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  1. F

    Will this work?

    As above, the advantages is not in the resistivity of the material, but rather the large CSA. Sculpt those same busbars from standard nickel sheet and spot weld directly to batteries, and you will have a winner.
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    Using a tool battery as a power supply

    Thanks for sharing :thumb: This wouldn't be beneficial, and with an additional current-limiting device, would actually be "lighter duty" than native 12V. If you need higher power or capacity, simply use the higher capacity packs and/or parallel them.
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    60v charger to charge 72v battery with a booster

    No
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    Using different cell batches in battery packs

    Unlikely to be an issue Actually best to distribute equally among parallel groups
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    US vendor for large heat shrink tubing wrap?

    Just cheap generic on Amazon and eBay McMaster-Carr if you need materials to spec
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    18650 vs prismatic - which is safer?

    I don't think it's that simple. And maybe I'm mentally oversimplifying, but I think the risk of high number of simple, reliable connections versus the low number of complex, failure-prone connections tends to balance out. I think it's a wash, and not a significant factor in answering the...
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    Can voltage drop damage a lithium battery?

    Not just can -- all but assured it damages the cell.
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    Single cell voltage isolated chargers?

    Sounds like you're looking for a node charger RCX BC168
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    18650 vs prismatic - which is safer?

    Agreed, but we're holding all else --including quality of interconnects-- equal. Spot-welding cylindrical cells is done reliably in third-world countries by the hundreds of millions, maybe billions? Non-solderable foil-tabbed automotive prismatics that are to be laser welded have at least as...
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    Charging an Electric Battery with Gas (a car does this)

    No, I mean ICE generator / ICE traction motor Either design requires both a electric motor and ICE, so that point was a wash Only with inefficient traction ICEs coupled with early (underpowered) EV powertrains at the high power (density) required for freeway driving. Also the Nissan e-POWER...
  11. F

    I am trying to figure out expected miles on my pack

    71V / 21s = 3.38V/cell = around 5% SoC 32mi * 5% = 1.6mi more https://www.diyelectriccar.com/threads/chevy-volt-soc-curve.168906/
  12. F

    18650 vs prismatic - which is safer?

    As above, other factors predominate But all else equal, cylindrical cells are safer
  13. F

    Charging an Electric Battery with Gas (a car does this)

    Generator = motor, so this is added either way Direct DC generators are available with integrated chargers It's not more efficient, hence the adoption of series hybrids. Running the ICE at peak efficiency as a generator more than offsets the conversion losses if you're already carrying an EV...
  14. F

    Charging an Electric Battery with Gas (a car does this)

    Probably not 52V, but plenty of 48V gas generators for charging
  15. F

    Charging an Electric Battery with Gas (a car does this)

    This would be terribly inefficient and subject to failure.
  16. F

    Strategies to increase range while on road (you can't use a gas station)

    As above, -increase Wh -decrease Wh/mile -- this varies by an order of magnitude
  17. F

    18650 fire!

    Seriously? -Aliexpress pack is invariably salvage or knockoff cells (or both :lol: ) and thus suspect -Pack was overdischarged, thus unbalanced -- both conditions are unsafe --Bulk charger did not properly detect/prevent unsafe charging of overdischarged pack ---Unbalanced cells would have...
  18. F

    Low Speed, High Torque Hub Motor?

    Assume 250rpm @ 48V: Kv = 250rpm / 48V = 5.21rpm/v Kt = 60/2π/Kv = 60/2π/5.21 = 1.83Nm/A torque = 1.83Nm/A * 7.5A = 14Nm speed @ 250r/m w/ 380mm (15in) diameter: circumference = πD = π*380mm = 1193mm 250r/m * 1193mm/r = 298300mm/m = 0.2983km/m = 18km/h Kv still too high / Kt still too low
  19. F

    How to charge bike battery to only 80% ?

    Docware's cell characterization tests are unrelated to john's blanket "3.65-4.10V" directive. It's not bad advice, but it's even more arbitrary than "only charge at 0.5C and discharge at 1C" is. It all depends on individual application. Degradation is influenced as least as much by calendar...
  20. F

    Low Speed, High Torque Hub Motor?

    It's not at all backwards if he has existing design constraints. He's obviously not designing from scratch...
  21. F

    How to charge bike battery to only 80% ?

    Can you share a reputable source for this? Would be great to save for future reference on similar topics. TIA
  22. F

    How to charge bike battery to only 80% ?

    High voltage is what ages cells, and percentage of voltage is used in the literature. Actual voltage limit as implemented by OEM is just an abstraction/application of percentage of voltage. Percentage of voltage is perfectly fine, if not ideal to use, since it allows estimating cell cycle life...
  23. F

    good balance charger recommendations please

    I highly recommend exploring node charging as a better method of balance charging. RCX BC168
  24. F

    How to charge bike battery to only 80% ?

    This is not the standard or correct method of calculating or describing SOC utilization, specifically because it is cumbersome and abstracts away the actual SOC window. SOC window terms refer directly to percentages of the LV and HV limits established in the cell datasheet, such that if the LV...
  25. F

    Hyperion Eos repair. anyone had success????

    If the design is marginal, higher output fans w/o grills may help. If you're already replacing FETs, uprated FETs direct from a reputable source.
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