Since our last update we’ve been working hard towards our Pre-Production Run. The past two weeks have been really busy, and we want to share all the progress with you.
As discussed in the previous update, our first batch of speed controllers is ordered. We’ll have the First Article production units in our hands to verify next week, and once approved they will produce the full Pre-Production Run of controllers.
After some aggressive ride testing earlier this month with production motors, we determined it was important to upgrade several components on the speed controller so that we could take full advantage of the additional power these motors can handle. This means the boards are faster and more powerful, and run as efficiently as possible. While these improvements do not change the speed controller design, the upgraded components had to be special ordered with a longer lead time than originally quoted to us. Our California-based controller manufacturer now has them in stock, and we know you’ll be happy with the improvements.
This is frustrating for us and has caused a delay that will push our initial pre-production run of boards back a few weeks. More on the new schedule later in this update.
The New ZBoard 2 Motor
In the last two updates we've hinted at the improved performance of our new motor that make the board faster, more powerful and smoother running.
Inrunner vs. Outrunner Motors
As we revealed in the last update we've decided to equip the ZBoard 2 with a large "outrunner" style motor. Our initial designs last year built around a different style of motor called an "inrunner," but months of testing on motors from dozens of suppliers have convinced us this outrunner setup is far superior, and results in a ZBoard that's even better than expected.
First, we'll outline the differences between inrunner and outrunner brushless motors. Then, we'll go over how far the ZBoard 2 motor has come in the past year.
An “inrunner” motor has its stator windings fixed to the outer casing, with its permanent magnets mounted to a spinning inner rotor. When the coils' magnetic fields change, the permanent magnets react and spin the shaft while the outer casing does not move. This type of motor works best when spinning fast, and can be - in theory - more efficient, which is one of the reasons we initially pursued it for the ZBoard 2.
Blue = Motor Shaft
Red / Green: Permanent Magnets (connected to the motor shaft)
Yellow = Copper Windings of the Electromagnet
Grey = Motor Casing
In our experience, the inrunner motors we tested had downsides we couldn't overcome. First, they lacked the torque we desired for the ZBoard to climb hills. They only produced adequate power close to their rated maximum voltage, but their efficiency fell off dramatically anywhere above that rated voltage, leading to excessive heat under the dynamic conditions they experienced. These heat spikes meant we had to significantly limit power and torque, reducing hill climbing and acceleration.
An outrunner motor is arranged in opposite fashion, with its windings around a fixed inner stator, and its permanent magnets mounted to a rotating outer can, which is attached at its end to the center shaft. An outrunner motor of equal rated power will have smaller, more numerous magnets, but since they are further from the center shaft it can produce much more torque. This type of motor can also handle more total power for a given size, and the spinning housing helps to cool the motor despite often having less peak efficiency.
Blue = Outer casing AND motor shaft (they are connected)
Red / Green: Permanent Magnets
Yellow = Copper Windings of the Electromagnet
We found that outrunner motors were more robust at handling the demands of a high performance electric skateboard. After evaluating outrunner motor samples from numerous suppliers, several of which we evaluated on our trip to China, late last year we selected a motor that truly impressed us. It has an exceptional combination of power, efficiency, and robust design, and runs great at the same voltages where previous inrunner motors fell flat and began to overheat.
An additional benefit of having more permanent magnets – or “poles” – is that we can more precisely read and control the rotational position of the motor, and cogging between motor positions has been virtually eliminated to make the ride as smooth as possible. This more refined control has allowed us to develop a motor control algorithm that dictates up to 5,600 pole positions PER SECOND!
All in, the new motor not only has more torque for climbing hills, faster acceleration, stronger braking, and performs better at higher speeds than ever before. Check it out in action:
New Motor Size and Power
For a given power rating, outrunner motors tend to be smaller in size. However, the dense iron outer can means the new motor weighs slightly more than originally projected. Between this, the thicker, sturdier deck, and wider truck hangers, the new projected weight for Z2 Blue will be approximately 17lbs, with Z2 Pearl being closer to 19lbs.
Checking in on Specs
As you know we've made some massive changes to our part mix over the course of the project but the entire time we've worked to meet or exceed the initial specifications we laid out originally.
Top Speed: 20mph
Yes, the new motor is able to hit this top speed, and it's awesome.
Range: 16 miles (Blue), 24 miles (Pearl)
Despite the motor changes, our ride tests confirm that the newer, better Z2 motor delivers the same maximum battery range originally intended. See the screenshot below from our latest test earlier this week.
Weight: 17 lbs (Blue), 19 lbs (Pearl)
As mentioned above, certain adjustments to the board have led to about a one pound increases of each board.
We've doubled the 500W we originally promised - the new motor has a full 1000W of power!
Check out stats from a Z2 Blue test ride earlier this week:
After receiving the pre-production batch of motors earlier this month we began test riding them and benchmarking their performance. We’ve learned that their performance slightly differs from the samples that we had approved previously. During discussions with our supplier we learned that while the samples they sent us were hand wound, meaning that one of their employees wrapped the wire windings by hand, the production motors are wound by a computerized winding machine, which is much faster and more consistent.
The machine-wound motors are actually more powerful than the hand-wound samples. It's great news as it means hill climbing, acceleration, and top speed will all be improved. However, the added power means they require additional tuning to ensure safe and reliable performance. We are hard at work on these firmware tweaks and have been assured that all motors moving forward will all be machine wound and perform consistently.
Delivery Schedule Moving Forward
Waiting on the speed controllers and the unforeseen additional firmware tuning work has pushed back our schedule for shipping the Pre-Production Batch of boards. Although not a significant delay, these set backs are very frustrating for us and we know they're frustrating for you too. We promise you that the boards are so close to being done and are incredibly fun to ride. We're almost there.
At this moment we haven't finalized a new schedule yet but we expect it to be within March. Over the next week we'll be contacting all of the Pre-Production Batch orders and will be updating them along with the rest of our supporters as the shipping schedule becomes more clear. While the Pre-Production Batch has been delayed slightly, the official 1st Production Batch's schedule has not been delayed, and still remains as expected (March - May). We will be refining that schedule as we gain more information
Shipping Address Verification
Starting this week we'll be reaching out to the Pre-Production Batch supporters to help walk them through the process of verifying their order contents and address through our website. For those outside of the Pre-Production Batch, we plan to contact you to verify your address and order details 2-4 weeks before shipping.
After seeing the slight differentiation between our sample motors and pre-production units, we've decided to delay international shipments until the first official manufacturing batch. We do not expect to run into any issues with the pre-production batch of boards but just in case we do, we want to make sure we can get them sent back to us for immediate adjustments if needed. We have years of experience maintaining boards internationally and knowing the difficulties it can present (language barriers, customs, expensive air shipping, etc). We feel strongly enough about this to keep the earliest initial pre-production batch domestic only, and we've reached out to the affected customers to explain further and apologize.
If you have questions about the delivery schedule or recent delays, our Co-Founder Ben will be chatting on our site from 9am-12pm PST on Thursday 2/25. To chat, click over to our site and click the "Have questions? We're here to help" tab in the bottom right corner.
Shipping Boxes Have Arrived
Our shipping boxes are made up of an inner structural insert (left) and an outer carton (right).
The inner box wraps around the ZBoard, protecting it from all angles.
Along with your board, in this box you'll receive your manual and charger.
Thank you for your continued patience and support. We know its been a long haul and we're 100% committed to making the Z2 worth the wait. We're so excited to begin putting boards in boxes and shipping them out to you!