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  1. PaulD

    Ways to use a cassette with a 10kw mid drive?

    If you're considering 10kw, I wouldn't gear the motor to spin your chainring at typical pedaling cadence.
  2. PaulD

    Ways to use a cassette with a 10kw mid drive?

    This is an old thread, but there are a number of ways to improve the odds of your cassette and freewheel surviving very high power. Use only the sprockets that are 16T or larger Use a shift sensor - generally side loads during shifting are what kill your chain Have a freewheel on the motor...
  3. PaulD

    Angle grinder resistant bike lock; Litelok X1

    Cool. Looks really tough. This one was shown at the Sea Otter that has a "diamond ceramic" coating: https://bikerumor.com/onguard-rock-solid-u-lock/
  4. PaulD

    Bikeon, "cassette drive" torque sensing motor

    It looks like there isn't a freewheel in the system to prevent the chain from over-driving the pedals. So, if you stop pedaling suddenly, is the motor and gearbox inertia going to throw your chain off the chainring or break the derailleur? Also, does that torque sensing device work in all gears...
  5. PaulD

    Rad Power Batteries are now UL certified and fully potted

    UL 2271 does not have any puncture or thermal runaway test. It is mostly electrical and software tests to ensure the BMS functions properly. The mechanical tests are shock and vibration (similar to UN 38.3), drop, and a few others. The ingress protection tests are very lax. There are also a...
  6. PaulD

    PaulD's lightweight mid drive development

    Going to 48V would increase the crank/motor speed by 33%. That is more than it is designed for. V4 will be very similar to V3. Off the shelf low offset JIS square taper ebike cranks are compatible. Miranda makes 155mm i believe.
  7. PaulD

    PaulD's lightweight mid drive development

    - I'll have an update with new pricing in the next few months. And only 36V batteries are compatible. Higher voltages result in motor and crank speeds that are too high. - No hot rodding allowed :-) There isn't much thermal overhead, and with a small battery more power is just going to drain...
  8. PaulD

    PaulD's lightweight mid drive development

    122mm must be the BB spindle length, not the q-factor. Even pure road bikes have 150mm+ q-factor. You need to add the offset from the crank arms. At this time, the numbers I mentioned above are the only option. This is limited by the torque sensing BB.
  9. PaulD

    PaulD's lightweight mid drive development

    Q-factor is about 180mm for a 73mm BB. Q-factor for a 68mm BB is about 175mm. Offset is 3mm towards the driveside. If you use an extra pedal washer or two on the non-drive side that would be pretty close to symmetrical. More info is here: Mid drive kit — Revel Propulsion Ebike Mid Drive...
  10. PaulD

    PaulD's lightweight mid drive development

    The short answer is yes. I do still plan on making another batch. I can't pinpoint the date yet, but it will be this year. I'm bogged down with a few big projects right now.
  11. PaulD

    Growing pain with ebikes.

    UL may weed out the worst of the junk, but there are still some shady batteries that get certified. If you've ever seen the inside of a UL certified Ecotric battery, it looks just like any other super cheap battery, except there is redundant circuit protection in the BMS. It doesn't matter if...
  12. PaulD

    Dynapack battery BMS wake up? Motocompacto battery dead

    I think that makes sense. When the BMS triggers that fuse, it ties the heater to ground, which puts pack voltage across the heater, which means after triggering, the output side of the fuse could be tied to ground, and the battery side would of course still be connected to battery positive.
  13. PaulD

    Ampy: Open source python display/interface project for ASI controllers

    Would you use "remote assist mode" address 506?
  14. PaulD

    Can anyone identify the name of this battery connector?

    This might be it, but you should check the dimensions. Suzhou Cusmade Electronic Technology Co., Ltd. Is there any branding molded into the connector?
  15. PaulD

    [$89 plus shipping. USA BASED] 48v 15ah 720wh 60A Li-Ion Battery, 2500 mAh cells, 13s6p configuration

    Woah. Problems with USPS?? That battery is almost 10X bigger than the legal limit to ship via USPS. Please don't ship batteries illegally.
  16. PaulD

    Is there a reliable torque sensor?

    The Erider relies on strain gauges. I don't think this is inherently bad. Sensitivis certainly doesn't think so: Strain-Gauge & Magnetostrictive Sensor Comparison I think perhaps the Erider has some design and QC issues. I've replaced a few on customers bikes, but most of them have 1000s of...
  17. PaulD

    Is there a reliable torque sensor?

    I don't have much data on these, but the dual sided magnetoelastic sensors that come from companies like Autorq, Bafang, Hyena, Mivice, PD, etc, seem pretty reliable. Not sure if they all come out of the same factory or if they are just stealing/ licencing each others designs. I know some ride...
  18. PaulD

    18650 voltage but no continuity

    I would guess that group of cells got overcharged, and the CID (current interrupt device) got triggered in both cells. A voltage may still be present at the terminals due to a high resistance connection inside the cell(s) if the CID doesn't completely disconnect.
  19. PaulD

    Bosch Powerpack 400

    Do they normally have 2.7 or 3ah cells? If it was under 3, then they would need separate UN certifications for a pack with cells that have more than 20% more capacity. Also, I would assume they would need UL testing for each cell model they use. Although, this IS the company behind Dieselgate...
  20. PaulD

    Make Motor Run Quieter?

    That picture is the stator. You're counting the number of slots, not poles. Look at the rotor and your number of pole pairs is half of the number of magnets on the rotor.
  21. PaulD

    Make Motor Run Quieter?

    I would double check your Kv and pole count numbers. Are you calculating Kv based on the crank rpm? what is the gear reduction from motor to crank?
  22. PaulD

    kWeld - "Next level" DIY battery spot welder

    Thanks, and it's not, but I suppose it wouldn't be terribly difficult to put it on an XY gantry from a CNC router or similar. If I was building hundreds of packs, that would be worth the effort.
  23. PaulD

    kWeld - "Next level" DIY battery spot welder

    Used my Kweld to weld some thermocouples. Not ideal, but seems to work. Paul Daniel on Instagram: "Welding some thermocouples with my battery welder. #battery #science"
  24. PaulD

    PaulD's Experiments with Endothermic Potting Compounds

    Some post mortem pictures of the heater cartridge cell: Nichrome wire wrap The goal here is to choose the trigger that best simulates a real cell thermal event while least affecting the test cell. Some observations: The rupture on the heater cartridge test was right underneath the heater. I...
  25. PaulD

    PaulD's Experiments with Endothermic Potting Compounds

    Well, both cell triggers work. The heater cartridge seems to work much more quickly at 100W than the Nichrome wire wrap. Not sure why. This is the heater cartridge: Both tests resulted in side-ruptures. The cells are Sanyo GA at 4.2V. Starting temp about 35C (it was a hot day).
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