With lot of ebikes kits available on the Internet, I wanted to make a try and transform a regular all terrain bike into an ebike.

You can easily find motorized wheels on eBay with the brushless motor controller, and also the throttle to add to the bike.

The main problem is the battery. If you want a good range, you need a big battery. If you buy them online, they are quite expensive and also with fixed sizes. So, it's quite difficult to integrate inside a bike frame to have something well integrated, like a fuel pod on a bike.

For that, I decided to make my own battery, and to solder it with a home made point solder unit, based on an Arduino program and a salvaged transformer of a microwave oven.

The battery is made from standard 18650 cells (like in the Tesla car for example). You can buy online. I was able in 2017 to buy them about 1.25€ each, now it's more expensive.

The battery I've used is the ICR18650-26F, with a capacity of 2600mah nominal. In reality, the capacity is a little more, at about 2900mah.

The size of the battery is 13S12P, so 13 elements in serie (48.1V nominal) and 12 elements in parallel (31200 mah nominal).

I needed to buy some nickel straps to solder with my solder unit. More info on DIY point soldering unit

All the elements on a table :

During soldering :

The battery pack once soldered :

You don't have to forget about adding a BMS (Battery Management System) to the battery pack, to preserve the battery life (you'll find enough informations on the Internet about why BMS are important).

During the tests, I've just attached the battery pack with black tape. It's Mad Max style but it's OK for the tests !

On this early first version, I've adapted a brushed DC motor of 2kW to the wheel with 3D printing parts. But that was not a good idea. The motor was quite cheap, and that was difficult to put the chain in the right place.

Also, After about 200km, I've burned out the motor because of too much current for a long period…

So, after that, I've bought a wheel with a brushless motor inside, and the result is much more better :

It's well integrated now.

After the tests, I've 3D printed the battery enclosure in ABS on a printer I've designed in my company and added 2 aluminium plates to close it.

The battery is well integrated to the frame and it's working like a charm.

As I've said, the brushed DC motor wasn't a good idea and burned out quite quickly.

After the installation of the brushless wheel, the results are very good.

The max speed I was able to reach is about 62-63 km/h on flat roads.

The range is about 200km with pedal assist set to 1 (minimal consumption, you need to pedal but without sweating you can reach 25-27 km/h.

If you go without pedal assist (just with throttle, like a bike and going beetween 55-60 km/h, the range is reduced to about 60km (1 hour in fact).

So, very good project, the global cost was about 700€, without the bike I already had.