Anybody else running an electric front hub?

Discussion in 'Electric Bicycles' started by Blaze, Jan 12, 2007.

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  1. Blaze

    Blaze Guest

    Does anybody here have the electric hub kit installed? I bought an electric hub kit from Spookytooth. It's the same type of hub I have seen from companies like Crystalite and Wilderness Energy.

    Mine is the 48v 600w brushless motor. The performance specs as advertised are 24mph with a 20 mile range when using 20Ah Sealed Lead-Acid batteries. The range is right where it should be, with the batteries taking me 21 miles without pedaling, even when starting and stopping a lot. The speed, however is only about 17 miles per hour. I was wondering if anybody else had built one of these and gotten it to go any faster. I weigh about 185 pounds, so we can factor that in. I saw one place selling motors saying that they were advertising top speed based on a 140 pound rider.

    One thing I am going to try is soldering the main power wires. Just the heavy wires carrying all the amps. That might help, 'cuz the connectors look pretty cheap and they look like they could be a source of high resistance. It seems odd to use such heavy gauge wire and cheap crappy connectors. It could be a voltage bottleneck.

    That said, the bike is still pretty fun to ride. This kit makes almost no noise at all and it climbs medium sized hills pretty good.

    ***** A note on the battery Amp/hour ratings *****

    Many makers of quality SLAs (sealed lead acid batteries) will build a good battery, then rate it 15% lower than what it is actually capable of, just so the customers still get the full rated power even after the battery starts to age a bit. This means a good brand like Panasonic or Yuasa will build a battery and label it as a 17Ah battery, even though it really runs at 19-20Ah. Since the good 17Ah batteries really hold nearly 20Ah, the Chinese battery companies have taken to labeling all of their 17Ah batteries as 20Ah, when the real rating might be lower. The basic idea here is that a cheap 20Ah battery has the same or even less power than a good quality 17Ah battery. Don't pass up a good deal on a quality 17Ah battery because you are holding out for a 20Ah battery. The 17Ah battery will be better if it is a reputable brand.

  2. Butch

    Butch Guest

    I also have the exact same front electric hub that you mentioned and was wondering why I wasn't getting close to the 24 MPH that spookytooth claimed. I too get a max speed of 17 MPH. I have 4 12V 10aH batteries.
    It's a lot of fun to ride but I'd like to get a little more top speed out of it if possible.
  3. gone_fishin

    gone_fishin Guest

    e-bikes...finally!!! :D

    it's now official guys, we have it all at MBc 8)

    we (the bike shop) will be building an e-trike up this way in the spring for the owner (an elderly gal), & i get to put one on a stretch cruiser, maybe i'll actually know something about them by then :)

    btw-i'd completely settle for a silent 17mph 8)
  4. Blaze

    Blaze Guest

    Is yours the version with the chrome and red circles on it, kind of like a bullseye? That's the one I have.
  5. Blaze

    Blaze Guest

    Yeah, it still is pretty cool, even if it doesn't break 20mph.

    One VERY important thing you need to know when putting that hub on: you MUST fabricate a torque arm to get the torque away from the axle! When you hit the brakes on a coaster brake, the axle would just spin around and mess stuff up if it wasn't for the little torque arm that's attached to the back hub. Same thing for a front hub motor. Mine has a lot of torque and has spun completely off a couple of times. Luckily, I was going slow (the most torque is when you start from a dead stop), and caught it, so it didn't break the wires. I stuck a 10mm wrench over the flattened part of the axle and used a hose clamp to secure the other end of the wrench to the fork. I did this on the side with no wiring, since that side of the axle is solid. The wrench worked so well, I decided to cut the box end off with a grinding wheel, paint it black, and now it is my permanent torque arm. I have very sturdy steel dropouts on my front forks, and the motor still had enough torque to bend the dropouts wide enough to let the axle spin off. I have no idea why these things would ever ship without a torque arm included in the kit. It is absolutety necessary! Do not deliver any bike to a customer without a torque arm to secure the axle from spinning out of the forks.

    Hey Butch- did you have any problems with axle torque?
  6. srdavo

    srdavo Active Member

    Nov 4, 2006
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  7. Butch

    Butch Guest

    Blaze, thanks for that suggestion. I haven't had any problems yet with axle torque but to be on the safe side I'm going to get started on installing a torque arm right away. Yes it is the chrome and red one that looks like a bullseye.
  8. Blaze

    Blaze Guest

    I have a tendancy to test the limits of an installation. I would repeatedly go from a dead stop to full throttle, and that's how it failed. I knew it would stress the forks, but I wanted to make sure that if I loaned the bike to somebody who didn't accelerate carefully, it would still work fine. I think the installation should be able to handle the full operating range of the equipment. In this case, that means going to full throttle from a complete stop. If the motor is capable of generating that kind of torque, then the forks should be capable of handling that kind of load.

