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  1. jbond

    Bafang or Cute? and freewheel question

    Been going through the same research. Although I want low weight, robustness and freewheel drag is important to me. On that basis, I don't like the look of the way the Ananda/Cute motors have a split axle bolted up inside the hub. It may not be a problem, but it just looks wrong to me. I also...
  2. jbond

    Will a 250w Bafang front hub run ok on 48v?

    But see also this much more recent thread. http://endless-sphere.com/forums/viewtopic.php?f=3&t=20736&start=0&hilit=bafang Several people reporting no gear problems with 48v-20A or even higher.
  3. jbond

    Will a 250w Bafang front hub run ok on 48v?

    What is it about off road and geared hubs that leads to failure? Over-heating shouldn't be a problem if the controller settings are correct and conservative, even using full throttle at low speed. The axle is hollow but substantial so there shouldn't be any problems with axle bending. So we're...
  4. jbond

    Will a 250w Bafang front hub run ok on 48v?

    Keep searching on here and you'll find people claiming that the small Bafangs can cope with 48v-20A. Your controller *should* be ok at 48v as well though you'll want to change the LVC. What's not clear to me is how much battery you really need to support 20A. A Ping (or similar) 48v-10AHr...
  5. jbond

    Building a quality 11t freewheel

    There's a *lot* of Shimano 7 speed freewheels out there fitted to cheap bikes. So a straight replacement that works with 7 speed shimano indexed quickshifters would be desirable. Personally, I'd be looking for an 11t-28t 7 speed or perhaps 11t-30t. The megarange bottom gear is fairly pointless...
  6. jbond

    Bafang or Cute? and freewheel question

    The rear motors have a completely standard freewheel mount. So there should be no problem with replacing the typical 7 speed Shimano freewheel with a BMX single free wheel. There are reports on ES of people running 40v-20A with the Bafang motor. If you know you only want 10A then get an...
  7. jbond

    Quick CA question (throttle override override)

    Arlo1, This is the key post I was working from. http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=14807&start=15#p327917 I've never read anything on ES about these speed settings affecting the PhaseCurrent or RatedCurrent settings. This is why it seemed to me that if conditions meant...
  8. jbond

    Quick CA question (throttle override override)

    Ok. That's not how I understood it. But hey. It's your controller. Here's what I'm thinking. Let's say you're in #1. You have a 30A current limit and a 48v battery. You're currently doing 35kmph. Open the throttle fully and you're going to go into current limiting. So now you have 30A and...
  9. jbond

    Quick CA question (throttle override override)

    Don't think so. The three % settings for mode I,II,III only affect the max voltage and hence the max speed at you get with 100% throttle. It doesn't affect the current limiting and hence doesn't affect the amount of power available. Re the question of current limiting with an over-ride. I...
  10. jbond

    Gps tracker for theft prevention

    http://cgi.ebay.com/Car-GSM-GPRS-GPS-Anti-Theft-Spy-Device-Realtime-Tracker-/320653991966?pt=GPS_Devices&hash=item4aa877a01e#ht_8484wt_1139 $70 ish. PAYG SIM. No fees beyond the TXT messages. No monthly sub. Shouldn't be that hard to wire it into the battery system of an eBike.
  11. jbond

    Same power, different voltage. Pros, cons, no difference?

    Really good to know.Thanks. A related question, I guess. How big a 48v LiFePo battery do you need to get 20A? Is a Ping 48v-10AHr too marginal? 48v-15AHr or 48v-20AHr is a *lot* of battery. The other alternative is an A123 based pack from cellman. I've heard of one setup of 16s4p of A123 from...
  12. jbond

    2 years after the summer of peanut butter gear Bafangs???

    Zukster, thanks for all that. Your 40v pack with a fully charged voltage of 42v in LiMn is what everyone else calls a 36v LiOn. It's 10s. The "20A" controller, I'd guess is programmed to 20A-50A for battery-phase limit[1]. The motor is a stock size running at it's stock settings and will run out...
  13. jbond

    2 years after the summer of peanut butter gear Bafangs???

