last week we celebrated what we call „The Wedding“ at Mellow. The fusion of software and hardware. It’s less of a social but more of a very nerdy event. It means that for the first time all the circuit boards and components got implemented into the physical shell of the Mellow Drive and were then put onto our test rig to see how well they get along. Our resumé so far: love at first sight.
Now let me hand you over to Kilian to fill you in about all the nerdy details:
So what are we actually doing?
These last weeks we have been heavily working on the Mellow Drives software and the test rig. The time we spent on developing, is now paying off and giving us a massive benefit.
On our test rig we are able to run the Mellow Drive with every combination of torque and speed – aka – we can simulate every riding situation (light rider vs. heavy rider, uphill vs. downhill) in a controlled lab environment. During testing we can monitor all voltages, currents, temperatures and we can even simulate wind resistance and rolling friction, to get very realistic results on range and real world top speeds. Pushing the power of the Mellow Drive to the max and meanwhile monitoring the systems every reaction is something that only intensive lab testing can provide. This will ensure that the you can safely take the Mellow Drive to the limits without risking your health due to system failures.
Our breaking system is the most powerful and reliable breaking system ever developed for electric skateboards and getting it right, is one of our top priorities. By adding the thermal breaking resistor we ensured the breaks of the Mellow Drive will never have to shut off due to a full battery or in order to not harm the Mellow Drives electronics. Even on long descents the breaks will stay fully functional, keeping you safe, way over the point where every other product would go up in smoke.
One more extremely important component is the Battery Management System (BMS) and we are proud to letting you guys have a first peak at it.
What does it do?
The BMS monitors the voltage of every cell as well as the temperature of the battery pack and the currents going into and out of the battery pack. Furthermore it provides a very advanced algorithm for the estimation of the energy content inside the pack, called “impedance tracking”. In comparison to “Coulomb Counting” and “OCV measurement” (our BMS features this as well) impedance tracking allows for the BMS to learn about the batteries “state of health” (SOH). Where lower quality BMSs would start losing track of the real energy content of the battery over the time, due to the aging of the battery our BMS will “learn” that the energy content of the battery is getting lower, allowing us to provide you very accurate range forecasts from day one throughout the entire battery life time.
The following video shows you how it works: With a variable current source we could simulate different states of charge displayed via the LED ring – from green to orange, red and flashing red. The connected phone shows the powerbank function up to the moment where the charge is so low that it shuts off the powerbank.
OK, thanks Kilian. If your head’s already spinning with all this geek-speak here’s something more down-to-earth.
These pictures show you how our tooling for the magnesium main frame has been made. This week the first test frames will be cast using these tools. These frames will then be used to built up our first product samples. Which also means, our next update will be „Bye bye prototypes, hello product samples!“ Excited!
So stay tuned, we’ll speak to you soon.
Have a great week!
Johannes & Kilian