Lithium battery options for electric racers/dragsters

[Ypedal]

Not exactly fast enough.. but looks the part !

[youtube]FF6t016ueUs[/youtube]

 

[liveforphysics]

Sorry about the long delay, I'm climbing a mountian, and everytime I'm on the back side I get no signal on my phone.

To answer the questions:

They do not use a differential, they use a spool in its place in a standard ring and pinion live axle. Differentials are extremely unsafe for cars with multi-thousand HP.

Since this rear axle has 6 critical suspension link points on it, it is always sold included with the chassis. Available rearend gearing ranges between 2:1 all the way to 6:1, and every possible step inbetween, and its all easily available and cheap.

Cars running in the 4s and low 5s are 1 speeds. Just a clutch that slowly clamps down until about 3/4 track when it finally grabs solid.

Cars running high 5s to 7s are generally all 2spd powerglides. The exception being prostock, which run low 6s on 5spd manual dog boxes.

Cars running slower than 7s can run about anything. You find a ton of TH400 3spds, a ton of powerglides, and manual trannys for the imports, unless they converted to a TH400, like so many supras do these days.

Basicly, for your 15 grand, you would have a chassis that is all setup. You bolt your motor in, make a custom driveshaft coupler to connect it to the input of the rearend, mount some batteries, a controller, wire it up and you're good to go. I think I could probibly have all the motors mounted and invincible driveline built in maybe 2 lazy weekends. Very easy stuff. I would make my own 5,000amp 500v controller, which would cost about $1,500 in parts, and take another couple weekends to build. Brushed controllers are sooooo simple.

If you want me to find you a chassis, crate it up, and send it to you, I could be persuaded to do that for you.

 

[CroDriver]

Sorry about the long delay, I'm climbing a mountian, and everytime I'm on the back side I get no signal on my phone.

No need to apologize

They do not use a differential, they use a spool in its place in a standard ring and pinion live axle. Differentials are extremely unsafe for cars with multi-thousand HP.

Since this rear axle has 6 critical suspension link points on it, it is always sold included with the chassis. Available rearend gearing ranges between 2:1 all the way to 6:1, and every possible step inbetween, and its all easily available and cheap.

Cars running in the 4s and low 5s are 1 speeds. Just a clutch that slowly clamps down until about 3/4 track when it finally grabs solid.

This would be great for 2-3-4 electric motors, just without a clutch

Basicly, for your 15 grand, you would have a chassis that is all setup. You bolt your motor in, make a custom driveshaft coupler to connect it to the input of the rearend, mount some batteries, a controller, wire it up and you're good to go. I think I could probibly have all the motors mounted and invincible driveline built in maybe 2 lazy weekends. Very easy stuff. I would make my own 5,000amp 500v controller, which would cost about $1,500 in parts, and take another couple weekends to build. Brushed controllers are sooooo simple.

I agree.

The machining stuff is pretty easy to do but it has to be very solid and precise at that high powers.

If you want me to find you a chassis, crate it up, and send it to you, I could be persuaded to do that for you.

You would really do that? Don't know what to say... Thanks for the offer! It's obvious that you have tons of dragster knowledge, exactly what I need.

If you see something that would be good for my project just send me a mail. I plan to purchase it at spring break or maybe sooner. I have to sell my BMW M6 and X6 because I have too many cars but the market sucks right now here.

Thanks a lot for your help!! Owe you a beer

 

[Doctorbass]

let's go back to the LiPO vs A123,

It is true that Lipo are better power to weight ratio than the A123. almost with the new 90C rated Lipo.

But Who know their performances constancy over High rate discharge?.. I mean.. it is great to have 90C or 45C discharge.. but LiPo have 500 cycle at around 1C.. but how many high performance cycles at 45C ... or 90C..?


I know that for drag race application you dont expect to use 500 cycles.. but let say you get 50 cycles out of an $$$ tortured battery, I'm wondering if the 10th or 20th other cycles will give you the same performance than the first cycles...


I mean the degradations...of performances..



