Electric downhill/freeride bike

[Ratking]

awesome, will be watching this one, i also would be interested to know where that gearbox that you got bolted to the motor was from, and what it can stand up to.

as for the prices, you got the heavy duty front freewheel for $131, I got a white industries freewheel, heavy duty one from sick bike parts (uncut gears, just 5 holes in it for bolts) for $60, what one were you looking at?

I haven't made up my mind about my setup jet, so the final decision still has to be made. I hope that the batteries that claim to have 20Ah and 22.2v is the real deal. Some people have bought some of them, just waiting for them to report how the specs are. My goal is to make this bike as thin as possible so the batteries have to be chosen before I can do anything more on the frame.

 

[Burtie]

Hi Ratking,

This looks like a very interesting project I will be keeping my eye on 8) .


I think you want to ensure that Turingy motor gets some air flow. If totaly enclosed, it will overheat after a short time when pumping it with 3 or 4 Kw. I found this out when trying to make a splash guard for mine.

BTW I have been using the same motor with a planetary gearbox for some months and hundreds of miles without a slipper clutch. Only thing that has broken so far was the freewheel adapter -now replaced with a stronger one.
link to Stinky thread: http://endless-sphere.com/forums/viewtopic.php?f=28&t=12768&start=75#p290660

I agree a slipper clutch could help to protect the drive train components, but I would be afraid it would also take away that direct connected, seat of the pants feel, that is so important on a good dirt bike.

Maybe if it was set up tight enough, it wouldn't notice, I have never tried one.
Best of luck with the build, -whatever you decide
Burtie.

 

[mdd0127]

I agree with the clutch setup. Just tight enough to keep things from blowing up would be the way to go. The clutch shouldn't slip much if any under normal operation.

 

[etard]

+1 on clutch. Maybe you could use that old longer shaft adapter and fit a neat little clutch in there. That would be ideal because your torque will be the lowest there so your clutch shouldn't need massive springs to hold the force.

Also, if the price tag scares you, maybe buy less batteries and strap everything ( yes duct tape is ugly) to the Big Hit frame as a proof of concept to iron out any problems and then build your custom frame. Or, since you already have a spare frame, in order to save time on building a frame jig and all the jazz, maybe build your enclosure around the Big Hit and weld everything together and then just cut out the Big Hit frame on the inside of your enclosure. Then all you geometry will be in place and perfect and you won't have to worry about you welds holding etc... That's actually a pretty good idea, can't beleive I didn't come up with that sooner. :lol: You could even get a cheap frame and do the same thing if you don't want to ruin the Specialized, although those old Big Hits can be had for peanuts, Specy must have sold a ton of those things.

Another way to save a little money in the long run is to buy a bicycle specific tool kit, I picked mine up for $50 at Performance Bicycle, one of the best investments I ever made.

Good luck man!

 

[MitchJi]

Hi,

I'm not against one, just afraid that my bike will be thicker where it should not be, between the legs :? . Do you know how thick a clutch will bee?
Any way possible to make it fit a 16mm shaft?

Matt said it adds about 13mm to the width of his drive. He fits it to a 15mm wide htd pulley:
http://endless-sphere.com/forums/viewtopic.php?f=28&t=20331

 

[MitchJi]

Hi,

Do anyone know why some of the pictures just are shown as links and not as tumbnails?
View attachment 2
View attachment 1

You can make them appear as images by enclosing them in the img tag like I did below. I used the Img button to create the tags, but I think its an option after you do the upload). But you need to scale them down to make them fit. I think the max is 820 pixels wide.

You can use the Quote button to see what the post looks like:

How how long did it take to make the adapter?

For planning purposes maybe you should plan on 6s/6,000mah packs. If the 20,000 packs are good you will have some extra space. OTOH if they don't work out its something you need to do anyway.


Here's the link for the slipper clutches (Matt sells them with pulleys modified to work correctly). Scroll down to Friction Torque Limiters and Sprockets:
http://www.mcmaster.com/#torque-limiters/=a05vq7

I don't think you can use them with a FW.

 

[Ratking]

MitchJi ;

Thanks for the explanation regarding the pictures, I think its easier to get a overview when they all are shown. I will use img tag next time.

