cycle world article

8/7/2019 Cycle World Article

1/6

L-____________ ____________~ I L _ ______________

MOTORCYCLESAre battery-powered bikes the future of motorcycling? Not yet, we say. Here's why,along with what they can do superbly and what they can't do at all.BY STEVEANDERSON

IF YOU TALK WITH N EAL SAKAI , TH Eman who began Zero Motorcycles,it's hard not to catch his enthusiasmfor electric motorcycling. Internalcombustion engines, he likes to pointout, are less than 30 percent efficient.Electric operation- where losses in thevehicle can be held to as low as 10 percent- is the better answer. Bring up theissue of limited range on current electricbi kes, and he waves it away as a passingphase. "They're getting quicker to recharge and quicker to have more energyper cell. In the next couple of years,we' ll have motorcycles with a couple ofhundred miles range.You won't have tocharge them every day, just once a weekor twice. The battery companies are taking care of the problems."

IIJ


2/6

Bill Dube, the energetic and creativebehind the most successful- andd-setting- electric drag-rac ing morcycle would agree. He routinely runs

is Killacycle through the quarter-mil ethe 7 .8- to 8.0-second range, with a-to-60 time of 1 second and terminaleeds as high as 175 mph, a ll on afew cents of electricity per run . "Anelectric-powered vehi cle could bethe quickest thing out there," hesays. "The batte ries will support it. We ju st don't havethe motors designed forth e application."As you start hanging

out in the electri cvehicle wo rld, that's

a common theme- almost all the partsbeing used for electric motorcycles andrac ing cars were orig ina lly designed forsomething else. No o ne has yet built adedi cated, optimized production motorfor an electri c bike--or a lightweight,short-fused, 5000-horsepower motor thatwo uld be perfect fo r running aga in st TopFuel cars.But the batte ries a re progress ing.Dube, sponsored by Boston-based A 123Systems, a specialist in hi gh-powerce lls, has been given a g ift by hi s corporate benefactor: a small pallet of A 123'sextremely limited-productionFo rmula 1 battery ce lls,intended fo r use in F1kinet ic energy recovery

8rammo's first bike, the Enema(above), has a 3.1 kW-h battery packand will carry its rider a little more than30 miles before needing a charge. Itslatest machine, the Empulse, can bepositively filled with batteries (a 10kW-h pack in the top-line model) thatoccupy all the space between theframe rails. Each additional 2 kW-hadds 30 pounds, so the 6 kW-h modelweighs just 360 pounds, while the 10kW-h model scales 42o-with claimedranges of 60 and 100miles for each.


3/6

systems (KERS) when such things werea llowed. They're the hi ghest-power ce llson the planet that aren't locked in a laboratory, and a 50-pound pack of them w illreadily support the 55 0-hp-or-so hi s hotro dded in dustria l motor is capable of onthe dragstrip. With the ir help, Dub e plansto take 150 pounds of f the K ill acyc lean d recover hi s very rece ntly lost title:owner and rider of the quickest electricmotorcycle on the planet. A ll the while,he believes it's only a lac k of reso urcespreventi ng him from being able to omitth e adj ective "e lectric" in that phrase.With a ll thi s optimism, and demonstrated pelfo rmance to boot , what's tostop electric bi kes fro m tak ing over?We ll , there's the li ttle issues of range andrecharging ti me. Many gasoline-poweredbi kes will go 150 to 200 mi les on a

tank of fue l, and repl eni shing those f ivega llons might take a ll offive minutes.Recent electric bi kes, such as those madeby Zero or Brammo, have both had li mited perfo rmance (top speeds less than 70mp h) and limited range. An enthusiasticrider could eas ily push a f irst-generationBrammo E nertia down to a 20-mileoperating envelope, and Zeros are onl y

The 2011 Zero S streetmodel has a 4.5 kW-h lithium-ion battery pack,good for a 45-mile range insuburban riding. The pack,also used in the new ZeroMXmodel, is put togetherwith patented interconnects between cells thatmake it capable of surviving the kind of highimpact events an off-roadbike can experience.margina lly better. Plus, a ref ill fo r either is measured notin minutes but in multiplehours . Both companies are offering newbikes with more speed and more range .But, the problem with electric bikesis clear: They offer superb performance

poss ibili ties, as demonstrated by theKi llacycle an d recent electric roadracerssuch as the MotoCzysz E IPC or the C hipYates SWIGZ electric racer, but withvery limi ted range a nd slow recharg in g.

