Exchangable battery for an eBIKE

With a exchangable battery, we can double the range of your e-bike. It is an interesting solution for people who:

  • cover long distances on an electric bike and one package is not enough for them to do a longer distance, e.g. 100 km
  • like dynamic driving, so the battery can often “disappear in the eyes” and “fun” ends so quickly
  • loops ride, e.g. on single tracks, and they can drive up to the car and exchange the package
  • they don’t mind riding with a spare battery in their backpack

For us, the above-mentioned points were a reason to add a new battery to Ania’s Cube AMS 125 pro bike. We have designed a new housing so that the package is quick and easy to replace (execution Mark from „Drukujemy e-rowery“). The previous solution (also from 3D printing) did not allow such a simple battery replacement. In this solution, we do not need any cable ties, wrenches or allen keys.

3D design for download

Here you can download the enclosure design for 3D printing – 13S3P package:

YouTube video

We invite you to watch the episode on our YouTube channel, how the housing on the bike looks and how the battery is exchanged in it (Polish language version)

Which electric bike to choose?

„Buy factory electric bike or do it yourself? How about buying a used one or ordering a company to make one for us? Which electric bike will be the best?”

These are very common questions we ask ourselves when thinking about owning an electric vehicle. After all, we all want a good electric bike. Good, which is what? Therefore, in this article, we will try to help you make the selection and pay attention to things that you may have missed in your analysis.

Which electric bike is the best??

In fact, when choosing an ebike, it’s hard to talk about better and worse bikes (apart from the actual condition). We would put it in other terms:

  • cheaper ebike – more expensive ebike
  • stronger drive – weaker drive
  • central drive – hub drive

When analyzing the choice, it is worth answering a few basic questions.

5 questions to ask yourself
before choosing an ebike

Of course, there may be more questions, but we consider the following to be the key questions:

1. What type of bike will be the most suitable for me? Division according to the type of frame: city, trekking, MBT or FAT-BIKE (with front shock absorption, rear shock absorption), enduro:

Which electric bike to choose? Excerpt from the guide: „Do it yourself - Convert your bike into an electric bike"
Bicycle type - frame / Excerpt from the guide: „Do it yourself - Convert your bike into an electric bike"

2. What type of drive should I choose? The motor in the rear wheel, front wheel or central drive:

Which electric bike to choose? Excerpt from the guide: „Do it yourself - Convert your bike into an electric bike"
Types of electric drives / Excerpt from the guide: „Do it yourself - Convert your bike into an electric bike"

3. What kind of electric assistance do I want? Cadence sensor / pedal torque sensor / throttle

PAS - Pedal Assistance System
PAS - Pedal Assistance System
Torque sensor for MPe computer - eRider T9
Torque sensor for MPe computer - eRider T9
Gas throttle
Gas throttle

4. What is my budget for the purchase?

5. Do I know how to use the drive that I have chosen?
You need to take care of the electric drive and the bicycle. Let’s take care of the appropriate bicycle service so that the ride is comfortable and, above all, safe. For rear wheel drives, it is a bit easier, because they do not require such frequent service, while for mid drives, we must reckon with more frequent service (grease, gears or bearings). 

The central drives require us a little more involvement with shifting gears on the derailleur. While in HUB drives, when driving with a cadence sensor or on a throttle, changing the gears is not necessary, for a mid-drive it is even a requirement. It is therefore worth getting to know the details of the selected drive before the purchase, because each of them has its own specificity, operating characteristics and requires a different service effort from us.

Of course, when choosing, we should also take into account such aspects as:

  • Where do we mainly want to ride this bike?
  • What range do we want to cover on a single battery charge?
  • What drive power do we expect?

Which electric bike should you choose?

When choosing an electric bike, it is mainly about the type of electric assist. Some will be satisfied with:

  • the use of a cadence sensor (commonly known as PAS support),
  • the second will depend on the pedal torque sensor, which, however, would be a bit like riding a bicycle and to be able to work on your condition
  • and still others will be satisfied mainly with the throttle.
Which motor / drive to choose?

