bafang BBS02B electric bike conversion kit

Bafang Electric Bike Conversion Kit Or How To Build An Electric Bike.

Hey there! This is a story about how I assembled a winter bike, and not a simple one, but with an electric motor using Bafang BBS02B electric bike conversion kit.
So if you’re wondering how to make your bike electric, this article is for you!

Let’s get to know the electric bike conversion kit together. The review is voluminous, it contains a lot of photos, technical features, and analytics, so I’ve created an interactive table of contents.


To someone, my choice will seem strange or the prices are ambiguous, but I was guided by my preferences.
My review is just a story about my purchase and my experience in using this ebike conversion kit.

I had a nice MTB bike. Carbon and rigid on 27.5″ wheels. But in winter it’s hard to ride it, kneading snow takes a lot of energy.
I didn’t want to buy an electric bike, because I knew how much does an electric bike cost and that was out of my budget. So I collected money, decided to upgrade my old bike for winter skiing and generally try new riding experience with an electric motor.

The electric bike was assembled on the basis of the cube AMS 100 double-suspension frame with a 26″ wheels.

Why did the wheels remain 26″?
Despite the fact that marketers are actively killing this wheel format and perhaps, there are no normal new bicycles with this size of wheels now in the market.
And there are two reasons:

  1. My short height is 170 cm.
  2. And most importantly, from the last bike, I still have strong wheels in a complete set (and this is a significant saving) and of course, it’s too inconvenient to keep two sets of tires at home.

Component Selection

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Motors for bicycles are of electric and gasoline types. Gasoline for an apartment is not an option at all.
There are roughly two types of electric motors for bicycles:
– motor-wheel, which in turn are gear or gear-less.
– mid drive or hub motor (instead of the pedal shaft).

mid drive vs motor wheel

The advantages of the mid drive electric bike compared to the motor wheel begin with its installation on a bicycle:

  • no need to change, the spoke wheels, the motor is installed instead of the carriage;
  • all connectors are compact and waterproof, it is impossible to connect incorrectly;
  • no need to think where to attach the controller, it is built into the motor;
  • no dropout amplifiers are needed, the installation is suitable for any type of dropouts (including the axis);

Geared drive vs direct drive electric bike

In real life, a mid drive electric bicycle beats the direct drive motor wheels (but not the geared motors) in the following:

  • suspension work does not deteriorate due to the fact that the wheels remain light as before;
  • with a dead battery, pedaling is as easy as on a regular bicycle, since the motor is located outside the rotating parts (on a muscular drive, the main forces are spent on spinning the wheel, the easier it is, the less we spend);
  • ordinary spokes and rims last longer since there is no “weight in the wheel” (motor), which creates a destructive effect;
  • the ability to choose a gear according to the road: when driving on loose soils, forests, and steep climbs, you can choose a lower gear and confidently and economically move forward, and in the city, you can comfortably merge into the stream by switching on a higher gear;
  • it is minimally noticeable as a low-power gear motor-wheel, but at the same time much more powerful at the rugged terrain and in elevations than even a 1000-watt motor-wheel, due to the ability to use gears;
  • it remains possible to easily remove the wheels to seal or replace the camera.

Of course, there are disadvantages to this option, but we will talk about them at the end of the review.

Why did I choose Bafang mid drive motor?

Branded mid-drive electric bikes have small flaws – huge prices and a software speed limit of 25 km/h (according to European standards, and also according to traffic rules).
In the Chinese market, the rules are softer, there Bafang/8FUN is a monopolist, I chose from the assortment of this company.

The Bafang electric bike conversion kit with a 1 kW BBSHD motor is certainly more interesting in terms of power and this is an electric bike kit with a battery, but:
– more expensive (~ $ 1000)
– larger
– heavier by almost 2 kg

I also needed to put my 150 watts in my legs somewhere 😉 and I decided to take the version of 750 watts. This is a certain optimum in terms of power/weight/price.

