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Thread: 18650 Format pack options

              
   
   
  1. #1
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    18650 Format pack options

    So... I've been playing around with both the A123 pouch cells and a variety of Panasonic, Sanyo and TriPeak (el cheapo ****e-o) 18650 options. I'd like to farther source some of the Sony VTC4 highpower cells aswell but haven't gone to the bother yet.

    None of these 18650 options are readily available in small quantities tabbed so I've been making do with a clamping arrangement although I believe it to be suboptimal and don't want to draw too many conclusions until I get past that - hence the plan to build a small spot welder in the near future (there's plenty of different takes on the best way to go about this online).

    In any case - to the inferred point of the post... I've been crunching a lot of numbers with respect to battery configurations of late and there is simply nothing out there with the energy/power density of these 18650's. They pack tighter and lighter than anything else on offer although from what I've played with so far, they also heat up a lot more than pouch cells and as such would require allowance for breathing space in any pack design. A pack would also require ~1600 of them for ~10kWh and that in turn would require significant compromise in any battery monitoring system. I'd favour simply monitoring the series banks and using relative sag as a "dud" cell indicator.

    I'm hoping to start playing around with them in banks of 15-30 or so in the next few months on a programmable load to see how they tolerate being hooked in parrallel, how much abuse they'll take and how any failures arising present themselves, however I expect they'll actually perform quite well if they're properly tagged and balanced.


    SO - has anyone else been playing with these cells at all yet and how are you getting on with them?

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    Moderator Nuts & Volts's Avatar
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    I agree. 18650 have the best offering of energy density by weight and volume and are very good on power as well. The common form factor and ability to trade out energy for power without redesigning a pack is pretty clutch.

    Ive tested so Sony, Panasonic and Samsung cells and was most impressed with the Sony cells. If I didn't have the EIG cells I would go 18650 for my bike. Just need a lot of design, a spot welder and time to assemble.

    It's tough thou when Enerdel and Nissan cells can be had for so cheap. I still want to design and make an 18650 pack some day.

    Sent from my SCH-I605 using Tapatalk
    Whats under my tank may shock you!!! R6 Build, Blog/, [/URL] OSU Current webpage

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    Electric Warrior CaptainKlapton's Avatar
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    Interesting. If I had the equipment, I would probably do the same. You may have already seen it, but this is the best resource for that form factor I have come across.
    "Never let schooling interfere with your education."
    -Mark Twain

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    yeah, I used it heavily in my initial selections but it doesn't list the Sony offerings on there at all oddly enough.

    It's a great resource though.

    N&V, how did you manage to get your hands on the EIG cells? They're away up there on the hit list as well - very impressive performers on paper but seemingly unattainable over here.

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    Senior Member jonescg's Avatar
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    Order them direct from EIG on Korea. Minimum AUD$100 each though

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    Moderator Nuts & Volts's Avatar
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    Quote Originally Posted by Spoonman View Post
    yeah, I used it heavily in my initial selections but it doesn't list the Sony offerings on there at all oddly enough.

    It's a great resource though.

    N&V, how did you manage to get your hands on the EIG cells? They're away up there on the hit list as well - very impressive performers on paper but seemingly unattainable over here.
    I know a guy. No these are used cells that are about 4-5yr old now that were old stock from when a company switched suppliers. That's about all the information I know about them. Came from Cali I believe. Traded a few hands now too. If you do some forum searching you can find more of the details.

    Anyways my favorite 18650s are the Samsung INR18650-25R (just now being released), Sony US18650VTC4, Sony US18650NC1, and Sony US18650V3.
    Whats under my tank may shock you!!! R6 Build, Blog/, [/URL] OSU Current webpage

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    Member mistercrash's Avatar
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    I've been using salvaged 18650 Sony cells from Makita tool packs for a couple years in a scooter I use everyday to go to work. Pretty tough little bastards from what I've experienced. I want to build a bigger battery so I looked at many other cells out there, I always come back to making plans using 18650 cells. Next time I will go with new cells, I'm pretty set on Sony US18650NC1.

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    Empulse R #24 frodus's Avatar
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    I've welded over 1000 26650 batteries, twice each end, both ends, and I'd never wish that on anyone doing the labor themselves manually. Its a huge pain in the ass and after all was said and done, it wasn't really worth it.
    Travis

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    The main things to watch out for on 18650s is the integrity of the weld, and adequate cooling. Ideally, you should try to keep them below 115F or so. They'll run fine hotter, but you start getting into some serious cycle life degradation. There are some other cell manufacturers out there besides those listed here that produce very nice cells at a pretty decent cost. Just becomes a matter of what you want capacity, performance, and reliability wise.

    On the BMS side, you're perfectly fine monitoring just the series modules rather than individual cells. Just make sure its a decent system that you can keep a good eye on your temperatures with.

    Assembly wise, if you choose to solder, please keep in mind that sinking too much heat into the cell can do some not great things to the cell. Best to use a bigger iron that you can quickly make the joint with. Preferable to spot weld though.

    Dicey

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  13. #10
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    Hi guys,

    here is some pictures of prototype 18650 cell battery kit.One smart guy want's to make it but have problem to find who can do nickel sheet cuting with laser.

    http://e-motion.lt/2013/12/12/akumul...ndriniu-celiu/

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