| |
|
I am
fourth row, on the inside as we come around for the start. Battery
temperature is 33 degrees C and the pack started at 391 volts. The
green flag drops. The car ahead of me gets a good jump and I am
right behind him. I am past the 6th place car and on the inside
of the track of the 5th place car. He brakes late and stay outside.
I roll
back on the power and do not feel the full surge. The fifth place
car moves back in front of me and pulls away. I rightly suspect
that I am on one motor again. I must have pressed the Regen pedal
in the first corner and the current limiting software did not react
fast enough to keep the voltage from spiking over the 400 volt hard
limit on one motor.
I make
my car as wide as possible and prepare to try a fast reboot. Entering
turn 6, the six place car bulls back by. I stay outside as a line
of cars stream by the inside. I flick the switch to neutral, cycle
both switches and press the start button. Flick the car back into
gear. Full throttle. Still one motor.
I am
driving like someone on a cell phone. Weaving while trying to look
down and press buttons. 15 cars have gone by. This is too dangerous
for everybody, so I pull off the track and behind a corner worker
station.
|
| |
 |
| |
|
Neutral,
cycle the switches, press the start button. Only one motor comes
on. Cycle the off motor switch. Press the start button. The other
contactor closes. I head back out towards the track.
|
| As
I get up to speed, the lead car laps me. I soon find myself back in
sixth place battling with the leaders but a lap down. I turn a 1:26.075
on my third lap. .7 faster then yesterday's race. |
| |
| Using
the whole road video (~1.12MB .wmv file) |
| |
|
Coming
into Turn 4 on my 7th lap, I smell a battery let go. I then smell
smoke and think about what corner station I can get to for fire
extinguishers. Exiting turn 5, I continue off the road and up the
hill, waving my hands at the corner marshals. As the car comes to
a stop, I activate the in-car halon extinguisher. Next, I pop my
belts, climb from the car and turn off the master switch.
|
|
The
marshal has arrived with a 'ABC' type extinguisher. There is still
a little smoke from underneath the metal panels behind the driver's
seat. I take the extinguisher and squirt some under the edges.
|
|
I shut
down the computers and cameras while keeping an eye on the smoke.
It seems to be lessoning. The track fire truck appears (gas race
cars catch on fire regularly) and they help me remove the Lexan
that separates the driver compartment from the back of the car.
I nix using a big metal crowbar on the top of the battery pack.
We just bend up the corner a little by hand and pull out some smoldering
plastic. The race has ended, so they tow me back to the pits. This
turns out to be unnecessary as the car despite two bad batteries,
can still run on it's own.
When
we get the racecar back to the shop and pull the battery covers,
we find that a wooden board that supports the outside of the battery
pack has progressively bowed out under the high G loads of the left
hand turns.
|
| |
| |
 |
| |
 |
| |
 |
| |
| Eventually
the farther outside cell (#001) developed too much of a bend and vented.
When it vented, the Coroplast plastic spacers began to burn slowly.
This fire also charred a wood support. The heat damaged cell #002
as well. The cells themselves did not burn. |
| |
 |
| |
| We
will have to redesign the cell supports to make them stronger and
out of a more flame resistant material. Flame resistant Coroplast
is desirable but we are still unable to find a supplier. |
| |
| The
'ABC' type extinguisher is a nightmare to clean up. In a high humidity
environment, it tends to cake and stick to everything. We are warned
that if left on, it will attract moisture and cause corrosion. |
| |
|
 |
