Since last time we got a very exciting news. We wanted to start the endurance test on the motors before the production kick-off. Before doing that, we needed to accurately test the motor performance to understand whether the 1000-hour test would have impacted on the performance. In order to do that, we needed a test bench. We initially searched for commercially available test bench, but those were either too expensive ( a bench which can brake 120Nm is a fairy large thing), weren't a good fit or had too long lead times ( 5+ months).
So we decided that we had to build a test bench ourselves. The picture here shows a glimpse of it.
So we took a 13HP electric motor to act as a brake, and we put some moltiplication in the middle, in order to lower the braking torque and increase the RPM, so that the output power of our motor would have been more manageable. The designed the test bench to brake 150Nm in order to allow more margin for the locked rotor torque and we finished the test bench build approx 20 days ago.
What a wonderful torque
During the first test of the motor with the production material we had a very pleasing surprise: at 150Nm of braking torque applied, still the motor didn't stop. And that was the 500W version on test!
Locked rotor torque is the torque that the motor can give you starting from a stop. 150Nm is a very impressive number considering that other mainstream ebike motors range from 70Nm to 90Nm as peak torque.
So we had to modify the test bench to check what was the maximum torque of our system. That modification costed more than two weeks, but at the end we've been able to add an additional mechanical brake to reach higher braking torque.
We repeated the test, anxious to see what was the maximum torque of the BEST motor. We reached 170Nm on the 500W version! Improved magnets, lamination and winding did their job and we surpassed our ambitious target.
This torque is not just a performance figure to brag about, it brings you a real advantage: the optimal efficiency of brushless motors is around 50% of their maximum torque. So if you have a motor with 90Nm as maximum torque, the peak efficiency will be at around 45Nm, so when you're pedalling on a flat road. With 170Nm you can have optimal efficiency at 85Nm, exactly where other motors stop. Higher efficiency means a battery which last longer because energy doesn't get dissipated into heat thus more miles per charge and less stress on electrical components.
Basing upon the endurance test results, we'll decide how much of this torque we'll made available in the production motors, but the efficiency advantage will still be there in any case.
Controller box casting
We launched the sand casting version and the moulds will be ready next week. Some of you asked about the position of the control box, so here's some picture of the box installed on the bike.
As you can see, the design doesn't affect the ground clearance. The color choice of the box will be as the motor, so black motors gets the black controller box. The next 10 days we'll be able to check whether the final look of the casing is acceptable so that we can use them on the production. In the last updated we indicated end of April/ beg of May as a possible shipment, now May is more likely.
Endurance Test is started!
After the motor performance test, we put the BEST system on the endurance test. That will be 1000 hours on 3+ systems. In order to get the motor running day and night at full power, we used a forklift battery.
We made a quick footage to see the endurance test going. Sorry again for the audio and background noise of the bike roller which is amplified.
The system is now doing approx 800km per day at full power.
Getting the right crankarm
The crankarm supplier finally did it right and we're waiting for the first batch next week.
Production line : work in progress
We started gathering all the materials to setup the production line. On the bench there are boxes with the presses and tools, waiting to be put in place.
We'll keep you posted as we plan to intensify the updates in the last final rush since everything is coming together at a higher pace. So you can expect the next update in 15 days.
All the Best,
Matteo, Luca and Bikee Bike Team.
in the last update we finished designing the motor mounting bracket and we needed to make some prototypes for testing and validation. That's exactly what we did, but it took us a second attempt to get it right.
In order to get some fast and accurate prototypes ( in terms of material and fabrication process) we went for the sand casting. We created prototypes with our 3D printer ( the first ones on the left in the picture below), made the surfaces smooth with metal filler and used those as models for the sand casting. In the middle of the picture you can see the sand casted parts. As you can see we put those on some stressful test and the mounting bracket didn't survive. That brought us behind the original schedule, since we had to re-designed the mounting bracket in stainless steel (AISI 304) so to be coupled with the controller box cover ( see in the below picture, on the right the mounting bracket + controller cover assembly). That proved to be reliable and strong in our first test even though the whole process delayed us of one month.
We made a short video of the making of the prototypes for those who like molten aluminum. Apologies for the audio, but we were not exactly in a studio.
We'll have to go through the testing phase ( approx 10 days) before validating this solution. The sand casting prototypes had very rough surfaces and isn't good enough for us. We will probably make a second attemp with the new design to see if we can reach an acceptable level look and feel. We'll make this second attempt just because it can cut the lead time of the kits of approx 20 days.
