10KW E-PK Ripper EXTREME!!!

Discussion in 'Electric Bicycles' started by recumpence, Apr 18, 2009.

  1. recumpence

    recumpence Member

    Hey guys,

    Here is the latest project. I am down to wiring at this point.

    The bike weighs 45 pounds and is pushing 14hp. :evilgrin:


    Attached Files:

  2. srdavo

    srdavo Active Member

    looks tough!!

    tells us more.... batteries....etc
  3. recumpence

    recumpence Member

    It is running two Astro 3210 motors (5,000 watts each). It has 48 Lipo cells for a total 48 volts 8.8 amp-hours. That pack is good for 12,000 watt output. With normal riding (20mph or so) it should be good for 15 miles between charges.

    The controllers are Castle Creations HV110 RC controllers (one per motor).

    The brakes are Hope Hydraulic 4 piston, floating rotor units. Phenomimal!

    Rear rim is an aluminum double wall 44mm wide Nimbus unicycle item. The tires are also designed for unicycles. They are 2.1 inch wide rear, and a 1.95 inch wide front.

    The rear hub is a Trial All brand Trails hub. It is hard finding hubs for this spacing with 36 holes and disc compatible.

    The fork is an aluminum Echo brand trials fork. That fork was bought because it is light, strong, has a disc brake flange, and is a bit longer than a normal BMX fork. That length gives more clearance for the motors and a more relaxed head tube angle for better high speed stability.

    The bike has 3 freewheels. It has one on the crank, one on the output sprocket, and one at the rear wheel. That allows motoring without pedalling, pedalling without the motor, or both together without any interaction.

    I have about 50 hours fabrication time and around $3,000 invested in it.

  4. srdavo

    srdavo Active Member

    beautiful work!!

    looks ready to do some serious off-road crazy ch*it!! hehehe :devilish:
    Electrics have soooo much more low-end torque.... your bike looks beefy enough to handle anything.

    Xtreme- -Dirt-Jumps

    what's the recharge time on those Lipos?
  5. recumpence

    recumpence Member

    Recharge time depends on the charger type. My charger would take about 3 hours to fully recharge it. However, the cells will handle a 30 minute recharge with a more powerful charger.

    With my other bike, I typically ride 5 miles, then recharge. That small recharge takes about an hour. By then I am itching to ride more.

  6. safe

    safe Active Member


    Good to see you. AussieJester invited me over here and so he and I both post here pretty regularly as well as on another forum. I remember you were just starting the "Urban Assault" bike a while back and it's good to see you got it together. (before the "forum that will remain unnamed" forced us out)

    Your bike looks impressive... I'd like to see more pictures of how you connected everything. Looks like a very complicated machine. (there are so many things going on it's hard to figure out what it's doing)

    AussieJester is going to use the KISS principle and go with an Etek or Perm. It's the easy way to get power, but it comes with a 25 lb weight penalty. It looks like dual RC motors is the lightest weight way to get Perm-like power.

    14 horsepower... wow. :tt1:


    Did you hear that I got to 58 mph on my Project #001 on flat land? Somehow I managed to squeeze the most performance possible from the cheapo Unite motors doing a rewind. I've been learning about how motor wiring effects behavior and found that you can improve on the generic setup pretty easily. My goals are more modest and I just want to get about 2-3 horsepower out of a 500 Watt Unite motor. (while keeping the voltage down to 48 volts)

    Anyway... my projects are still continuing and I'm still learning new stuff all the time. (you seem to be still at it as well)
    Last edited: Apr 19, 2009
  7. JinbaIttai

    JinbaIttai Member

    So at full throttle how long--I don't want to this to sound wrong because that is an incredible looking build -- but at 14 horsepower, how many seconds is the battery good for?
  8. recumpence

    recumpence Member

    At 14hp, the pack would be drained in about 2 minutes. But, at 14hp, how long will the front wheel be on the ground?

    Basically, I want this much power to do crazy snap-wheelies. That only requires small 1 or 2 second bursts. Most often the bike will be tooling around at 30mph drawing somewhere around 700 watts.

