default Re: 4680 cell lights

    Well, some lights, like the BLF GT, take eight 18650 cells. A couple of 4680 cells would actually make some sense in that kind of large light.

  13. #13
    *Flashaholic* idleprocess's Avatar
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    Default Re: 4680 cell lights

    Quote Originally Posted by ChrisGarrett View Post
    I’m not saying that there aren’t applications out there, for some people, just that personal lighting apps probably aren’t that practical and as somebody who has two Emisar D4s and a 3Tronics triple, we’re already on the cusp of the ‘thermal apocalypse.’

    Chris
    The difference in heat management between the D4 and D4S is significant, with the D4S managing not only longer time at peak output but also a greater sustained output. The step up from 18mm to 26mm is slightly more than double the surface area; if we assume a head height equal to the radius the volumetric difference is a bit more than triple. Applying the same metric to 46mm, the surface area is ~3.1x and ~6.5x between 26mm and 18mm respectively with the nominal volumetric difference being ~5.5x and ~16.7x. While this won't scale in a neat linear fashion to passive power dissipation ability, it does suggest that a simple increase in size with resultant additional thermal mass will allow for prolonged operation at significantly higher power than smaller lights.
    I apologize that this letter is so long; I did not have time to write a short letter

  14. #14
    Flashaholic* orbital's Avatar
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    Default Re: 4680 cell lights

    +

    If you have a three SBT 90.2 setup only running off 8.4V*, you'll need big amps, maybe 20A
    Improved heatsinking efficiency, boards, wiring, everything, needs to be more robust & you'll have one incredible searchlight.

    *from two 46800 in series.

  15. #15
    *Flashaholic* idleprocess's Avatar
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    Default Re: 4680 cell lights

    Quote Originally Posted by orbital View Post
    +

    If you have a three SBT 90.2 setup only running off 8.4V*, you'll need big amps, maybe 20A
    Improved heatsinking efficiency, boards, wiring, everything, needs to be more robust & you'll have one incredible searchlight.

    *from two 46800 in series.
    Google says the Model 3 can deliver a maximum 371 kW to the motors. Using the back-of-the-napkin figures in post #3:
    • Model 3/Y 21700 : 371kw / 4416 cells = 84 W / 3.6 = 23A
    • Model 3/Y 4680 : 371kw / 960 cells = 386 W / 3.6 = 107A

    Suggests a peak ~4.2C discharge rate.
    I apologize that this letter is so long; I did not have time to write a short letter

  16. #16
    Flashaholic* orbital's Avatar
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    Default Re: 4680 cell lights

    +

    Without looking into it, do you think Tesla jumped right into Polymer tech?

  17. #17
    *Flashaholic* idleprocess's Avatar
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    Default Re: 4680 cell lights

    Quote Originally Posted by orbital View Post
    +

    Without looking into it, do you think Tesla jumped right into Polymer tech?
    From what I read up on their 4680 design, it's conventional li-ion tech with some evolutionary improvements to the existing recipe. Different manufacturing methods allow for a modest increased in density and a nice bump in power delivery so they can greatly reduce cell count per pack.
    I apologize that this letter is so long; I did not have time to write a short letter

  18. #18
    Flashaholic* orbital's Avatar
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    Default Re: 4680 cell lights

    +


    I started this thread last August:: https://www.candlepowerforums.com/vb...ements-thread&

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    Default Re: 4680 cell lights

    Quote Originally Posted by orbital View Post
    +

    Tesla was saying their new cells are specifically designed for high Amp currents.

    Would I want a 2 x 46800 light?? no , yes , no , kinda
    You could smack someone upside the head with it like a Streamlight.
    It ain't easy being me, but someone's gotta do it.

  20. #20

    Default Re: 4680 cell lights

    HAHA the 5-D Maglite. More of a club than a functional flashlight.
    GOOD TINT!