Rear wheel hub motors

Rear wheel hub motors
Rear wheel hub motors

For rear wheel hub motors: for example, adding an MPe COMPUTER to e-bikes will enable all three of these electric assist solutions. Adding this drive often increases the weight of the bicycle. These engines are rather not as frequent servicing as, for example, central drives.


Mid-drive - TSDZ2 - city bike
Mid-drive - TSDZ2 - city bike

On the other hand, central drives seem to be the perfect solution for people who are looking for a light ebike with good off-road handling or want to train a bit with a torque sensor. Most of the factory electric bikes are based primarily on this kind of sensor.

Additional tips for analysis:

  • It is worth being „flexible” in choosing or modifying an ebike. If this bike can’t be upgraded too much, then maybe it’s worth selling it and buying another one.
  • Pay attention to the quality of the bike, e.g. whether the frame is solid.
  • Let’s not be afraid to ask someone for advice and ask for help in choosing.
  • If we have the opportunity to test ride an electric bike, let’s take advantage of it. We used the loafing room ourselves and such a test drive helped us a lot.
  • It is also worth testing the size of the bicycle frame and the suspension, e.g. with full suspension.

The art of compromise

We can see from our own experience that choosing the right electric bike is often an art of compromise. We are looking for and selecting a bike and drive that at the moment will best meet our expectations for the driving style and terrain on which we most often want to ride. And often when investing in one drive model, you have to give up the advantages that a second drive would give you. For example, for Ana the bicycle model „Cube AMS 125 pro”:

eMTB - mid-drive TSDZ2 (light bike 20,4 kg)
eMTB - mid-drive TSDZ2 (light bike 20,4 kg)

The art of compromise:

Definitely „YES"

  • Light ebike (20.4 kg)
  • In the off road ride, the ebike is great
  • Pedal torque sensor (TSDZ2 drive) and the feeling of cycling
  • Full shock absorption front and rear
  • Certain „shortcomings”

Certain „shortcomings"

  • TSDZ2 drive is not super powerful (after uploading the open firmware max. 750 W)
  • Frequent service of the drive
  • It’s definitely louder to use than gearless HUB motors
  • Resignation from the throttle for the temperature sensor
  • The frame may be a bit too big for her height

Fortunately, the electric bike is not with us forever. We can sell it and buy another one. We wish you fruitful analyzes and successful compromises in choosing your electric bikes. We encourage you to leave comments on your selection. You can also WRITE TO US.

the Bikel.pl crew

Kelly KLS controller – configuration

How to configure the Kelly KLS controller

Configuration applies to all Kelly KLS series controllers, regardless of the size or voltage of the controller.

Basic parameters for configuration
Kelly KLS controller

In order for the controller to work, the following fields must be configured in the program: 2 tabs.

First run procedure
and pairing the motor with the controller

Changes in the Vehicle tab:
1. Set the operating voltage of the controller min. max .:
For the „Low Volt” field: enter: 3.0 V * number of sections in the battery and „Over Volt”: enter (4.2 V * number of sections in the battery) + 2.0 V
For example:

2. Pre-limit the driver currents to 30%: „Current Percent” and „Battry Limit”.
3. Set the throttle type to 2 (for a Hall sensor based throttle – most ebikes): „TPS Type”.
4. Set the „Identification Angle” parameter to 170 – this will force the Hall test to run after restarting the controller.

Changes in the Motor tab:
5. Set the parameter: „Motor Poles” – enter the number of magnets (not pairs).
6. Set the parameter: „Sensor type” – enter 2 for Hall sensors.

Halli test / pairing the controller with the motor:
7. Press the buttons: „Write”, „OK”, „Quit”.
8. Disconnect the USB cable.
9. Restart the bike / controller.
10. Wait for the Hall test to be performed, the wheel will spin very slowly, and finally the red LED will start flashing with the code 3,2 internal reset – it means it’s ok and the Halli test is over.
11. Restart the bike / controller.
12. Activate the throttle gently and check the direction of wheel rotation.
13. If necessary, connect to the program and change the direction of the wheel rotation / change the „checkbox” – „Change dir”. Press: „Write” button and restart the controller.
14. Carry out a road test.
15. Increase the „Current Percent” and „Battry Limit” currents („Vehicle” tab) as desired and needed.
16. If necessary, configure the remaining configuration parameters.

