Brushless Drag Bike!

[Arlo1]

Ok so I have 2 jobs I work for my self and a bike wrecker and the owner of the wrecker is the crew cheif for the Steve Drain Nitro Harley!
I mentioned to him getting some sponcers together for building an electric drag bike! He was very stoked
He has a rolling chassis ready for the task!
I was looking at numbers and they figure the nitro bike makes 950-1000 hp to go in the 6's and 205 mph!
So thats ~746000 watts! I was looking at the nano-tech batteries and I will still need a lot of batteries.
I will put pics up later and at this point its just a idea so I want to look at the numbers first!

 

[Arlo1]

And did I say it Has to be brushless!

 

[Arlo1]

Ok so in terms of batteries
I used the 1000 hp number 746000 watts for a refernce!
I want the ability to be competive (if not now one day) with the Top nitro Guys
So the batteries would need to be able to produce 746000 watts!
Now the cool part is its only for 6 seconds at a time so even if you used a 10 second number to leave a buffer and a little for a burn out!
So for a 10 second drag at 746000 watts Thats 1/360th of a hour so 746000/360=2072.2 watt hours to make a run!
So On that note I just need to find the Highest discharge batteries possible!

 

[gogo]

Why brushless?

 

[Tiberius]

Ok so in terms of batteries
I used the 1000 hp number 746000 watts for a refernce!
I want the ability to be competive (if not now one day) with the Top nitro Guys
So the batteries would need to be able to produce 746000 watts!
Now the cool part is its only for 6 seconds at a time so eve if you used a 10 second number to leave a buffer and a little for a burn out!
So for a 10 second drag at 746000 watts Thats 1/360th of a hour so 746000/360=2072.2 watt hours to make a run!
So On that note I just need to find the Highest discharge batteries possible!

10 seconds is 360 C
6 seconds is 600 C

How many cycles do you expect?

Nick

 

[The Stig]

This would be an amazing project. You would need some serious sponsors.
I would say the battery tech to make this possible exists with 90C Lipo available from polyquest. There is the potential for gigantic lipo fires but hey.
What I would like to know is if there is a company out there that could make a compact controller/inverter that can take that kind of power. An AC induction motor may be desireable at these power levels as the looses in a brushless DC motor would be significant. Then there is finding a source for a lightweight, water-cooled 700 KW AC induction motor. The biggest I've seen for EV applications is 200KW. Maybe if you cooled that one with liquid nitrogen you could push 700KW through it

As far as batteries go there are some out there that you could arguably use to make a prototype. Polyquest 45C-90C Lipo http://hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=10090

Lets look at this battery hypothetically:

Discharge: 45-90C
Capacity: 4400mAh
Voltage: 22.2v / 6S1P
Weight: 748g

The max power of one of these batteries at 80C would be:
80C * 4.4Ah = 352A
Voltage would sag a bit we'll use 21.5V * 352A = 7.6 Kw

So the number of these packs you would need to produce 700Kw is:
700/7.6 = 92 Polyquest packs
Weight of Battery = 92 * 0.748 = ~70Kg
The battery would most likely need cooling and a tough box and all the connections and water cooling, so it would probably come out to about 80Kg

The cost of this battery pack would be:
If the retail price of these packs is $242, then the cost of the equivalent number of cells per pack, straight from the polyquest factory should be about $50-$100
The cells and connections between them should cost about $100 per equivalent polyquest pack. So that is 92 * 100 = $9200
We're looking at a $12k-$15k Battery pack.

This Battery would have: 22.2V * 4.4Ah * 92 = 9 KWh approximately

This would be about enough for 45 seconds of run time at max power of 700Kw.
All this is hypothetical of course.



Now lets look at hypothetical performance characteristics.
At 90% efficiency we would have 700*0.9 = 630KW on tap.

To get to 200mph(90m/s) you would need this amount of time:
Estimate the weight of the vehicle + rider at 350kg
0.5 * 350kg * (90m/s)^2 = 1.42 Mega Joules

1.42MJ / 0.63MW = 2.25 seconds
Add a second or two to account for drag and other losses: 4 seconds to reach 200mph!

Theoretical performance characteristics matching the top fuel pros who do over 220mph in a little less than 6.5 seconds!! You may need a fatter rear tire for that future brushless drag bike, seeing the size of the bikes they use to get those times: http://www.youtube.com/watch?v=VKe74wWwteM

 

[Arlo1]

Why brushless?

Because it's so much better! And it's a challenge!

 

[Arlo1]

Tiberius.
The option for multiple lipo batteries will lower the needed c rating! So if you needed 100c from one battery you only need 50c from two ect.

 

[def215]

where are you gonna get a brushless motor that puts out that much power? are you gonna use something like an AC motor meant for an electric car? that would be a sight to see.

after seeing your e-bmx, im pretty dure you can accomplish buuilding an e-drag bike.

