Your garden-style car alternator can already be reused as it is, but with a little modification, it can actually be used as a powerful brushless motor. In order to demonstrate the function of one of these reconstructed alternators, [DIY King] bolted one to the back of an old bicycle and got some impressive results, frankly a bit scary.
We should state in advance that the modifications required for the alternator are quite extensive, so before you get too excited about building your own budget electric bike, you should check the previous guide [DIY King]. In short, you need to machine a new rotor and fill it with neodymium magnets recovered from the hoverboard motor.
Once you have your modified alternator, the rest is relatively easy. The trickiest part of this construction looks like cutting off the rear wheel bracket of the bicycle and replacing it with a plate holding the alternator and a pair of reduction gears drawn from a 125cc motorcycle. In addition, it is mainly electronic products.
Of course, you also need a very powerful speed controller. In this case, [DIY King] used a 200 amp water-cooled model for a large RC boat, although interestingly, he didn't seem to actually let water flow through this thing. He also assembled a custom 1,500 watt-hour battery pack installed in an MDF box installed under the seat.
In order to test his craft, [DIY King] took to the streets and allowed his bike to reach 70 km/h (43 mph) before his courage ran out. He thought the motor should be able to push it up to 85 kilometers per hour, but he said the bike started to shake too much that he couldn't really turn it on. In terms of range, he calculated that when cruising at a more palatable speed of 30 km/h (18 mph), he should be able to travel 100 km (62 miles) on a single charge.
If you like to re-adjust the motor and speed of the suicide bike, you will like this construction that uses a washing machine motor to push the rider to 110 km/h. If you are not worried about speed or range, then this super capacitor electric bike is certainly worth a look.
[Thanks to Mike for the tip. ]
I want to know what makes it swing at high speed. 43mph happens to be the fastest bike I have ever ridden, and my bike has become very stable and easy to handle anything over 10mph. But I have seen children shake their bicycles obviously when they go downhill. I just don’t know what causes this to happen on some bicycles, while others don’t.
It may be without a ball wheel. Due to the weight of the valve, the wheels of my beautiful road bike sway at a speed of> 50 km/h
Speed swing is the subject of a lot of splashing ink: https://www.sheldonbrown.com/shimmy.html https://selleanatomica.com/blogs/homepage-blog/the-speed-wobble-surviving-the-terrifying-cyclist-experience
Why a particular bicycle starts to swing at a particular speed is not clear, but there are many variables...
My experience is that additional spokes can increase stability. I have 36 spoke wheels, which are a bit heavy, but very suitable for urban potholes. I reached 55 mph on the long descent with no stability issues at all.
The "old-fashioned" steel frame provides the rider with the best power by reducing vibration and may also help stability. Aluminum and carbon fiber are too hard and will transmit vibration to the rider.
Steel bicycles are designed to have a fairly sturdy frame, but with a compliant front fork to provide the kind of riding experience you call it. It is not inherent to steel, which is what racers like. The carbon fiber frame is also designed to have a hard front fork, because this is the current style. If you put a slender thin steel front fork on the carbon fiber frame, it will bring you more classic luxury touring riding characteristics. This is the cool thing about carbon: you can give it any stiffness properties you want by changing the stacking direction. I have had 24 spoke wheels over 100 km/hectare several times. Wheel balance is very important. It is very important not to hit the resonance frequency of the tuning fork. The resonance frequency of a tuning fork is affected by its stiffness, head angle and rake angle. But only forward tilt/head angle/load can also cause oscillation conditions, especially for touring bicycles with heavier loads. As mentioned above, this is a very complex system, and there is rarely only one thing.
It should also be noted that the shimmy mentioned by people may be an unbalanced wheel, it feels like a radial disturbance, or a classic shimmy, which also involves yaw, or I’m not sure what its name is, but straight forward/ The fork swings backwards, there is no yaw (a little tilt), it feels similar to an unbalanced wheel, but it is much more dangerous. High-speed fork oscillations often lead to fork failures and terrible severe crashes.
The wheels are unbalanced and need to be taken to the tire shop because they have machines and counterweights to correct it. Although it is doubtful whether it applies to bicycle wheels.
You can consult a bicycle shop that specializes in bicycles used by world-class cyclists.
There may be other issues because your typical el-cheapo bike is not designed to ride at highway speeds.
If it were me, I would give up this method and buy a used scooter or 125cc street motorcycle.
If you check the geometry of the bicycle fork. Few (or no) rakes. More rakes will suppress oscillations. I have a lot of experience riding road bikes at speeds exceeding 60 mph (100 km/h). You will get vibrations from unbalanced wheels, but they will not shake.
ps My speedometer stopped at 72 mph and only exceeded it a few times. Speed excitement!
60 miles per hour! Wow. You must have more Olympic medals than this person: https://mobile.twitter.com/chrishoy/status/668112825894748161?lang=en
There is a maximum* difference between reaching a speed of 80 mph on flat ground through muscle power alone and obtaining that speed, because you are converting gravitational potential energy into kinetic energy (that is, going down a steep slope).
Yes-I often travel at 80 km/h on a large local mountain (riding a pretty good bike). No problem, and very stable-I can go faster, but I don't have the right gear... This seems to be much faster than when you are driving at 80 km/h in a car.
On the flat ground, I have no chance to do this..
Please note that I rode a motorcycle on flat ground at a speed of 220 km/h, which felt faster than 300 km/h in a car (I also did it).
In-depth/extensive in-depth discussion on this topic at https://marginalgainspodcast.cc/bifurcation-and-marginal-gains/
Strangely, in this case, this may be due to weight distribution/offset and tourq from the motor.
My brother recently encountered the same problem when using the cargo bike he had been using. Has been rebalanced to the wheels etc... but in the end it was due to how he concentrated his weight near the rear axle of the bicycle.
In the case of this bicycle, the swing may be due to the need to move more weight/mass to the front. Due to the Tourq of the guy on the bike and the air resistance, the front wheel is raised.
If the battery is installed on the top post, between the seat post and the handlebar. It will have better weight distribution.
My fat tire electric bike hasn't shaken yet, I have completed the downhill bomb at 54 mph! Maybe bigger is better?
From the pictures showing the location of the alternator, it is obvious why the bicycle is swinging at a higher speed. It is not centered, so there is more weight on one side of the bicycle. I bought a 1000 watt electric bicycle rear hub motor kit from ebay and a 52 volt 20 amp-hour triangle battery-put it in the triangle of my frame to balance the weight! Starting to fully charge on a flat road, I can reach 43 mph by not connecting the two blue lines on the controller! I can only use the throttle to stay at around 250 watts (approximately 15 mph) and drive on flat roads or drive more than 40 miles! Don't step on the pedal!
Haha, our settings are almost the same! Mine is Violamart 1500w 48v rear hub motor, UPP 52v 20aH triangular battery. Bicycle towing@$$! 40 mph cruising, maximum 45.6 mph Ebay has a 17-inch Raleigh aluminum frame, reused/rebuilt the Manitou susp fork of the 00s, at a bike shop for $15. A lot of parts were transferred from other mountain bikes around me. I think the money in me is less than $1,000, but except for Sur-Ron Lite Bee (which I also want to own), it prohibits all factories. Not shaking, as solid as a rock. It's just a matter of twisting and paying close attention to things. I am an old professional shop bicycle wrench, so it is easy for me.
Some older motorcycles have so-called layered dampers. It is a small shock absorber installed from a bicycle frame to a layered front fork. This will prevent the bicycle from swinging at a higher speed. I hope this information is helpful to you. A friend of John Anst.
So, are those rental scooters that have been littering the sidewalks of our cities for the past few years are another good source of neodymium magnets? B^)
My vote for the cause of the swing is rear wheel alignment. If the rear is not fully pointed forward, will this happen on a motorcycle?
This is a lot of torque from a small diameter motor. I thought that only planetary gearboxes can match the load
If you have a gear lever, especially an older model with a direct drive starter motor, just the starter motor can pull your car out of the ditch. Only try with an old agitator, the flywheel teeth may peel off, and the motor may be burnt if it gets stuck. Your battery is not very good either.
When your car breaks the timing belt, this is the way the countryman moved to the trailer.
When you run out of two blocks, it also applies to reaching the gas station...
From the video, it sounds like he is also surprised by its effect.
When you try to break the speed record on the salt flats, even a motorcycle will swing at high speed like some people. Part of the reason is that due to lack of air downforce, the reason why the tires actually start to leave the road more is simply due to the bending of the tires, because they are not designed for high speeds, and they lack a tread that has a contact area with the road. In the case of wheels with small spokes, the spokes are actually under pressure and will not maintain a perfectly round wheel. The entire package of the bicycle and the rider is also impacted by the air, which moves above and above the bicycle and the rider. The faster you go, the more you will be affected by these forces, all these forces. I used to ride a Kawasaki Super Street Bike equipped with a full fairing at 140 mph, and did not notice any shaking, but I think most of the reason is due to the bicycle’s fairing and design, and its design purpose It is to drive fast. Bicycles are not designed to run fast, they are not equipped
Road bikes are definitely designed for fast cycling, look at the downhill on TDF, driving at 100 km/h on windy French country roads, and the road surface is poor. Look at the ratio of top gears! Check the aerodynamics of helmets and bicycles and clothes, and even shoes are tested in the wind tunnel. The design of the bicycle undoubtedly takes speed into consideration.