    The wrench idea is working great. I wouldn't use too cheap of a wrench, but then I wouldn't use a Snap-On wrench either. I used an Ace Hardware 10mm wrench. Grind the box end off (you dont need to, but it keeps it from looking like you forgot your wrench on the bike) and paint it to match you forks. The order I bolted it together goes from the hub out on the side without the wiring: washer, wrench, washer, fork, nut. The first washer keeps the wrench off the area where the bolt changes from round to flat. Then the wrench. The next next washer keeps the wrench off the fork. Then the fork. I didn't have room for the last washer, so I put the nut on without it. I didn't really want to, but the nut was slightly bigger than the washer anyway, so I went ahead and did it. Before you tighten everything down, hose clamp the wrench to the fork next to where you ground the box end off, then tighten the side with the wiring. This will force the axle to rest against the edges that will be handling all of the load. Lastly, tighten the side with the wrench install on it, and you should be ready to go.

    I have another idea on how to grind the wrench down a little to eliminate the need for one of the washers and hold the wrench in better, but I haven't tested it yet. I will draw it real fast and put it in this post...

  9. Blaze

    Blaze Guest

    Well, my wheel popped off again today. When I got it back home, I ground down the wrench and axle to keep the wrench locked to the axle. After putting it back together to test it, the system no longer works. That was the 4th time the wheel fell off, and this time it finally broke something. The wheel turns, but it only turns at about 7mph now, with the wheel lifted off the ground and not being ridden. I'm not sure what's going to happen next. I sent an email to the guys I bought it from. They still never responded when I told them their 24mph motor only goes about 18mph.
  10. Wheels

    Wheels Guest

    Blaze, you draw like Leonardo, thanks for the techs.

  11. psuggmog

    psuggmog Guest

    I used to have a front drum brake that was made in Norway. It had a torque arm attached with an end that looked like an open end wrench. The U shaped end of the torque arm fit into a pin brazed on the inside of the corresponding fork blade. That kept the hub brake backing plate from rotating, and made it really easy to remove the wheel. No clamps to undo, just the axle nuts.
    Another ideas, what if you made the dropout slot narrower to tightly fit the flats on the axle or made retainers which locked the axle in the dropout. On planetary multigear rear hubs the axle shouldn't rotate either, they use similar methods to prevent axle rotation in the dropouts.
  12. Blaze

    Blaze Guest

    torque arm

    I like the pin idea. For now, the hose clamp is working well, but I might switch over to something like that later. My primary concern is keeping the torque arm attached to the axle. As far as the dropouts being tight enough to hold the axle, that was how it started out. The problem was that this design depended entirely on the dropouts to hold the axle in place. That's too much torque. Even my steel dropouts got bent open wide enough to let the axle spin.
  13. Blaze

    Blaze Guest

    I took apart my brushless hub motor and controller

    OK, I finally decided to take this thing apart and see if I could find the problem. Looks pretty solid in there. Getting it apart was a challenge. The bearings are pressed in pretty tight. I actually pryed it open bit by bit using the prying end of a claw tooth hammer and placing washers under the edge as I moved the hammer around the outside of the hub. Eventually one of the covers popped off and it got easier after that. Reassembly requires that you not get your fingers anywhere in between the hub and the cover as you put the windings back in. This thing snaps together with enough force to break a finger and probably keep it in there, so watch out if you try this at home, kids.

    Taking the side covers off the controller just revealed that the ENTIRE CASE had been filled with some sort of rubbery glue. There was no way for me to look at the circuit board and be able to tell if anything had burnt up. That was a waste of time.

    Since my hub wires were pretty much trashed where they go into the axle, I cut the entire harness to remove the section with the torn insulation and bare wires, then spliced it back into the wiring inside the hub by soldering them together. Satisfied that my hub wiring is solid, I put everything back together and still had the same problem.

    I know that my motor turning rough and only moving 7mph will be either the motor or the controller. I ruled out the wiring harness at the axle.

    The next step is to disconnect the battery and short the three big wires from the motor harness and spin the wheel (short them to each other, two at a time). If the wheel moves a little bumpy, that means the entire cicuit from the wire all the way through the motor windings is good. The motor should generate a little power and send it back through the shorted wires to give it a little bump as it rolls. If any wire doesn't cause the bumpiness when shorted, that's the problem.

    I'm not sure about the Hall sensors. This is where I think the problem is, but it could be at the motor or at the controller. There are spots where the wheel stops where it will not start again until I move it a little.
  14. psuggmog

    psuggmog Guest

    Do you have electrical specs for all the components in this system? A multimeter would be a useful tool to have in this situation. I spend a lot of time away from grid electricity. This post has got me thinking about making a hybrid. Use an electric hub motor, batteries and a little gas motor running little permanent magnet motor as a generator to constantly charge the batteries, plus regenerative braking as a charging source.
  15. Blaze

    Blaze Guest


    No, I don't have any specs. I'm just troubleshooting based on basic electronic theory. I did actually isolate the problem as being a bad hall sensor, but I can't seem to get info on how to abtain a replacement. Hopefully, I will hear back from the manufacturer soon. If I had the specs, I could just order a new sensor based on the requirements, but instead I am dependent on the factory either sending me new sensors or telling me where to find them. All I have to go by right now is just the number "41f 634" printed on the sensor.

