How we build Vekkit

How we produce Vekkit e-bike kits

Jun 23, 2021
230 km
4500 m

The production of good conversion kits is much more difficult than e-bicycle production. This may sound strange but it is enough to just open any big online e-bike shop and see how different all those e-bikes are: different brake types, different fork widths, different handlebar diameters (in case of handlebar battery bags), different frame geometries, different wheel sizes and so on.

Even those 5 mentioned parameters provide lots of possible combinations which lead to multiple types of kits and problems with installation; whereas in case of e-bicycle production all those parameters are known. We can’t predict which kits will be ordered in July and which in February - that’s why we originally decided to establish our production in Krakow instead of ordering everything in Asia. This way we are able to make highly-customizable kits with many options and to apply changes to them (upgrades and fixes) very quickly.

To create one kit we order components from 54 suppliers in Europe, USA, Taiwan and China - each kit consists of more than 400 elements. It is difficult to hope that all suppliers will deliver the components in time - especially considering the pandemic difficulties. So we try to produce those rare components ourselves. For example, in March we developed our own battery lock and stopped depending on lock supplies from China. Now we are developing a kit mount for the handlebars and the seat post so that we stop depending on Klickfix suppliers. For each supplier there are 1-4 reserve ones (the total number is 108) - but even that quantity is not enough sometimes and we experience delays in production. Of course, we do everything we can to minimize those delays and we contact every customer to update the order’s status. We have special customer pages where our client can view the status of his kit’s production.

For someone who doesn’t know how e-bike conversion kits work they may seem like simple devices. That’s why we decided to share all the stages of production and the principles of its work. Our team developed everything - from cable holders to mobile apps. During that process some open-source projects were very helpful. So if you yourself are an author of a popular open-source project we will gladly make you a discount!

Stages of production

Order confirmation

We manually work with every order before adding it to the production list to be sure that we can implement all preferences most customers mention in their orders. To make this process effective we developed our own system. We chose Trello as a base to manage projects and linked it to the database of kits, to the processing of payments in Stripe and to the database of components. As a result we have a great instrument for managing orders, components and kits.

Motor driver and Vekkit Controller assembly

The production begins with soldering the “brain” of the kit (we call it the Vekkit Controller) and the motor driver. At this stage we still have lots of automating to do: for example, to install our pick&place machine. The Vekkit Controller is based on two Nordic Semiconductors chips (the same as used in smart watches) which allow it to process data from the pedal sensor, the handlebar remote and the mobile app via Bluetooth at the same time. The controller of the motor is based on a powerful chip from STM32. This combination makes the performance of the motor very responsive and natural.

Printing and assembly of the kit’s body

All parts of the kit’s body are printed with 3d printers. This allows us to create complex parts and make the production eco-friendly. Some parts are printed with FDM printers and the bodies of the pedal sensor and the handlebar remote are printed with MJF technology using very strong nylon. At this stage we fully assemble the kit’s body and prepare it for uploading the firmware and then hermetic sealing.

Pedal sensor and remote control assembly

Since May 2021 all bodies of our pedal sensors and remote controls are printed with MJF printers using very strong nylon. The wireless communication between the sensor, the remote control and the kit is established via RF (for example, radio-controlled toy cars are operated this way). We don’t use Bluetooth for this communication to minimize all delays and maximize the stability of those connections. In our current version every message from the pedal sensor is received by the kit in just 15-20 milliseconds (one second consists of 1000 milliseconds). You also don’t have to worry about reading manuals or pairing the wireless parts: they are always connected to their kit, which even makes stealing them useless.

Battery assembly

The kits’ batteries are also made in our workshop. The batteries consist of 20 Li-ion elements which are produced in Japan or Korea. We were the first to start using the 21700 elements in conversion kits (for example, the same elements are used in the production of batteries for Tesla cars). This allowed us to create the smallest 360Wh e-bike battery. All batteries that we produce have the same size and can be taken out of the kit: this allows to take our special 5.2Ah battery onboard of a plane while using the more powerful 10Ah battery at all other times.

The kit bag

The bags for our kits are made in Krakow from the strong waterproof Cordura fabric produced in Germany. It is quite boring to make only black bags, so we have a choice of 6 colours. Each bag has a handle for carrying. From the very beginning we decided to use 2 fasteners with a special overlap instead of a zipper to prevent possible difficulties. This construction makes the bag easy to use.

Wheel building

Each wheel for Vekkit is built by hand with a tolerance under 0.3 mm. For 26” and larger wheels we use the strong Accent and Mach1 rims. For Brompton - the AlexRims or Ryde rims. The spokes are black or silver Sapim Leader (2 mm or 2.3 mm). After the wheel is built it goes on a test ride and then the trueness is checked again.

Firmware, motor settings and testing

Our controllers use the FOC algorithm - the most effective for BLDC motors. But even such advanced systems have downsides: in this case it is the need to develop unique settings for each motor individually. That’s why after the kit is fully assembled we upload the firmware and then create the unique settings for the kit’s wheel. Finally, we test the whole kit with a high load at 15A in the workshop and then on a real uphill outside to make sure that everything works perfectly at all speeds.

Packing and shipping

We don’t use plastic packaging at all. And the filler that is used in the small inside boxes is water-soluble and biodegradable (just try out yourself).

And that is the whole process of producing a Vekkit! As you can see we take testing very seriously to avoid shipping kits that don’t work well. And in case something goes wrong after you start riding we aim to repair the kit in 2-3 working days including shipping within EU and in 3-5 working days including shipping outside EU.

If you have questions feel free to contact us at hey[at]

230 km
4500 m