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  1. liveforphysics

    are 18650 safe overchrged from 4,2V to 5,0V?

    Definitely not safe, even if you do it once or twice and don't experience immediate thermal runaway. It would be something to do of your need to win an event or something is worth throwing away the pack after a single cycle, as it will be end of life conditon degraded after. It's also not safe...
  2. liveforphysics

    Electrical Contacts: conduction improving agents

    Unfilled dielectric gels and greases actually measure lower R joints in the last few hundred tests I've ran. I even tried to do my own filled grease with single wall carbon nanotubes and one with micronized silver metal. Both performed worse than unfilled dielectric grease/gel.
  3. liveforphysics

    Suzuki GSX-R e899 K2

    Respect to you upgrading the controller parts yourself. Be so certain you've got the torque clamp load they recommend for all joints. True EV hotrodding! I love to see it my friend! May all your runs on that nice machine stay rubber side down. :bolt:
  4. liveforphysics

    When a Lithium ion cell explodes how much damage can it do? :)

    You realize whats shown in that image is a spot welder not a battery charger right?
  5. liveforphysics

    When a Lithium ion cell explodes how much damage can it do? :)

    Also, on the topic of what it takes for cells to explode, our lab has never failed to initiate thermal runaway on any type of cell we were requested to test. We do fiber optic laser initiation, nail penetration, hot-wire, hot-nail, molten salt bridge, all types of electrical stress...
  6. liveforphysics

    When a Lithium ion cell explodes how much damage can it do? :)

    Our website has a handful of podcasts that mention some of these topics. Condensed version is I like to wire bond my cell interconnects, and then pot them in a polymer with intumescent properties loaded with a low activation temperature (~105degC) thermal decomposition endothermic filler in the...
  7. liveforphysics

    Joby eVTOL

    Wright brothers props were efficient only because they were spinning 350rpm with 6hp going into a large disc area. Huge respect to you PaPaSteve, I don't know if we ever met in person at Joby, but the propeller is 95% of the design magic in a VTOL being practical to use in urban environments...
  8. liveforphysics

    Joby eVTOL

    They are crazy quiet for a propeller craft. More quiet than being near a busy highway. So much love and respect to Joby and there incredible team of premium engineers and scientists to come so far in perfecting EV VTOL. Joben has been a major inspiration and influence in the path my life has...
  9. liveforphysics

    are 18650 safe overchrged from 4,2V to 5,0V?

    dree0rTr1HM Around a decade ago I was finding out these answers as a hobby for fun. Now we find out these answers for global EV industry, but inside 1.5inch thick 316ss ARC calorimeters with gas samplers and scrubbers on the byproduct gases, and with excellent PPE including powered...
  10. liveforphysics

    HESC V1 150v 600Amp VESC based motor controller

    In a car you would not want a sensorless system that has equal chances of going backwards as forwards when it begins to get rotor motion. That's a crude sensorless. A good FOC setup will not go backwards for a rotor tooth before it goes forwards.
  11. liveforphysics

    are 18650 safe overchrged from 4,2V to 5,0V?

    When a cell is fresh (100% SOH), the cell has a generous anode overcapacity in additional graphite, a ratio between 1.2:1 1.35:1 is typical. This enables the cell to age to end of life and not blow up from overcharge while just at 4.2V. The anode ages faster than the cathode, loses capacity...
  12. liveforphysics

    fastest Ev discussion

    Our Plaid Model S family sedan so far is undefeated in every race with anything I've encountered. Sportbikes, hotrods and supercars of all types have fallen prey, however one modded awd lambo stayed beside it for a second or so before it shifted and fell back and eventually became quiet behind...
  13. liveforphysics

    fastest Ev discussion

    You won't take any top fuel records using off the shelf EV powertrain parts. The mass of motor controller alone gets impractical using units that have cooling to be thermally stable. You have time only to coast on heat capacity.
  14. liveforphysics

    fastest Ev discussion

    Batteries exist now which match the kW/kg of top fuel dragsters. If our RnD biz continues to thrive and grow in the next few years, you will get to see all Top Fuel records fall to pure EV power as a company racecar project.
  15. liveforphysics

    Pulsed Charging will speed up the charge, less heat

    Just charge. Regen on a very cold battery at a high SOC% might make dendritic growth. This would be a rare corner situation though.
  16. liveforphysics

    Pulsed Charging will speed up the charge, less heat

    We quantify the threshold of lithium plating by adding reference 3rd electrodes of lithium metal to the cell. We also build cells from coated electrode foils between microscope slides and charge and discharge to observe the current density threshold of dendrite formation. For normal bike...
  17. liveforphysics

    More thinner strands vs less thicker strands

    https://chargedevs.com/newswire/wafios-speedformer-three-in-one-bending-concept-for-motor-hairpin-production/ Many clever ways to get turns while keeping the advantages of bus bar fill factor.
  18. liveforphysics

    More thinner strands vs less thicker strands

    I meant sizes, because of the physical thicknesses of the bus bars used in small stators not letting them ever get thick enough for skin effect to matter. If you're doing motors with stator slots large enough its whole inches across the slot, you may run into skin effect related issues...
  19. liveforphysics

    More thinner strands vs less thicker strands

    The inductance is only different beyond commutation frequency ranges of laminated iron core stators. It's not the PWM frequency the inverter uses to control current that matters for the stator winding inductance, it's the commutation frequency, which for most ebikes is under 400-500Hz, with a...
  20. liveforphysics

    More thinner strands vs less thicker strands

    Even a high reduction mid drive is irrelevant to skin effect in windings. Square winding of the size of the slot is most ideal, with second most ideal being whatever gets the most copper cross-section in the stator slot.
  21. liveforphysics

    Dendrite build up, killing batteries

    I was at AABC too, you should swing by our lab next time you're in SoCal Jack.
  22. liveforphysics

    More thinner strands vs less thicker strands

    At motor inverter commutation frequency range, skin effects are irrelevant in ebike sized motors, and being a solid fat bus bar would always be the optimal efficiency and torque and continuous HP etc.
  23. liveforphysics

    Upcoming Major Changes and Updates to the ES Site

    Congratulations my friend, I hope the transition to new software goes smoothly! Cheers to your family and good luck in e-sailing too!
  24. liveforphysics

    Suzuki GSX-R e899 K2

    Congratulations on getting into the 11's! Thats a huge achievement! The new rim looks beautiful! Excited to see it running with 800Amps.
  25. liveforphysics

    Gonna get a used model S

    I've got friends who bought older Model S and drive them everywhere with no issues. I think you want to to be newer than 2014-2015 for best reliability, but I'm not a model S expert. Used Model 3 is another awesome car. We put 70,000miles on ours and its only needed 1 set of tires and a 1...
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