lemma, it's necessary to retreat back to ahi gh-school phys ics course and co ns id erthe di fference between power and energy.Energy is what's used in do ing work. Ittakes a certa in quantity of energy to heata pound of water 100 degrees or to t rave lfor an hour at 70 mph , fig hti ng w indres istance and rolling drag the entire way.It 's not something motorcyc lists typica llythink much about, because with gaso li ne,they almost always have enough. If youstart running s hort, you j ust f ind a gaspump. You co uld eas ily thin k of energyas s imilar to the amount of money youhave in your bank account: Just as withenergy, it takes a certa in quantity ofmoney to do certain thi.ngs.Power is so mething e lse; it's the rateat w hi ch yo u can use energy. Haveenough power, and you can acceleratequick ly a nd go very fast; have enoughmoney, and you can buy the machinesthat enabl e you to do so. A low-powereng in e is li ke having an ATM/creditca rd w ith a ve ry low limi t: Yo u mi ght

Alternat ive Fuels fo r Motorcyc lesA rundown of the options

What if the European Union had passedthe recently proposed stringent carbon dioxide emissions standard for motorcycles?What if the peak-oil Cassandras are correctand gasoline becomes more valuable than20-year-old Scotch? Don't worry, motorcycles will still exist, and still be capable ofever-increasing performance , but poweredby something other than pure gasoline.Here 's a look at the most likely paths towardchanging how we ride .ElectricAs discussed in the "Electric Motorcycles"

64 /CYCLE WORLD

feature , battery-powered bikes have alreadybegun to evolve into higher-performancemachines , if currently short-ranged. Butelectric energy from the grid still has tocome from somewhere. So far, hydroelectric ,wind farms and thermal solar are the mostpromising renewable energy options , withcoal , natural gas and nuclear making up thebulk of current U.S . electricity production . Ifwe built nuclear breeder reactors , such asthe canceled-in-1994 Integral Fast Reactor,there is sufficient uranium already in currentU.S. inventories-much of it unusable inother reactor designs-to match total annualU.S. energy consumption (petroleum , naturalgas, coal, hydroelectric, everything) for the

next 400 years! Nuclear fusion is anotherpossibility, but it suffers from aweird corollary of Zeno 's Paradox in which commercialimplementation is always 20 years from thecurrent year, with the new start date updatedeach January 1st.BiofuelsThe most obvious of these is ethanol,already used in gasohol throughout the U.S.and amainstay of the transportation systemin Brazil , where it is produced from sugarcane . Motorcycles would need to have fuelsystems suitable for high-alcohol fuels suchas E85 or E1 00; use in older machineswould be problematic, as many of their fuel-

www.cycleworld.com


4/6

The MotoCzysz E1PC won the FIM e-Power support electric race at MazdaRaceway Laguna Seca in 2010 but is likely to be quickly superseded in performance without rapid updates. The thoughtfully designed machine is builtaround a 12.5 kW-h battery pack (the five big aluminum boxes in front of therider's knees) that utilizes large-format l ithium-polymer cells.have a lot of money at the bank (i.e.,fuel in the tank), but if yo u can onlywithdraw $20 a day, you're not go ing tohave the sa me possibilities- fo r betteror worse- than if you cou ld get it a llmore quickly. Converse ly, lots of powerwith little energy is like be ing in Vegaswith a no- limit ATM card but just $200in the bank: You're soo n goi ng to bestanding by the s ide of the road w ithyour thumb out.