  21. #21
    *Flashaholic* ChrisGarrett's Avatar
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    Default Re: 4680 cell lights

    Quote Originally Posted by markr6 View Post
    HAHA the 5-D Maglite. More of a club than a functional flashlight.
    Yeah, no joke.

    I had two 6Ds when I ran movie theatres here in Miami, for AMC.

    They were intimidating back then.

    Skull crushers, I called them.

    Chris
    Convoy: S2, S2+, M1, M2, Fenix: P1D, PD32, HL30, ET: D25C Ti, SF: 6P, ZL: SC-600, Klarus: P2A, Jetbeam: BA-20, Icon: Rogue 1, L3: L10, Xeno: E03, ShiningBeam: I-Mini, Olight: i3s, SWM: D40A, M11R, V11R, Maglite: 6Ds, MMs, Solitaires, LaCrosse BC-700, Maha C-9000, XTAR VP2, MP1S, XP1, MC1+, WP2 II, NiteCore i4, v2.

  22. #22
    *Flashaholic* idleprocess's Avatar
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    Default Re: 4680 cell lights

    Quote Originally Posted by ChrisGarrett View Post
    Yeah, no joke.

    I had two 6Ds when I ran movie theatres here in Miami, for AMC.

    They were intimidating back then.

    Skull crushers, I called them.

    Chris
    A friend of mine that used to hang out with bouncers claims they can't properly recognize a 5/6D maglight without - ahem - rust stains on the head.
    I apologize that this letter is so long; I did not have time to write a short letter

  23. #23
    Flashaholic* orbital's Avatar
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    Default Re: 4680 cell lights

    +


    Not your grandmas tactical : blind em & then a solid attitude adjust.




    ^ substitute the horse for some jackass

  24. #24
    Administrator Kestrel's Avatar
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    Default Re: 4680 cell lights

    OK folks, back on topic please.

  25. #25
    Flashaholic* fivemega's Avatar
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    Default Re: 4680 cell lights

    These cells can be good choice for Ebikes.

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    Default Re: 4680 cell lights

    Quote Originally Posted by fivemega View Post
    These cells can be good choice for Ebikes.
    That is a great application for something this size, although evokes are supposed to be electronically limited.
    Great spirits have always encountered violent opposition from mediocre minds.
    -- Albert Einstein

  27. #27
    Flashaholic* orbital's Avatar
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    Default Re: 4680 cell lights

    +

    Wouldn't you want 40~60V for a ebike?
    because then you can use a lower KV motor that draws less Amps to make your watts. (lower Amp draw will give longer runtime)

    46800 cells may be rather big, to have enough of them in series, to get at least 40V on a bicycle.

  28. #28
    Flashaholic* fivemega's Avatar
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    Default Re: 4680 cell lights

    Just imagine a battrry pack of like this (1:24 minute) but 8 cells inside each oval bar of bike triangle frame and two of them will make 16 series cells. (16x3.7=59.2V)
    It's also possible to custom made carbon fiber triangle frame box. In this case, battery pack can be replaced when needed.
    We are getting close to two seatter Ebike with long range.

  29. #29
    Flashaholic* orbital's Avatar
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    Default Re: 4680 cell lights

    Quote Originally Posted by fivemega View Post
    Just imagine a battrry pack of like this (1:24 minute) but 8 cells inside each oval bar of bike triangle frame and two of them will make 16 series cells. (16x3.7=59.2V)
    It's also possible to custom made carbon fiber triangle frame box. In this case, battery pack can be replaced when needed.
    We are getting close to two seatter Ebike with long range.
    +

    Like the idea.

    _____

    Last summer I was on my '02 Honda and rode up next to an older woman on what looked like an Ebike. She just just cruzzin down the street by this soccer field area.
    She was going maybe 15mph.
    While riding next to each other, I asked her if that was electric, she said Yes. Then I asked if it was fun,, she smiled & laughed a bit & said 'Yes it is'

    Ebikes are here to stay.

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