Well, I’ll immediately give you a low-budget option, who decided it was very expensive LOL:

how to make an electric bike with a drill

Package and equipment

bafang conversion kit package

Amazon delivery worked like a charm, in one week the box appeared in my hands. The Box with the electric bike hub motor conversion kit with battery weighs 12 kg!
Reliable packaging:

bafang conversion kit package inside

Inside, everything is packed in polystyrene foam.

Parts listed inside the box:

bafang electric bike conversion kit parts

There are a lot and you can even get confused at once, but we will consider everything in sequence. The important thing is that this is a complete electric bike hub motor kit for converting a regular bike into an electric one.

Mid drive electric bike motor Bafang BBS02B

bafang mid drive motor

This electric bicycle mid drive kit is not a new egg on the market; there are voluminous threads on the electric transport forum about it.
Mid-drive electric bike motor specs:

bafang mid drive motor specs

Marking B at the end of the Bafang BBS02B motor means an improved controller with MOSFET transistors IRFB3077.
I have a 68-73 mm version for a carriage, there is also a version for fat bikes with a 100-120 mm carriage.
The front sprocket fits on a gray flange with five threaded holes:

bafang mid drive motor rear view

It rotates independently of the pedals. Connecting rods – square.
Thread on end of carriage shaft for fixing motor:

bafang motor front view

5 wires come out of the motor:
– Power from battery
– Speed ​​Sensor Connector
– Shift sensor connector
– Splitter connector, everything else connects to it
– Wires for headlights 6 Volts

bafang motor cables

The following things you need to connect to it:
– Controller control screen
– Brake Ends (2 pcs.)
– Gas handle
Rubberized connectors are everywhere, they are inserted tightly and there are guides and arrows on them – you can’t insert them incorrectly, very thoughtfully.
Weight of the motor (in grams):

bafang motor weight

The controller is integrated into the motor, flooded with a compound and looks like this:

bafang motor inside

USB cable is for thin controller programming. It is also possible to connect a gear shift sensor, which turns off the bicycle electric motor when shifting gears on a cartridge (this reduces wear on the chain and cartridge).

The electric bike battery

How large is an electric bike battery?

Form factors and mount points of batteries for an electric bike are different:
– trunk mounted
– seatpost mounted
– into a triangle in a frame
– to the place of the bike bottle in the frame (my case)
There was an option to buy a battery case and supply your 18650 cells and install a BMS board.
Included battery from Bafang electric bike conversion kit is of regular size:

the electric bike battery

Electric bike battery specs:

  • 624 WH Li-ion battery (48V 13AH battery)
  • Cell: 4.2V 18650 2600mAh cell 1.5C discharge
  • Assembly: cell 13S5P, 65 pcs.
  • DC discharge current: 20 A
  • Maximum discharge current: 40A
  • Weight: 4 kg
  • Gives range: 45 km (750 W)
  • BMS: charge balance, overheat protection, low voltage protection
  • Disconnect from voltage, disconnect from low voltage, etc.
  • Charger: 48 V 2 A
  • Lifetime:> 800 cycles
  • Charge temperature: 0 ~ 45 ° C
  • Discharge temperature: -20 ~ 65 °
  • Here is a more capacious version for the same voltage of 17.5 Ah
  • Dimensions:
electric bike battery size

Bottom with the mounting bracket removed:

electric bike battery bottom

The base of the mounting plate is a steel DIN rail

electric bike battery plug

Anderson type power connector, excess cable lengths.
There is a general charge indicator (4 segments):

electric bike battery charging lights

Charging port with rubber plug:

electric bike battery sockets

The general switch is somehow tiny.
It is a pity that in this model there is no USB 5V 2A port for powering devices, it would be useful.
Locking mechanism:

electric bike battery lock

and two keys included, this is for anti-theft protection.
Battery Weight:

electric bike battery weight

And all this hangs on a pair of M5 bolts on the frame, I think we need to insure with screeds.
The inside parts are not tricky:

electric bike battery elements

Battery assembly type 18650.
In my case:

electric bike battery parts

Ordinary Samsung do not hold frost at all – I know by block 4×18650 to the bicycle headlight, but what kind of dynabat MX18650-26p is here… will hope they will work on frost.

