Is Capacity and Weight It?

[Mithion]

My question is- is the capacity and weight of current batteries the biggest "downfall" electric vehicles have?

Basically-

How much has electric motor technology advanced?

Is there a significant difference in the chassis needed for an ICE bike vs an electric?

Other areas remain the same the way I see it such as - Wheels, tires and auxiliary gear should be basically the same as ICE vehicles so back to the first question-

Are batteries the main and only real "downfall" of electric vehicles?

[FreepZ]

Are batteries the main and only real "downfall" of electric vehicles?

The short answer is yes. Note that recharge time is also a variable.

If we could magically replace the energy source with something that could weigh 1/10 of the current battery pack, and could be refilled instantly (or not need refilling ever), then an electric motorcycle would beat the pants of any ICE bike.

Just take a look at Jensen Beeler's review for the Mission R.
Or read Wes Siler's review for the Empulse.

Jensen says "Hold all these elements [of an ideal motorcycle] in your mind for a moment, and then open your eyes. The motorcycle I just described to you is the Mission R"
Wes says "The Empulse is simply a more pure experience than any gasoline-powered bike could ever be. "

The only real advantage that the ICE has over an electric drive train (I don't count noise as an advantage) is the the high energy density and fast replenishment of it's energy storage system (i.e. gasoline vs batteries).

Recharge rate is an important factor, since if we could instantly recharge a battery, it would not need to be so big. Currently, EV manufacturers try to make the battery big enough so that you don't have to charge them except when you're done traveling. That's not possible if you're travelling long distance, which is why EVs are better suited for city driving.

[protomech]

High energy density for fuel isn't a huge advantage for gas bikes. Gas bikes typically have 100-200 miles of range in their gas tanks - electric bikes are encroaching on that range in "typical" riding, 60-70 miles for the Zeros and 70-80 miles for the Empulse. Storing additional fuel would cost very little in weight for the gas bikes - and some touring bikes do hold 6-8 gallons of fuel - but it's simply not needed most of the time.

The huge advantage is the existing install base of fuel supply points and the very fast refuel times. If you figure 50 mpg and 1 gal/10 seconds, the "recharge rate" is 18000 miles/hour. If you figure a typical fuel stop lasts 5 minutes for 3 gallons, then the effective "recharge rate" is 2400 miles/hour.

A 15 kWh pack - per Neil Saiki - charged from 20% to 80% in 5 minutes (7.2C) would require a 120 kW supply, and would give a 720 freeway miles/hour "recharge rate". A more reasonable 15 minute charge (2.4C) would require a 40 kW supply and give a 240 freeway miles/hour "recharge rate". Probably acceptable at that point, given a sufficiently high density of charging stations and batteries that are happy to be charged that quickly.

Level 3 charging stations - existing CHAdeMO and the forthcoming SAE Combined Charging - can easily handle 40+ kW. Bike batteries may have to become significantly higher voltage - it's not clear to me what drives the selection of a 65 V system (Zero), 88 - 103 V (Brammo), 300+ Volt (KTM) .. possible that the smaller manufacturers don't have access to suppliers for higher voltage components or the resources to build them in-house.

The other area that can be tackled for freeway travel is aero drag. A feet-forward faired bike could easily double highway range and effective "charging rate". A 40 kW charging station would charge at 500 freeway miles/hour .. 15 minutes of charging every ~2 hours of riding.

We have the technology or very nearly to do this today. We just haven't put the pieces together.

[protomech]

Oh, and yes there are different needs for ICE chassis vs an electric bike. ICE chassis is typically adapted to the packaging requirements of its motor / transmission. When an existing chassis is repurposed for a home EV conversion then you have to decide how to fit the batteries in - and very often the home-built EV bikes have < 5 kWh of capacity onboard. Zero and Brammo can fit more because they're using top-notch dense batteries, but also because their frames are purpose-built around the batteries.

