Electric motorcycle race in Isle of Man TT

An area for all you bikers who now run your two wheeler on battery power, scooter owners to.
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Postby MalcolmB » Fri Aug 22, 2008 10:34 am


They're obviously keen to make this a proper race, which is good as it should give very positive publicity to the EV movement.

Just making it to the finish line at an average speed of 70–90 mph could be a challenge though, especially since the FIM regulations limit streamlining.

What sort of energy consumption could we expect to see at those sort of speeds? Would 200 Wh/mile do it?

200 Wh/mile over a 37-mile course would mean an 8 kWh pack, which would weigh around 70 to 100 kg depending on battery chemistry. It would also take up a lot of space.

How would you go about it Paul?

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Green TT, qualification and scrutineering

Postby ex925 » Fri Aug 22, 2008 10:45 am

Hi, Paul.
That note from the organisers makes sense. There would be no point in making the effort to add anything less than a real race to the schedule.

So, how does an entrant obtain precise design and construction requirements
to be sure of passing scrutineering?
Has anyone got such information?
If not, does it exist?
If not should entrants start pressing for clear boundaries to be provided?
Alternatively should the BVS be seeking information?

All the best,

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Postby Jeremy » Fri Aug 22, 2008 11:27 am

They really are looking to push the boundaries a bit with this race. Those qualifying guidelines pretty much exclude any sort of budget privateer entry, as the costs will be pretty high to develop something to do 100mph max and average over 50mph.

As the power requirement goes up in proportion to the cube of the speed, bikes will need lots of battery capacity, this will push the weight right up, so the bikes will need to be bigger too, which then increases the drag and rolling resistance needing an even bigger motor and battery..........

My (very) rough guess is that around 8,000 to 10,000 Wh of battery capacity will be needed, as the bike will be using between 200 and 250 Wh per mile. This is a lot of capacity to try and pack in to a bike frame.

I retract all the stuff about a light bike option, this is now a race for behemoths only!


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Postby EVguru » Fri Aug 22, 2008 12:12 pm

It's my guess that most of the 'Teams' at the moment are Universites and I think they're talking up their numbers. They seem to be getting gradually higher, Kingston University were only talking about a top speed of 70+mph at the TTXGP launch.

You can acheive 60mph on about 6Kw on a conventionally faired motorcycle. To simply do the TT distance based on those numbers would take 3.16KWhr, but that's constant speed on the flat. The question then is how much more energy is it going to take to navigate the TT course. There's a 1400ft climb to consider and the question of how much speed it's possible to carry through corners.

I wonder how many of the speed estimates have been based on telemetry obtained from a run round the course. Throttle percentage times and apex speeds would be very useful.

I'm planning to use a Gilera CX. The name came about becuase it's an alternative term for 'Cd' since aerodynamics were meant to be a feature of the design. Quoted top speed was 105mph with an engine output (rear wheel?) of 21Kw. Based on what I achieved with the Freccia, I think I can keep the weight down to 180Kg with a 10Kwh battery. I'd want the CofG of the battery a LOT lower than I could acheive on the Freccia, that took quite a lot of muscle to make change direction. One thing is certain, it's going to take a lot of money.

There has been talk of varying the FIM streamlining regulations. A very quick electric EcoMobile having something to do with it. I'm not sure it will be this year whatever happens.

Another major stumbling block is the Licence requirements. It looks like the minimum requirement is going to be an ACU National, which means recruiting a rider.

There was talk of providing a CAN bus interface to the onboard BMS to talk to the gps/transponder unit provided by the organisers, but I hope I've headed off that requirement. What MAY now be the requirement is a simple energy meter than can be logged. They really don't know what they're doing or should bedoing at the moment and I'll be working hard to make sure that the University teams don't freeze out amateurs by default by agreeing to ideas like the CAN interface from the organisers.


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