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Thread: A series of questions to get me going.

              
   
   
  1. #1
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    A series of questions to get me going.

    First of all greeting from Ireland, thanks for accepting to be to this great forum I have been creeping around for a while.
    I have decided to build my very own electric bike.
    I was hoping that i could run my plan past you guys and you would be able to tell me if it seems half sane or looks like it'll end in tears.

    1. Buy donor bike, and deICE.

    2. buy the following kit Conversion Kit - Motenergy ME1003 Motor, Alltrax Controller, Contactor & Accessories

    3. set the kit up and run it off a (cheap proof of concept 12v) battery, just to see the the motor turn and be sure I have it set up right.

    4. then with the same battery install the kit in the bike and get the sprocket lined up and get the back wheel spinning (off the ground).

    5. decide on a battery pack (no longer test batterys but good ones), and also work out a charging solution.

    The bike I hope to get as a donor (this weekend if luck is on my side will be a ninties sport bike 600/1000cc), 17inch back wheel and a 1:3 ratio between front and back sprocket.

    so aside of a yay or nay on my build plan, I would also like recommendations on battery pack / chargers.
    I would like a 140km (86.992miles) top speed and a 100km (86.992miles)

    My budget for the project is 2501.48 US Dollar. so 1500 after i buy my kit (from point 2).
    Is one 1500 enough for my batterys, on-board charger, dc dc converter and instrumentation ?

    I am happy to compromise top speed or range if i can add to the bike later modularly with more batteries later.
    Thanks to all who attempted to read my little essy, any thoughts or questions welcome
    Last edited by andy; 26 March 2015 at 1615.

  2. #2
    Senior Member tomdb's Avatar
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    No.

    Motor specs;

    3050 rpm at 72V Unloaded
    11.5KW continuous,
    23KW Peak for 1 minute @ 72Volts

    Top speed of 140km/h- possible with around 16 Kwh (dependent on weight). Wheel rotations per second of roughly 18 which would equate to 1080 rpm, so less than a 1:3 is needed to reach 140km/h before max motor rpm.
    Your acceleration will be not allot of fun, especially since your donor will be heavy to start.

    Range, look at bikes that get similar range. Your budget will get you no where near that.

    Lets say you get around 100wh/km or 10km/Kwh. This means you need around 10KwH of battery to get near that, if you are resourceful 300$ per KwH is possible and lower. So at least 3000$ for batteries alone.
    This is then without any extra's like charger, cabling or a dc/dc. Also cheap batteries are usually heavy which impacts your consumption which then again impacts your range.

    A budget as tight as yours, I would set the bar allot lower and just see it as an toy to start out.
    Last edited by tomdb; 26 March 2015 at 1534.

  3. #3
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    Thanks for your reply.

    your advice is to aim lower, if i stayed away from motorways I could live with 80/90kms top speed.
    what kind of range do you think my budget would get me (if i lowered my sights to top speed of 90km)?
    My goal is really to learn and have fun building, and have something to take the the shops and get around locally.
    I may have gotten a bit optimistic with those original speed distance goals

    do my build steps seem realistic, practical?
    Last edited by andy; 26 March 2015 at 1611.

  4. #4
    Senior Member JoeReal's Avatar
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    Your build steps are realistic. I am on your step 5 right now. Just put on 6 SLA batteries to get her running; now trying to figure out my Li battery pack.
    One thing is, I bought a 2005 motorcycle for very cheap, and I already have $2500 into the bike- $1300 for motor and controls, $800 in getting rolling chassis and getting all new seals and bearing, $400 for a few extra SLA batteries (I already have a few).
    There's a lot of great info in this site, do some searches for other's builds.
    I will be putting up some videos soon you might be interested in.
    Good luck.
    Joe


    Sent from my iPhone using Tapatalk

  5. #5
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    Thanks for your reply and certainly send on those videos when you have them.
    I'm glad to hear my steps are do-able.
    I can't wait to go bike shopping tomorrow, and I'll be ordering my parts as soon as i have my bike.
    what is your donor bike out of curiosity?

  6. #6
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    I bought my donor bike today, an NSR 125.
    Pics to follow

  7. #7
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    It's just the second one (the nsr other was uploaded in error )
    Attached Images Attached Images
    Last edited by andy; 29 March 2015 at 1341.

  8. #8
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    OK, project bike is deIced and I have been sanding and painting a few parts while the weather permits it.
    Should the rain come (and in ireland it's never far away) I will be in the shed simplifying/redoing the 12v system deIced.jpg

  9. #9
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    got my motor and controller
    have a cardborard template done for what i need and starting to work through a wooden one . im looking to do some cad work and once i have it in steel ill mount the motor and worry about fitting the rest

  10. #10
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    Quote Originally Posted by tomdb View Post
    No.

    Motor specs;

    3050 rpm at 72V Unloaded
    11.5KW continuous,
    23KW Peak for 1 minute @ 72Volts

    Top speed of 140km/h- possible with around 16 Kwh (dependent on weight). Wheel rotations per second of roughly 18 which would equate to 1080 rpm, so less than a 1:3 is needed to reach 140km/h before max motor rpm.
    Your acceleration will be not allot of fun, especially since your donor will be heavy to start.

    Range, look at bikes that get similar range. Your budget will get you no where near that.

    Lets say you get around 100wh/km or 10km/Kwh. This means you need around 10KwH of battery to get near that, if you are resourceful 300$ per KwH is possible and lower. So at least 3000$ for batteries alone.
    This is then without any extra's like charger, cabling or a dc/dc. Also cheap batteries are usually heavy which impacts your consumption which then again impacts your range.

    A budget as tight as yours, I would set the bar allot lower and just see it as an toy to start out.
    Tomdb if I may ask, how did you come up with these numbers? The 1080rpm and 16KwH?

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