# [EVDL] Smoke Screen S10



## EVDL List (Jul 27, 2007)

The S10 Smoke Screen ran about 12.80 in the PS 240 volt class for a new nedra 
record at Speedworld last night. Dennis Berube 
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## EVDL List (Jul 27, 2007)

Dennis wrote -


> The S10 Smoke Screen ran about 12.80 in the PS 240 volt class for a new 
> nedra
> record at Speedworld last night. Dennis Berube

I drove up to Speedworld to see Dennis run, it was a learning experience to 
see how he tweaked the car, the tires, the zilla, putting ice in the zilla 
cooler, charging time etc to slowly keep decreasing the time and increasing 
the speed. He had already tweaked the motor timing at home to get a little 
more torque at the beginning of the run.

He took 6 runs-
1) 13.12 secs, 91 mph
2) 13.00 secs, 92 mph
3) 12.91secs, 93 mph
4) didn't hook up
5) 12.88 secs, 94 mph
6) 12.82 secs, 95 mph

The batteries were Lithium ions. IIRC he had 90 packs in series of 3 cells 
paralleled. The pack temp in the beginning was about 90 and between each run 
the temp increased by about 6 or 8 deg, but what was interesting was that 
depending on how fast they charged the temp either increased or decreased. 
So a slower charging, 25 min instead of 15 min would cool them off by about 
3 deg and since the air was pretty cool, they cooled off a little more just 
sitting. He charged them up to 238 to keep it well under the 240 limit, at 
the end of the runs the voltage was down to about 227 and during the runs it 
would sag to between 180 and 167.

He readjusted the zilla at the end of the 3rd run, upped the battery amps to 
1700 (if I remember correctly) and he thinks that is what stopped him from 
hooking up on the 4th run. It just spun the tires right there at the line. 
So on the next run took the amps down to 1650 and it hooked up just fine. He 
also made shorter burnouts than he did at the Firebird competition....
http://www.youtube.com/watch?v=rya6QaQOYfg (Thanks Ricky)

What was great was the people who would come over to check out the "car that 
makes no noise". They were really interested in how an EV worked and asked 
the usual questions. Others came up and asked about the Current Eliminator, 
they were surprised to see him in the S-10.

It was a great night - Congratulations again Dennis!!!!

Rush
Tucson, AZ
2000 Insight, 62lmpg, #4965
www.ironandwood.org
www.Airphibian.com
www.TEVA2.com


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## EVDL List (Jul 27, 2007)

Just as a point of reference, when we run Crazyhorse at the track we get 
similar improvements as the batteries heat up. That really is the only 
tweaking we do. Our motors are fixed at 12.5 degrees advance so there 
is no tweaking there on our part. We do air hose off the commutators and 
contactor tips each run to keep the dust down. We set tire pressure to 
15 psi from the start and have to air down a little as the tires heat up 
to keep them at 15 psi. I'm sure our battery resting temps (in Alaska) 
start out quite a bit cooler than Dennis' (in Arizona) so our times 
start out slower. But after 3-4 runs and they are up to temps we see 
the same small incremental improvements as temps rise slightly. Usually 
by mid to end of day we are forcing air over the batteries to keep their 
temperature stable in the sweet spot. We have a closed water coling 
system that we do not have to mess with. With our ambient temps 
significantly lower than in Arizona it seems to do just fine without 
resorting to ice. We typically do 30 minute turn arounds but could 
realistically do 20 minutes if the track was ready for us right when we 
staged up. We have done back-to-back runs but the second usually comes 
in 1 to 1.5 seconds slower than the first. It still impresses folks 
that we would turn right around and immediately stage back up to run 
again.

Here's what a set of our times would look like starting the day iin 65*F 
weather.

Hank 14.3150 @ 86.54 time of day 11:12
Mike 13.5528 @ 91.27 time of day 11:43
Hank 13.0762 @ 97.21 time of day 12:15
Mike 12.748 @ 100.21 time of day 12:49
Hank 12.8059 @ 100.01 time of day 13:23
Mike 12.5981 @ 102.04 time of day 14:47
Hank 12.7193 @ 101.36 time of day 16:27
Mike 12.4781 @ 104.13 time of day 17:10
Hank 12.5170 @ 104.95 time of day 17:42

Mike




> Rush wrote:
> 
> > Dennis wrote -
> >
> ...


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