So here's the new estimated lead time for your kits if plan B doesn't work. By March the 10th, if the test goes well on the new bracket design, we'll kick off the two castings. The casting lead time is approx 30 days, let's keep 40 because there's always something that comes up. That brings us to the end of April/ beginning of May. We really hope plan B will work, we will post the pictures of the second attempt for you to validate and we'll ask you what's your feedback.
In either case, in the meanwhile we'll perform the 1000-hour test for 3 systems on our test bench of the final configuration with the sand casted parts. We want to get this test passed before shipping the product. That will take 14 days if we run the motors 24/7 and if everything goes smooth. More details about than in the next updates.
CARBON FRAME COMPATIBILITY
More time means more refinement. While re-designing the mounting bracket we kept in account of the compatibility with carbon frames. Some of you visited our factory, bringing their bikes with carbon frames demanding for the compatibility. We exploited the re-design need to increase the contact area between the mounting bracket and the frame so to better distribute the load on the frame. To make it clear: we still cannot guarantee full compatibility with any carbon bike frame, but that's a step forward. In the next update we'll give you more details about that.
HALF GRIP THROTTLE
We finally got the sample of the ultimate half grip throttle. It's a one-piece throttle, very compact and stealthy.
We plan to send the next update around March, the 20th.
Appreciate your patience, we are working around the clock to bring you the finest product as quickly as possible. We'd also like to add that we are thinking how to sweeten your wait because you deserve all our gratitude for making this real.
All the Best,
Matteo, Luca and Bikee Bike Team.
We made giant steps forward in January, here's the list of what we'll be covering in this update:
Before going ahead, please note that the 25% off promotion is about to end: only 20 kits available yet ( here: online shop ) . After that the price will switch to the full price.
Motor Die casting toolings
As you can see in the pictures below, the first casting test arrived to our factory. Those are not yet machined and are just meant to assess the overall quality of the mould. They look very good and the no additional modification to the moulds should be required. We'll go ahead with the machining process to verify that everything works. After this step, we'll receive the machind castings to go ahead with the production.
After some assembling testing we saw that the riveting of the lamination wasn't good enough. For that reason, our supplier modified the riveting fixture to improve the strength of the bond. That's now completed.
Endurance Test for the new controller
Our custom controller is based on an already existing controller. We wanted to go this way to exploit its current reliability. On top of that we plan to run a 1000-hour endurance test on it to double check reliability and performance over time.
The design of the torque arm is completed.
After that we received the final version of the custom controller we had to re-design it's aluminum case: some dimensions were changed from the intial project and that required minor modifications.
In this box both the motor controller and Smartbox are fitted into. We prefer to keep the controller outside the motor unit because high-performance motors generate electromagnetic noise and heat, and you want to keep electronics away from that. We managed to fit everything in a very compact box: it fits inside the motor outline shape, except for a little angle on the front, as you can see in the first picture above. Most important, the box won't affect the ground clearance. In the above pics, we highlighted the box with orange color, but the production will have satin aluminum finish.
The torque arm is the part which anchors the motor to the frame and gives a reaction point to the motor so that it won't spin inside the bottom bracket. This part is critical in many ways: from one side it has to be resistent and, on the other side, it needs to be adaptable to any bike. Its design comes as a consequence of the control box design, that's why we completed that only now. The good news is that in the meanwhile we tested the design against more and more bike model, perfecting the mating interface.
This design is now completed and we're ready to go ahead with the aluminum die casting tooling opening for the box. This process usually takes 30 to 45 days and that's what's currently slacking the product shipment. As a corrective action we are looking to get the first batch done with sand casting instead of die casting. That would cut the wait time in half. The challenge of sand casting is that the thickness of the part is too small: we'll verify that next week.
If everything goes smooth, we'll be able to ship in the second half of March.
Beta testing for the final version of the app
The app is now working, we need just to fix some minor bugs ( for example the power reading which is not correct in the video). That will take approx two weeks. The look and feel is very positive. The raw footage below shows the main screens and displayed values. I did that with the smartphone during the project review, so please bear with me for the quality. In the next update you'll see the full explanation of all operating modes and features.
We plan to release the next update between Feb, the 15th and the 25th.
All the Best,
Matteo, Luca and Bikee Bike team.