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  1. fechter

    60v 1500w Chinese controller problems

    You can try measuring the voltages on the throttle wires when it's on. Measure against ground or battery negative. You should see 5v on one wire and the signal line should go from about 1v to 4v as you advance the throttle. One wire is ground, so should read zero.
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    Mxus 3k V3 - Clicking / clunk sound when changing direction. (regen/throttle)

    Possibly the motor stator came loose from the axle.
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    Throttle response changed after increasing battery voltage

    One thing that comes to mind is there may be a significant voltage drop in the ground wire going to the throttle. You could try measuring voltage between the throttle gound (at the throttle connector or inside the throttle) and the battery negative when it's turned on. This should be zero volts...
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    BBS02 very stiff and generates power when bike rolled backwards

    That's normal behavior for a BBS02. Going backward, the freewheel clutch allows the motor to spin, which will generate power. The amount of resistance will depend on the load from the tail light. If you disconnect the lights, the resistance should be less.
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    Chain jumping off main chainwheel

    Possibly the chain itself. I had one where a link got stuck and didn't pivot which caused it to jump sprockets. Make sure each link pivots smoothly.
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    Sondors MSX throttle "sticking" power trickling.

    Right. You should be able to make a generic throttle work, but the wire colors most likely won't match and you'd have to figure out what each of the wires does. There's a 5v supply, Ground, and the throttle signal. You could possibly "fix" the existing throttle by putting a resistor from the...
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    Hub motor troubles -- possibly Hall Sensor -- not sure how to properly test

    Is the 3 pin connector the only one coming out of the motor? If so, it would appear the motor doesn’t have hall sensors. You can use a multimeter to measure resistance between the pins coming from the motor. It should measure essentially zero ohms between any two pins.
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    watersnake slither on 4s li-ion?

    I wouldn't worry too much about it. Once you start running it, the battery voltage is going to drop and get below 14.5v fairly quickly. I think the failure mode would be overheating of the windings or brushes. Another approach would be to drop the voltage using a big DC-DC converter, but that...
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    Bamboo Treecycle

    From a Google search:
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    Mod this charger 40v down to 12v

    You could try it, but my guess is you'll run into the same limitation. On Meanwell power supplies, they usually adjust the low side of the divider. This way if the pot wiper goes open, the voltage drops instead of going too high. With fixed resistors, that's not an issue.
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    (Another) pre-charge circuit?

    I'm all for using available materials, especially when the price is right. What are the squares with "in, out, gate, norm open"? Personally, I would avoid using a pushbutton for the precharge. Too much chance of something getting switched out of sequence. Also, did you test whether you can...
  12. fechter

    (Another) pre-charge circuit?

    I'm not sure I'm following everything in the schematic, but I see one contactor for the precharge, and two additional contactors. Normally I'd only use one because they're big, heavy, expensive, use signficant power and are a potential failure point. One is enough to break the circuit. Are the...
  13. fechter

    Mod this charger 40v down to 12v

    The next best guess would be these resistors: They look like they're in parallel. Try removing one and see what that does. You might be able to remove both of them and use a pot. There may be a limit to how low the supply can go and still function properly. I'm being lazy and avoiding tracing...
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    Was bound to happen?

    California county takes unprecedented step of banning throttle e-bikes for kids California county takes unprecedented step of banning throttle e-bikes for kids I see these kids all the time around here. Riding wheelies in the middle of traffic, no helmets, etc.
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    la Nina rears her ugly head

    Things are approaching maximum greenness for this year. It will turn brown soon enough. I have a chance for less than 0.1" Sunday night. That might be the last for this season, we'll see.
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    Mod this charger 40v down to 12v

    It's a little hard to see everything in the pictures, but the two resistors pointed out appear to be in series. These look like the voltage sensing part. Also the "431?" in the picture, take a look at the number on the part and see what it is. I suspect that is the 2.5v voltage reference. Try...
  17. fechter

    (Another) pre-charge circuit?

    But the contactor isn't going to prevent a controller FET short from locking up the motor. Normally you wouldn't put any kind of switch between the controller and the motor. But as a contactor, yes, FETs tend to fail shorted, so may not be as safe as a mechanical relay. The power wasted by...
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    75 Rupp Centaur

    Just for reference, here's one that's fully assembled. This one belonged to Elvis Presley. I wonder what the turning radius is on one of those?
  19. fechter

    Mod this charger 40v down to 12v

    Most likely you can do that. It would be necessary to trace out at least part of the circuit. Can you post a picture of the back side? Somewhere there should be a voltage reference and a divided output voltage going to one of the sections of the 324 that regulates the voltage.
  20. fechter

    (Another) pre-charge circuit?

    For that voltage/current level, you could use FETs instead of mechanical relays. Smaller and way less standby current draw.
  21. fechter

    (Another) pre-charge circuit?

    How many amps are you planning to run? If you want to really overbuild it, use an Arduino or similar to control the logic for the relays so nothing can blow up. User just needs an on/off switch. Then you can do things like preventing the main contactor from closing with a shorted load and...
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    la Nina rears her ugly head

    0.5" between yesterday and today. Mostly a bunch of drizzle, but a few short intense spots. More coming tomorrow but not much. I'm ready for the dry season now.
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    Bike dead with 10 error

    Possibly the PAS sensor shorted and pulled down the 5v supply, which would also cause the comm to fail.
  24. fechter

    Inherited A2B metro

    It looks like it has an external controller. It's very easy to put a battery on the rear rack and run it, but the battery inside the frame is probably toast. I have one that looks very similar that I should probably sell off since I don't ride it anymore (I have better bikes). I agree you could...
  25. fechter

    Defining a straight solar EV

    Lithium Titanate batteries are probably the most practical for this kind of application. A bank of supercapacitors could work but would be much more complex due to the wide voltage range they would need to use. If the total storage capacity of a small battery isn't enough to capture all the...
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