I blame Energica. Oh, and Paul Sneyd at Panopticon Imaging, my sponsor. Push is coming to shove, and the stars and planets are aligning, and I want to build a state-of-the-art bike with 600cc-class performance on a late-model rolling chassis. Here’s the plan.
On the motor side, I’m looking at this liquid cooled PMAC 38KW baby from Motenergy.
– 4 pole motor (8 magnets).
– Phase to Phase winding resistance: 0.013 Ohms
– Maximum recommended rotor speed: 6500 RPM
– Voltage: 0 to 120 VDC input to the control
– Torque constant of 0.15 Nm per Amp
– The Inductance Phase to Phase is 0.10 Milli-Henry with a 28 turns per phase.
– Armature Inertia: 45 Kg Cm Squared
– Current: 180 Amps AC continuous (220 Amps DC into the motor control)
– Peak current: 480 Amps AC for 1 minute (660 Amps DC into the motor control)
– Weight: 35 pounds
– Peak Stall Torque: 100 Nm.
– Cooling: Water cooled (50% Glycol)
I’d love to go with something nastier, like a YASA or an Emrax, but it’s too pricey for now. As with any project, the idea is to set the chassis up to accept any number of motors you may be interested in using at some point in the future. As yummy as the YASA looks, it’s unobtainable at the moment, and for all it’s narrow profile, it’s got a huge diameter which causes all sorts of problems in relation to the swingarm pivot. At only 35lbs, with liquid cooling and a good RPM range, it seems like the Motenergy is a good place to start.
So lets drive that with a Sevcon Gen4 Size 6, shall we? Seems like pretty much the bench-standard, and I could use it for some of the other motors I might graduate to.
On the battery side, I have a line on some A123 prismatic packs which were built for grid-backup testing. Here’s something like what they look like.
mmm. Beefy. They’re about 95lbs, and give you 120AH at 44V nominal. That ranges up to 55 or something at max charge, so two of them give you 110V top end. That’s what? Around 11KWH? Not bad, and you’re looking at a range of something like 75miles. They can dump the amps, and they’d sit vertically in the center of the frame.
I need a BMS. I’m thinking the Orion looks good, have good reports, and aren’t prohibitively expenseroo.
The weight? Well, roundest of round numbers, but 200lbs in batteries with under 100lbs of motor, controller, cooling and whatever on about a 200lbs chassis? If I can get it around 450lbs I’ll be happy.
Performance? I’m looking for a top speed of 120mph, and 0-60 of 3-4 sec. The range isn’t too important to me, but with that big a pack it should be respectable. For a decent idea of what I’m looking at, let’s look at Danny Ripperton’s bike from 2012, here: “an ultra-lightweight build based on an R1 with a liquid-cooled version of the Motoenergy AC ME0913 and a 7.5kwh interchangeable A123 pack”. I’m not sure what the current state of Ripperton’s bike is, but I know that bike rocked. Maybe one of you boys in OZ can update me?
Stay tuned. Obsession is such an ugly word.