batteries can't release electricity quick lyenough to ach ieve that leve l of power.For electric ve hi cles, and particul arlyin reference to battery capabilities,power is a lmost always expressed ink ilowatts, not horsepowe r. It 's mere ly aun it change, however, s ince I kilowattis eq ual to 1.34 horsepowe r. And whendea ling with electri city, energy is ge nera lly expressed in terms of kilowatthou rs, or kW-h, rather than in horsepower-hours. The po in t of a ll thi s is thatwe can use those same units to co mparebatteries and gasoline.It turn s out gaso line is very energe tic,indeed. A s ingle ga llon of gaso line,when burned with the oxygen free lyavailable in the a ir, can release 36 kW-h

of energy in the form of heat. But,because interna l-co mbu stion enginesaren't te rr ibly effic ient in convertingthat heat in to work, perhaps on ly asli ttle as 6.7 kW-h of that is actua lly usabl e. Measured aga in st weight insteadof volume, gaso line, as processed in toenergy by a typ ica l eng ine, is good forabout 2.3 kW-h per kilogram (and we'reus ing metric here beca use a lm ost no onetalks about battery specific e nergy inany o ther units than kW-hlkg).The bad news about batteries is thatcompared to gasoline, they 're almost offthe chart in specif ic energy. Lead- aci dbatteries, at 0.04 kW-h/kg, are pathetic;in tenn s of riding range, almost 370pOUl1ds of lead-ac id batteries would beneeded to match what an eng ine can dowith a ga llon of gasoline. It's only whenyou get to the latest IithiUl11-ion batteries,a battery type that has only been commercia lly ava ilable for about 15 years,does it get much better, and even then it'sonly a matter of degree. It takes 60 lb. ofthe latest, greatest and most-expensiveli thium-ion ce lls to equal what a ga llon (6lb .) of gasoline can do. And in an actualmotorcycle, those cells will have to beencased, protected, monitored by additional electroni cs and have some attentionpaid to contro lling their temperature. Thehardware necessary to do a ll that wi ll add10 to 20 percent to the pack weight.What's more, although lithium- ionce lls have been ga ini ng e nergy densityever s ince they f irst became commercia lly avai lable, the ri se is linear andnot exceptiona lly rapi d. It 's go ing to

Electric vehi cles work on the sa meprinciples but diffe rently. In an electricvehicle, the batteries are the energysto rage device, not a combustible fue l.The batteries release energy through areversib le chemical reaction as electricity that is capable of di rectly poweringan e lectric motor. But a battery's designand size set limits on both energy andthe rate at which it ca n be releasedthat is, batteries are both power andenergy limited. Ge nera lly, the moto rs onelectric vehicles are sized to t he limitsimposed by the batteries; there's nopoint in havfng a 100-hp moto r if the

"Lots of power with little energy is like being in Vegaswith ano-limit ATM card but just $200 in the bank:

system components are incompatible .Withone-third less energy per gallon , ethanolgives both less range for agiven fuel-tanksize and requires substantial rejetting orECU reprogramming in existing machines.Plus , current ethanol production from cornis a) uneconomical without agovernmentsubsidy; b) raises food prices ; and c) usesalmost as much or more petroleum in itsproduction as it replaces .Much research isfocused on more-efficient ethanol productionfrom plant waste (corn stalks , etc.) and maybring more cost-effective ethanol productioninthe next decades.Methanol is currently produced from natural gas and is avery attractive fuel if the infrastructure were there to support it. Direct-

You're soon going to be standing by the side of theroad with your thumb out."injection spark-ignition engines burningmethanol can meet emissions regulationswith turbocharging and 14:1 compressionratiOS , and do so with more power than anygasoline engine and overall energy efficiencyrivaling diesels .Methanol can also be produced from biomass, but as with ethanol ,economic production to compete with $3-agallon gasoline has yet to be achieved .Synthetic fuelsSynthetic gasoline can be produced fromcoal-a technology developed by Hitler 'sGermany and perfected in South Africa whenaworldwide ban on exports to that countrywas enforced during the apartheid era . Itgenerates substantially higher carbon-diox-

--------- .....ide emissions than would burning the coalinelectric power plants for electric vehicles,but it will power current vehicles.Improving gasoline efficiency in newmotorcyclesMotorcycle fuel consumption could likelybe halved,with motorcycles capable of 60-plus mpg becoming common . This involvesfollowing the path of the auto industry andpursuing every possible efficiency increasewith internal-combustion engines. For highperformance vehicles , direct injection of atiny amount of supplemental methanol du ringhigh- load conditions can prevent detonation,allowing substantially higher compressionand the improved power and efficiency it

