# Lawless "Hammerdown" Dragster Quickest in NEDRA History with a 7.89.



## LawlessEV (Oct 2, 2011)

Here is a video link to the backup run Friday night:
http://www.youtube.com/watch?v=F78RzcZVpcI


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## ishiwgao (May 5, 2011)

LawlessEV said:


> Here is a video link to the backup run Friday night:
> http://www.youtube.com/watch?v=F78RzcZVpcI


wow what a great achievement. 2000HP must be insane. wish I had the opportunity to build something like that.


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## major (Apr 4, 2008)

LawlessEV said:


> On May 2nd, Ladies Night, at Virginia Motorsports Park, Kristen Stacy became the quickest NEDRA driver on 4 wheels ever, male or female.


Congratulations Shawn. This and the Swamp Rat 37 are outstanding accomplishments. Great work by you and your team.

The recent passes by Big Daddy in the Swamp Rat 37 were quicker and faster than these by Kristen. Didn't they qualify as a record for some reason. 

I'm sure many here are curious as I am. Can you share what motors and cells you're using?

Thanks,

major


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## LawlessEV (Oct 2, 2011)

Hi Jeff. Hope all is well. It has been some time. In answer to your questions: 

The "Hammerdown" runs were "official" NEDRA sanctioned runs with car and driver both NEDRA members, required tech forms signed and submitted to NEDRA officers along with time slips for validation.

We are running a single GE motor with custom Helwig brushes and our Zilla 4K motor controller. By removing all the A36 1/2" plate and replacing with moly tube we were able to shave hundreds of pounds from the car and went with one motor instead of two which saved even more weight. This makes the car a lot easier to push down the track AND easier to pick up and move around.

While HTS has provide us with excellent battery packs in the past it is time that we take over that part of the build so that we can configure and reconfigure at wiil. I visited a battery manufacturer while I was working in Guangzhou, China and after some back and forth brokered a deal for them to supply our new cells and BMS boards. My teamed designed a solid but lightweight pack with multiple intercell connections for reliability. The pack is 330 volt nominal, fully charged it is at 378. It has a peak output current of 6000 amps. We have not yet gone to half of that number. To date it has performed perfectly however we have not pushed it very hard. We have dubbed our new batteries L.E.D. - Lawless Electrical Design. I guess you could say we are using led batteries....


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## major (Apr 4, 2008)

Thanks Shawn.


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## Karter2 (Nov 17, 2011)

congratulations on a new official record.

( can anyone do something with that photo scaleing ?)


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## Duncan (Dec 8, 2008)

Hi Guys
I dropped the size of that photo
I hope nobody is offended


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## LawlessEV (Oct 2, 2011)

Cool on the photo. For future reference what is the standard size and rez to post?

Shawn


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## davidg11 (May 6, 2014)

Hi, I was curious if Ultracapacitors have any value in electric drag racing cars, such as yours, off the line, or does such a high powered battery back make it unnecessary?



LawlessEV said:


> Hi Jeff. Hope all is well. It has been some time. In answer to your questions:
> 
> The "Hammerdown" runs were "official" NEDRA sanctioned runs with car and driver both NEDRA members, required tech forms signed and submitted to NEDRA officers along with time slips for validation.
> 
> ...


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## dougingraham (Jul 26, 2011)

davidg11 said:


> Hi, I was curious if Ultracapacitors have any value in electric drag racing cars, such as yours, off the line, or does such a high powered battery back make it unnecessary?


You can't store enough energy in them at this time to make it down the track at these power levels. And that is not even considering that you need quite a lot of electronics to get all the energy out of them. I've done the numbers and at the moment the LiPo cells similar to what the RC guys use to power their models have the highest power levels for their mass. You can find packs that claim discharge rates of 130C (full discharge in 27 seconds). So you build a pack that can do the currents you need and with a minimum sag voltage just above the motor max and expect to replace it frequently. A pack like this to turn my car into a pocket rocket would cost under $3000 and would weigh less than 100 lbs. It would give me around a 20 mile range if driven on the street so not a large pack at all. For a dragster like the ones this thread is talking about it would be about four times as much just for the cells and then you get to assemble it into a pack. At this time a bank of ultracaps capable of carrying enough energy to power the vehicle would be larger and weigh more than the whole vehicle currently does. It is a problem of diminishing returns.


