Warp Factor II Battery Modules

[liveforphysics]

Isn't that 60ft a little slow for that chassis? 1.5's are pretty easily had by FWD Honda Civics on slicks.

I think if you want to drop a lot of ET, you gotta go something like 3000MA, and you could leave BA at 1500-2000 if you don't want to stress it. Get the 60ft into the 1.3's and I bet it will be running a single digit.

 

[Hillhater]

Test #2:
2000 BA (each controller)
2000 MA
200 Motor Volts
(Pack was at 230V)

2000 BA into each controller, so is that 4000 A total load on the pack ??

 

[EVDragRacer]

Isn't that 60ft a little slow for that chassis? 1.5's are pretty easily had by FWD Honda Civics on slicks.

I think if you want to drop a lot of ET, you gotta go something like 3000MA, and you could leave BA at 1500-2000 if you don't want to stress it. Get the 60ft into the 1.3's and I bet it will be running a single digit.

I agree Luke. These runs were just shake-down runs to check for damage. The pack work flawless and the car launched nice. Last year we ran a 1.4 60', 10.08 1/4 mile @ 128mph with the same settings. The car is a little lighter, but I experimented and installed 3.00 rear ring & pinion, compared to my last years gear of 3.25. I was hoping for a better top end and maintain the 1.4 60', but that did not happen. I am getting data from a dyno this week before I change anything. I know I can get 1.3 60' time if I up the MA to 3000amps, but might need more motor voltage for a higher top end. Many tests ahead.

 

[Arlo1]

WHats the stalled motor resistance? You might need more voltage to get the motor amps up!

 

[EVDragRacer]

Test #2:
2000 BA (each controller)
2000 MA
200 Motor Volts
(Pack was at 230V)

2000 BA into each controller, so is that 4000 A total load on the pack ??

The pack delivered 4000amps with ease.

 

[EVDragRacer]

WHats the stalled motor resistance? You might need more voltage to get the motor amps up!

The data will show what is needed. I definitely agree that more voltage will be needed to get more motor amps.

 

[EVDragRacer]

This is info I received from an expert in the field.

"Ron,

Yes, the controller is perfectly capable of delivering 3000A to the motor while only drawing 2000A (or even much less) from the battery. All that is necessary is that the motor voltage be 2/3rds the battery voltage when it does so. If your 230V pack did not sag at all then your motor could be driven with a maximum of 153V at 3000A while pulling 2000A from a 230V battery.

The caveat here is that motors require more voltage both to spin at a higher RPM and at a higher torque load (current). That is to say, the more current you push through the motor the more voltage you need to spin at a given RPM.

Because your times didn't change much in going from 1500A to 2000A, I suspect you are maxed out on motor voltage. I don't remember the precise details of your setup in Warp Factor II, but I seem to recall you were running a similar battery voltage back then, no?"

 

[Hillhater]

The pack delivered 4000amps with ease.

Did you get any voltage (sag) data from the runs ?

 

[EVDragRacer]

The pack delivered 4000amps with ease.

Did you get any voltage (sag) data from the runs ?

Very little, pack is stiff. Temps only rose to 35c to 40c after each run. The EMUS BMS worked flawless!

Will be getting data at EVCCON, they back to the track at full power.

 

[Hillhater]

Ron has been a little quiet on here lately ?
..but i notice he posted this on another forum recently..

...I know why I am stuck at 10.2 seconds in the 1/4 mile, it's the sag which dropped my voltage down to 113V from a 230V pack. I think adding cells in series will lower my 1/4 mile ET,

So , 50% + voltage sag is "very little" is it Ron ?


And appears to have revisited his pack design tab connection method in a 15p module ..

 

[liveforphysics]

The moment you sag past 50%, you extract less power from the battery by pulling additional current.

At 50% sag you're also dumping an equal amount of energy into heating the battery as you are extracting power from it.

 

[Hillhater]

for those interested ..
http://www.diyelectriccar.com/forums/showthread.php/warp-factor-iii-now-alive-74864p17.html

 

[EVDragRacer]

Ron has been a little quiet on here lately ?
..but i notice he posted this on another forum recently..

...I know why I am stuck at 10.2 seconds in the 1/4 mile, it's the sag which dropped my voltage down to 113V from a 230V pack. I think adding cells in series will lower my 1/4 mile ET,

So , 50% + voltage sag is "very little" is it Ron ?


And appears to have revisited his pack design tab connection method in a 15p module ..

I'm glad you are following me so closely, can you scratch my azz since your so close?

 

[EVDragRacer]

We have decided to stick with our 10P packs and build two separate packs for each Shiva. The picture shown above will not happen. Our 10P batteries cannot be separated so I am drilling & tapping in three location on each 10P side. Plenty of copper to work with, the new series connection method will use a thin copper strip to connect all six holes, and a large braided battery strap from each 10P center hole we tap. Pictures coming soon, I am still testing the condition of all my 10P cells.