# [EVDL] 40% Efficiency?..lets do some Math!



## EVDL List (Jul 27, 2007)

> John Wayland wrote:
> 
> > Jeff, I think you are way off on that 40% efficiency thing. I
> > have said it's about 75% for the combo of the Zilla
> ...


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## EVDL List (Jul 27, 2007)

On Sat, Feb 2, 2008 at 8:15 PM, Roger Stockton <[email protected]>


> wrote:
> 
> > The ADC8" curves clearly show the efficiency dropping at a rate of 5% for
> > every 150A increase in current above 250A. Even with a peak efficiency of
> ...


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## EVDL List (Jul 27, 2007)

>efficiency of 90%, this puts an ADC8" at just 32%
>efficiency when 2000A is
> pumped through it.
Amen Roger, I have very much respect for Mr. Wayland,
but when it comes down to this amperage we must face
reality, which you have just posted. I would really
like to hear from Jeff Major on these numbers, he has
the experience to back this up. Saturation of the
field coils really sucks out the efficiency at high
amps. Lets remember that these motors were never
designed to submit to the punishment that our racers
have subjected them too! It's just amazing that they
still work after the 1/4 miles in the White Zombie and
Killacycle. I only posted this because I think we
need to realize the efficiency these motors put out
when being subjected to these current levels, and I
think Roger has posted some realistic numbers.
Rod


> --- Roger Stockton <[email protected]> wrote:
> 
> > John Wayland wrote:
> >
> ...


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## EVDL List (Jul 27, 2007)

Dyno data would end all the guesswork!

Anyway, I have done this before and just ran it again... If you assume the Zombie has 2000 Amps, 28 batteries that sag down to 6 V each (for 448 hp), and 2300 lbs (with driver). I also put in an AdVC efficiency curve, and varied the overall efficiency to get the numbers to match reality. I also assumed you were traction limited in current limit at 1.0 g, and constant power (moderated by efficiency) above that.

Anyway, the time was 13.0 at 101 mph in the quarter. I had to ratchet the efficiency down to 50% to do this.

Again, real life dyno data (as a function of battery voltage and current) would be great!

----- Original Message ----
From: Roger Stockton <[email protected]>
To: Electric Vehicle Discussion List <[email protected]>
Sent: Saturday, February 2, 2008 7:15:14 PM
Subject: Re: [EVDL] 40% Efficiency?..lets do some Math!

John 
Wayland 


> wrote:
> 
> >
> Jeff,
> ...


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## EVDL List (Jul 27, 2007)

> Roger Stockton wrote:
> > The ADC8" curves clearly show the efficiency dropping at a rate of 5% for every 150A increase in current above 250A. Even with a peak efficiency of 90%, this puts an ADC8" at just 32% efficiency when 2000A is pumped through it.
> >
> >
> ...


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## EVDL List (Jul 27, 2007)

> John Wayland wrote:
> 
> > Reality check... White Zombie hit 94 mph in the 1/8 mile on its 11.466
> > second run...I kinda doubt it only had 168 hp!
> ...


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## EVDL List (Jul 27, 2007)

John, any chance of getting the White Zombie on a chassis dyno while
it's still powered by lead?

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## EVDL List (Jul 27, 2007)

I'd like to see that.
John, round up a video crew, drive the WZ to the nearest DEQ testing station
and work your charm on the guys there to do a dyno test. If you catch them
at a slow time and their manager's into it, you might get a free dyno test.
OTOH, maybe WZ would break their dyno.

-Myles Twete, Portland, Or.

-----Original Message-----
From: [email protected] [mailto:[email protected]] On Behalf
Of Ryan Stotts
Sent: Sunday, February 03, 2008 9:12 AM
To: Electric Vehicle Discussion List
Subject: Re: [EVDL] 40% Efficiency?..lets do some Math!

John, any chance of getting the White Zombie on a chassis dyno while
it's still powered by lead?

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## EVDL List (Jul 27, 2007)

> Morgan LaMoore wrote:
> 
> > That efficiency curve is for 96 or 72 volt operation. His
> > motors are running on 210V. If we assume that the efficiency
> ...


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## EVDL List (Jul 27, 2007)

> Dan Frederiksen wrote:
> 
> > could you link to that data? I think you might be misreading
> > it. voltage is important.
> ...


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## EVDL List (Jul 27, 2007)

> I wrote:
> 
> > Yes, it is true that the Zombie's motors are operating far
> > off the known curves, both in current and voltage, and it is
> ...


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## EVDL List (Jul 27, 2007)

> I wrote:
> 
> > At the low duty cycles associated with low RPM operation, the
> > switches will be off a lot of the time, and the diodes will
> ...


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## EVDL List (Jul 27, 2007)

> John Wayland wrote:
> >
> >
> > (1) 360V pack of Hawker AGMs sagging to 210V at 1500 amps into the
> ...


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## EVDL List (Jul 27, 2007)

short of theoretical insight, some actual measurements could help.

we are also overlooking the batteries which at their max power are less 
than 50% efficient.

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## EVDL List (Jul 27, 2007)

> Tom Parker wrote:
> ...
> > Do you know how many Wh you consume from the battery in a run? Was the
> > EVision in place for this run? Does it have enough resolution to capture
> ...


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## EVDL List (Jul 27, 2007)

> Victor Tikhonov wrote:
> 
> > Electrical data that will be only about battery side of things -
> > voltage, current and power.
> ...


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## EVDL List (Jul 27, 2007)

> --- John Wayland <[email protected]> wrote:
> 
> > Hello to Jeff and All,
> <snip>
> ...


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## EVDL List (Jul 27, 2007)

> --- John Wayland <[email protected]> wrote:
> 
> > Hello to Jeff and All,
> >
> ...


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## EVDL List (Jul 27, 2007)

> Dan Frederiksen wrote:
> 
> > short of theoretical insight, some actual measurements could help.
> 
> ...


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## EVDL List (Jul 27, 2007)

I have been careful to state electrical horsepower when referring to the electrical draws from the batteries.
I may still slip occasionally when *estimating* rear wheel horses, but I have no real data to go on not having the car on the road. I do plan to hit the dyno early on though so I can put out actual numbers.

The Zilla calculates the motor voltage and current from the duty cycle that is being called for. I plan still to put in a motor shunt (at least temporarily) so I can record actual motor power too. But until I get the car moving, I'm still guessing like the rest of you. I try to make that distinction but forgive me if I get a little excited about the prospects.

There sitll isn't anything wrong stating the Max volts since in theory you could add voltage to your string as the battery voltage sags to keep it at the max rating. Not that it would be easy or that I'm planning on trying to do it (yet). I'm trying to keep the goal set at least as high as the design limits are on the equipment, and work to try to keep operating parameters there. Its just a little slow going.

Mike

----- Original Message -----


> From: Jeff Major wrote:
> 
> >...........And often times,
> > maximum volts and peak amps (Mike W.). Unless you
> ...


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## EVDL List (Jul 27, 2007)

> Jeff Major wrote:
> 
> > I have been thinking about how to do some math on it. Seems
> > like there is no dyno data available.
> ...


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