    Safe, I will post some other pics and explanations soon.

  9. mabman

    mabman Member

    I was going to say, or so, what? I suppose it is all in how you gear it but with that power to weight ratio it should outrun just about anything on the road, well except a radio that is:helmet:
  10. ozzyu812

    ozzyu812 Member

    One Word

  11. safe

    safe Active Member


    Recumpence is actually the guy that got me thinking about motor rewinding. These RC motors have two big advantages over the typical motors we use for ebikes. First, they are brushless which means less friction and that increases efficiency. Second, all these RC motors are wound so that they use VERY LOW resistance in their windings.

    It was when I realized that low resistance allows more power at lower voltage that I started doing rewinds.

    14 horsepower is definitely realistic too... (dual RC motors)

    These little motors have potential that are not being exploited by most people.

    A Third good thing is that these RC motors are really, really lightweight. So you are getting power levels out of them that equal the big 25 lb Perm or Etek motors while weighing less than 5 lbs each.
    Last edited by a moderator: Apr 23, 2009
  12. veloman

    veloman Member

    Awesome job, wow. Clearly that took some skill and hard work to put together. What is your 0-30,40,50,60 mph times?

    That is serious badass.
  13. safe

    safe Active Member

    It's Recumpence's bike... my guess is that he's been posting his bike on every electric bike related forum and will get back to this one eventually.
  14. recumpence

    recumpence Member

    I haven't run it yet. I am out of state right now. I should have it running in about a week or so. I am guessing it should do 0-40 in about 4 to 5 seconds considering what my recumbent is capable of........... That is if I can keep the front end down.

    Those motors weigh 3 pounds each.

  15. safe

    safe Active Member

    I can still remember the days when the "high and mighty" talked about their 25 lb hub motors as the "Holy Grail" of ebikes because they could produce some decent power. :tt1:

    3 pounds each... that's just incredible...

    The "secret" of these little motors seems to be that they spin fast and flow current easily. I've used that and copied it into the generic brushed electric motor and found results that are excellent too. (you might check out the rewinding thread) If you hadn't arrived on the scene with the RC motors (and stunned us all) I doubt that I would have ever imagined that it was possible. The RC motors got me thinking.
    Last edited: Apr 23, 2009
  16. AussieJester

    AussieJester Member

    GREAT to see you over here Matt i seen you have been a member for awhile too...I'm loving the PK Ripper definitely the ballsiest rc build about and definitely the most professionally done .. How far odd is the video of it in action and you flipping it at 30mph?!?@#?!??!? hehee...Best of luck with the final steps of the build mate...

  17. safe

    safe Active Member

    I want to see the "Worlds First Ebike Backflip" too. :cool:

    Just be sure to get a foam pit to practice... the pro's make it look easy, but that's because they spend hundreds of hours practicing in the foam pits. Don't practice it without the protection...
    Last edited: Apr 24, 2009
  18. recumpence

    recumpence Member


    They don't make smileys big or crazy enough!

    This thing actually scared me pretty soundly. Holy ****!!!!

    So, at 75% charge, I couldn't take it anymore. So, I took it off the charger and went for a ride. HOLY ****!! This thing is almost too powerful. I nearly flipped it a bunch of times. It winds out about 40mph. But, at what feels like 35, I hit the throttle while leaning over the bars and it still wheelied! I had no idea it would be this crazy. WAAAAYYYYYYY beyond my wildest expectations!

    Man, oh Man, this thing is WICKED!!!!!!

    I have to find someone to video me. But, it is hard to get a handle on the power without riding it.

    Oh, did I say INSANE?!?!!!

    Triple wicked!

    Total E-diction!!!

  19. mabman

    mabman Member

    Nice Matt. Keep the rubber side down!
  20. duivendyk

    duivendyk Guest

    Seems totally nutty,normally running at 600W for 45 mins at 6% of peak power.You should take up dragster-electric racing next.
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