About the limiter, I bought two different sizes because of the limited gearing I have if I use a torque limiter at the output shaft at the gearbox. I looked at the torque rate, and the clutch I need is so big that the smallest sprocket I can fit is 18 tooth. Thats to large and the next best alternative is to fit the limiter at the crank. I know that its not optimal, but I don't see any other option. Its slightly larger and heavier, but I'll manage

 

[Ratking]

Hello guys

Been a long time since I made any noticeable progress, but I've been thinking alot about what I want to make, and I may not use the gearbox I first intended due to complexity and weight. And I also plan to ramp up the power to two turnigy's . There will be one build, and I prefer to get it right the first time. This is a rough drawing about what I have in mind. The axle with the large sprocket serve as both a axle for the sprockets and the rear frame. I will buy two hv 160's since it works good for Matt and sharing the load on two controllers will be much more easy for them. I also love the lightweight and small size so I think this combo is a winner. The bike will also be much thinner with the motors sticking a few cm out of the frame for cooling.

 

[etard]

I have to say that of the different configurations I have seen of the dual motor setups none look as clean or as well thought out as Matt's (recumpence). He mechanically combines his motors using a longer shaft and two equal sized toothed pulleys on the opposite end of the motors and then powers to the larger driven sprocket by the chain coming off only one of the motor shafts. Let me see if I can scrounge up a pic for you...

Edit:

That's the wrong pic , but ES is moving at a snails pace right now, so I will try to find another on, probably in his reduction drive thread. This is his setup on the yellow KMX, it is probably more the direction you want to go.

 

[MitchJi]

Hi etard,

I have to say that of the different configurations I have seen of the dual motor setups none look as clean or as well thought out as Matt's (recumpence). He mechanically combines his motors using a longer shaft and two equal sized toothed pulleys on the opposite end of the motors and then powers to the larger driven sprocket by the chain coming off only one of the motor shafts. Let me see if I can scrounge up a pic for you...

Edit:
That's the wrong pic , but ES is moving at a snails pace right now, so I will try to find another on, probably in his reduction drive thread. This is his setup on the yellow KMX, it is probably more the direction you want to go.

I think this is what you meant (I think two 26t pulleys - 13t belt teeth contact):
http://endless-sphere.com/forums/viewtopic.php?f=28&t=9534

Yo can get a good look at the other side here:
[youtube]N2sSgJ3QUDQ[/youtube]

 

[Ratking]

Thanks guys, nothing wrong with Matt's build
A pleasure to read that 10kw was enough to give him a hard time riding it, two Turnigy making 13kw should make a bike even more interesting :lol:

But there are some solutions that don't work for me, I need a sealed frame that is bulletproof from both thieves, rain and sabotage. And an open frame doesn't give any protection at all.
If I had the money to just buy two 3220 I would just go for that, but they are too pricey when I can get a Turnigy 130 for 100 bucks.
I also would like chains for the hole drive train, that way I stay away from expensive parts that easily breaks. I guess I have to accept the noise, I prefer that over failure any day

I'll take the time to make a better drawing, a picture says more than thousand words.

 

[Ratking]

Hello guys

I never gave up this bike, havent been a day without thinking of it. I've been able to get a hold of a lot of makita batteries and I am trying to get them alive again.
Is this the right way to do it ?

This is by the way current that is measured, not voltage.

 

[bandaro]

ohhhh, not looking good, if that is 3v for the entire pack, then you got a toasted pack. the total pack voltage should be around 12, i think, depending what cells they use.

but by all means i would chuck it in a safe area, and trickle charge it (100-300 mah) up to 13 or so volts then charge it on a regular lithium charge at .5A or so. cycle it a few times until it gets to capacity, and if it will still do that in a few days, you should be sweet. But be careful, if the 3v is the total pack, then it has a decent chance of exploding, so no flammable antiques around it

 

[AussieJester]

Thanks guys, nothing wrong with Matt's build
A pleasure to read that 10kw was enough to give him a hard time riding it, two Turnigy making 13kw should make a bike even more interesting :lol: .

Not "interesting" un-rideable...check Rodgah's thread with his twin Astro 3220 downhil mountain bike, lasted about a week before he ripped it apart, I'm all for high powered setups but twin turnigys on a stock fame is asking for trouble, Rodgahs Specialized MTB experienced alot of frame flex under acceleration, it was literally impossible to keep the front wheel on the ground and accelerate up to speed at any great rate, sounds fun but add in the limited throttle control of a HV160 and theres no way in hell you can control the monos so have no choice but to back right off the throttle...Unless you are able to extend the wheelbase of the bike some your going to have a bike thats fast and will pop uncontrollable wheelies anywhere up to 70KM/hr ...I Wish you well but i would again suggest checking Rodgahs video before wasting money...all the best.