 

[Arlo1]

where are you gonna get a brushless motor that puts out that much power? are you gonna use something like an AC motor meant for an electric car? that would be a sight to see.

after seeing your e-bmx, im pretty dure you can accomplish buuilding an e-drag bike.

Working on it but the 12kw out runner is a step in the right direction they are stackable so I was thinking 3 stacked by 3 sets all beside each other for a total of 9 motors and 9 controllers. But right now this is all calculations and speculations!

 

[Doctorbass]

Watta great idea Arlo :wink:

Brushless is the key i also think. no brush to blow no plasma... just mosfet high endurance! :lol:

You would need like two tesla brushless motor!

I saw some 100C lipo today over the internet.. that might help your project...

or the SAFT VL 10V Fe cells .... up to 250C or

175C CONTINUOUS
http://www.saftbatteries.com/doc/Do...cell.911c645b-8e4a-46c3-a926-1ba6e8f8970c.pdf

normally used for military stuff

or this one:http://www.saftbatteries.com/doc/Do...heet.a2c55356-164e-4fe3-b957-86bbed023422.pdf

Doc

 

[The Stig]

or the SAFT VL 10V Fe cells .... up to 250C or

175C CONTINUOUS
http://www.saftbatteries.com/doc/Do...cell.911c645b-8e4a-46c3-a926-1ba6e8f8970c.pdf

normally used for military stuff

or this one:http://www.saftbatteries.com/doc/Do...heet.a2c55356-164e-4fe3-b957-86bbed023422.pdf

Doc

Those Saft cells are just the thing for that drag bike.

 

[Arlo1]

Yes thanks Doc
Amazing!
With a 24s 3p pack I would have more then enought amps avalible! And just enough watt/hours!
Great find!

 

[Arlo1]

This would be an amazing project. You would need some serious sponsors.
I would say the battery tech to make this possible exists with 90C Lipo available from polyquest. There is the potential for gigantic lipo fires but hey.
What I would like to know is if there is a company out there that could make a compact controller/inverter that can take that kind of power. An AC induction motor may be desireable at these power levels as the looses in a brushless DC motor would be significant. Then there is finding a source for a lightweight, water-cooled 700 KW AC induction motor. The biggest I've seen for EV applications is 200KW. Maybe if you cooled that one with liquid nitrogen you could push 700KW through it

As far as batteries go there are some out there that you could arguably use to make a prototype. Polyquest 45C-90C Lipo http://hobbycity.com/hobbyking/store/uh_viewItem.asp?idProduct=10090

Lets look at this battery hypothetically:

Discharge: 45-90C
Capacity: 4400mAh
Voltage: 22.2v / 6S1P
Weight: 748g

The max power of one of these batteries at 80C would be:
80C * 4.4Ah = 352A
Voltage would sag a bit we'll use 21.5V * 352A = 7.6 Kw

So the number of these packs you would need to produce 700Kw is:
700/7.6 = 92 Polyquest packs
Weight of Battery = 92 * 0.748 = ~70Kg
The battery would most likely need cooling and a tough box and all the connections and water cooling, so it would probably come out to about 80Kg

The cost of this battery pack would be:
If the retail price of these packs is $242, then the cost of the equivalent number of cells per pack, straight from the polyquest factory should be about $50-$100
The cells and connections between them should cost about $100 per equivalent polyquest pack. So that is 92 * 100 = $9200
We're looking at a $12k-$15k Battery pack.

This Battery would have: 22.2V * 4.4Ah * 92 = 9 KWh approximately

This would be about enough for 45 seconds of run time at max power of 700Kw.
All this is hypothetical of course.



Now lets look at hypothetical performance characteristics.
At 90% efficiency we would have 700*0.9 = 630KW on tap.

To get to 200mph(90m/s) you would need this amount of time:
Estimate the weight of the vehicle + rider at 350kg
0.5 * 350kg * (90m/s)^2 = 1.42 Mega Joules

1.42MJ / 0.63MW = 2.25 seconds
Add a second or two to account for drag and other losses: 4 seconds to reach 200mph!

Theoretical performance characteristics matching the top fuel pros who do over 220mph in a little less than 6.5 seconds!! You may need a fatter rear tire for that future brushless drag bike, seeing the size of the bikes they use to get those times: http://www.youtube.com/watch?v=VKe74wWwteM

Thanks Stig.
Yeh I knoticed this is a 10 inch tire bike. But... To get started might be a good place then work up to the Nito Bike tire size even if it meen a whole new chassis. The chassis is clearly not going to be the expensive part!
Very interesting. I am realy thinking about this I have a lot of the conections and support I need to do very well. And I just want to cry when I here Killacycle is Brushed and with A123 batteries...

 

[Tiberius]

Tiberius.
The option for multiple lipo batteries will lower the needed c rating! So if you needed 100c from one battery you only need 50c from two ect.

Absolutely true.
But if you are stacking up 50 C batteries, then you have enough for 72 seconds running time. So during the run, 11/12 of your battery is extra dead weight.

