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ELECTRIC SUPERBIKES: very fast! The Sounds of Silence Amid the ear-shattering scream of superbikes hurtling down Brabham Straight at around 280km/h came a couple of rather special bikes doing not much less speed . . . but significantly less decibels! In fact, compared to the rest, it was almost silent – just the whoosh of the wind, a bit of chain noise and the (albeit minimal!) tyres-on-tarmac note. W e were at Sydney Motorsport Park (aka Eastern Creek) to witness practice day for the round of superbike racing on the following two days. And while the petrol superbikes were rather impressive, that’s not what we were there to see. Instead, we had been invited to watch purely electric-powered bikes put through their paces by a couple of Australia’s leading electric motorcycle racing exponents, as part of the Electric Formula Extreme Challenge. Danny Ripperton had his own Ripperton bike while Jason Morris was aboard a bike from Varley. They’re perhaps better known for the electric 16 Silicon Chip tugs used to pull jumbo jets around airports! But let’s wind the clock back a few weeks and tell you how all this came about. Knowing of our interest in electric vehicles, we were approached by the promoter of the 2013 Electric Superbike series, Victor Fenech. Victor was producing a series of TV programs for the free-to-air community television station TVS and wanted to know if SILICON CHIP was interested in also promoting the electric superbike concept. Hence this feature! We received a considerable amount of feedback from readers when we featured the all-electric Nissan Leaf car (August 2012) and the all-electric Vectrix motorcycle (May 2008). While some readers were quite critical of the concept of electric vehicles the vast majority were most interested in the technology and the way it had advanced in recent times. Therefore we were sure our readers would also be interested in the concept of electric superbikes. Who knows, some of it might be a vicarious desire to be screaming down the straight at more than 200km/h! What’s it like? The electric superbike is not too dissimilar to those petrol-powered speed demons you’ve seen fanging siliconchip.com.au By Ross Tester around Eastern Creek or Philip Island (and other racetracks, both here and overseas). In fact, we’d already heard about the electric superbikes’ prowess from their involvement in the Isle of Man Classic race, earlier in the year. In that race, an electric superbike averaged speeds greater than 160km/h. But what makes the electric bike quite different is, of course, that there is not even a nanolitre of petrol involved, nor is there any internal combustion. They are not hybrids – in the case of the Ripperton bike (the red “No46” above) they derive 100% of their power from not one but two “tandem” siliconchip.com.au high performance, water-cooled 175V electric motors, each rated at 50hp. Both motors drive the one shaft; the bottom motor has a sprocket and chain to drive the rear wheel in a somewhat conventional way. It’s only somewhat conventional because there is no gearbox or clutch. As you would no doubt realise, an electric motor delivers its maximum torque at zero rpm, so there’s little need to go “up through the gears” to deliver maximum power when you need it. Unlike fuel-powered bikes, the electric-powered model has what amounts to a “reverse gear” – very handy for manoeuvring around the often limited confines of the pits and garage behind. It’s not a true reverse gear – it’s simply a switch which swaps two of the three motor wires and makes them turn backwards! A three-phase controller handles delivery of power to the motors, dependent (of course!) on the amount of “throttle” applied by the rider. Motor speed is monitored by a Hall Effect sensor on the main motor (the second motor, by definition, must be rotating at the same speed). The controller is fan-cooled but also relies (as does a lot of other cooling) on the not inconsiderable cooling power of a 200km/h airstream! The motors are driven from a stack of 42 very-carefully-managed Lithium Polymer cells. On board the bike is a range of engine and battery management technology which is available for analysis after the race to ensure optimum “tuning” next time out. Safety is vitally important in electric superbike racing: here you can see the “big red button” which cuts off all power to the bike (underside) along with the large red light on top which tells everyone the bike is powered. There’s no screaming motor to warn you! The entire battery pack is removable from the bike – it is charged outside the bike. Each cell is individually monitored during the charging process, with a shunt resistor across the cell being brought into play if the cell voltage exceeds the 4.15V intended charge. The battery pack weigha about 55kg and measures around 750mm high x 250mm wide x 220 deep and sits basically under the rider and in the bike frame, much where you’d expect Here Victor Fenech, resplendent in his “SILICON CHIP” yellow shirt, is interviewing