[youtube]tryRNoNB2LI[/youtube]

KiM

p.s if you want twin motors still Rodgahs twin 3220 and Recumpence drive are for sale, he bought a single turnigy and neugart box to replace them. FYI : i have data logs from my own 80-100 130kv Turnigy showing peaks of 10kW so expect a shit load more than 13kW from two of them.

 

[rodgah]

yeh I concur AJ but I can remember I couldnt be told it wasnt going to be fun to ride when I started either. For your information in that video it was with the throttle regulator....which did a good job of keeping the currents down a fraction...around 9-10kw in that video MAX. Oh and its was a kona stinky AJ :wink: , Max output I seen was 17KW on the Cycle analyst....but mind you it would of been for a moment ( < 0.25sec) before i quickly would of been grabbing the back brake. Even with 4 litres of water (2 x 2litre bottles) taped to the fork legs, with the setup exactly as it was in that video it would still wheelie at full throttle and hardly made a difference....i was trying to replicate what extending the wheelbase might do. If you want a powerfull bike that has a useable throttle stroke but can still pull a good power wheelie then i suggest keep it under 10kw. after that the throttle is too touchy, at any moment it feels as though the bike will just loop out from under you, and yes that does mean at more than 70km/h. I have NEVER ridden something that gave me that feeling before it, that includes 1000cc road bikes, lots of dirt bikes, nothing compares. I put this down to the fact that say 1mm of throttle movement = 5km/h speed change. compare this to a conventional bike with gears and that 1mm now becomes = 0.2km/h change (this is just a comparison im not talking facts). Now because the drive with over 10kw just simply has the power to deliver that speed change instantly you see why the throttle is soooo touchy. Touchy like hitting little bumps or rocks on a really smooth surface ment a little twitch in the throttle and boooom before you know it your arms are getting ripped out of their sockets and the front wheel is sky high. And not joking i was too scared to power on up a jump incase i ghostied the thing into orbit.

This is why i have gone to 1 motor and gears. Using gears will hopefully keep me happy with the throttle stroke and having a fairly tall top gear means it will still have the same top speed of 80km/h, yet now able of putting along at 25km/h flat out in lowest gear. As for frame flex well yeah you will soon work this out, my chain stay bearings at the time of putting them in were a press in fit, after having that drive running for a few weeks and dismantling the bike the bearings were loose in the chainstay....like falling out loose. Id hate to think what the forces were but im sure MR KONA never designed his bikes with this much 'pedal power' intended haha.

Rodger

 

[Ratking]

ohhhh, not looking good, if that is 3v for the entire pack, then you got a toasted pack. the total pack voltage should be around 12, i think, depending what cells they use.

but by all means i would chuck it in a safe area, and trickle charge it (100-300 mah) up to 13 or so volts then charge it on a regular lithium charge at .5A or so. cycle it a few times until it gets to capacity, and if it will still do that in a few days, you should be sweet. But be careful, if the 3v is the total pack, then it has a decent chance of exploding, so no flammable antiques around it

Thats the current I monitoring, its showing alittle over 3 amps . I can understand that it was hard to tell because there are no symbols showing v/a/ohms

I think I'll just leave the packages with under 16v alone and try to get only good packs. That depends on how good my supply is. I would love to have a spotwelder so I just take all the good cells and make a huge battery.

 

[Ratking]

Thanks guys, nothing wrong with Matt's build
A pleasure to read that 10kw was enough to give him a hard time riding it, two Turnigy making 13kw should make a bike even more interesting :lol: .

Not "interesting" un-rideable...check Rodgah's thread with his twin Astro 3220 downhil mountain bike, lasted about a week before he ripped it apart, I'm all for high powered setups but twin turnigys on a stock fame is asking for trouble, Rodgahs Specialized MTB experienced alot of frame flex under acceleration, it was literally impossible to keep the front wheel on the ground and accelerate up to speed at any great rate, sounds fun but add in the limited throttle control of a HV160 and theres no way in hell you can control the monos so have no choice but to back right off the throttle...Unless you are able to extend the wheelbase of the bike some your going to have a bike thats fast and will pop uncontrollable wheelies anywhere up to 70KM/hr ...I Wish you well but i would again suggest checking Rodgahs video before wasting money...all the best.

[youtube]tryRNoNB2LI[/youtube]

KiM

p.s if you want twin motors still Rodgahs twin 3220 and Recumpence drive are for sale, he bought a single turnigy and neugart box to replace them. FYI : i have data logs from my own 80-100 130kv Turnigy showing peaks of 10kW so expect a shit load more than 13kW from two of them.