    Could you give some details? Motor spec (eg 26"), sensored/sensorless, rim size (eg 26"), battery (eg 36v15AHr LiFePO), Controller LVC, current, phase (eg 31.5, 20A, 50A)
  14. jbond

    power problem on a new build. (might be solved maybe ?)

    Just a thought. What's the LVC set to on the controller? Are you sure it's the battery cutting out, or could it be the controller? BTW. What's a recommended Controller LVC for a LiFePo 48v battery? (and a LiFePo 36v).
  15. jbond

    Same power, different voltage. Pros, cons, no difference?

    I think that scenario is a trade off for slightly higher efficiency in the motor when the controller is not current limiting for slightly worse efficiency in the controller when it is. We've moved the non-current limiting range up to a higher speed so you're probably less likely to use it. And...
  16. jbond

    Same power, different voltage. Pros, cons, no difference?

    This is true for the motor with no current limiting, but is it true for the motor+controller combination? And that's the core of the OP's question. Set the current limit in the two cases so the max output is the same. Now how do the curves compare for the whole system? I think the 48v system is...
  17. jbond

    Same power, different voltage. Pros, cons, no difference?

    Yes, but. Typical Bafang/Cute and other geared hub winds are designed to meet EU regs. They have a no-load rpm limit at 36v of about 20mph. At a nominal 250w, they will pull without any pedal effort to 16-17mph. The controllers then cut power at 15mph/25Kmph to stay legal. The extra few mph is...
  18. jbond

    Conhismotor 48v 10ah LiFePo4 (LiMn2O4) in aluminium case

    I've seen dire warnings elsewhere to avoid DNP due to quality issues. Mainly that the gear material is just not up to it and the ratchet/bearings break up. Be very interested to hear how it holds up. 26", 48t + 11t-30t 7 speed makes a lot of sense to me.
  19. jbond

    Same power, different voltage. Pros, cons, no difference?

    That's the human problem. Which leads to the "too much is never enough" spiral. Take a 36v system with a decent controller with say a 20A max. Bump it up to 48v but leave the 20A limit the same assuming your controller can handle a 48V battery ok. Now you've bumped the motor power up and top...
  20. jbond

    Same power, different voltage. Pros, cons, no difference?

    Then there's cost. A 48v10A Ping battery is cheaper than a 36v15A battery.
  21. jbond

    Same power, different voltage. Pros, cons, no difference?

    I've wondered something similar. Limit the current so the motor is doing the same 250w at 15mph[1]. With a 48v battery, the controller will be running with a lower PWM duty cycle. The average voltage actually shown to the motor will be the same. So will the controller losses be higher? Now take...
  22. jbond

    Commuter Booster - <1kg Friction Drive

    I think there are two time constants in this. 1) The 2K resistor+100microF capacitor on the Servo input control how fast the throttle input rises when the push button is pressed. Should be possible to make this variable with a pot instead of the 2K fixed. When the button is released with the...
  23. jbond

    Constant Power control?

    I'm thinking just a bog standard hall sensor pedelec sensor. I think there are two types. One outputs a pulse stream that goes straight to an infineon style controller PAS input. The controller integrates it and works out that pedalling has started or stopped. The other (Cytronex?) emulates a...
  24. jbond

    Commuter Booster - <1kg Friction Drive

    I was looking at this again. http://www.recumbents.com/wisil/tetz/E-AssistMetric/default.htm and noticed his experiments with current limiting an RC-ESC combination. http://www.recumbents.com/wisil/tetz/CurrentLimiter/default.htm...
  25. jbond

    Constant Power control?

    Re the OP. Forget the torque sensor for a moment. I keep suggesting the following idea, but I can't get anyone to bite. :) It really comes down to two ideas. - Fixing the annoyances of the raw PAS systems out there. - Implementing an economy mode. First the PAS. PAS is a very intuitive way of...
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