Photo: This typical electric bicycle, a Sanyo Eneloop (now discontinued), had a range of about 30–55 km (17–35 miles) and a top speed of around 24 km/h (15 mph). Note the 250-watt hub motor on the front wheel and the 5.7Ah lithium-ion battery pack (black, marked "Sanyo," just in front of the back wheel). Picture by kind permission and courtesy of Richard Masoner, originally published on Flickr under a Creative Commons (CC BY-SA 2.0) licence.
Parliament has decided to approve the speed pedelec – a type of super electric bike that can reach speeds of up to 45 km/hour – for riding on cycle paths. Danish Parliament has decided that as of July 1 2018 those operating the super bikes only need to have turned 15 and wear a helmet, while the licence and number-plate demands will no longer be in play. 
During nighttime operation, the bicycle must be equipped with a front headlamp, a rear-facing red reflector, and reflectors on the front and rear of pedals, and the bicycle or rider must have reflective surfaces on each side. Minn. Stat. §169.222, subd. 6. An electric-assisted bicycle can be equipped with a front-facing headlamp that emits a flashing white light, a rear-facing lamp that has a flashing red light, or both. The bicycle can carry studded tires designed for traction (such as in snowy or icy conditions).
The rest of the bike is equally impressive. Integrated lights in the front and the rear run directly off the main battery, so you’re never replacing coin cells or AAA batteries. And the disc brakes give you plenty of stopping power. The 36-volt battery attaches to the down tube and is designed to be easily removed for recharging. A key-lock at the top of the mount ensures that no one can steal your battery if your bike is left in a public place. And a built-in alarm system, activated with a car-like key fob, is ear-splitting enough to keep thieves away altogether. (Miller promises the alarm’s sensitivity is tuned so it shouldn’t go off if the bike is jostled at a public bike rack, but I didn’t have the bike long enough to test this out.)
A response to an inquiry made to the Mass DOT/RMV indicates that Massachusetts does recognize the federal low speed electric bicycle Federal Law (15 U.S.C. § 2085) and interprets that to mean these ebikes do not require license or registration. However, some of the materials available on the RMV website do not distinguish between "Motorized Bicycle" and low power ebikes. One form, Bicycle Conversion to Motorized Bike, does document the exemption of low power ebikes.
But electric bicycles—e-bikes—are new territory for me. Broadly speaking, there are two basic options in e-bike land: power-on-demand and pedal-assist. With the former, the rider can control the speed with a throttle instead of just pedaling. Think moped but with an electric motor instead of internal combustion. Pedal-assist, by contrast, requires the rider to do some of the work. The electric motor won't engage unless the rider is pedaling.
As you evaluate the different folding electric bikes on the market, you’ll notice that there are a lot of inherent similarities from one brand to the next, even though the look of each brand’s attempt has some unique aspects to it. No matter how the bike looks, each of your options will have a motor that’s powered by a battery, a hinge that allows the bike to fold roughy in half, and a series of other features that you would regularly find on a normal bicycle, such as pedals, brakes, handlebars, etc.
Another big upgrade here is the 36V battery. Instead of the 8Ah that the Ancheer had, Rattan has a 10.4Ah battery. The battery actually looks a lot like this one that goes for $190 on ebay or a little more on Amazon. Rattan tells me it is full of genuine LG cells which seem to perform quite well. On cold days, my 15 km (10 mile) very hilly commute would use up about half of the battery (Ancheer would be dying on the way back home). I imagine someone significantly under my 200+lbs could approach the 25 miles Rattan says you can get on throttle alone or up to 50 miles of pedal assist. I’ll just say it was significantly more than the Ancheer.