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  1. J

    hacking into chinese bms board to get overcharge signal

    The arduino (attiny85) is only connected to +12v from the charger and gnd to the 12v battery and all it does it turn on the full charge led. The controller is actually connected to another 40v pack and I use the 12v pack with dc-dc boost to charge it. So when the 12v pack is cutoff, the 40v...
  2. J

    hacking into chinese bms board to get overcharge signal

    Instead of voltage divider, I use a 5v regulator that has only 1.2uA current draw (quiescent I think its called). So now when the gate is turned on the regulator outputs 5v and when its off it outputs like .3v. I have used this idea for sensor input on other project to detect a 12v signal is...
  3. J

    hacking into chinese bms board to get overcharge signal

    Thanks for the suggestions. I changed the resistor that supplies that power to the gate from 1M ohm to 110k and then used a 120k+22k divider to ground. I get a good signal to the micro now. However before the board consumed 7uA just sitting there, and now the resistor to ground increases it...
  4. J

    hacking into chinese bms board to get overcharge signal

    I am trying to finish up an ebike setup and the last thing that is driving me crazy is to setup a led to indicate the battery is full while the charge is hooked up. My charger is just a dumb power supply and have lifepo4 cells. I am using one of those cheap chinese bms boards that has mosfets...
  5. J

    Any thoughts on investing in this start-up company?

    Diesel exhaust is OK, but some rare case of a fire in a EV we should be more careful? All those soccer moms better not have EVs then right? :roll: Garbage trucks are good too because they are stop-n-go-stop-n-go-stop-n-go, so you can regen, but they run all day, and then have long drives to...
  6. J

    Any thoughts on investing in this start-up company?

    Don't invest in startup companies, invest in yourself. I think there is a big opportunity to convert school buses to electric. Remove the diesel engines. Kids don't need to breath diesel exhaust. There is a company in Sacramento that does this, and our district bought a dozen of their school...
  7. J

    Four wire rotor position sensor? In WheelChair motor

    Got it hooked up for a test. The controller has trouble on start with a load. It shakes a bit before it moves. This is with just one motor powered. Waiting for the cable for the other one. I'm hoping with two motors maybe one will be a better start position. It has about the same top speed...
  8. J

    Four wire rotor position sensor? In WheelChair motor

    Thanks for those links, really appreciate it. I tried to look at them when the system was down. That motor appears to be similiar to mine, has same shape and connector, but different in a few ways. Bu I'd assume the sensor is the same. I just don't know which wire is +5v and Gnd, don't want...
  9. J

    Four wire rotor position sensor? In WheelChair motor

    I picked up a free Invacare Arrow electric wheelchair with dead batteries and a missing joystick control. I am trying to see if I can hack into the motor controller, it uses a MSP430 processor to control the two motors. I could not figure out from the circuit board what the position sensors...
  10. J

    3 phase without 6 switches

    So more thoughts, maybe this thread is just my personal notes.. The switched reluctance motor (SRM) with only 3 switches does not reverse the polarity of the coils, and thus it doesn't change the magnet polarity, which in a normal bldc it will push away the magnet as well as pull in one magnet...
  11. J

    3 phase without 6 switches

    hmm, seems to me would just be simpler put the diodes to go back to the positive rail just like a dc motor controller does, the coil collapse would raise its voltage enough to flow by itself, and the freewheel current then routes into the next coil, but I'm sure I'm confused. So maybe better...
  12. J

    3 phase without 6 switches

    well well it seems switched reluctance motors are replacing inductive motors now since they can be more efficient and controllers are now cheap, no need to run on 60hz main power only. anyway, found another example of a controller, it looks like the diodes are hooked up differently?
  13. J

    3 phase without 6 switches

    I have one of these washer motor stators picked up at the junkyard to prototype with. I know all about blowing up fets..
  14. J

    3 phase without 6 switches

    Thanks, yeah that is pretty much my idea with the "Miller inverter". I get redundancy too with multiple drivers for a wheel subset, so the truck can keep going if damaged from shrapnel or debris. Also less chance of over heating with the coils are off 2/3 of the time vs ON 2/3. I am going to...
  15. J

    3 phase without 6 switches

    Ok, gotta ask this question..I'm building a wheel/hub bldc motor and was thinking can I make a controller that simple cycles through three coils? So instead of delta or star, it is star with a permanent ground at the star. Thus, turn on power to A, then B, then C, then back to A. Now I...
  16. J

    Prius taxi logs 600k miles on original battery pack

    The Prius battery is 6.5ah. The car continues to work until the batteries are down to 1.5ah. The battery pack can be well past dead in terms of capacity and still work. This isn't possible in an EV. A pack with only 25% capacity would not 'work' anymore. The Prius is a gasoline powered car...
  17. J

    Have any enclosed bicycles come out like the elf lately?

    BugE http://www.bugev.net/index.html Has been available for years.
  18. J

    30 FOOT MOTOR CRUISER, what would it need?

    Boats take a huge amount of energy to move at speed. If you go really slow, they need much less. So a fast electric boat is just not a viable option, unless you are just going a few miles and back.
  19. J

    20kWh of energy needed, battery choice advice anyone?

    Then he should join electric-boat-forum.com and start a project on there. I'm building a 64ft solar boat. Life is a very safe chemistry that is a good choice for boats, as weight is not so important. Using thousands of little cells is really only ideal for a company that wants you to pay a...
  20. J

    Investing in Tesla General Discussion Thread

    GM sells the all-electric Spark EV, which apparently is now outselling the Volt, even thought the Spark is only sold in California and Oregon. The Model S is a gross e-polluter, hauling around 4,500 lbs to move a single person. You'd think at least the e-bike people would understand this. What...
  21. J

    Gigafactory Chemistry Confirmed

    Did we know how these batteries are going to be recycled?
  22. J

    Tesla Powerwall $350 / kwh Retail

    Billionaire worship, sad state of affairs in America.
  23. J

    Tesla Powerwall $350 / kwh Retail

    No question lithium batteries are better, although the cycle life claims are just that, claims, I recall the early days claims of 5,000 cycles, what a big lie that was. What maybe you don't understand is that we've had lead forever, its cheap, it works. Having lithium does not suddenly change...
  24. J

    Tesla Powerwall $350 / kwh Retail

    Lead acid batteries have been used in RV and boats for decades, they have no real issue with all that nonsense. In stationary applications, there is even less issues. Musk wants to create low cost lithium batteries, that is great. But this Powerwall is a stretch, and not a single bit of...
  25. J

    Tesla Powerwall $350 / kwh Retail

    And what prevents using a lead acid battery pack for this power storage, which is half the price and has been available, I dunno, for about 100 years already. And is completely safe and simple, and also HIGHLY RECYCLED. Has Elon announced his factory to recycle his batteries?
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