How to improve and enrich the action
of Kelly KLS controller?

The Kelly KLS controller in terms of its small dimensions and very good performance (continuous current 50 A, temporary 120 A) is really worth recommending. Unfortunately, it is very limited in its functionality as it only has the option of connecting a throttle. It offers nothing more. Therefore, to this controller, you can add the MPe on-board computer, which, in addition to adding the PAS support (torque sensor and pedaling sensor), will give us a number of other possibilities, including:

  • remaining distance on battery
  • possibility to protect against overheating, e.g. of the battery or the motor (with the drive cut-off function)
  • limiting the power of the throttle
  • pedaling assist power limit settings (full freedom – e.g. 250 W)
  • cruise control
  • and many others

We appreciate the addition of a pedaling torque sensor. Driving with this computer is very comfortable, safe and fun, and even improves your condition 🙂.

The entire MPe offer can be seen on the website about this device:

If you have questions, ask them in the comment at the bottom of the article.

Why an electric bike?

Find out 10 reasons
why it is good to have an electric bike.

One thing is certain: ebikes become very popular today and appear more and more often on our roads.
Why do we choose an electric bike? I will present my and Marek’s reasons why we’ve decided to have an electric bike. They will be based on our history. Let’s get started :

Reason No. 1:
Let's get less tired

Electric assistance relieves us. And that was the reason number 1 why Marek chose an electric bike:

„I just don’t like to get tired.” 😉

Reason No. 2:
We can get much further

For an out of shape cyclist, driving 20 km can be a challenge. I remember in 2015, when Marek and I went on a trip. Back then, we were still riding ordinary bikes, without electric assistance. We were supposed to drive about 30 km. For me, an amateur cyclist, it was easy, and for Marek it was a test of fitness. Well, we finally did 50 km and Marek was very tired😜.

Today, on an ebike, we even 100 km. Our butts hurts, but the condition is no problem.

Reason No. 3:
We're cycling faster

Driving up to 50 km/h (and more) is possible with an electric bike. However, we should remember about our own and others safety. And always wear a helmet, even at 15 km/h.

We always ride in a bicycle helmet
We always ride in a bicycle helmet

Reason No. 4:
Driving upwind is not a problem

The wind is a challenge - not for ebike
The wind is a challenge - not for ebike

„I’m not going today, it’s windy.”

While driving with the wind is great, going against the wind is a challenge. We turn on the electric assistance and we do not get tired.

Reason No. 5:
Electric bike
it's a cheap mean of transport

What is the cost of riding an electric bike?

  • (0,25$ for battery charging per 150 km).There is no more to say.

Reason No. 6:
We take care of our physical health

While riding a bike (even an electric bike), we strengthen:

  • calves
  • thighs
  • buttocks
  • stomach
  • hands
  • neck
You need strength to ride a bike
You need strength to ride a bike

Also on an electric bike it is possible to get tired physically and we often decide how much we want it.

Reason No. 7:
We take care of our mental health

Electric bike and endorphins
Electric bike and endorphins

When cycling, endorphins are produced, which means well-being and contentment 😀

Reason No. 8:
Ebike for disable people
(heart defects, motor disability)

Electric Tricycles with MPe computer
Electric Tricycles with MPe computer

There are many people who, unfortunately, cannot afford to ride a bicycle physically. Heart disease does not allow you to exercise. Turning on the electric assistance can relieve us or we can also use a throttle.

Reason No. 9:
Anyone can build electric bike

„Building an ebike is so hard and complicated.”
„I don’t have a workshop or tools to build an electric bike.”

We know these statements. We thought the same when we wanted to build our first ebike ourselves.

„Where to start, what drive and bike to choose? Can my bike be converted into an electric one? “

And although we encountered many problems on the way in building an electric bike, we know today that it does not have to be that difficult. Today knowledge is common on the internet and you can find a lot of information. It is enough to want and reach for knowledge.