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - -66 /CYCLE WO RLD www .cycleworld.com


5/6

be a long time before batteries catchup to the specific energy of gasoline.That wi ll almost certa inly requ ire astep-leap upward with an unpred ictablebreakthrough in getting an exotic cellchemistry to work somep lace other thanin theories.Why electric vehicles weren 't happening before, though, was the cost. Untilrecently, a rule of thumb was that acompleted lithium-ion battery pack for avehicle cost abo ut $1000 per kW-h. Thatwould have placed a pack that matchedthe usable energy in a ga llon of gasolineat north of $6000- and that's the manu facturer's cost. It would have added$12,000 to the sticker price, and unlessthe manufacturer offered an unu sua llyheavy discount, a rep lacement packwould have reta iled for around $20,000 .Fortunately, even as carmakers havebegun to embrace some degree of electrification, the entire consumer electronics industry beat them there, withlithium-ion batteries essentia lly standardin every laptop computer and ce ll phonemade. The resultant vo lume increaseshave started driving prices down; current costs are perhaps half as high asbefore and sti ll fa ll ing. Indeed, the ubiquitous 18650 size ce ll (l8mm in d iameter, 65mm long, just a little bigger thanan AA alkaline), which can be fou nd inmost Windows laptop computers, hasfallen to the point that if you aren't buying cutting-edge energy capacity in eachcell, a manufacturer could put a pack ofthose together for about $350 per kW-h.Curiously, as General Motors looksto drive lithium-ion battery-pack pricesdown for the Vo lt and its other hybridsby using large-format prismatic cellsthat w ill simplify pack construction,California start-up Tesla is riding theconsumer-electronics learning curveand b uilding its pure-electric cars .around battehe s consisting of litera lly

brings ; bu t it would require asmall on-boardmethanol tank, perhaps ahalf-gallon or so.Variable valve-timing can improve low-loadoperation, and smaller, turbocharged enginescan be moreeffic ient during cruise whilestill hitting big peak power numbers . Widergearbox ranges with more gears would allowmore-efficient highway cruising . Better aerodynamics and lighter vehicle weight alwaysimprove efficiency. If peak power weren 't thehighest goal, rel atively long-stroke enginesturning at lower rpm can be more efficientfor touring bikes and cruisers.Other AlternativesCompressed Natural Gas (CNG) , agasmixturecons isting of mostly methane, is

60 /CYCLE WORLD

thousands of those tiny 18650 ce lls. Itsnext car, the Tesla S sedan, may actually u e 8000 ce lls in its opt ional highcapacity battery pack.Why? Because Tesla expects to beable to put packs together for $200 perkW-h by 20 12 using the ce lls that everybattery company in the world seems tobe making, with the competition driving prices down faster than the seemingly more-rational GM approach. Bo thToyota and Panasonic, a major lithiumion ce ll supplier, have invested in Tesla.The company looks to solve the rangeproblem by brute force: get the batterycost low enough that you can afford tobuy a rea lly big and heavy one.Indeed, the amount of research going into battery technology right nowis unprecedented, and electric vehiclesare interesting because of some of the

already commonly used to power low-emissions internal-combustion engines in urbanfleets such as taxis and city buses , and youcan buy a few CNG-powered cars directlyfrom manufacturers.One CNG drawback for motorcycles is thatthe compressed gas is less energy-densethan gasoline; and to achieve equal range, thecapacity of the 3600-psi-capable CNG tank(which for structural reasons almost certainlymust be round or cylindrical with round ends)would have to be three times greater than agasoline tank. But natural gas is readily available in the U.S.; and thanks tonewextractionmethods, the available gas is equal to a100-year supply at current usage rates.Another gaseous fuel frequently discussed- - - - - - - - ~