I will build a custom frame based on a big hit. I havent made so much progress because I have to learn how to use Autodesk Inventor in order to let the lasercutter work with my drawings . I think that is so cool that all my sheet metal will be cut out with laser. No drilling or cutting as long as the original drawing I make is accurate. Thats why I have to make this right the first time.

As for too much power, I tough that two hv160 with current limited to 160 amps would be 320amps total @ 50 volts giving me 320*50=16kw continuous. I guess that is uncontrollable but my secret weapon is a good current based throttle. I have a friend that makes analog electronic and I have been talking to him about this. I think fetcher have made similar things, but I don't think many of you guys have tried it. It would be based on a 300a shunt and some op amps. More on that later when I have a frame under construction. One of the reasons I want to motors and controllers is less stress on the components that usually popp. Thats always the controller or motor. With so much power it would be almost impossible to kill the setup. Isnt that what we are after? And thank you for your concern, maybe I will hate myself for not taking your advice(but you have to admit that two is more fun than one )

 

[Ratking]

yeh I concur AJ but I can remember I couldnt be told it wasnt going to be fun to ride when I started either. For your information in that video it was with the throttle regulator....which did a good job of keeping the currents down a fraction...around 9-10kw in that video MAX. Oh and its was a kona stinky AJ :wink: , Max output I seen was 17KW on the Cycle analyst....but mind you it would of been for a moment ( < 0.25sec) before i quickly would of been grabbing the back brake. Even with 4 litres of water (2 x 2litre bottles) taped to the fork legs, with the setup exactly as it was in that video it would still wheelie at full throttle and hardly made a difference....i was trying to replicate what extending the wheelbase might do. If you want a powerfull bike that has a useable throttle stroke but can still pull a good power wheelie then i suggest keep it under 10kw. after that the throttle is too touchy, at any moment it feels as though the bike will just loop out from under you, and yes that does mean at more than 70km/h. I have NEVER ridden something that gave me that feeling before it, that includes 1000cc road bikes, lots of dirt bikes, nothing compares. I put this down to the fact that say 1mm of throttle movement = 5km/h speed change. compare this to a conventional bike with gears and that 1mm now becomes = 0.2km/h change (this is just a comparison im not talking facts). Now because the drive with over 10kw just simply has the power to deliver that speed change instantly you see why the throttle is soooo touchy. Touchy like hitting little bumps or rocks on a really smooth surface ment a little twitch in the throttle and boooom before you know it your arms are getting ripped out of their sockets and the front wheel is sky high. And not joking i was too scared to power on up a jump incase i ghostied the thing into orbit.

This is why i have gone to 1 motor and gears. Using gears will hopefully keep me happy with the throttle stroke and having a fairly tall top gear means it will still have the same top speed of 80km/h, yet now able of putting along at 25km/h flat out in lowest gear. As for frame flex well yeah you will soon work this out, my chain stay bearings at the time of putting them in were a press in fit, after having that drive running for a few weeks and dismantling the bike the bearings were loose in the chainstay....like falling out loose. Id hate to think what the forces were but im sure MR KONA never designed his bikes with this much 'pedal power' intended haha.

Rodger

This is very good information, thank you for giving first hand experience to me. As I see it, the biggest problem is a voltage based throttle and not current based. With that I think the bike would have been extremely funny. Did you try to make different throttle setups such as longer physical throttle throw or a current based throttle? If 1/3 throttle would give 3,3kw out of 10kw that would make a world of difference instead of what we are using. I may be wrong but as I understand the throttle we have now a different value will give 100% throttle until the now value is the same as wanted value. Thats only good for propellers

 

[AussieJester]

I have a friend that makes analog electronic and I have been talking to him about this. I think fetcher have made similar things, but I don't think many of you guys have tried it.