Brammo uses a central spine with battery modules mounted above and below - as on the original Enertia, carried forward to the Enertia Plus and Empulse. Zero builds their frames such that the large battery enclosure can be vertically slid in.

[Richard230]

I think that frames for electric motorcycles can be built differently that for IC bikes, if for no other reason than they don't have motor vibration to deal with.  IC vibration needs to be dampened out so that it does not reach the rider or the motorcycle components, whereas EVs make very little vibration and you should be able to design a frame to take advantage of that lack of stress that would be less expensive to manufacture, as well as being lighter, stronger and handle better.

In addition to the obvious need to increase battery density and charging speed, I think there might also be a need to improve electric motors for motorcycle use.  I suspect that the current electric motors being used in motorcycles are being plucked off the shelf and likely will need to be optimized in the future to accommodate being exposed to environmental elements and the performance requirements of motorcycle use.  The technology is still very young and no doubt has a long way to go before it matures to the extent that IC technology has, what with its 110 years of design, manufacturing and ownership experience.

[protomech]

A better metric for refueling times is minutes/mile .. or perhaps minutes (hours) / 100 miles.

Additionally, we can add in travel time to arrive at a total trip rate and speed. Traveling 100 miles @ 70 mph takes 1.43 hours.

Zero S charges around 0.8 kW to the battery. Freeway usage is 182 Wh/mile:
13.7 mins/mile or 1365 mins (22.8h)/100 mile; 100 miles in 24.2h = 4.1 mph

Empulse is a 3.5h charge for 9.3 kWh, average 2.66 kW delivered to battery. Bulk charging may be faster.
Freeway usage is 166 Wh/mile:
3.74 mins/mile or 374 mins (6.24h)/100 mile; 100 miles in 7.67h = 13.0 mph

Lightning claims 100 freeway miles from their 12 kWh pack. J1772 30A charging should support a 2 hour charge.
1.20 mins/mile or 120 mins (2.0h)/100 mile; 100 miles in 3.43h = 29.2 mph

A hypothetical 40 kW charge with an aerodynamic design halving highway power requirements (83 Wh/mile or 5.8 kW @ 70 mph):
0.12 mins/mile or 12.5 mins (0.21h)/100 mile; 100 miles in 1.64h = 61.0 mph

A typical ICE bike refueling stop, 5 minutes for 3 gals of gas @ 50 mpg:
0.03 mins/mile or 3.3 mins (0.055h)/100 mile; 100 miles in 1.49h = 67.1 mph

***

Realistically, to travel long distances requiring several midtrip charges with either the Empulse or the Zero you will probably want to run at 40-45 mph speeds to minimize total trip time.

At 40 mph I get around 100 miles of range on the S (79 Wh/mile), so recharging gives me 5.9 mins/mile or 9.8h/100 mile.
With four chargers and a 30A J1772 station this could be increased to 1.5 mins/mile or 2.5h/100 mile. At 40 mph it will take 2.5 hours to ride 100 miles, so average full replenishment trip pace of 100 miles in 5.0h = 20 mph.

At 55 mph the Lightning bike might get around 100 Wh/mile, recharging at a 30A J1772 station gives 1 mins/mile or 1.7h/100 mile. Full replenishment trip pace of 100 miles in 3.1h = 32.3 mph.

***

Level 3 quick charge stations are not cheap. Nissan recently released a lower-priced charger @ $10k (specs here). Installation may run a couple thousand dollars additional.

However, compare to the cost of a typical two-product fuel dispenser. One such, Bennett Pacific 1000 series is $13.5k retail.

A complete multi-dispenser setup, including underground tank, concrete work, canopy, etc can cost up to $200k (PDF).

Each of the Pacific 1000 dispensers uses an average of 360 watts (PDF) .. apparently a low power design. A set of 4 fuel dispensers will consume 34.6 kWh per day - or as much as two 70% quick charges of a Nissan Leaf.