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Wednesday, October 5, 2022
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Swappable Batteries

Honda was recently the first of major manufacturers to unveil its “swappable” battery for lightweight motorcycles and scooters. Part of a consortium also comprising fellow Asian giants Yamaha, Suzuki and Kawasaki, the idea is to produce batteries that are not only swappable but interchangeable amongst brands — the benefit being, of course, that the one-battery-fits-all Mobile Power Packs (MPP) will allow all electric bikes to exchange batteries at the same centralized station.

As the solution for urban-only scooters and perhaps even 125-cc-like mini motorcycles, these swappable batteries are absolutely ingenious. Incorporated into lightweight scooters, each battery is good for anywhere between 35 and 50 low-speed kilometres and, when depleted, they are easily and quickly exchanged, by hand, at the proposed multi-brand battery-swapping stations.

All these advantages have electric motorcycle advocates dreaming that such swappable batteries could be the paradigm shift that brings zero-emission bikes out of the shadows and into the mainstream. Unlike electric cars, which are starting to make inroads in market share, sales of full-sized electric motorcycles remain preposterously slow. So could Honda’s swappable battery be the battery technology breakthrough motorcycling has been waiting for?

Umm, the numbers would suggest that the answer is no.

Lost in all the hype are the specs of the new battery. Most crucial is that the Honda’s MPP is rated for 1,314 watt-hours. That might sound like a lot, but, in fact, when measured in the terms current electric vehicles are commonly rated with — kilowatt-hours — it’s a measly 1.3 kilowatt-hours. The other spec worth paying attention to is that each of those 1.3 kWh batteries weighs some 10.3 kilograms.

Now, the good news is that, save for possibly the elderly, infirm and those with physical disabilities, a 23-pound battery should be easily manhandled into and out of a scooter. The bad news is that its energy density — the amount of those kilowatt-hour things per kilogram of weight — renders the technology all but useless for anything other than scooters and minibikes.

By way of example, the LiveWire — which Harley says is not only the most advanced electric motorcycle for sale in the U.S., but also the best-selling — boasts a full 15.5 kWh of lithium ion beneath its seat (of which 13.3 kWh are usable). Simple long division says the LiveWire’s current battery is the equivalent of about 12 of those swappable jobbies. Do the math again — this time simple multiplication — and we’re looking at 120 kilograms — about 265 pounds — of battery alone.

Now, EV proponents will blow holes in the simplicity of that algebra. And rightly so. Each of those individual small batteries has to have its own “management” system built in, whereas a larger single battery would have but one, making the total less than the sum of its parts. Nonetheless, despite that seemingly simplistic computation, the numbers fit into the range — 90 to 113 kg — generally estimated for the weight of the LiveWire’s battery (electric motorcycle manufacturers are loathe to release unflattering numbers such as battery weight and actual sales numbers, so we don’t know for sure).

Let’s now consider what 100 or so kilograms of battery gets you. Lost in the rosy predictions of 235 km of urban riding range and 153 km of combined riding is the fact that Harley says the LiveWire is good for 70 miles when cruising at a steady 70 miles per hour. That’s 112 km at 112 km/h. In a recent long-distance test pitting the Harley electric against an Energica Eva (with a larger 21.5 kWh battery), Motorcycle News’ reporters were searching for a charging station after as little as 64 miles (100 km) despite being on b-roads instead of highways.

Now let’s compare that with my pedestrian, everyday 2018 Suzuki DL1000XT. Assuming there’s no tornado-like headwinds, my XT will easily knock off 350 km at a steady 110 km/h, more than three times what the LiveWire can manage on the best of days. If, using today’s premium battery technology, you wanted the same sort of cruising range — and, by the way, serious tourers would consider 350 klicks to a tank, er, full charge, a pittance — you’d probably need somewhere between 40 and 45 kWh.

Using even the most efficient, higher-voltage current automotive batteries as a guideline, that kind of range would require a battery weighing in the region of 220 kilograms or more. We’re talking almost 500 pounds of battery. Now, while cars can disguise that much weight simply by hiding it in the floor pan — they actually aid handling somewhat by lowering the centre of gravity — there’s no such way to hide a heavy battery in a motorcycle. And no, advancements in battery technology, at least in the foreseeable future, are not going to improve the situation dramatically enough to make a lightweight, long-distance adventure touring bike possible.

Indeed, returning to the original question of whether Honda’s swappable battery will be the salvation of electric motorcycling, here’s one final bit of algebra for you. Using the Harley’s efficiency as a guideline, those 10.3 kilograms of swappable battery everyone is touting as the future would get the LiveWire somewhere around 10 km of range at a steady 110 km/h. At that same speed, 10.3 kilograms of gasoline — about 13.5 litres — would get my Strom from its suburban Toronto garage all the way to Shannonville Motorsport Park — some 197 km away — with just enough fumes left over for a few hot laps.

So no, as ingenious a solution as they may be to the needs of scooter riders, swappable batteries may not be the game-changing technology we’re all waiting for.

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