There's probably no way round this; its part of the engineering challenge. But it does mean that EVs might mount a better challenge to ICEs in events that last a minute or so - maybe hill climbing.

Nick

 

[Arlo1]

Tiberius.
The option for multiple lipo batteries will lower the needed c rating! So if you needed 100c from one battery you only need 50c from two ect.

Absolutely true.
But if you are stacking up 50 C batteries, then you have enough for 72 seconds running time. So during the run, 11/12 of your battery is extra dead weight.

There's probably no way round this; its part of the engineering challenge. But it does mean that EVs might mount a better challenge to ICEs in events that last a minute or so - maybe hill climbing.

Nick

Tiberius
Check out the post from Doc and the "Saft" cells Problem solved!

 

[Kiwi]

Check out the discharge graph on the safts, are they really that great? First they hardy make their capacity, less than 80% at 175c and down to less than 2 volts. They look more like they are suited to 10c. The max you are going to get out of each cell is about 3kw for 16 seconds(is that right?) based on 20w/h (usable 8ahx2.5v).

So for 746000w /3000w = 248 cells, total weight 150kg (+hardware)

Unless I have my maths total wrong, (which is quite possible) this is twice the weight of the polyquest packs.

I must have this wrong??

 

[liveforphysics]

The Saft LiFePO4 cells are a joke.

But the Saft LiCO2 ("Li-Ion" ) seem to be the best option I've seen for this application.

You would need roughly 150cells of them.

Roughly 52Kg or 115lbs of weight in cells alone. That actually puts it in the realm of the possible things from a weight/performance aspect.

50S3P pack, and perhaps 8x rewound colossus motors arranged in series pairs with 4x controllers each made from 6 of this FET: http://ixdev.ixys.com/DataSheet/VMO1600-02P.pdf

I think it's possible, and likely for less money than most any other nitro-class drag vehicle. The FET cost would be ~4,000usd, all assembled, the controllers might be ~8,000usd. That's not far off of what a top-notch motec setup, professional wiring harness and install, plus many many days on the dyno teaking and swapping parts costs for a typical pro-drag vehicle.

If you could land a cell sponsor or something and get them for say, $50usd each, that would only be $7,500 in cells. I think I remember hearing those things were over $150usd per cell though (which would make it $22,500usd in cells), but I don't remember if it was the "Li-Ion" or the LiFePO4 versions. I also remember the GM Volt crew did a bunch of testing on them and was less than thrilled, but I can't remember what aspects of them turned them off (hopefully just price? GM/Ford/Mopar = cheap bastards).

If the chassis is free, maybe $20k-30k in parts should buy the drive system components. If you show Saft a professional plan, show them pro-nitro-bike team experience and show them it works on paper and that you've got the skills to make their product look good, I bet landing a Saft sponsor would be a possibility.

 

[GTR2EBIKE]

If you do end up going through with this, I know someone who can ride it for you assuming you don't plan to yourself.

 

[The Stig]

If your going to go through with this a lot of ES people may be interested and I know I would be willing to pitch in any work that can be done remotely.

You should strongly consider going for a drag car. You should have much larger potential for sponsership going for a car, and so you may be able to go for higher power for cheaper!

 

[Arlo1]

Stig cars are not out of the option! But power to weight.... Its going to be a bike if we do it. But having a sister Car is a option down the road.
Thanks for all the info guys!
I am in a very great posistion for a bike build...
As for a dyno luke these guys with their nitro bike said its a bastard to run on the dyno I will ask why again.

 

[Arlo1]

Ok so this might be happening!
My boss has a guy trying to dig up $20 000 for us to get started!
Ok so I calmly think holy shit we dont have a controler yet HOLY SHIT!
The motor I can build but the controler is a challange!

 

[Arlo1]

Ok some more math.... The bike I use for base data is a nitro harly that makes 900-1000 hp peaking at 4600 rpm and the second gear is 1-1 ratio with a 2.08 final gear ratio and first is 1.37
I calculate from this to get torque and see if maybe we should be looking at torque and not HP.

So torque in first gear is ~ 2928 ft/lbs - 3253 ft/lbs and second gear is ~ 2137 ft/lbs - 2374 ft/lbs

 

[liveforphysics]

What is the weight on those bikes?

And I don't know if you caught my last round of nano-tech test vids, but they can handle 200C for a few seconds, and 100C for >15seconds.

I pulled >800amps off a 4Ah "45-90C" pack.


This means your battery size/weight requirements can be a lot smaller than we first estimated for the dragbike.

 

[Arlo1]

What is the weight on those bikes?

And I don't know if you caught my last round of nano-tech test vids, but they can handle 200C for a few seconds, and 100C for >15seconds.

I pulled >800amps off a 4Ah "45-90C" pack.


This means your battery size/weight requirements can be a lot smaller than we first estimated for the dragbike.

Uhm I saw the test with the car starter thing on the honda but I will log onto youtube and check out your vids right now!
Seriously under rated hu?