Bill Dube's Killacycle is perhaps thebest example of the kind of performance that can be obtained fromelectric bikes for short distances: 7.8seconds and 175 mph in a quartermile. It uses high-power A123 26650cells originally designed for DeWalt36-volt cordless tools; it takes 1210of them to make up the 200-poundpack in the current Killacycle.results. Remember earlier when we saidthat batteries are limited in both powerand energy capacity? Well , it's possibleto optinlize for one or the other, so thereare both "power" ce lls and "energy" cells.Amelican battery company A123 hasspecia lized in the first, and its cells, whilehaving less than ha lf the energy of thehighest-energy ce lls of its competitors,have exceptional power, as much as 20kW/kg (12 hp/lb.) for its Fonnula I cells.As long as you're willing to live witha ga llon of gaso li ne 's worth of energycapacity, it's possible to put together acomplete electric powertrain- motor,contro ller and battery pack- that eithermatches the weight of sportbike and racing eng ines or is on ly slightly heavier.Try to match f ive ga llons, though, andthe complete powertrains get piggishlyheavy. What's more, the power ce lls arecapable of being charged exception-a lly quickly- as long as you 've spent----------for the future is hydrogen , whose only exhaust by-products areheated air and a littlewater vapor. Hydrogen requires adirect-injection system and the tailoring of an enginefor its extremely fast burn characterist ics.It also is a difficult fuel to store ; thevolumeof ahydrogen tank filled to 5000 ps i hasto be four tim es larger than an equivalentrangegasoline tank- unless you want todeal with liquid hydrogen at -423 degrees F.And for hydrogen to be a low-carbon fuel ,it has to be made by low-carbon en erg y,either renewable or nuclear. Finally, there isessentially no current hydrogen distributionne twork for vehicleuse, and the energy lostin compressing and transporting it would besignif icant. - SteveAnderson

------www.cycleworld.com


6/6

The most recent electric motorcycle to make the news is the Chip Yates /SWIGZracebike that made the podium in a club race against Open-class Superbikes.With an 11 kW-h battery pack and a 190-hp electric motor, it can out-accelerateand out-speed club-level Ducati 1198s, but not for long: Range is 25 miles atbest. It also looks like the product of a mad inventor in a home garage.several thousand doll ars to have a hi ghrate, 220-volt charger in stalled in yourgarage. A standard 120-volt out let islimited to 1.5 kW, making a high-powerhome circuit essential for fast charges.But what does a ll this mean for electricmotorcycles? In the near future, there 'sgo ing to be a complicated trade-off between power, range and cost. If a manufacturer chooses a relative ly large batterypack, the price, weight and range willincrease, particularly if power and performance have stayed relatively modest.This will likely be the strategy of

Brammo and Zero for their urban commuter and off-road models. For ultimateperformance, high-powered electricbikes priced like Bimotas (or more) maysoon be able to hang w ith or even betterin ternal-combustion-powered sportbikes,even on th e racetrack, but only for minutes; th e ones with longer range w ill betoo heavy. Electric roadracers over thenex t several years eventually are likelyto set some impress ive lap times. but it'sgo ing to be only for race lengths muchshorter than a 50-mile AMA Superbikera ce o r a 45-minute MotoGP race, at

least until batteries improve to th e pointwhere a 35 or 40 kW-h pack can be partof a 375-pound motorcycle.In fact, the most interest ing applications of electrificati on are for bikes thata lready have tiny gas tanks, such asmotocross or tri als, and that also o nlyspend a sma ll fraction of their timeat full powe r. With only the ex pectedimprovements in battery performance,it should be poss ibl e within the nextseveral years to build an extremely competitive e lectric motocrosser capable off inishing 20-minute motos and be ingrecharged between heats. This shouldopen up entirely new pos ibiliti es ofquiet urban motocross on co urses builton vacant lots in industrial neighbor-hoods. And drag rac ing, with its definedquarter-mile commute, is idea l for hi ghpower, low-energy applica tions.But what will rea lly make or breakelectric motorcyc les will be how current motorcyc lists reac t to them. Withseamless performance, no gear shi ftingand the loudest sounds being only motorwhine and the annoy ingly loud whir ofa chain (no longer masked by exhaustnote), it may si mply be that electric motorcycles aren 't as engagi ng as internalcombustion models.For that, only t im e, and tastes, wi llte ll. i:!l

cycle world article

Documents