    The hybrid idea sounds really cool. You could plug it in to charge it and if you were lucky, you would never have to run the motor. If you run out of battery, on goes the motor and now your batteries are recharging. That would be great.
  16. psuggmog

    psuggmog Guest

    Blaze, since you have both an electric and an "infernal" combustion engine powered bike, I interested in your opinion about and comparisons of the two methods of propulsion. any comments?
  17. Blaze

    Blaze Guest

    electric / gas comparison

    If I had to choose just one, it would probably be the gas powered bike. When you really look at it, it's just the same reasons nobody drives electric cars.

    I would much rather use electric power, but it's just not ready yet. My electric bike is so quiet you can hardly hear it at all, and it runs very smoothly. There just isn't any vibration from the motor. I love it. And I love not burning any gas.

    I haven't had my electric long, but once I get everything ironed out, I expect it to be pretty maintenance free, except for the batteries. The gas bikes vibrate everything loose, and tend to need adjusted every now and then. Nothing major, but if you have a gas bike, you had better know how to fix it.

    Electric bikes are always clean. My gas bike usually has burnt 2-stroke oil all over the back wheel and frame. Cleaning that burnt oil off sucks.

    The biggest problem with electric is batteries. Sealed lead acid batteries are very heavy. 55 pounds of batteries (48v 17Ah) will only get me about 21 miles, and then I have to recharge them for about 10 hours. Not very practical for scootering around all afternoon with friends. Sometimes we have put 40 miles or so on our gas bikes. Only being able to go 21 miles per charge is a pretty bad limitation. After that you are pedalling a bike with about 100 pounds of dead weight on it in the form of batteries, controller, and electric motor. Not fun.

    A gas bike with less than 1/2 gallon of gas can outlast all but the most expensive electric bikes, and the gas bike will have full power the entire time. 1/2 gallon of gas weighs about 3 1/2 pounds, compared to 55 pounds of batteries to power the electric. The gas bike will climb any hill with ease and it will be capable of going full speed all day long. If you should need more gas that day, which is unlikely, you can refuel in a minute or two. The range is practically unlimited. The cost of gas is irrelevant when you are only burning a couple dollars worth for the entire day.

    The advertised top speed of my electric motor was 24mph. bullsh*t. Mine goes 18mph when the batteries are fresh, and slows to around 15mph before they go dead. Most gas bike are in the 20-30 mph range. Like real, actual 20-30 mph.

    NiMH, Li-Ion, Li-Po, and newer batteries are too expensive to be practical. You can build an entire new gas bike for about $300 ($180 for the motor and shipping, $120 for a new bike to put it on), while a 48v 13Ah NiMh battery pack will cost $460, and will eventually need replaced anyway. Bear in mind, that's only 13Ah, would give me less than 20 miles. If I was willing to spend more money, I could build an electric bike with Li-Po cells and it would be light and have awesome range and everything; or, for the same amount of money, I could build an entire fleet of gas bikes, all of which would perform better than the electric.

    So the bottom line is that I would rather have an electric, but they aren't good enough to replace gas yet. I will be keeping my gas bike, thank you. It's the same as electric cars.

    I want an electric that goes as fast as gas, weighs the same as gas, and drives as far as gas. Until then, electric will not be as good. It will be fun, just not as useful.
  18. foyeburger

    foyeburger Guest

    blaze well said i concur larry ca
  19. jerryt

    jerryt Guest

    I've been on the fence between a gas and electric power for about a month now and was leaning toward electric until I read the post by Blaze.
    He presented a very good and well thought out comparison between gas and electric and helped me make up my mind.
    I just looked at a Giant Suede E that costs $1000 and really like it for my needs until I found out from a user group over at Yahoo that a replacement NiMH battery would cost $500 or 1/2 half the purchase price of the bike. Even generic batteries for this model are kinda pricey.
    So blaze, I appreciate your comparison and I totally agree with you that electrics are great but the technology is not quite there yet. I'll go with gas as my primary rider but may get into a less expensive electric just for fun.
  20. azvinnie

    azvinnie Guest

    blaze, l have the black electric hub on my trike and l'm 140lb and my trike will do 20+ with an extra battery(4 total 12v 12ah). l think that electric is great, they also make different controllers to get your speed up but loose range. the electric hub is going to be changing, for the better.
    l think that electric is good for older people who want to have a casual ride in town, and l think that gas is good for all us hot rods who want to go balls out. l have a gas and an electric(spookytooth), and im more than pleased with both.