two of the leading movers and shakers in the electric superbike world for the TV show he’s producing: at left is Varley rider Jason Morris and in the centre, Danny Ripperton. December 2013 17 The 42-cell Lithium Polymer powerhouse sits vertically in a specially-designed cradle underneath the rider’s seat. Extensive on-bike electronics monitors the cell charge levels, temperature, loading, etc. At 55kg, getting the battery pack out is no mean feat – and virtually impossible from alongside the bike. Here Danny Ripperton stands on the supported bike to extract the 750mm-deep pack. to find the fuel tank and engine on a “normal” superbike. However, the shape of the battery pack and motors means that a conventional bike frame is unsuitable for electric power, so many iterations of frame have been produced to find one that gives that miniscule increase in performance over other types. When your lap times are measured in thousands of a second, any advantage you can obtain is an advantage you DO obtain! Just as a fuel tank on a petrol bike only holds a certain amount of energy, so do the batteries. They typically last about 5-7 laps around Eastern Creek, although after four laps they’re getting pretty hot. Again, battery temperature is one of the parameters that’s carefully monitored. Only rechargeable batteries can be used – one-time batteries could achieve better results but these are not permitted under race rules. Interestingly, the rules do permit more than one driven wheel (eg, using in-wheel motors) but so far, no bikes have been entered with more than one wheel driven. Yet! Race rules say that the bike needs to be able to complete 18+ kilometres at race speeds, including the warm-up lap (the warm-up lap is not so much to warm the engine, as it is for petrol bikes, it’s to get the rider used to the bike at race speeds and heat the tyres – which of course petrol bikes need too). The day we went to Eastern Creek, the first run of the Ripperton electric bike, being ridden by Australian Champion Kevin Curtin, achieved less than two laps and ignominiously returned to the pits on the back of a recovery vehicle. The pit crew spotted the problem in an instant: the power lead which plugs into the battery pack had somehow vibrated loose and off. No power = bike stops! Later, the Varley bike, ridden by Jason Morris, also impressed us on the track. Safety Batteries are charged outside the bike with every cell monitored. A dedicated computer gives instant feedback via “Batrium EV Suite” software. 18 Silicon Chip While a bike is out on the track, another battery pack (or packs) are usually charging in the garage behind the pits. It is mandatory for a competent team member to be present and monitoring the charging process. At Eastern Creek, we were able to see the charging and monitoring siliconchip.com.au process with all cells being analysed and displayed in real-time via a laptop computer. On the Varley bike the batteries are not removable: they’re chaged “in situ” The Battery Management System is a vital and compulsory component as batteries could present a risk of overheating and fire. The BMS must provide a feedback loop to the charging system to disable charging in the event that a cell or cells exceeds the charge voltage limit specified by the cell manufacturer. It must also be capable of discon- Like all racing bikes, off the track the tyres must be kept warm for maximum adhesion. At the same time the motors, batteries and electronics must be kept cool. Here a powered tyre heater sits alongside a blower fan – one heating, one cooling! The Battery Management System and other monitoring circuitry takes a fair amount of space (and adds weight) on the electric superbike. Weight must be kept to a minimum to remain competitive. siliconchip.com.au necting power if the overall pack voltage is greater than (or less than) the cell manufacturer’s specifications. The BMS is also (usually) the component responsible for regenerative braking – that is, recovering energy from the momentum of the bike under braking, picking it up from the motor powering the rear wheel. However, we were told that given the short, sharp braking typical of racing circuits, the amount of energy that can be reclaimed is miniscule. The conventional (hydraulic) brake is on the front wheel only. The rules state that voltage is limited to a peak of 700V between any two points. This means a maximum of 700V DC or 700V peak for AC. And in cases where the voltage of the power circuit exceeds 42V, the power circuit must be well insulated from the onboard circuitry. There must be two emergency stops on each electric superbike. One is via a lanyard which disconnects power should the rider and bike become separated. The second is via a “big red button” on the back of the bike (immediately behind the rider) which is a mechanical switch, capable of being activated by anyone in the event of an incident. The circuitry must be set up so that the voltage across the capacitors in the power circuit falls to 65V or less within five seconds if the general circuit power breaker is opened, or if the December 2013 19 Duties of a scrutineer Malcom Faed, photographed above with Victor Fenech, is well-known to SILICON CHIP readers from his fuel-to-electric utility conversion (SILICON CHIP, June 2009). Malcom is an electric bikes scrutineer for the Electric Formula Extreme Challenge. Here he covers just some of his role . . . 