Junkyard dog 36V Brushless hub Trek E-bike

Discussion in 'Electric Bicycles' started by Hawaii_Ed, Jan 17, 2011.

  1. Hawaii_Ed

    Hawaii_Ed Member

    I recently was hired for a job about one mile from my house. Parking is HORRIBLE at the facilty, and it is so short that biking made perfect sense. The only problem in coming home is a steep uphill haul! I am in average shape, but do no feel like working like that after a long day! I have my gas bike, but the oil and chains have messed up some pants, and the happy time has been giving me some issues lately! (Time for a new motor)

    So with the short commute, I decided that an e-bike might be perfect. I can actually roll all the way to work, and only need power coming home.

    - My friend owns a machine shop, and he was given a Trek "Snap-on anniversary" bike years ago for buying a batch of tools. Not being a bike rider, he tossed it in the rafters, and the crank got bent when some equipment fell on it. I thought it'd make a good e-bike being strong steel and none suspension, and it is a decent quality bike. Also, it was free!
    - I had a spare set of cranks from my shift kit, so easy fix!

    - My good friend 5-7 heaven used to run electric, and he graciously let me have his brushless hub motor for free as well. He ran it at 72v with no issues.

    - My other good friend pickettblanco was moving, and had a spare set of excellent MTB tires I picked up for free as well! Nice upgrade on the bike!

    - I had an old frame rack and topeak bag from my pedal bike commuting days, perfect mount for the batteries!

    - I had bought a pack of 3 14amp 12V batteries for my son's schwinn scooter, but the controller died on it, so I highjacked that for this project! I also used the scooter 36v charger. Will need to get him a new set though eventually! ($120)

    - Picked up an ecrazyman controller and throttle for $50 on E-bay, it is rated to 48V

    - I salvaged an old heavy duty extension cord for motor wiring, and some old electronics wires to hook up the hall-effect sensor.

    - No brake switch safety, but I may add it since my 13 year old son will be riding this at times...

    - a little solder/heat shrink and zip ties, and it is on the road!

    I do not have a speedo on the bike, will add it today. Seems to be rolling at 18-20, sure is quiet compared to my gas bike! LOL!

    So total cost is just under $200, should be drop dead reliable, and clean! I can still get some pedal assist exercise, but not kill myself going home! :D


  2. Ypedal

    Ypedal Member

    nicely done !! and on the cheap = Bonus !

    I could recommend mounting the controller outside the bag, it needs free flowing air if at all possible.

    Other than that, the short commute would work with a 5ah lipo pack, replace 40 lbs of lead with 5 lbs of lipo !
  3. Hawaii_Ed

    Hawaii_Ed Member

    was wondering about that with the controller! Thanks for tip! I agree 100% on Lipo, that is on my list, but may go a little bigger for longer range when I want it. Just picked up a new speedometer to install later today, topping off the batteries, and will get some data!
  4. Hawaii_Ed

    Hawaii_Ed Member

    got my speedo hooked up today, and the top speed is:

    18 MPH!!!!

    Lol, not going to give up on my shift kit bike anytime soon! The e-bike is perfect for running around on my work commute! I may have to go for 48 volts!

    I also hooked up a toggle switch for the power today, easier than unplugging the battery pack!
  5. Hawaii_Ed

    Hawaii_Ed Member

    total bike weight is 72 lbs (I have 3x 12v 14 amp SLA). Lighter than I thought!
  6. Ypedal

    Ypedal Member

    Yeah, 48v is much better, but 48v of lead is alot of weight.. if you can get 2 batts in the frame and the other 2 on the rear rack it's not " as " bad.. but still.. gotta ditch the lead.

    100v in a 20" rim is where the real fun can be found !!!