I'm extremely surprised to hear that soldering the XT90s was hard. Even a $20 Pinecil (well, maybe I shouldn't say "even", it's a fantastic iron) can handle those no problem.
Also, what cost 1200 EUR? That motor costs 30 EUR, an ESC another 40, and the batteries maybe 80 EUR for Li-Ions (less weight). Were the CNCed plates that expensive?
EDIT: Added the praise I meant but realized I forgot to actually write.
But if you take that perfectly good soldering iron and apply it to AWG 10 wire, you're going to have a bad time - because the wire will conduct heat away almost as fast as you can apply it.
ps. thanks for the tinning walkthru below
Once the wire goes in, you remove the iron, hold the wire there for a second or two until the solder solidifies, and you're done. I used 12 AWG but it should be pretty close.
EDIT: I just did it again, make sure you hold both the wire and the XT90 firmly with helping hands or something similar.
A 2400W motor is very powerful for a bike. For Americans, 750W is one horsepower so that's over 3 HP which should get the bike to ~40mph or 70km/h.
I have a 2500W Luna Cycles fat bike (52V BBSHD mid drive motor and 12 speed drivetrain). It climbs hills effortlessly. It powers through sand and snow. It's been a lifesaver on uphill technical singletrack when I've had to stop and a blip of the throttle gets me going when I wouldn't have been able to just with pedal power.
I have no idea what the top speed of the bike is and don't care. 90% of the time I'm doing under 20 mph and almost all of the remaining time I'm doing 20-30 mph. I've ridden 750W hub drive bikes and they're not even remotely comparable. This is what people who cling to the antiquated eBike class ratings and watt limits don't understand. It isn't about top speed (I think doing >35 mph on a bicycle is crazy) it's about torque application in circumstances that demand it. I'm considering upgrading it to a 72V battery and 4000W controller.
Before I got the bike I wanted the most powerful one available but I realized after getting one you don't really need that. And it's actually kinda dangerous, even for a experienced cyclist who's used to speed.
Even the standard tier batteries are more than enough for any urban biking in terms of distance. I rarely use even 20% at 48V, 10.5A.
Cargo e-bikes tend to be at or less than around 1kW. 750W is still considered fairly powerful, and 500W is much more typical and still plenty enough for even a cargo bike to get up a hill, with appropriate gearing. 250W is about the standard for low-end e-bikes.
2.4KW is gross overkill, especially if you're not doing direct drive. More watts just means you can go up the hill faster. This assist motor is driving the wheel through the rear derailleur so it potentially has a pretty wide range of gearing.
Tour de France cyclists racing up mountains generally sustain around 400W, which is enough to go 25+km/h for hills that aren't too steep.
So far the simplest assist I can think of would be a front wheel hub motor and a switch that turns on a constant amount of torque. This would still let me control my speed by how hard I pedal. Of course I'm scratching my head over how I would control it, since it would probably not be an off the shelf controller. But I'm also fascinated by the electronics, and having to design my own controller would be a benefit, not a liability. I also have an obsession with knowing how things work, that I have to contend with.
Of course all of this is until I think of something better.
On the controls side of thing, I have the ECU and an Arduino Nano. The Arduino uses the BEC port of the ECU as a voltage supply to run a simple routine translating the analog output (potentiometer) from the throttle handle to a PWM signal that the ECU can understand.
The way that the assistance work is that while you are pedaling, you can turn the throttle and adjust until you get the assistance you want - pretty simple. After a while it becomes natural.
The simplest: sure. However if you're used to cycling chances are you're not going to like that front wheel hub all too much. It feels weird overall (might depend on geomerty though) and has the tendency to slip on upwards sloped unless you do an effort of getting weight over the front. For my personal taste, hub in the backwheel feels the most natural.
Mine will pull almost 750W going uphill on a freshly charged battery.
It has a very prominent "200W" label on the outside of the battery holder.
If I rode it like an asshole, doing 45kmh on sidewalks, I doubt my "200W" label would do me any good. But I've had it eyeballed by police when they're doing their semi-regular "fine everybody without a helmet or a working bell" crackdowns on CBD commuters and have stopped me to check my bell works, and never had the power questioned.
Otherwise looks good!
When I got a 3D printer it was amazing to be able to make my own designs, but I wish I had the capability to work with more durable materials.
Thanks!
3d printing is here to stay, but load bearing parts are problematic. I had to change some of them to metal.
(Sorry if that's answered in your linked post, I skimmed it perhaps a little too quickly...)
The high-end E-Bike I rode briefly did a marvellous job of detecting road conditions and maintaining semi-constant speed. The ones I use on the street are more crude, they use pedal effort as a primary guide to intent but back off aggressively, I guess to limit risk to pedestrians. I am pretty sure off-road wouldn't want that. (not a big e-Bike rider, just fascinated)
If it walks and talks like a bike, and only goes as fast as the average cyclist, it is probably a bike. But if it has a throttle and goes faster than your average cyclist, it's probably closer to a moped at which point you need a license, different kind of helmet, turn signals, registration, so on and so forth.
