I found these on alibaba a while ago. The company says this is their first shipment.
I was interested in testing because their claims were stretching the truth.
“first production of only 500sets at the mid of June” Interesting.
As an engineer, I have questions based on what I have read.
Your batteries cannot meet your specifications at 67.2 Wh. Based on nominal voltage,
67.2Wh * 1000 / 42V (12s) = 1,600 mAh 67.2Wh * 1000 / 35V (10s) = 1,920 mAh 67.2Wh * 1000 / 28V (8s) = 2,400 mAh 67.2Wh * 1000 / 21V (6s) =3,200 mAh
The most practical battery type is like 6-8s. Since your price per spare battery is $65, they are probably LiPo Polymer pouches. Even if I ignore LiPo battery safety and life cycle performance, 2.4Ah is insufficient for your board design to achieve its specified mileage: “12-15km” or “20km”, especially either “35km/h” or “20% grade”.
Consider the following:
Boosted Board (USA), 12s1p (99Wh, 2.35Ah), 2000Watt Dual Motor, 8-10km @ 35km/h & 25% grades. Yuneec E-Go (USA), 7s3p (232Wh, 7.8Ah), modified 1000Watt single Motor (operating at 400Watts), 20-30km @ 20km/h & 10% grades.
I could give more examples, but I do not need to. Direct drive is less efficient than geared (modern fact, cannot be questioned).
I know 2x1100Watts is not efficient dual 0.53 horsepower model (2000-3000Watts) requires 1-15Amp each to reach 35km/h on flats and up to 25Amp discharge per motors for 120kg on a 20% when starting from 0km/h. Your motor’s ability to climb a hill is questionable and would likely overheat the motors causing serious winding damage and battery strain (fire hazard).
Your maximum speed is also questionable because a motor wound 240Kv and geared at 13:36 can achieve a maximum of 30Km/h @ 10s (35V). Dual hub motors can achieve 30-40Km/h @ 10s (35V) but are wound at 170Kv. Your 8s (28V) motor could not reach 35km/h unless the motor Kv was very high, at which point you lose the ability to climb hills due to torque reduction.
Your board, which obeys the laws of physics, cannot achieve the specified minimum average milage of 12km unless on a downhill trip (especially true given the complete kit weight of 3.5kg) nor can it achieve both 35Km/h top seed and 20% hill climbing power as a hub motor with your battery configuration.
Your advertising information is either incorrect/false - could you please provide more information about your build to refute the above concerns?
I haven’t heard from the manufacturer since. Given that they also sell other products with boosted board and yuneec board photos mixed in with the actual products picture, I think its safe to say it won’t meet expectations. Its design concept is solid though.
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