# One Shiva or Two?



## Ziggythewiz (May 16, 2010)

Those are some impressive numbers.


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## Ziggythewiz (May 16, 2010)

How does 200 (or 250) / 2 = 118?

Why not option 1.5? 1 Shiva @ 400V & 2500A for 1 GW. Same as option 1, but half the controller weight/space.


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## Yabert (Feb 7, 2010)

Based on this: 


GeoMetric said:


> My new modules produce 2500A & 2.0V under load.


Despite if you build a 120S battery pack, the peak power coming from your pack will only be 600 Kw (240v after sag 2500A)... not enough to break reccord!
Because 1500A per motor isn't enough, you will need to stick with 2 Shiva. 

Just like that, if those numbers are for K2 LPF300HPS 73Ah module, that is 1.7 Kw / Kg.... a really ordinary result!
By reference, Calb CA cells was test at over 1.5 Kw / Kg...

Carry 600 Kg of battery will not help you to break record!


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## GeoMetric (Aug 13, 2010)

Yabert said:


> Based on this:
> 
> Despite if you build a 120S battery pack, the peak power coming from your pack will only be 600 Kw (240v after sag 2500A)... not enough to break reccord!
> Because 1500A per motor isn't enough, you will need to stick with 2 Shiva.
> ...


The K2 Energy cells compare very closely with the A123 cells, in some cases even better. The Power Modules are built for quick amps, the Calb's are built for density, they do not produce much amps. Try and get some Calb's to deliver 2500A @ 2.0V a cell you will need to parallel many heavy boxes. K2 Energy Power cells deliver amps much longer than a Calb, it's like comparing apples to oranges.

If we can deliver 500KW or more at sag to each of our 11" Warp Motors we will run the 9's, even with the added weight. 

Try this, find a battery that can deliver 2500amps @ 2.0V (during sag) and weighs only 6lbs?


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## DIYguy (Sep 18, 2008)

GeoMetric said:


> Try this, find a battery that can deliver 2500amps @ 2.0V (during sag) and weighs only 6lbs?


I love the A123 batteries, in fact, I think for an all around battery, it has to be the best. BUT and a big BUT, it all depends what you want. For power density, these cells just can't hold a candle to lithium polymer when it comes to sag.

Any of the high rate lipo can beat 2500 amps at 2 volts and 6 pounds. For example 6200mAh 65/130C RC lipo at 2p2s packs X 4 would be over 3000 amps (burst, at spec) sag to maybe 5.3 or 5.4 volts (2.6 or 2.7 vpc)and less than 3 lbs.


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## GeoMetric (Aug 13, 2010)

DIYguy said:


> I love the A123 batteries, in fact, I think for an all around battery, it has to be the best. BUT and a big BUT, it all depends what you want. For power density, these cells just can't hold a candle to lithium polymer when it comes to sag.
> 
> Any of the high rate lipo can beat 2500 amps at 2 volts and 6 pounds. For example 6200mAh 65/130C RC lipo at 2p2s packs X 4 would be over 3000 amps (burst, at spec) sag to maybe 5.3 or 5.4 volts (2.6 or 2.7 vpc)and less than 3 lbs.


Yes, most high rate lipo cells can beat 2500A @ 2.0V, BUT and this is a huge but, nobody can build a safe large lipo pack. I am taking the safe route and sticking with LifePo chemistry instead of lithium polymer. That is my choice.


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## DIYguy (Sep 18, 2008)

GeoMetric said:


> Yes, most high rate lipo cells can beat 2500A @ 2.0V, BUT and this is a huge but, nobody can build a safe large lipo pack. I am taking the safe route and sticking with LifePo chemistry instead of lithium polymer. That is my choice.


OK, well, I didn't know . . . u didn't qualify it. LiFePo4 will always be safer than Lipoly for sure. That said, if u wanna go fastest, u should be looking at lipoly. It's not that tough to build a "relatively" safe lipoly pack. Then again, I'm sure I won't change ur mind.


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## Yabert (Feb 7, 2010)

GeoMetric said:


> I am taking the safe route and sticking with LifePo chemistry instead of lithium polymer. That is my choice.


Good choice Ron...
But 500 Kw per motor imply 1300 lbs of battery... Sorry, it seem that you will be slow this year too!


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## GeoMetric (Aug 13, 2010)

Yabert said:


> Good choice Ron...
> But 500 Kw per motor imply 1300 lbs of battery... Sorry, it seem that you will be slow this year too!


The 1300lbs of lithium battery weight will produce two very powerful battery packs. Last years pack was about 500lbs, so it's only 800lbs additional weight. We have a few tricks up our sleeve to reduce additional weight to compensate.


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## Karter2 (Nov 17, 2011)

GeoMetric said:


> ... so it's only 800lbs additional weight...


 ..thats probably the first time i have heard a drag racer say that ! 




GeoMetric said:


> ... We have a few tricks up our sleeve to reduce additional weight to compensate...


... you are going to need David Copperfield scale magic to make that much weight disappear 

I see an amusing year ahead watching this play out.


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## McRat (Jul 10, 2012)

This is intended as humor, not a slam:

Run one rear slick, not two.

Battery doubles as seat, cables as seat belts.

PVC rollcage.

2 bicycle wheels up front steered by ropes.

A LONG extension cord.


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## GeoMetric (Aug 13, 2010)

McRat said:


> This is intended as humor, not a slam:
> 
> Run one rear slick, not two.
> 
> ...


Awesome LMFAO!


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## GeoMetric (Aug 13, 2010)

Karter2 said:


> ..thats probably the first time i have heard a drag racer say that !
> 
> 
> 
> ...


Honestly, I am running all the numbers to see what makes sense.