Yes i had a Fetcher throttle interface worked but not as well as a sero tester not
anywhere near as well as a servo tester actually, alot of surging with it here's an
example of what happened when ES member Deecanio tried his Fetcher box mated to a Astro
3220 on a Kona Stinky -->

[youtube]6H7HkjcEvBs[/youtube]

^^A result of a twitchy throttle on a light short wheeled based bike with high powered motor

I wish you well am subscribed to the thread will be interesting to watch your
progress

KiM

p.s that was Deecs first ride on his bike ....and last for sometime i believe it still parked up LoL

 

[rodgah]

I may be wrong but as I understand the throttle we have now a different value will give 100% throttle until the now value is the same as wanted value.

thats correct, even the small increments to the throttle see the motors providing 10+kw till the new speed is reached. Having a current based throttle will work with a dual motor setup....as your suggesting everything is running alot further from the point of failure than if you were using 1 motor. Phase amps shoot up with partial throttle opening ( which is what a current based throttle is going to do) but there is seriously no way to avoid it, and i have never had a problem with it. I had a servo regulator inline with my hv160s....so that no matter how far or fast i turned the throttle the rpm built up at the same rate every time. That rate was adjustable, at its lowest it was a real kitten to ride....the only issue is it introduced a dead spot at the start of the throttle.....which in the video you can see by the breaks between when i power on and back off, i was actually applying the throttle again straight away but the dead spot delayed its start up.

 

[gwhy!]

I may be wrong but as I understand the throttle we have now a different value will give 100% throttle until the now value is the same as wanted value.

thats correct, even the small increments to the throttle see the motors providing 10+kw till the new speed is reached. Having a current based throttle will work with a dual motor setup....as your suggesting everything is running alot further from the point of failure than if you were using 1 motor. Phase amps shoot up with partial throttle opening ( which is what a current based throttle is going to do) but there is seriously no way to avoid it, and i have never had a problem with it. I had a servo regulator inline with my hv160s....so that no matter how far or fast i turned the throttle the rpm built up at the same rate every time. That rate was adjustable, at its lowest it was a real kitten to ride....the only issue is it introduced a dead spot at the start of the throttle.....which in the video you can see by the breaks between when i power on and back off, i was actually applying the throttle again straight away but the dead spot delayed its start up.

I setup a switch to change the full throttle resolution i.e switched 0-30% and unswitched 0-100% over the full range of throttle twist.. as I still wanted the instant response/hit from the throttle. This works well but still takes a bit of getting used to when switching. It would be very easy to set something up like this from a servo tester but the only prob might be that rc controllers do not like partial throttle for long periods.

 

[Ratking]

I may be wrong but as I understand the throttle we have now a different value will give 100% throttle until the now value is the same as wanted value.

thats correct, even the small increments to the throttle see the motors providing 10+kw till the new speed is reached. Having a current based throttle will work with a dual motor setup....as your suggesting everything is running alot further from the point of failure than if you were using 1 motor. Phase amps shoot up with partial throttle opening ( which is what a current based throttle is going to do) but there is seriously no way to avoid it, and i have never had a problem with it. I had a servo regulator inline with my hv160s....so that no matter how far or fast i turned the throttle the rpm built up at the same rate every time. That rate was adjustable, at its lowest it was a real kitten to ride....the only issue is it introduced a dead spot at the start of the throttle.....which in the video you can see by the breaks between when i power on and back off, i was actually applying the throttle again straight away but the dead spot delayed its start up.

I setup a switch to change the full throttle resolution i.e switched 0-30% and unswitched 0-100% over the full range of throttle twist.. as I still wanted the instant response/hit from the throttle. This works well but still takes a bit of getting used to when switching. It would be very easy to set something up like this from a servo tester but the only prob might be that rc controllers do not like partial throttle for long periods.

Then I will be your guinea-pig to find out what will work This project is making a powerful bike and thats the main point for me. First I have to make a good and solid frame, this problems will be taken care of when they show up.

 

[Ratking]

Hello

I've recevied my order from hobbyking, and I have started to play with makita packs and konion cells. I got 10 packs and will have a bunch more in a couple of days.
Let the charging begin. I got some pictures of my set up, it's just some cheap b6 chargers, I will buy a hyperion when the bike is finished, but for now, this will do just fine.

Interesting fact, three of the packs took over 3000mAh in one charge. One was 3300mAh and two was around 3200mAh. I know they are charged a bit high, and they will be charged to 4.1v cell in the future.

Another thing is that my new motor cogs alot more than the older unused one. I don't hope that indicates any difference in the powerband

 

[kfong]

You will need enough konions in parallel to keep those motors happy and not stress out your pack.

Good luck with the build, I look forward to the finished ebike.

 

[Ratking]

You will need enough konions in parallel to keep those motors happy and not stress out you pack.

Good luck with the build, I look forward to the finished ebike.

20 new makita packs is on the way and out of them I will make a 12s20p pack. That equals 30Ah and with 10c rating I can draw 300A for short burst of time. If I got enough space I will make it 12s24p. That is 360A of current just waiting to lauch me out to space 8)

You are right, I too look forward to the first ride, its gonna be legendary