ElectricMotorcycleForum.com
General Category => Electric Motorcycle Events => Topic started by: skadamo on May 07, 2010, 11:43:09 PM
-
(http://plugbike.com/wp-content/uploads/2010/05/william-yates-ebike-600x520.jpg)
384 Volts nominal. I've never seen this kind of voltage in a motorcycle. Any electrical guys know what the implications are?
360 LiFePO4
295 ft/lbs Torque
145 kW
11.5 kWh plus KERS
http://plugbike.com/2010/05/07/exclusive-specs-on-the-swigz-pro-racing-ttxgp-bike/ (http://plugbike.com/2010/05/07/exclusive-specs-on-the-swigz-pro-racing-ttxgp-bike/)
-
I think high voltage is good. I'm no EE but I think it's more efficient and less prone to voltage sag.
Anyone who knows better, feel free to correct me.
-
sag is related to current draw, so it all depends on how much current is being drawn at the time. Voltage sag can be more obvious at higher voltage, because each cell will sag, and there's more in series.
IMHO, I think higher voltage is better, because of lesser losses due to heat. The conductors have less loss due to lower current being drawn. You can also use smaller cables for the motor/batteries. This also requires smaller windings, which can help with the heating in the motor.
-
Looks like batteries weren't so good. Since the bikes being unveiled with its new front wheel KERS at THE Battery Show, I think they have a battery supplier lined up.
http://green.autoblog.com/2010/08/29/chip-yates-opens-electric-superbike-kimono-will-take-it-complet/ (http://green.autoblog.com/2010/08/29/chip-yates-opens-electric-superbike-kimono-will-take-it-complet/)
(http://www.blogcdn.com/green.autoblog.com/media/2010/08/swigz-bike-early-dev-2.jpg)
-
I got a chance to talk to Chip about his bike and the issues they are having with batteries. The Headway cells he originally bought were heavier than he was told they would be. Added 40 lbs to the bike.
The second issue is his KERS system is capable of generating 10 C. He knows of one battery supplier who will stand behind a 5 C charge rate. They are Saft (http://www.saftbatteries.com/).
They have a test rig that allows them to simulate an entire race. Throttle application, KERS, and everything is simulated. He mentioned that the testing his team has done shows the cells take a charge faster if they uses pulses of current. The frequency of these pulses can affect the efficiency of the charging. Crazy stuff.