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  1. BatteryMooch

    Tabless design cylindrical cells tests

    Interesting…it’s not just flux. It’s essentially solder + flux.
  2. BatteryMooch

    Cycle life tests of High Energy density cylindrical cells

    Looking forward to this! Batch/date code OH1T did very well in my testing but the P85T code cells I had seemed to be a lower grade…noticeably worse performance.
  3. BatteryMooch

    4680--4695?

    Ni-plated steel is our friend. 🙂
  4. BatteryMooch

    4680--4695?

    Laser or ultrasonic welding.
  5. BatteryMooch

    Copper Tape?

    Haven’t tried to quantify it (as a separate cooling mechanism). You’ll have to do some testing for the applications/conditions you’re focusing on.
  6. BatteryMooch

    Copper Tape?

    It’s not possible. You cannot stack two strips directly on top of each other, double the current, and measure the same temp rise. When you stack two strips you decrease the surface area exposed to ambient air. This reduces convective and radiative cooling. Though the latter is minimal with bare...
  7. BatteryMooch

    Tabless design cylindrical cells tests

    Yea, definitely not a tabless pack (that’s the 18V+). 🙂 Those are P42A’s.
  8. BatteryMooch

    Tabless design cylindrical cells tests

    The calibrated thermocouples? Sorry, I don’t remember where I bought them, it was years ago (I stocked up when I actually had some spare cash 😂). One of the big lab equipment companies though.
  9. BatteryMooch

    Tabless design cylindrical cells tests

    Along with @Pajda’s description of his low thermal resistance setup this is a great opportunity for all to see how three different setups can all get great comparative data but slightly different results. The details matter. 🙂 And even if any setup has an offset (due to voltage drop) or slower...
  10. BatteryMooch

    Tabless design cylindrical cells tests

    I agree. The tiny bead-welded and “butt joint” welded thermocouple tip types are necessary for good thermal coupling and short response time. Even the “flat” thermistors, with a relatively fast (for a thermistor) response time are pretty bad compared to a decent thermocouple. And you are so...
  11. BatteryMooch

    Tabless design cylindrical cells tests

    Ahh…so not the spot-welding some might use…yea, that can weld on some serious copper to sink more heat. Wow, very jealous!
  12. BatteryMooch

    Tabless design cylindrical cells tests

    IMHO what type of holder and the gauge of the connected can have a big effect on the final temp, i.e., the total mass of the contacts. Standard 0.2mm copper strip isn‘t going to pull a lot of heat away on its own but it could sink more than some compression holders, especially if large gauge...
  13. BatteryMooch

    Parallel use of capasitors.

    No sagging needed. The voltage spike is created when the current flow stops but wire/circuit inductance wants to force the current flow to continue. The voltage rises in an attempt to do this, creating a spike. It’s all about the inductance, not the sag. More inductance and/or more current =...
  14. BatteryMooch

    Copper Tape?

    The laser or ultrasonic welding that’s typically used is pretty unreachable for most IMO. 🙂
  15. BatteryMooch

    Copper Tape?

    TBD when I do the teardown. Bosch is huge though.
  16. BatteryMooch

    Copper Tape?

    …and @YoshiMoshi…all copper interconnects (but thin!), more photos (in the tabless testing thread) when I do the teardown to determine what cell is used.
  17. BatteryMooch

    Tabless design cylindrical cells tests

    Thank you…awesome. 🙏 Looks like about 4%-5% more capacity retention at 500 cycles for the 40T3? Okaaaayyyyy….so they definitely didn’t use the P42A for cycle life. 🙂
  18. BatteryMooch

    Tabless design cylindrical cells tests

    The P42A can perform a bit better than the 40T3 but it might be other design changes in the pack that reduced the overall IR? The P42A has a min capacity spec of 4000mAh so they might be going off that? Underrating a touch and simplifying the number can help with marketing too. Do you remember...
  19. BatteryMooch

    Copper Tape?

    - Built to a price point and not a performance spec? - The vast majority of their customers wouldn’t notice the difference if beefier connections were used? - Most people don’t use their packs hard enough to overheat them? - The warranty fine print might have enough provisions to keep pack...
  20. BatteryMooch

    Tabless design cylindrical cells tests

    I received the pack (partially disassembled) with those mystery cells and it’s the standard cell 18V pack, not the tabless cell 18V+ pack. I suspect that these cells will indeed be regular Molicel P42A’s but I’ll be able to test them this weekend.
  21. BatteryMooch

    Copper Tape?

    You need to properly address all aspects of good pack design and protection, physically and electrically. The BMS can certainly be used for over- and under-temp protection (and should) but it will be with a thermistor and multiple ones should be used for larger packs and they must be properly...
  22. BatteryMooch

    Tabless design cylindrical cells tests

    The SA10 4Ah 18650 has a 12A cont/20A pulse rating but, yea, the AC IR is 25mΩ (max)…pretty high. Actual cycle life test results will be interesting to see…some day. I looked around and couldn’t find that power tool test…do you remember where you saw it?
  23. BatteryMooch

    Copper Tape?

    Sorry, never tried to calculate it. What were you considering using it for?
  24. BatteryMooch

    Thread for new battery breakthrough PR releases

    I always like to remember that any company that says “NMC” in their title along with “Lithium Polymer” and “solid state” may not be a trustworthy source for energy density figures. 🙂 I’m assuming it’s the standard exaggerated spec. But if it’s not there are a few ways the pouch can have good...
  25. BatteryMooch

    Tabless design cylindrical cells tests

    In response? No. Cell development takes years, literally years before it’s ready for full production. But I’m sure there are already cells in development by multiple companies that will all be vying for the same market segment as the JP30.
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