[Tesseract]

...I will have a new chart with a little more data using the Helwig brushes. I am putting up to 199V on each warp9 now....

Which reminds me... it would appear that in exchange for much higher zorch-resistance, the new Helwig brushes seem to wear down at an alarmingly fast rate* - have you noticed a lot more carbon dust around the brush assemblies since switching over to the Helwigs?




* - which I have dutifully filed under the category, "TANSTAAFL"

 

[John Metric]

Thanks for the detailed answer.
How much do you expect the 199V to push the peak power rpm out too?

I am not sure that I will find out with my current pack. 199V and 2000amps is 400kW or about 536eHP each motor. See below. You can extrapolate the charts below. perhaps 2500rpm???? I would be well into the nines there and my car will need a major overhaul, roll cage, certification, parachute, competition license, etc....
Another point, I have been finding that the higher my voltage MV setpoint, the quicker I go up in rpm. For example. I can just get to 199V by the end of the track and the car is still accelerating like mad. See data below.

http://www.youtube.com/user/dcplasmaracing?feature=mhee#p/c/1/fIkIWUOEByQ
This has the seat of the pants feeling of actually moving the peak power point up rather than to the right. As I went from 170V to 180 and 190 I found the shift point around the same rpm. I just get there quicker. It may have something to do how the zilla approaches peak voltage.

Some cars, reach their peak voltage and peak rpm about the same time.
Some cars reach peak power at a point well below peak voltage. For example, here is Waylunds latest curve from mid '10, showing he doesn't reach peak power at peak voltage. Raising his peak voltage wouldn't help with his peak power point.

You can see his peak power is limited by battery sag around 3300rpm. My pack is now suffering at this point as well. My power curve would like to continue up and to the right but I truncate this by controlling the LBV setpoint in the hairball.
I project that if I let the pack sag a bit more or I add some more batteries (26Ahr now) I would push the peak power point up rather than to the right. If it does go right maybe 100rpm? Near the the same 3200rpm as Waylunds Impulse9s. Except we will be making around 850 battery HP at that point.

I would like to re-clarify the dyno sheet projection was using real data, was the input to the motor not the output and theoretical knee point with unlimited pack and controller. I am there with one motor, one zilla and my pack. When I use two motors and the overdrive, my pack is starting to show its limits, and I am below the knee point near 2800rpm. I was trying to create something that was truly only the motor limits. For real life, the peak rpm knee on the Warp9 motor dyno sheet may be closer to 2800rpm.

 

[John Metric]

Which reminds me... it would appear that in exchange for much higher zorch-resistance, the new Helwig brushes seem to wear down at an alarmingly fast rate* - have you noticed a lot more carbon dust around the brush assemblies since switching over to the Helwigs?
* - which I have dutifully filed under the category, "TANSTAAFL"

No extra dust, probably vaporizing it, but if you look at the difference between power output between the top two lines, 170V and 190V figures, it doesn't seem in line. I don't think all the extra power is going into the driveshaft, I would say I am making about 50eHP in heat at the brushes. In my favor, with the overdrive, I am only at 4100rpm at 128mph. I have a viewing window into my motors while racing, I have yet to see any arc flare brightening the cab(I mostly race at night). I am thinking of putting a camera on them during a run.

 

[John Metric]

We will be racing against Shawn Lawless S11 Lemonjuice on Thursday at Bradenton Motorsports Park, FL. You may witness the fastest EV race of all time between two electric conversion cars.

We are racing Pro-Modified Street Conversion. Both currently 333V. he has run a 9.8 I have a best time of 10.4

I will try to let it all hang out and see if we can take him.

Metric

 

[John Metric]

Re: DC Plasma - Build Thread - 9Sec Fiero

Has everyone seen the drag race video by now?

http://youtu.be/2rflqt918MI

We ran
60ft 1.551
1/8 6.321 112mph
1/4 9.898 134mph

http://www.youtube.com/dcplasmaracing
http://www.evalbum.com/2453
facebook lonestar ev racing john metric

 

[John Metric]

Here is the run chart for the 9 second run.
We made a peak battery HP of 862
We crossed the line at 134mph and 4300rpm (torque calculation is based upon inputs and needs to be multiplied by estimated motor efficiency to get motor output torque.)

 

[John Metric]

And the new controller output summary

and new battery PVI diagram

 

[Bowser330]

Re: DC Plasma - Build Thread - 9Sec Fiero

holy shit you launched like a bat out of hell! The Fiero just took off!
Solidly into the 9's, wow congratulations John.

