I've recently taken delivery of an Airwheel S8 to replace my Focus Designs SBU for medical reasons. The device assembles in a matter of moments, easily and intuitively. The overall quality appears good, although a cap for the seat post through which the post passes appears to have been over-tightened and the screws have cracked it. Replacement is pending, due to Chinese holiday until the end of the week!
The battery had a storage charge, so it was left overnight to top off. The charger has a red (charging) and green combo LED which is dim and challenging to view in bright light, but indoors or dim lighting presents little trouble. I've found that two hours or less will complete a charge from a fifty percent discharge.
There's an app for the device, connecting by Bluetooth, of course. The auto-connect fails every time, but the manual selection is faster and connects quickly enough. The outer ring shows current state of charge, which varies depending on instantaneous load. It drops a few percent when accelerating and climbs back when idle. A convenient digital presentation of the speed is centered in the ring, along with distance traveled in kilometers to two decimal places. It's amusing to see the purported accuracy to be ten meters with such a display, but there's no reason to disbelieve it, either. I have no problem with metric, but prefer US miles for distances, especially as all my previous trips with the SBU were based on miles.
The secondary menu provides additional information such as duration of operation, but there's no logging feature. The data vanishes when the device is turned off. Curiously, one can close the app and later re-open it to retrieve the operational data for that session as long as the scooter hasn't been powered off or locked. I'd like to have a logging feature of some sort, as it gives me an idea when a pack is getting weak.
A feature for which I have little use other than entertainment is the remote control option. It defaults to minimum speed and presents a target circle with a touch center. Drag the center circle in any direction and the S8 will turn and travel in that direction. Lag time is severe, which explains the minimum speed default.
I had little problem changing from a single wheel to two, although the inability to tilt the vehicle into the turn took some getting used to. The seat and foot-pad combination wants to throw one's upper body to the outside of the turn and it doesn't have a particularly wide track. I learned to bend like a reed in the wind for the turns and especially for the jiggle-bumps one encounters on the sidewalks or road surface. If one wheel is lifted when the other is not, one will experience an un-commanded turn if one is too stiff. Upper body flexing easily compensates for that. Sometimes the bumps are severe enough to require flailing arms like an auto dealer's air-filled puppet display, but it's tolerable.
Turning is effected by applying rotational pressure to the seat. There's very little travel in the z-axis, but bumps can move one's body enough to cause a bump-steer of sorts. The sensor is not an on-off type, but rather pressure relative. Push gently, the scooter turns slowly. Push more firmly and it will spin enough to toss you off. I don't plan to test that aspect.
A characteristic of this particular device is the ability to remain seated at a stop. With the SBU, it was always necessary to place one foot on the ground or perform an Arte Johnson. It manages quite well to remain stable at the balance point. I've stepped off the S8 and used the remote fob to power it off (on carpet) and was surprised to see it remain upright. Oh, yeah. Two fobs are included and are required to go from power on to drive-away status. The bluetooth will not engage until the fob is used, preventing operation if one misplaces the fob.
Top speed is about 15 kph (~9 mph) at which point a very faint beeping emanates from the base. If the app is running, the phone vibrates as a warning. A bit faster results in a horizontal pogo, which I'd experienced with the SBU as well. I'm hopeful that there is a few kph safety margin built into the warning and I'm not keen on testing that feature either. I'd managed to over-accelerate my SBU in the past and found that I cannot run 15 mph very easily.
Range hasn't been fully tested and I don't think I want to walk home too far if the battery goes flat. The battery indicator on the phone app doesn't show expected range remaining, but if one can manage a bit of math, it's not too difficult to determine. All of the online information seems to be missing any range figures. The one video I found suggested a 13 mile range (about 20km) and my own use suggests something close to that, if one cares to run the battery to the near-zero point.
Ten inch wheels means the bumps are not handled too badly. I was surprised how well it manages bumps that required me to slow while riding the SBU. I haven't determined yet if the tires are airless or if there's a hidden tire valve somewhere.
Due to knee and hip problems, a stand-up version wasn't in the works for me. The seat on this one is reasonably wide, although hard as plastic. I'll be modding it with Temperfoam (firm) in the future, to provide a bit more than the bleacher-board numb-butt I now experience on extended errands.
A fellow makerspace member desperately wants something of this nature, but his bulk precludes all of the existing devices on the market. I think this device has a 250 pound max weight (not certain) and I'd hate to be that heavy on this scooter. Response time and safety margins are both a concern when one operates at the edge of weight limits.