The Charger:

electric bike charger

How long to charge an electric bike battery?

Well, my full charge time is around 5-6 hours. Heats up very much when working.
Charger Specs:

electric bike charger specs

Standard connectors:

electric bike charger plug

Inside parts

electric bike charger parts

Consumption from the network when charging about 100 watts, for one charge wraps around 0.4 kW in 5 hours:

Consumption from the network

Rest of the e bike conversion kit

Another important element of an electric bike kit is the motor controller control panel.

electric bike LCD

C965 Control Panel Features:

  • Display: LCD
  • Rated voltage: 24/36/48 V
  • Support PAS modes: 0-3 / 0-5 / 0-9
  • Protocol: UART
  • Dimensions: 107x58x70 mm
  • Steering wheel: Ø 22.2 / 25.4 / 31.8 mm
  • Backlight: yes
  • Protection: IP 65
electric bike LCD description

Information displayed:

  • Current speed
  • Maximum speed
  • Average speed
  • Trip duration
  • Trip distance
  • Odometer
  • Battery level
  • Error Codes

Control buttons:

electric bike control buttons

I put under my left hand. The buttons are small, in winter gloves are uncomfortable to press!
By modes and functionality:
Power button (long press) – turns on the screen, starts the controller, and also turns off.
Short press – switching the data of the bike computer (mileage, travel time, average speed, maximum speed, etc.).
The + and – buttons switch the support level. I have 0, 1, 2, 3 configured (There are options 1-5 and 1-9).
Long press on plus – activation of the headlamp.
Long press on minus – P mode (pedestrian) – the bike rolls 5-6 km / h.
Press + and – at the same time – enter the menu.

In the menu you can configure:
Resetting the bike computer, screen backlight level, auto power off, bicycle maintenance reminder, etc.
But the most interesting is already in the additional, engineering menu (the entrance to it is from the main one using password 0512): Here you can set the diameter of the wheels and remove the speed limit, or rather you can set your limit.
Speed, by the way, shows 1-2 km/h higher than GPS.

Square hole crankset:

Square hole crankset

Now you need to have a squeeze for the connecting rods in the tool kit.
Options for front gear for the motor:

Options for front gear for the motor

My gear is 44 tooth and it has offset and plastic protection:

Throttle grip:

electric bike Throttle grip

The speed sensor works on the principle of bicycle computer sensors: magnet and reed switch.

Brake levers for mechanics:

electric bike Brake levers

Mounting wrench for installing the motor:

Mounting wrench

It looks courageous. Cut out in a fast laser from black rolled 4 mm thick.
It is not convenient for them to work, which is natural, since there is no bend for convenient access to the carriage.

Bicycle part

I just wanted a two-suspension. Since my riding style is country-trophy)) Electric motors are less likely to be installed on suspensions, as it is more difficult.
Frame Cube AMS 100 the year 2011.

Frame Cube AMS 100

I was looking for it, despite the pop brand. I bought it on E-bAy. The frame is reliable, and lightweight (triple butting), with available bearings in the suspension.
I liked the suspension work. Four-link rear suspension, 100 mm travel.
I had a Cube XMS 120 2013, and I did not like it. The frame is heavier and easier to suspend.

Air fork 26″ with 100mm “Manitou machete pro” is expensive, but it works fine. I will tell you about it separately.
It was possible not to bother and put a spring-oil inexpensive fork, but I decided that since the rear suspension was in the air let the fork be the same.
As it turned out, finding a normal 26″ fork in the air with 32 mm legs on eBay is not so easy. It’s more logical to look in local stores or on forums.

normal 26" fork

Wheels, switches, and brakes have remained from the past 26″ bike. Transmission 10 speeds. Until I will understand better in electric bike transmission behavior I will not invest in new iron.

For my new electric bike, I decided to buy serious wings. Usually, I cut out bits of plastic paper folders, but this is not the case – the dirt flies abundantly from under the wheels at high speed.
The choice fell on the SKS grand d.a.d and grand m.o.m 26″ respectively.
The wings are cool and wide. The only negative is the sophisticated front wing mounting system.

wings are cool and wide

How to install an electric bike motor?