Older bikes used the circumference of the wheel and a count of rotations to calculate the speed, so people could de-limit them by changing the stored circumference constant in the eeprom. Modern e-bikes use a combination of sensors at various locations to detect motion, acceleration, pedal force and tilt angles to decide how to apply the power but I think even with those added sensors, the speed is still detected via the wheel rotation sensor.
Seems some people don't like the regulations as the parent comment got downvoted, rest assured I did not single handedly write the global regulations, and I don't like the speed limiter either.
The motor sticks out uncomfortably close to the pedals and particularly on a MTB I could see a rider accidentally stepping on it...and it looks like an outrunner, so that would also be quite bad, as the foot would get launched backwards pretty violently.
This is a lot of effort compared to just bolting on a Baofang mid-drive motor. The components are also placed such that unless you have a pretty good front fender, they'll be covered in crap in no time.
To get up steep hills, you need not only a powerful motor, but also chains and gears to handle that power:
https://electrek.co/2022/02/23/biktrix-xd-unveiled-as-mind-b...
I also love that it's internally geared, I've always felt this made way more sense for mountain bikes anyway given the weather protection. Good stuff!
It appears this e-bike only has a single-speed chain drive, and only a throttle for adjusting motor speed.
- chamfer all exposed 90 degree angles
- shrinkwrap the whole thing so it is protected from the weather and dirt
- add a connection at the top of the motor frame to the bike to better deal with the reaction forces
Any estimates of your expected range?
I think we're about to see a lot of innovation in scooter- and bike-adjacent mobility things - I don't mean the motors, but the frames etc... eg we might see more cargo e-tricycles?
Very useful site with more similar examples, but just in case you want to save them some bandwidth in load ( it contains multiple images of the bike):
>Hey, congratulations. Traffic is flooding in from ycombinator to this thread and we're getting slashdotted :shock: I just now had to upgrade the server to a huge one temporarily.
Are you important on there or something?
* A VESC based ESC instead of the HobbyWing one will give a lot more control and telemetry, including a phone app and detailed current use logging. I know from RC planes that HobbyWing ESCs are very high quality, but VESC is specifically written for drive systems and has a lot of features.
* LiIon or LiFePO4 round cells are safer and more energy dense than LiPo pouch cells, at the expense of current sink capacity you don't need. They're also cheaper.
The ECU selection was primarily budget driven. I need to have a look at those VESC.
Battery selection was again budget driven. The also hat to have certain dimensions to fit inside the kit.
https://pine64.com/product-category/pinecil/?v=0446c16e2e66
About bicycles, unfortunately I'm too big for them; even if I wasn't overweight, my mass would exceed 100Kg anyway, but hope to see 3 wheeled EVs imported or produced in Europe. Someone here mentioned Arcimoto a while ago and now I'm in love with their Roadster model after seeing a video. Unfortunately, high price aside, it's US only at the moment.
Or simply use too small an iron for the job. XT90 isn't the problem here, more likely it is the fact that the wire drains heat so fast that you don't get to a nice temperature.
I suppose a throttle is a much more direct connection between your mind and the motor control, unfortunately they are illegal in my country.
[1] https://hubsink.com/products/high-performance-domino-twist-g...
Given the KV rating of the motor and your max voltage you can calculate the max rotational speed of the motor = KV*V. From there it is just a matter of multiplying by all gear ratios along the drive train to calculate the rotational speed of the rear wheel. Knowing the circumference of the 26" wheel gives you the max speed.
noise: quite a bit
also bear in mind that just 100w added to someone which is already sportive is quite sufficient for commuting. going harder would put excessive wear on bike chains that for me are already excessively thin.
now, tires and brakes. did you use bicyle grade tires that are way too soft or some ebike rated tire that are much harder ? also brake, olease check your brake, you don’t need to be electric for make the brake suffer, so that you need bigger discs, ceramic pads…
After building this, I'm dreaming of building something very elegant - a 50W to 100W torque generator that is tiny in size and very lightweight, and it fits within the hub of the wheel. Maybe not using batteries at all, but supercapacitors the are charged when you brake and discharged when you accelerate.
I was watching a video of some Russians converting a very old bike using the motor of a washing machine. Very amusing: https://www.youtube.com/watch?v=dDizHIjZqBM
That contraption looks a bit scary of course but it goes to show that building a e-bike is not that hard. Which is I guess why there are so many companies doing that right now.
This one is really nice though.
I live in a big city (Berlin) and e-bikes are perfect for getting around town. You see a lot of the delivery services using them. Also in a weird bit of investor inception, you see drivers of one VC funded company basically using the e-bikes or scooters of other VC-funded companies.
