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the
voltage is 333 or what we guess is about 65%charge. By race time
is has rising to 338 volts. Best guess 70% charge.
We
arrange to start from pit lane. The rest of the cars will do a warm
uplap and then take the green. Our plan is to come out behind them,
do a slowlap to get a clear track and then do three hot laps.
Everything
is working fine. The pack thunders by and we are waved out ontothe
track. I am light on the throttle, keeping the amps below 150. I
carry speed in the corners and the tires come in quickly. I get
a little too enthusiastic through the chicane and use too much of
the exit curb. It launches me straight, and to the outside of the
tarmac. I catch the car. Definitely, not the fast line through this
corner.
Just
before turn 9, I look ahead to make sure I will have a clear run.
Thru turn 10, I am hard on it.
The
car accelerates and accelerates. It hits 5,600 rpm and keeps on
going. It reaches 6,315 RPM. I lift a little early to get my braking
right.
Regen
current is 280 amps and voltage rises a little to 343 volts (3.89
per cell). This means around 156 lbf-ft of retardations by regen.
I am trying to go to full brake with the regen and then modulate
the friction brake pedal to give me the total slowing that I need.
Looking at the data trace, I seem to have modulated both. Total
time regenning 4.6 seconds. The car slows rapidly and the transition
through turn-in is smooth.
I feed
on the throttle and back to 600 amps quickly. 4,852 rpm before turn
3. Again full regen 240 amps taper off as I modulate for 2.7 seconds.
The
turn 3 and 4 complex is a fairly long double apex corner. Half way
through, the car is filling with white smoke. This is not good.
I exit the corner and move off the racing line. The smoke clears
a little. The turn 5 flag station does not really have a good place
to pull off close enough for the workers to get an extinguisher
on the car quickly. As I use regen to slow the car for turn 5, I
get some more smoke. I keep going, torn between mashing the pedal
to get there and my suspicion that this will only make the problem
worst.
I pull
off just beyond the corner worker station at turn 6. The smoke immediately
dissipates. I wait with my hand ready on the built in fire extinguisher.
No more smoke.
I signal
OK to the corner workers and pull further off track. I sit and let
the car cool. I wait until the all the racecars pass me twice, then
drive quickly back to the pits. Everything works fine including
regen. No more smoke appears but the smell remains. The batteries
read 42 degree C, up from 26.6 C starting temp but still below the
60 degree C maximum recommended by Kokam.
First
thing the crew checks is the tires for rub. That could give us white
smoke when cornering but the smoke didn't smell right. We speak
with Dr. Kim from Kokam and he assures us that if the batteries
were off gassing, the smell would be very unpleasant. This is a
relief, but we still need to find what was smoking.
What
about the 'bundling' tape. We used lots of it as we assembled the
car. It is a silver plastic tape that can be easily pulled off without
leaving residue. This makes it incredibly convenient. What would
happen to it if something beneath it got hot?
We
plug in a soldering iron and put some tape on it. It melts producing
a faint white smoke. It smells a lot like the smoke inside the car.
The whole crew crowds around sniffing the soldering iron. I'm not
sure this is going to help our reputation any.
The
smoke seemed to have come from the behind the seat. If so, it will
require removing the inverter before we can pull the battery cover
and see. There is only a little time before the next race, so we
decide not to push our luck. There will be other weekends.
Kw-hrs
used: 3.48. warm up lap 2.25 miles at .225 = .506. Hot lap 2.25
used 2.97 = 1.32 kw-hr per mile.
And
so ends the Electric Imp's soft debut.
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