Can you help me read the graph and say why the Zilla data is adding up the motor amperage (4000A) but not the motor volts (only 200V)...Unless motor volts are on the secondary axis on the right-side of the graph...

 

[DIYguy]

John, it's time to change the thread title.

 

[John Metric]

Re: DC Plasma - Build Thread - 9Sec Fiero

John, it's time to change the thread title.

I would if I could.

Here are some links to the video.
http://www.youtube.com/watch?feature=player_profilepage&v=dFf5ObTBofk

and the gopro footage of Shawn Lawless in an unusual position of coming in second....
http://www.youtube.com/user/dcplasmaracing?feature=mhee#p/c/A3E4F9ED20798E34/17/2rflqt918MI

 

[John Metric]

Re: DC Plasma - Build Thread - 9Sec Fiero

Can you help me read the graph and say why the Zilla data is adding up the motor amperage (4000A) but not the motor volts (only 200V)...Unless motor volts are on the secondary axis on the right-side of the graph...

This chart is a summation of two zilla logs.
The two motors are in parallel, with each zilla providing power to one motor.
The motor volts are limited to 199V, that doesn't add together. There are actually two voltage lines nearly on top of each other, but I hid one to make the chart a little clearer. But the current is 2000amps each and that does add together for 4000 amps total.

The other tricky thing is the motors make 4000 amps (2kX2) and about 170V when the pack is around 250V and 2500Amps.

I had the battery limit here set at my previous setting of 2500 Amps. I will try 2800amps next (approx. 90C factory rating)
Also, I am tempted to play with the 199V setting.

Metric

 

[John Metric]

Re: DC Plasma - Build Thread - 9Sec Fiero

holy shit you launched like a bat out of hell! Can you help me read the graph and say why the Zilla data is adding up the motor amperage (4000A) but not the motor volts (only 200V)...Unless motor volts are on the secondary axis on the right-side of the graph...

It is also not adding the torque calculations together, I just noticed.
That is the calcs(pre-motor efficiency) for one motor.

 

[GerhardRP]

Here is the run chart for the 9 second run.
We made a peak battery HP of 862
We crossed the line at 134mph and 4300rpm

Great run.
Can you comment on the current dip at about 1.5 seconds? did you lose traction?
Also, can you PM me the raw data for further analysis?
Gerhard

 

[John Metric]

Great run.
Can you comment on the current dip at about 1.5 seconds? did you lose traction?
Also, can you PM me the raw data for further analysis?
Gerhard

Yes, that is a bad habit of mine, I lifted my foot around the 60 foot mark because at my home track in Baytown, that is where you switch from a deep concrete slab to a shallow one and the dew builds up there and I have broke traction at that exact spot DOZENS of times. So I tend to lift a little there to try to get through that area. You can see this on the line labeled "pedal" where it drops from 100%. I also slightly lift the pedal during when I am looking down for the overdrive shift button. I have already broken one pedal due to bracing myself for the acceleration by standing on the pedal so now I have this ultra light touch on the plastic.

I will send the hex dump if you want. Can you interpret it?

 

[John Metric]

Great run.
Can you comment on the current dip at about 1.5 seconds? did you lose traction?
Also, can you PM me the raw data for further analysis?
Gerhard

Here is a run chart of what a traction break looks like at that exact spot from mid summer. Followed by one without.

 

[GerhardRP]

I will send the hex dump if you want. Can you interpret it?

HEX is cool as long as I know what the columns mean. I've PM'd my email.
Gerhard

 

[GerhardRP]

HEX is cool as long as I know what the columns mean. I've PM'd my email.
Gerhard

There seems to be a calibration factor for motor volts, about 199/115.
Is that true?
Gerhard

 

[Otmar]

There seems to be a calibration factor for motor volts, about 199/115.
Is that true?
Gerhard

Assuming he is sending you direct Zilla data, yes about 1.75V per bit.
All the details for raw data are here:

http://www.cafeelectricpress.com/blog/?p=16

 

[John Metric]

DC Plasma raced the Texas Mile today and ran a 134mph in the 1/2 mile and 155mph in the full mile. From a standing start. You can see the first uploaded video by Mike Dunn here.

http://www.youtube.com/watch?v=I6x-zCkYPL0&list=FL9pAXoc92fS7PtTrXudLJ1A&index=1&feature=plpp_video

Metric

This is the run chart from the 155mph run. See the overdrive shift in the middle. We ran at 1200max amps on the battery where the factory rating is 2500amps max.

 

[John Metric]

Compilation of videos from Bradenton. Very Cool

http://www.youtube.com/watch?v=Fvg-j40N0ek&feature=relmfu