Yes, many people don't realize the speed that a bicycle can reach. I once picked up and drafted a semi truck on the top of the hill of my Cannondale R1000 road bike. Driving at 62 mph (99.7 km/h), then I flinched, haha! The whine of those slender 24c tires is terrible...only one meter from the bumper!
Rail bikes can easily reach a speed of 110 km/h. Likewise, every part of the bicycle is designed for these speeds and has nothing in common with a standard bicycle.
It is also possible that the rim loses shape at this speed and starts to oscillate. Due to the weight of bicycles, motorcycles either have sturdy rims or strong spoke wheels, so they are not easily affected, although they can shake if they are not properly balanced. He should tie a high-speed camera to the side to see if he can see the value point or the complete deformity of the tire shape itself at high speed. I think it may also be a slight misalignment on the wheel hub.
I installed standard Sun 36h front rims on a standard Shimano super-large front hub-my DIY e-rig cruises at 40 mph and is rock solid. It's just a matter of keeping the wheels properly tensioned and trimmed. Unpowered road bikes and mountain bikes always reach a speed of 40 when going downhill.
Why do I need to replace the rotor? If you just send a controlled current through the field winding and use a simple PWM controller, it should work without any other modifications, except for replacing the rectifier diode with a three-phase controller. The car alternator is basically a SepEx motor and can be driven in this way.
From what I have read, it is not that efficient or powerful. The shape of the rotor poles is like a triangle instead of a bar, and the stator poles are. It might be to make it quieter instead of complaining. Delcotron's pulley fan has non-uniformly distributed heat sinks, I think it is to reduce noise. After all, there is more power available, so it slides more and does not cause too much cogging load on the fan belt.
When using 4:1 gear reduction, the alternator can only run at 2500 rpm at 70 km/h, which is far from its peak power-it needs to consume a lot of amperes to get the required power, just to heat the motor Winding. The I^2R term will kill you.
Of course, this is HaD, but it is obvious that this thing has only been hacked. You know, it's not actually by design. Adjusting it to a ratio of 8:1 or 10:1 to make it around 8000 rpm will be more efficient and powerful. The motor heat loss will be reduced by 75%.
Indeed, the acceleration of the alternator is usually very significant on the car, 4:1 sounds very believable, and the same is true on the engine of 6-8000 rpm.
However, I don't know if this translates to optimal efficiency when used as a motor-usually the transmission on the alternator can provide a lot of power, and the engine cooling fan spins when the car is idling in traffic and the AC is running at full speed.
In the 1970s, I used to go downhill at a speed of more than 60 mph on the Royce Union 10 spd. According to today's standards, this is considered rubbish. I did not encounter any stability issues. I could easily run faster, but I have reached the limit of my legs and cannot keep up with the pedal speed.
Lol...people didn't survive until they drafted a semi truck down the hill! I jumped one on 18 pounds. Cannondale R1000 road bike-slowing down at 62 mph... The combination of the silence of my tires and more and more whining became terrible, hiding behind the trailer bumper... . I had to let go, he didn't know I was there, so... if... it's super dangerous, he just stepped on the brake!
The performance seems to be similar to my 1500kW electric bike. There is a huge difference in efficiency between such hackers and engineered products, or there is a problem with the way they measure power. It would be great if they use peak power for six minutes to see if the battery is dead.
My previous comment was deleted, apparently to point out the same thing. I was even careful to avoid swearing, so I really don’t know why the editor felt the need to review me.
This design only uses 4:1 deceleration, so the motor only runs at around 2500 rpm at "full" speed. If it is allowed to be reduced at a ratio of 8:1 or 10:1, then it will get more power and be more efficient. Under the same output power, it will reduce the motor current by half and reduce the motor resistance loss to a quarter. . OP even pointed out that the motor is very hot at the end of short-term operation.
I made a DIY electric motorcycle/bike, which cruises comfortably at a speed of 40 mph and a top speed of 45.6 mph. It is as stable as a rock at these speeds because it is specially manufactured. It is just a 26-inch Raleigh 17-inch aluminum mountain bike frame with a redesigned 00's Manitou Pro suspension fork in the front. (At motorcycle speeds, at least the front suspension is a must!) Cheap but fully sufficient double-inner tube, new inner tube combination tire, rear puncture-resistant inner tube, both are available. The standard 36h Sun rim has a V brake at the front and a Violamart 1500w 48v hub motor at the rear with Shimano discs and 12ga spokes. The 20aH 52v battery provides me with enough range and power to allow my daily commuting equipment to carry 80 pounds. The trailer loaded with groceries, propane and water returned 8 miles, increasing the altitude by 2,000 feet.
Due to various eccentric rotational forces caused by the offset installation position, the structure of the alternator may fluctuate, not to mention the individual static weight offset!
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