A. For electric vehicles of all kinds, range is product requirement #1. From a marketing standpoint, for motorcycles the magic number is 100 miles. Still, a bike that only goes 100 miles does not have enough range to qualify as a distance touring bike, and if power is used to make the bike competitive with sport bikes it won't have a 100 mile range. Current technology relegates the electric motorcycle to a commuter and city riding application.
Empulse has a motor that's almost twice as powerful as the Zero. It weighs 130 lbs more and has a multi-gear transmission that will have some mechanical loss.
Yet in city riding it is rated to use only 11% more energy per mile than the Zero and in highway riding it is rated to use 9% less energy per mile on the highway. Because highway is by far the largest consumption of energy, on the 50/50 city/highway blends the Empulse uses 4% less energy per mile.
You're thinking about gas bikes too much. On an electric a larger motor is not necessarily less efficient for an identical workload.
B. Getting 100 miles plus out of an electric commuter/city bike means optimizing for weight/power ratio.
Out of a city bike, yes. But if you ride a city bike 100 miles, it will take you more than 4 hours.
Who rides a bike for 4-7 hours at 20-25 miles per hour?It's useful to distinguish commuter bikes from city bikes: a commuter bike might mean 60 miles each way @ 80 mph. Commuter just has the expectation of a relatively fixed distance and a long period to charge on either end (to distinguish from touring).
C. At close to $1K per kWh for lithium, 9kWh is the most stored energy that can be viably marketed for a commuter/city bike.
Yes. I think even at $200-300/kWh, 100 miles is more than enough for a city bike.
Perhaps it's more useful to think in terms of time than range.
For commuter applications, one "leg" of a trip is unlikely to exceed one hour of riding.
If you consider at most you need two legs of riding .. a city bike (20-35 mph) will need around 4 kWh, a suburban bike (45-55 mph) will need around 12 kWh, and a highway bike (70-80 mph) will need around 30 kWh. Good aerodynamics will significantly decrease the battery needed for suburban and highway riding.
At $200/kWh, those bike packs will cost $800, $2400, and $6000 respectively.
Someone who primarily commutes in a suburban environment may turn up their noses at the $3600 price delta.. they can ride for 2 hours @ $2400, $6000 would buy them 5 hours of riding but how often are they likely to do that?
D. A 9kWh battery requires a light sub-300lb bike to take the bike and rider > 100 miles.
Brammo does 121 city miles in 9.3 kWh and a 470 lb bike.
Zero does 114 city miles in 7.9 kWh with a 340 lb bike. A hypothetical 9.3 kWh Zero would weigh around 360 lbs.
Air resistance is far more important than weight, especially when you start to talk about those 30-50 mph speeds.
E. A 300 lb bike, ICE or electric, is too light for extended highway riding, so optimize for 30MPH to 50MPH.
A + B + C + D + E = no gearbox
A bike like the Zero is good for only occasional highway commuting. It handles fine on the highway, but the energy usage is too high and the charging is too slow. Charge recovery is 4.5 highway miles per hour charging. A 40 mile one-way commute would deplete 92% of the pack energy and it would take around 8 hours to charge back to full.
A bike like the Empulse is still very much constrained by range, but lower highway energy consumption combined with a fast charger -- supposing that you have access to J1772 charging stations -- changes things. Charge recovery is 19 highway miles per hour charging. A 40 mile one-way commute would deplete 71% of the pack energy and it would take a couple of hours to charge back to full.
The current state-of-the art for electric motorcycles is the commuter/city bike application, an evolutionary step up from the previous short-range dirt bike application that the bikes were limited to before power density was doubled and regen braking was added.
If the economics of the batteries and drive trains doubles again then so does the calculation above, and new applications are opened up. If the cost falls to $500/kWh then range can be increased to approach ICE distance cruiser range, or the power can be used to increase speed and acceleration and ICE sport bike configurations start to make sense.
Brammo's error is to try to achieve a sport bike application within the confines of commuter/city bike technology. This is why they will fail. Fatal error.
I'm curious what you will think if Zero introduces a sport bike next year.
Even if the batteries halve in price and weight, people still kvetch about range. "100 miles of highway driving is barely enough to get me to the good roads", they say. "That's not enough to handle my 5 hour commute", they say. "Who buys a bike you can't do the Iron Butt Rally in", they say. "40 minutes on a race track is awful, I need at least 8 hours for my track session".
But every time the batteries improve it makes the electric bikes more reasonable for more people. A slow gradual process to be sure.