From: "Bill Dube" <billdube@killacycle.com>
To: "Electric Vehicle Discussion List" <ev@lists.sjsu.edu>
Sent: Sunday, September 30, 2007 9:52 AM
Subject: [EVDL] 8.083 @163 MPH, Back-to-back!
> We are getting so close to the 7's, we can taste it. :-)
>
> We all pitched in and managed to put the KillaCycle back together and
> to build a newer, slightly larger, A123 Systems Nano-phosphate
> battery pack in time for this race. Steve got the data logger up and
> running for this race too. Whew! It was an intense few weeks.
>
> Derek worked like the devil welding cells and soldering BMS modules.
> The new pack is 110 in series by 11 in parallel to make a total of
> 1210 cells. We switched over to copper "bussbar" strips instead of
> the standard nickel tabs. They are a bit more tricky to weld to the
> cells, but they are lighter and conduct much better.
>
> The addition of 220 cells put 34 more pounds on the bike. This
> shifted our CG forward and down slightly. Because of that, we had to
> find a new combination of launch current and throttle ramp rate to
> make the bike transfer weight correctly on the launch. We kept
> hopping or spinning the tire. In the end, we had Scotty run the bike
> "seat-of-the-pants" on the manual throttle instead of using the
> button to run the launch sequence.
>
> With Scotty running the throttle, we managed to get the bike to hook
> up decently (1.21 sec 60 ft) and we ran a 8.083 @159 MPH. We were
> right at the end of our available track time, so we simply ran the
> bike past the pits and directly to the starting line without
> recharging or even cooling the controller. With a slightly warm
> controller, the sixty foot time stretched out a touch to 1.22 seconds
> and we didn't pull as hard on the front half, but the warmer
> batteries made up for it in the back half to give us 8.083 seconds @
163
> MPH.
>
> It was pretty nifty to demonstrate, on national TV, that the A123
> Systems batteries can put out full power for multiple runs without
> recharging. We really wowed these guys with these back-to-back
> record-breaking runs.
>
> Rich Rudman (bless his little heart) lent us a monster PFC-50 charger
> for this race. We were grinning like the Cheshire cat when we were
> able to recharge the bike, on camera, in 3 minutes, 36 seconds!
> Again, we floored the TV crew when we were able to recharge in LESS
> time than we predicted using LESS electricity than we predicted. We
> LOVE this PFC-50 charger!
>
> I suspect that the larger pack and the copper interconnects are
> making our internal pack losses significantly lower. These lower
> losses result in higher efficiency and naturally fewer Watt-hrs per
> run. We managed to fill the pack back up to 375 volts (ready to run
> again) with just 550 Watt-hrs, (~6 1/2 cents) of electricity.
>
> You will see all of this on Discovery Channel "Mean Green Machines"
> in January or February.
>
> Bill Dube'