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  1. O

    Technical info on spot welding?

    I'm looking into getting four malectric, open source car battery powered spot welders. More info on them here: https://malectrics.eu/product-category/arduino-spot-welder/ They have an "auto pulse" mode where they automatically fire a set time after an electrical connection is sensed. I need...
  2. O

    Anyone ever weighed a Tesla battery module?

    I have it from Okashira that they weigh 60 to 52 pounds, with the newer ones being lighter, this means only 14% of the mass of a new module is non-battery, pretty good. Thank you Okashira!
  3. O

    Anyone ever weighed a Tesla battery module?

    The mass of a whole pack was obtained by Car and Driver in 2013 but the pack includes a shield on the bottom and plays double duty as a structural element in the car. A better measure of the energy density Tesla has achieved would be module level mass. I know at least a couple users here have...
  4. O

    Having a hard time soldering A123-26650-M1A batteries

    That sounds like a giant pain :evil: If you didn't catch it from the first post (don't want to be an a@@ but most people haven't heard of this stuff) silver epoxy is itself very conductive, easily conductive enough for a123 cells at 25C discharge (and don't get the cheaper stuff! It has ~10x...
  5. O

    Having a hard time soldering A123-26650-M1A batteries

    OP you ever get this resolved?
  6. O

    NMC Lithium modeling with dynamic data - megawatt hours!

    I'm assuming you have the SimuLink Power Systems module? Could you source a new cell that is not in use for pulse discharges?
  7. O

    Tesla Model S 18650 Cell Test Data

    :pancake: Somebody is short TSLA.
  8. O

    Having a hard time soldering A123-26650-M1A batteries

    You could try high end silver epoxy too: http://www.amazon.com/MG-Chemicals-Conductive-Extreme-Conductivity/dp/B018AAT4VC/ref=sr_1_7?s=industrial&ie=UTF8&qid=1453580131&sr=1-7&keywords=silver+epoxy Just make sure you keep the bond line thickness low, keep it under pressure for half a minute...
  9. O

    Good LifePO4 these days?

    That GBS system will work fine I think, but I'm not sufficiently familiar with the cycle life and safety specs on it to give a good comparison with the LFP options.
  10. O

    Good LifePO4 these days?

    Cylindrical and prismatic cells are both still used, you won't get laughed at for form factor choice (not for any good reason anyway.)
  11. O

    is this good news? (Graphene battery)

    Gravimetric energy density almost identical to a123 26650s, price higher in quantity, less safe... But that cycle life and fast charge capability sure look interesting, and perhaps these cells are not less safe, one can hope...
  12. O

    Good LifePO4 these days?

    Round cells handle internal pressures better which is fairly negligible as factor.
  13. O

    Good LifePO4 these days?

    There are a number of LFP automotive battery replacement packs that are essentially 12V LFP packs. These guys have a solid BMS though the 100ah is $1300... I doubt you'll get cheaper: http://www.lithiumion-batteries.com
  14. O

    Good LifePO4 these days?

    I second A123, you can get them here: http://www.a123batteries.com As to whether they can be balanced, yes of course they can; but you're either going to have to pay for a module with built in BMS, add the BMS yourself, or do manual balancing.
  15. O

    Good LifePO4 these days?

    You looking for individual cells that you plan to assemble yourself?
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