Frame Cube AMS 100 side

I left the frame of the front derailleur, it will work as a chain protection. There is a shift of the Q-factor of the pedals to the right. Despite the fact that the connecting rod could definitely be placed a couple of cm to the left if you set a goal. Hello to Chinese engineers 🙂

How to install electric bike motor

On the Cube, the carriage is 73 mm, so the second nut from the motor mount kit did not screw on, there was not enough thread.

How to install electric bike motor

I decided that this motor mount is unfinished. Only the frictional force between the bracket of the carriage and the nut keeps the motor from turning around the carriage.
First I put one nut – the motor cranked, then put the nut on the thread lock, the motor cranked again.
To exclude rotation, the emphasis is needed; on one friction, 4 kg do not hold during vibration.
The new bracket is the result of my R&D)):

The new bracket
The new bracket and mid motor

How much the motor reduces the bike clearance:

How much the motor reduces the bike clearance

Now the total bike clearance is 24 cm on the rubber 26 “Schwalbe Nobby Nic 2.25” pressure 1 bar.

How much does a electric bike weight?

The total mass of the bike came out 22 kg. Is this a lot? Yes, a lot for a regular bike. For a mid-drive electric bike, it’s an initial level.

How to wire up an electric bike?

How to wire up an electric bike

Measurements of current without load around 2.9A:

Measurements of current

Bike photo

Habitat photo:

bike photo

I ride 90% in the evening and at night.
This is how the control panel backlight works:

ebike at night LCD

In daylight:

ebike on daylight
ebike in forest
ebike in snow
ebike lcd in snow

Conclusion with impressions

Special features of the Bafang electric bike conversion kit:
They write about the noise of the carriage motors, I do not agree. The sound of the gearbox is a bit noisier than the sound of tires, certainly not like a car.

Integrated motor controller. This solution has both pros and cons.

The gas trigger immediately gives full gas.
Smooth gas control is possible only after reprogramming the motor.
The control panel screen is inconvenient (high), it can be inadvertently broken when turned over – therefore I’ve installed the bike horns.

Battery performance in winter is a concern. Capacity drops rapidly! At -10C there is enough for 30 km of everything. If you bother for winter, you need to take LiFePO4, which works in the cold. But they are more expensive and heavier.
Well, about the stupid mounting of the motor, I wrote a lot.

What I would like to change/add:

  • Cable for reprogramming the motor – you want to configure it for yourself.
  • Need as wide tires as possible – I think to put in front of 3″.
  • We need good brakes no lower than Deore – my elixirs are weak, and the motor trailer can not be put on them.

Of course, the mid drive motor has many disadvantages:

  1. The price of the motor. Bafang imagines himself as a monopolist and breaks high prices. And then, for the mid drive electric bicycle motor kit, the price is higher than separately for the components.
  2. The weight. The bike is getting heavy. In my case, 9 kg was easily added (my ordinary bike weighs so much).
  3. Quick wear of the transmission. The high power circuit and cassette will need to be changed more often.
  4. You need to be careful about shifting gears, like in a car.
  5. Handles for mechanical brakes included this past century.

Impressions of riding an electric bike:

What is it like riding an electric bike? Yes, it rules! Serious power, sometimes even knocks sideways.
First impressions are a delight. You can’t twist it with your feet – slopes, rugged terrain, snow virgin land – no problem.

Support levels depend on speed: the first up to 16 km/h, the second up to 24 km/h, the third up to 40 km/h. The first is not very convenient, it would be nice to lower the speed. Conveniently, you can adjust the thrust/speed ratio by switching the sprockets on the cassette.
It is also quite possible to ride without motor support.
It is winter, I ride only on support, I pedal – it’s so warm and the battery does not quickly sink.

You need to manage such power wisely, select gears and the level of support according to the condition of the road. And if you ride on snow like me, you need winter tires, mud on ice is helpless.
But overall I love my electric bike so much!

Thank you for reading, now you know more about Bafang carriage electric bike conversion kits. You can buy this Bafang kit from Amazon here.

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How I ride electric bike video: