My New 48V Crystalyte Hub Motor Ebike Conversion

Discussion in 'General' started by antrey, Mar 19, 2013.

  1. antrey

    antrey Well-Known Member

    I recently finished an electric bike conversion project and have just over 120 miles on the bike from commuting to work over a couple of weeks. I have been very happy with the performance and am even more convinced that electric drive is here to stay! The bike has a Phoenix II 48V 20Ah LiMn kit purchased from Electricrider.com. With the wind at my bike I can hit 40mph. 35 to 38mph with no wind or a slight headwind. I usually ride it with the speed limiter set to one (24mph) as near 40mph feels a bit too fast really. Using the kill-a-watt meter to measure energy required to recharge the pack and a 33.4kWh/gallon of gas conversion factor yields over 600mpg (is 33.4 the correct factor to use?) in typical use so far. Will try some hypermiling next :D

    [​IMG]

    Over approx 20miles including a 3watt phantom load after pack was fully charged:
    [​IMG]
     
  2. ksstathead

    ksstathead Moderator

    Jealous!

    Is that the 4840 kit?

    Where do the LiMn batteries come from (the site shows LiFePO4)?

    40 mph seems too fast in traffic since you are hard to see and have very little traction area for emergency stop/maneuvers. Fun when little traffic though.

    With my short commute, I've opted for the folding bike, human power only. But would LOVE your ride.
     
  3. antrey

    antrey Well-Known Member

    ksstathead,
    Yes it is a 4840 kit and the option for LiMn is shown on their battery pack specific link. They have several options not listed in the kits to try and keep things simple for most:

    http://electricrider.com/batteries/index.htm

    In reality much less traction area is needed for a bike since you are trying to control much less weight. I do plan to switch out the knobbies for more road oriented tires to reduce the squirmy feeling that knobbies give on the road. Downhill racers and road racers often reach speeds higher than I'm seeing :eek:
     
  4. RedylC94

    RedylC94 Well-Known Member

    Yes. That should also improve the rolling resistance significantly, too.
     
  5. ericbecky

    ericbecky Member

    The Crystalyte 4840 is a great controller.
    I've got one paired with a 53xx front hub motor.

    I run it with 48 cells from a used NiMh hybrid pack. (8 sticks each with 6 cells. ~5.5ah, 16 lbs ) About 70v hot off the charger!
    Fun stuff. You can buy the sticks used for $40 apiece or so, so they make for an economical pack.
     
    Last edited: Mar 21, 2013
  6. EdwinTheMagnificent

    EdwinTheMagnificent Legend In His Mind

    24 MPH is plenty fast for the brakes on that bike. But I agree , 40 MPH would be fun sometimes. Wonder what the range would be at a constant 40 MPH ?
     
  7. ksstathead

    ksstathead Moderator

    I hear what you say on weight vs contact area ratio, however a car has 4 wider tires, abs, vsc, etc., and is far less likely to be rendered out of control by a little gravelly spot.
     
  8. WriConsult

    WriConsult Super Moderator

    Although human powered bikes do frequently reach high speeds on downhills, they don't spend very much time at those speeds. I wouldn't want to be traveling for extended periods on a bike 30mph+. A bike actually can't stop as fast as a car from those speeds, nor IMO is it more maneuverable at those speeds.

    Although bicycling is NOT more dangerous than driving (contrary to popular but ignorant "I want a steel cage around me" meme) overall, the primary reason for that is that the bicycle travels most of the time at much lower speeds (the secondary reason being increased situational awareness). Increase overall speed substantially and you increase the danger radically, into motorcycle territory. Reaction and stopping distances go up exponentially with speed, as do the forces of impact. I personally would find 24mph a bit much for my comfort level, at least in busy areas with lots of conflict intersections -- but it sure would be tempting!

    My own interest in the e-bike is for the ability to climb big hills at "normal bike speeds", rather than the ability to go way faster on the flats. My commute involves 500-800' of climbing each way, and electric assist could very substantially reduce my commute time while still keeping my speed in a safe range most of the time.
     
    Last edited: Mar 21, 2013
  9. EdwinTheMagnificent

    EdwinTheMagnificent Legend In His Mind

    And it could extend the useful life of my poor old knees. I'm going to ride anyway , but I would ride further if I had some "help" on hills.
     
  10. ksstathead

    ksstathead Moderator

  11. herm

    herm Well-Known Member

    They should just limit the speed of an unregisterable vehicle down to 15mph or so
     
  12. WriConsult

    WriConsult Super Moderator

    Actually herm, that's exactly what most e-bikes and kits do. I've been doing a bit of research and it appears most of them have a built-in limiter where the electric assist cuts out somewhere between 15 and just under 20mph, for FMVSS compliance.

    By the way, it looks like the ideal conversion kit for me is the Clean Republic Hill Topper. It's considered a lower-end but high quality kit with a 250W motor, which I think would be fine for my needs. The "Sprinter" model has a 200Wh Li-ion battery pack, adds a total of just 10 pounds of weight, and costs just $500.
     
  13. herm

    herm Well-Known Member

    That Hill Topper looks nice, I guess the throttle is an on/off kind of thing when you need it.
     
  14. WriConsult

    WriConsult Super Moderator

    Yes, from what I've read it is just on/off.
     
  15. ericbecky

    ericbecky Member

    Anyone who is truly interested in electric bikes should check out endless-sphere.com.

    That forum has been around a long time and has ideas about all kinds of electric bike options. Front hub motor, rear hub motor, direct drive, and much more.

    Good stuff.
     
  16. antrey

    antrey Well-Known Member

    Hypermiling for the next "tank" resulted in over 898MPGe!
     
  17. antrey

    antrey Well-Known Member

    The Crystalyte Kit does have a limiter. On the lowest current setting, top speed is close to 20mph and thus pretty much legal if kept in that setting. For my standard commutes, I keep it limited to conserve battery range and keep things legal. Downhills speeds do exceed 20mph but they do as well when I'm pedaling a standard bike. This is what speeds look like when limited:

    http://youtu.be/3vdN4ZnXer4
     
  18. WriConsult

    WriConsult Super Moderator

    Out of curiousity, is it a a current limiter or a speed limiter? Most e-bikes have a speed limiter, not a current limiter. The difference is that if you're going downhill at over 20mph you will not get ANY assist. So if you can pedal down the hill at 25mph you can't use the motor to kick your speed up to 30mph.
     
  19. antrey

    antrey Well-Known Member

    The manual does describe it as a speed limiter. I would have to run some tests while the current is being displayed to determine if it is speed based or current based. All I know now is that the top speed while limited is quite variable depending on terrain but that is not enough to determine what the system is doing either way. You've piqued the interest of my engineery brain :)
     

Share This Page