This bike impressed me right when I saw it. I love that Haibike offers spec-heavy options with the Yamaha PW system. I think the PW system gets a bad rep sometimes for being less powerful than the Bosch, but to be totally honest not everybody needs the power of a Bosch system. Haibike makes up for the lower torque of the PW system by offering a premium Shimano Deore XT drivetrain with 20 speeds. This is great for riders who want to stay in the action a bit more, but still not arrive sweaty and out of breath.
Unlike most e-bikes, the Brompton's battery is integrated into a bag that sits on the front of the bike. While that detracts slightly from the classic, streamlined design, it's handy as it can be unclipped for charging or riding as a regular bike – it's probably one of the easiest to ride without battery assistance thanks to its weight. The battery also powers two lights for safe commuting.
Torque sensors and power controls were developed in the late 1990s. For example, Takada Yutky of Japan filed a patent in 1997 for such a device. In 1992 Vector Services Limited offered and sold an e-bike dubbed Zike. The bicycle included NiCd batteries that were built into a frame member and included an 850 g permanent-magnet motor. Despite the Zike, in 1992 hardly any commercial e-bikes were available.
For many bikes, battery range is more important that total power (because they're all pretty powerful). You want a bike that delivers a range long enough for your rides at the power levels you want. Most e-bikes will have three to five levels of assist kicking in anywhere from 25 percent of you pedal power to 200 percent boost. Consider how fast the battery takes to recharge, especially if you'll be using your bike for long commutes.