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## Karter2 (Nov 17, 2011)

The detail often overlooked when thinking of "ultra Capacitors" is their voltage characteristic.
They are very capable of supplying high current ,fast discharges, but unfortunately as they do, the voltage drops much more rapidly than a battery cell to effectively unusable levels for most voltage dependent devices like motors or controllers.. 
In effect this means that only a fraction of the capacitors stored energy is actually useable in a high voltage drive system.
Its like carrying around a 20 gallon tank of gas that you can only ever use 1 or 2 gallons from !


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## davidg11 (May 6, 2014)

Sorry, I should have been more specific. I know Ultracapacitors aren't energy dense, but they do deliver high power instantly. So I guess what I'm asking is whether or not for the first couple of seconds off the race line that burst of acceleration power from an ulracapacitor would be greater than a battery pack could provide off the line for a couple of seconds, and then have the battery pack take over after the high power from the ultracapacitor was diminished. 


In other words, does it make more sense to simply keep an all battery pack in racing, or does it make any sense to build a hybrid solution where the initial boost off the line is from an ultra capacitor and then taken over by a battery pack for the remainder of the run?

Some electric vehicles (non drag racing obviously) take 8+ seconds to go 0-60mph. Considered relatively slow. So I've always wondered if it wouldn't make sense for ultracapacitors to be used for just the initial acceleration off a stop so that going 0-60 would be faster and then switch over to battery power. 

Thanks!


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## major (Apr 4, 2008)

davidg11 said:


> .... So I guess what I'm asking is whether or not for the first couple of seconds off the race line that burst of acceleration power from an ulracapacitor would be greater than a battery pack could provide off the line for a couple of seconds,.....


Actually, at launch, the battery current is relatively low. Motor current is pretty much instantly high (up to current limit), but the battery current ramps up as the motor speeds up. You can see this in some of the plots drag racers pull off the Zilla data. For instance here:


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## dougingraham (Jul 26, 2011)

davidg11 said:


> Sorry, I should have been more specific. I know Ultracapacitors aren't energy dense, but they do deliver high power instantly. So I guess what I'm asking is whether or not for the first couple of seconds off the race line that burst of acceleration power from an ulracapacitor would be greater than a battery pack could provide off the line for a couple of seconds, and then have the battery pack take over after the high power from the ultracapacitor was diminished.
> 
> 
> In other words, does it make more sense to simply keep an all battery pack in racing, or does it make any sense to build a hybrid solution where the initial boost off the line is from an ultra capacitor and then taken over by a battery pack for the remainder of the run?
> ...


Major beat me to it. If you look at the plot you can see that the beginning thing was the burnout (pre 3 seconds) and the run actually starts at about 3.3 seconds. The battery amps ramp up to a peak at six seconds on the scale. At that point the motor controller is on full and the battery volts and motor volts are equal as are the battery amps and motor amps. After that point the power level gradually drops because we are past the linear range of the torque curve. White Zombie has only a single reduction ratio and would clearly benefit from a gearbox. Because of the way electric motors work you get full torque at zero rpm but this is not where the max power point is. So Ultra caps will not help you at the launch in a drag race. Actually with modern batteries about the only time you might see an advantage is if you can store braking energy in them and recover it for use in the acceleration out of a corner. But the modern batteries can accept charge at the same rate as discharge for the most part so even there it probably wont help unless you are really limited in pack size as might be found in a Hybrid. Until they are capable of supplying the energy for the whole run and the ultracaps plus their electronics weigh less than the battery they don't have much place in this.


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