4-6 weeks before a bike first competes, we review the TCF (compulsory Technical Construction File) documents of the machine entering the series. Over the following week or so clarification and additional information and photos is requested from the team, or even a visit to the bike in order to understand the machines construction, technologies and implementation of the technical rules. This gives the teams sufficient time to make any necessary modifications required by the scrutineer. 2-3 weeks before the event, each team is contacted to review any rule amendments or concerns. Any modifications to the machines are also reviewed and the TCF documents updated accordingly. On Race Day Arrive bright and early to the venue. (Sydney Raceway, Queensland Raceway, Wakefield Park and Winton have hosted previous events). Sign on with the organisers. Meet the recovery crew and the ambulance crew and give a safety briefing on the over-current sensors on the batteries are tripped. When the bike is in a powered-on state, a flashing red light mounted on the rear bodywork and visible from at least 30m away, from both sides and rear of the machine, must be activated. All electrical cables inside the motorcycle must be protected by means 20 Silicon Chip measures to take should a bike be involved in an accident. This needs to occur three times over the weekend as often there are different crews each day. Meet the teams and perform electrical scrutineering before the event. This consists of verifying that the emergency stops, horn and visual indicators are functioning and meet the rules. During the event – 3G coverage permitting – I will update the eFXC Facebook and Twitter accounts with event information and race times in order to promote the event. There are also many people overseas keeping an eye on Australian developments. The details for the electric Formula Xtreme Challenge (eFXC) are available www.formula-xtreme.com.au/xtremema. nsf/1-FrontNewsPage Thanks to the Australian Formula Xtreme Challenge for hosting the fledgling sport of electric superbike racing along with the petrol bikes. Over the course of the weekend notes are recorded on the scrutineering, any incidents and notes to assist the organisers in future events. of over currents trips rated according to the diameter of the individual conductors. There are also significant rules regarding the battery mounting, insulation and even its behaviour in the event of an incident. The entrant must ensure that the electrical components used cannot cause injury under any circumstances, either during normal operation or in foreseeable cases of malfunction. Are they competitive? When you look at top speeds of conventional bikes, you might think that e-bikes are not really competitive. But that’s not really the case because you need to compare apples with apples. The electric-powered bikes are on a pretty steep development curve (three years ago there was no such thing!). But already, they’re managing about 205km/h or so down the long straight at Eastern Creek. The best riders on the best 1000cc superbikes currently attain a top speed of about 280km/h. But when you look at the 450 and 600cc classes, the electric bikes really are right up there. 450cc bikes can manage 195km/h and the best 600cc with a top-notch rider can push that up to about 220km/h. So you can see that the electric bikes are well in the race when it comes to the 450 and 600cc classes. It’s the aim of people like the Ripperton and the Varley teams, some of the leaders in electric bike development, to get them up there with the big boys and they believe they are well on the way to achieving that aim. In fact, we at SILICON CHIP are in awe of people like Ripperton and Morris – and the teams behind them – who are on the cutting edge of this technology. As we mentioned earlier, three years ago, there was no such thing as an electric superbike but through sheer persistence and “never say die” attitude, they have developed their bikes to the point where they are today . . . and are continuing that development unabated. What we are witnessing is the early stages of a developing racing class. But it’s a class that needs more entrants. There is a real collaborative spirit in the pits and a strong interest from various groups just wanting to get involved in building a bike. With no shortage of riders awaiting the challenge of riding an electric superbike the next step is getting more bikes on the grid. If you are interested in getting involved, or you would like the challenge of building (or supporting the building of) a competing bike please contact Victor Fenech at victor<at>evmotorcycle.org Act early and your bike could be competing in 2014! SC siliconchip.com.au