The story of another electric bicycle with their own hands: reloaded

Greetings, dear Habrasoobschestvo.
Inspired by the articles by chomper
"The story of another electric bicycle with his own hands"
and "The story of another electric bicycle with my own hands v2.0" , decided to create something of their own.

What happened, so to speak, "based on" as well as a lot of photos and text - under the cut.

Adherents motor-wheels I will say right away - I do not want a weight weighing 7kg either on the front wheel or on the rear one. I work on the third floor and carry this charm upstairs - no, thank you.

From the original sources, the concept was taken and rethought to suit your needs.
The motives of the construction are partly trivial - I want to go to work by bicycle, but one slide completely kills all impulses, and partly not - I wanted to touch the “electric bike” with my hands.
')
The basis was taken mongrel bike, bought many years ago from peddlers “used. from Europe ".

From the purchase:

- Front sprocket B. at. 50 teeth, I do not know from which system, was chosen from what it was.
- Perekidka, used. for use as a chain tensioner.
- Left carriage cup with clamping ring (Contraking?)
- And of course the chain.
- Fasteners in stock.

I had an old rear sleeve.

Now on the construction nodes

It was decided to abandon the fastening by the needles of the sprocket transmitting force to the wheel immediately.
I used a regular mount under the disc brake with the disc. The asterisk is bolted to the disk.
I apologize for the dusty bike.



I anticipate questions about the 2 screws between the 6th disk mounting - these are screws that fix the thread of the disk mounting from unscrewing. I agree, the decision is controversial, but it still works.
Yes, there are rear bushes in nature where the disk mount is a single whole with the sleeve and then you would not have to use "matches and acorns." But under certain circumstances, I had to do so.

Freeville (ratchet)

Fastens on the cup from the carriage, countercontacted by a native ring from the cup.

Rear hub used as intermediate shaft

Installed in the P - shaped section of the pipe.

Large gear wheel

Fixed from turning on the shaft with a pin, without it the sleeve itself “clamped” with cones.
A groove is milled in the gear wheel, a hole is drilled in the shaft and a pin is inserted, which lies in the groove in the wheel.

Small gear wheel

Fixed on the motor shaft with 2 tacks.

Engine

Fastened with a standard crosspiece for the L-shaped structure found in the bins.

Chain tensioner

Attached to the side of the trunk.



Everything is mounted on a structured plate of hard aluminum, which in turn is fixed on the sides of the trunk.

General form

For the most attentive

Why is there a lanyard.



This "crutch" appeared in the process of refining the design. The engine has enough torque to deform the carrier plate, while the tension of the belt weakens and it slips. Solved the problem "in the forehead" now everything is fine.

According to the electrical circuit

In the servo tester, the variable resistor was removed and a hall sensor was connected from the gas knob instead.
Also installed is a resistor of backwater 1k in the button chain, since without it, switching of modes was observed, apparently due to interference.

At the moment, the scheme looks like this.



In order not to pull the power wires through the entire bike, a wattmeter has a shunt removed according to the method from this site .

Also, the “+” power supply and “+” measuring are separated, in the future I’ll put an isolated 5V to 9V converter (found in network cards with BNC), as in the current circuit there is still some underreporting.

The battery is operated without BMS, to prevent overdischarge, it used a battery monitor tuned to 3.3 V. When it reaches the set or less voltage, it can squeal very loudly at any bank.



I charge IMAX B6 clone in Li-Io mode with balancing. Why not Li-Po? Because a charge of up to 4.1 volts instead of 4.2 should theoretically increase battery life.

What happened in the end

Total reduction - small gear 15 / large gear 72 * freeville 16 / large star 50 = 0.0667
Maximum engine speed at a rated battery voltage of 22.2 * 200 = 4440
After the reduction of 4440 * 0.0667 = 293.5 rev / min per wheel.
With a wheel diameter of 650mm (let it be 640 under the load of the rider), the theoretical speed is 35.4 km / h
In practice, a speed of 33-34 km / h has been recorded along a straight line and on minor slopes, which is close to theory.
Energy consumption - peak consumption (according to the wattmeter, and they can be slightly "in parrots") 1200 watts
Average consumption with fast movement uphill with a slight slope of 600-800 watts. In a straight line 100-300 watts.

Proof

I tried to shoot a video.
Taking into account the road and shooting “from hand”, the video turned out to be so-so, but something can be considered. For a general impression, there are cut frames - the beginning of the slide , approximately the 8th second of the video and the 27th when there was a maximum current consumption. I don’t know the slope of the hill without the help of the legs, only on the electric motor at the maximum "gas", for those who want details the route from Google Maps.



Another video, driving in a straight line, at the end of a slight acceleration (to catch the green) route .

findings

In general, the concept is quite viable, the impressions of the system are positive. He copes with the task completely. Because of the sensorless engine, it doesn’t naturally pull from the spot, at first we accelerate to 10-15 km / h with our feet, then smoothly give "gas". If on the climbs to help the electric drive with your feet “without straining” and maintaining a speed of about 20 km / h, it turns out to be very economical.

There are plans to increase the battery capacity, install a casing on the drive, clean up the electrical part.

About recovery

The idea of ​​recovery is still in the air, but very controversial.
If in my case, to remove the ratchet, then due to the high reduction, it would be very uncomfortable for me to just go on the pedals. And with my modernization I wanted to keep the opportunity to just ride a bike, which I do on straight sections of the road. This is one of the cons, plus there will be a significant complication of the electrical part with the need to design rather specific nodes.
And the most important point, the battery is not recommended to be charged with large currents, and recovery just provides just such a mode, a large current in a very short time. And this will lead to a decrease in battery life.

Thanks

I want to say a big thank you to my godfather Andrew, without whom my crazy ideas would never have been embodied in metal.