I can keep the car with two Shiva's and two Warp11" motors and add two battery packs, weight will increase way over 3000lbs. The max power will be delivered to each motor.

or

I can go very light 2300lbs, with one Shiva producing 3000A @ 200V to one Warp11". This will need only one battery pack and the car will be very very light.


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## palmer_md (Jul 22, 2011)

3000A, 200v @2300lbs = 260 va/lb or 
2500A, 200v x2 @ 3100lbs = 322 va/lb

right?


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## Karter2 (Nov 17, 2011)

Ron, i hope you will be getting independent tests done on these cells before you build a full pack!
I know K2 claim a 4200 A , 5 sec pulse potential, but even at 2500 A it will be pulling 90A per cell , from a cell specified with a pulse rating of 50 A, ( K2 specs)
With an IR of <9mohm, the heat generated will be significant, and it makes me wonder just how much testing has been done at those levels.


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## GeoMetric (Aug 13, 2010)

Karter2 said:


> Ron, i hope you will be getting independent tests done on these cells before you build a full pack!
> I know K2 claim a 4200 A , 5 sec pulse potential, but even at 2500 A it will be pulling 90A per cell , from a cell specified with a pulse rating of 50 A, ( K2 specs)
> With an IR of <9mohm, the heat generated will be significant, and it makes me wonder just how much testing has been done at those levels.


I have spoken directly to Jim Hodge from K2 Energy, these modules have new designs, and the cells can handle as low as 1.6V safely.


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## GeoMetric (Aug 13, 2010)

Well, I will start the 2013 season with one Shiva, two 11" motors and one hell of a battery pack. I will split the amps 1500A to each motor, and use as much voltage as the Warp 11's can handle. I am shooting for 250V to each motor. I am raising the rear gears to 3.50, this will compensate for launching at 1500A per motor, the higher voltage should handle the rest. 

The GearVendors OD unit needs a rebuild, I will do the job, have not looked inside yet, I think something broke. All my new power modules will be complete in time to start early in 2013. I am driving the car to Jeff Disinger's house for new graphics soon.


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## ruckus (Apr 15, 2009)

GeoMetric said:


> Try this, find a battery that can deliver 2500amps @ 2.0V (during sag) and weighs only 6lbs?


NEB 60ah supercapacitor batteries: 3.81lbs = 1500A.
NEB 100ah supercapacitor batteries: 6.17lbs = 2500A.

Actually, I would surely hope the sag is less, resulting in more power output. 

Here is the chart showing the data: (scroll down for chart).
http://www.electriccarpartscompany....thium-br-Super-Capacitor-Batteries_p_156.html

I believe the company is called Liyuan New Energy Co.

Now.... who has test results for these??


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## Stiive (Nov 22, 2008)

ruckus said:


> Now.... who has test results for these??


Who needs test results, eh Ruckus?


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## GeoMetric (Aug 13, 2010)

ruckus said:


> NEB 60ah supercapacitor batteries: 3.81lbs = 1500A.
> NEB 100ah supercapacitor batteries: 6.17lbs = 2500A.
> 
> Actually, I would surely hope the sag is less, resulting in more power output.
> ...


These have never been tested, K2 Energy cells have been tested.


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## ruckus (Apr 15, 2009)

Hello,
I haven't seen the test results for the K2. Can you point us to it or share it?

The k2 is on the list of high-power cells viable for racing. So I am interested.

I would like to see some competitive cell testing of the same sizes in exactly the same conditions. That is the only way to really know.

Sag seems to be the performance killer. In Jack's latest show the CALB's sag to 78% at 8.5C and down to 67% at 12C. This means a 400v system would be running at a paltry 268v under full load.

Do you have test results showing voltage sag under high C-rates for the k2?

Regards,
Marcus

ps. good to see a fellow "red-dotter"


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## GeoMetric (Aug 13, 2010)

ruckus said:


> Hello,
> I haven't seen the test results for the K2. Can you point us to it or share it?
> 
> The k2 is on the list of high-power cells viable for racing. So I am interested.
> ...


Marcus,

You can view www.electricmotorsports.proboards.com for K2 Energy testing data. What you must keep in mind is the weight of Calbs and the duration of burst amperage. Calbs are at the bottom of the list for quick discharge published by Elithion.


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## ruckus (Apr 15, 2009)

GeoMetric said:


> Marcus,
> 
> You can view www.electricmotorsports.proboards.com for K2 Energy testing data. What you must keep in mind is the weight of Calbs and the duration of burst amperage. Calbs are at the bottom of the list for quick discharge published by Elithion.


This is a new forum? Are you on there? 

Yes, I have spoken with Davide. I think the information is very useful, but much of the list is conjecture based on specs published by the manufacturers. It would be nice to get a few cells each and do some tests..

1800A at 400v seems a bit difficult without a 1200lb battery... 

Which model of k2 are you going with? Did they give you a deal?

Cheers


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## GeoMetric (Aug 13, 2010)

ruckus said:


> This is a new forum? Are you on there?
> 
> Yes, I have spoken with Davide. I think the information is very useful, but much of the list is conjecture based on specs published by the manufacturers. It would be nice to get a few cells each and do some tests..
> 
> ...


*K2 Energy Specs:*

LFP 73AH Power Battery (1P)
(28P of LFP26650P)
AKA: LFP 300HPS
6.61 lbs each 

For 1800A sag = 2.3V
For 1800A (268V sag voltage) = 116S (766 lbs)


*Calb Specs*

CAFI Series
For 1800A 12C:
40AH = (4P) 1920A (12 lbs)
60AH = (2P) 1440A (8.8 lbs)
100AH = (2P) 2400A (14.8 lbs)

Not sure the sag @ 1800A, but sure a 268v sag pack of Calb's weighs over 1200lbs!


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