Lithium-ion battery pads
Lithium-ion battery pads

Often times, electric bikes are built in the center of the room. You don’t really need complicated tools.

Reason No. 10:
Ebike as a new hobby

Mark from the Bikel.pl company / eBIKE COURSE - lesson 8 - about HUB motor
Mark from the Bikel.pl company / eBIKE COURSE - lesson 8 - about HUB motor

The very fact of riding an electric bike can be a new life idea for us. We know it together with Marek and we spend every possible moment together, visiting and getting to know new places, as well as new people. 😊: Taba na rowerze). 

Electric bike -
definitely on


Electric bikes are our passion, spending time together and developing – our company Bikel.pl 😉.

We want to wish you such a passion.

Or maybe you have other arguments why an electric bike? Let me know in the comments.

Bikel.pl crew

Construction cost of e-bike with MPe

How much does it cost to build an electric bike?

The cost range of building an electric bike is really wide. Prices can fluctuate here, even from 144 Euro / 160$ to over 7300 Euro / 8000 $.

In this article, you will find out the cost we incurred to build our „Minion” e-bike.

Price of e-bike with MPe computer

We will show here one option for building an electric bike, taking into account the MPe computer set with  display:

  • MPe computer with large MaxiColor 850C display
Construction cost of e-bike with MPe computer and MaxiColor 850C display
Construction cost of e-bike with MPe computer and MaxiColor 850C display

Performance and possibility

Now it’s time to take a look at what our e-bike “can”:

  • Vehicle weight 28.5 kg. This is a pretty low result for an electric bike.
  • The 16S7P battery (1100Wh, LGMJ1 cells) will allow you to travel approx. 70 – 100 km (smooth ride up to max. 30 km / h, relatively flat terrain).
  • Top speed: 54 km/h.
  • Acceleration 0-40 km/h: 5.5s (test performed on the GT 1500, 45A controller)
  • Maximum power (indications from MPe computer): 2400W
  • Quiet operation of the Sabvoton Mini SVMC072045 45A controller. Initially, we had a GT 1500 45A square wave controller for a long time, which is much cheaper than the Sabvoton. However, the GT 1500 has several drawbacks. You can read about why the decision to change the controller was made. Read: HERE
  • The construction of the electronics box cost a lot of nerves, not to mention time. Read: HERE
  • The Kellys Madman 50 L, 21 frame is in our opinion quite large, even at a height of 180 cm. In the field, sometimes a slightly smaller frame (M, 19 ′) would be “more comfortable”.
  • Wheel / tire size: 27.5 ″ / 2.2
  • This bike certainly lacks full suspension. Although the NCX suspension seatpost is much more comfortable to ride than without it. We recommend this solution for every bicycle without rear suspension. It perfectly absorbs bumps on the road (by buying from the source below you support our business without losing any penny – the so-called affiliate link).

Extra possibilities for an electric bike -

MPe computer

Above you can see the cost of converting it into an electric bike of this class. The Minion is additionally equipped with an MPe computer, which gives it many unique possibilities. Today we CANNOT IMAGINE driving without this MPe computer.

Features of the MPe computer give us a number of capabilities
Lots of possibilities for an electric bike - MPe computer

Computer MPe price

in relation to the total cost of building an e-bike

Building an electric bike can bring great satisfaction. Especially when the bike starts to work and assist us. It is also often not a small expense, but do you have to have everything at once? We often buy, e.g. a controller, frame, battery pack, and then replace it with another, stronger, bigger, better one. We want more watts, more power, more adrenaline. And changes are associated with further expenses. And so it goes on:

we put aside money 🐷(new ideas)

collect savings 💲

and finally we make a PURCHASE and we have a PRIZE 🚲

And it is beautiful because there are more opportunities to make our dreams come true. And after all, riding an electric bike is a beautiful passion, but also a hobby that allows you to build a great vehicle.


If you want to show yourself how much it cost you to build an electric bike, write about it in the comment at the bottom of the article. We are curious.

And stay up to date 😎:

FB group e-BIKEL-owcy technically about electric vehicles

FB group „e-BIKEL-owcy"

In the Facebook group we exchange experiences and comments on electric vehicles