While the Harley-Davidson LiveWire marks a notable moment as mainstream motorcycle firms begin to take the prospect of electric bikes seriously, the real tipping point will surely come when one of Japan's mass-market manufacturers launches its own affordable, competitive battery-powered bike.

We’ve seen dozens of electric concept bikes from the likes of Honda, Suzuki, and Yamaha over the years but, apart from a handful of electric scooters, production versions have been conspicuous in their absence. That doesn’t mean development isn’t going on; it’s clear that every major manufacturer now has dedicated teams of engineers working on electric bike projects. Each is hoping to be ready to cash in as soon as the electric-bike market reaches a tipping point where rising customer demand and dropping component costs mean there’s a profit to be made.

Yamaha has previewed its own electric-bike project in the form of the PED1 and PES1 concepts back in 2013, followed by the PED2 and PES2 in 2015. In 2016, the firm's annual report revealed that production electric bikes based on the PED2 and PES2 were planned. We're still waiting, but there's progress; Yamaha has filed a spate of patent applications revealing work that's underway on a range of different electric-bike designs.

The latest documents deal not with the complexities of an electric powertrain or the subtleties of battery technology but with a much more practical aspect of electric bikes that will have a direct impact on all their future owners: Where to put the charging socket? The few electric bikes on the market at the moment have tended to follow traditions set by gas-powered models, putting sockets on top of the “fuel tank” area where you’d expect to find the filler cap. That might make sense when it comes to familiarity as riders swap from gas to electric power, but it’s not necessarily the most sensible position.

After all, you fill a conventional bike in a matter of seconds, holding the fuel hose and right there to keep the bike steady if needed. An electric bike might be plugged in for hours, even overnight, introducing a whole new consideration of where to position the charging socket. Yamaha’s latest designs propose three potential socket positions, each on a different style of bike.

charging socket
Yamaha’s PES2 shows the charging socket in a normal fuel tank filling location.European Patent Office

First, we have the PES2, which is still likely to be representative of Yamaha’s first mass-production electric motorcycle, other than the tiny e-Vino and EC-03 scooters. Here, Yamaha suggests a variation on the normal “tank” position for the socket, offsetting it to the right-hand side so it’s directly on top of the bike while it’s tilted over on its sidestand. The idea is to maximize stability, so you can use some force to insert the plug and the bike’s less likely to be toppled if the cable gets accidentally tugged while it’s on charge. Alternatively, Yamaha suggests the socket could be hidden under the instruments or positioned near the steering head.

charging socket
The charging socket, labeled 50, is found under the rear seat in on this naked electric design.European Patent Office

A second design shows a larger electric naked bike, based on the MT-07’s design. Here, Yamaha’s idea is to put the socket under the pillion seat.

Two drawings from Yamaha
Two drawings from Yamaha show a charging socket, labeled 50, at the front of this sportbike, one in the nose and one in the headlight assembly.European Patent Office

Finally, there’s a third design that resembles an electric version of an R1-style superbike. Here, Yamaha suggests positioning the charging socket either at the base of the windshield on the bike’s nose, or hiding it inside a headlight assembly.

sportbike charging socket
A more detailed drawing of the electric sportbike charging socket located in the headlight assembly.European Patent Office

While the representative drawings in the patent won’t exactly reflect the styling of Yamaha’s future electric bikes, it’s clear the firm is considering a whole lineup of electric bikes to cover the same spread of customers that its gas machines currently cover.