Let's be realistic:

If someone drive 400kg of LiPO at 45C , that will take a serious thermal managing and cooling system!!! otherwist the battery would probably explode!!.. remember that the cell in the middle of the battery volume will heat alot more!!


A123 cells can endure 250 Celsius without any explosion, thermal runaway or fire!!

Let suppose you have 50 cycles at 45C use of a Lipo, that's pretty expensive to drive!! at 15000$ that's 300$ per race



but let say you are rich and dont care with that...

I'm pretty sure the performances will degrade significantly over each race so you may have problem to tune and ameliorate performances over the time without absolute performances reference..

I remember that Bill Dube was very satisfied and impressed to see how the killacycle pack was constant over each race.. and that helped them to easier tune the ebike due to power constancy.



Also I know that they heat the pack to 70 celsius before each run to lower the internal resistance to the minimum to minimize the Vdrop

They are 13P configuration with the Zilla 2K ( assuming 2000A) that's 153A per cell) WITHOUT ANY FIRE DANGER OR CELL DEGRADATION!

I've reed that Bill done more than 175 cycles on the last battery pack and did not noticed any degradation.!!.

If you need 5000x A123 cells I guess the chineese would ALSO give you a rebate... probably 4$ per cells that's 20000$

so at least 175 cycles for 20000$ is 114$ per drag race.. less than half the price per race than the LiPo




Yes guys.. I'm still sticked to the A123 again... :wink: almost for drag racing use.. these cells have the lowest degradation when are tortured... and give probably more tortured cycles for the entire life of the battery... and will not inflate!.. Pouch have tendensy to inflate when tortured...

These cells are more tough about vibrations or puncture or heat due to the cylindrical shape..

A123 can be charged in 15 minutes ( 4.3C) and for drag racing it's usefull!

otherwise the supercapacitor outerpass the A123 power to weight ratio.. or maybe the SAFT battery at 250C !!! .. but are expensive!

That's my opinion.. but i can be wrong..

Have you any pics of that 11" motor??.. Because - or 2 MegaWatts in a motor is .. IS.... ISSSSS... unimaginable...what kind of brush it would use??.. Nirogen presurized motor to blow out the plasma to prolong their life?...

The guy that make the killacycle motor completly need to rebuild them at every event.. or ... race.. for... "only" 0.5 Megawatt..

Doc

 

[liveforphysics]

Doc- I've posted up discharge graphs with a temperature line on the graph for older lipo at 40C discharge. It barely got warm, less than 10deg increase over the full DOD. Battery temps are an absolute non-concern when you've got 1.xmOhm per 4.4Ah cell. Battery thermal concerns are for you guys with LiFePO4 A123 cells.

Your lifecycle specs are not even close. There are helicopter guys that average 30-50C discharge, charge at 3-4C, and have over a thousands cycles. Some guys have 2,000+ cycles even on older LiPo packs.

For a drag setup, A123 is heavy and wimpy. Its also a cell that hasn't improved for the last 5years? If I'm not mistaken, didn't they dial back the performance of the cells they make now due to safety/fire concerns with the original M1 cells? A123 was pretty cool 5 years ago. Now its half the power, twice the weight, twice the cost etc. Just doesn't make sense for a drag setup.

 

[Doctorbass]

When you say:

average 30-50C discharge, charge at 3-4C, and have over a thousands cycles

I am pretty sceptical about that.. 40C average charged at 3.5C and.... AND... 1000+ cycles for a lipo.... :? normally LiPO are 500cycles max not 1000+ at 40C !

I know that LiPo miliohms per Ah is pretty low and it's at their advantage butI only see one drag racer on the NEDRA that is using that chemistry...

I thing you like Lipo as i like A123 cells... .. no more debate on that :wink:

Doc

 

[liveforphysics]

You can't pull a spec sheet from 5+year old LiPo, and use it to try and judge 3rd generation LiPo design. Not all battery designs have been been sitting on their thumbs for the last 5 years

 

[tostino]

I think we've seen from the ebikes that use lipo, that it is more than capable of pushing a car down the strip faster than a123. I would love to see someone cycle a high quality lipo cell for 1000+ cycles, so we can see just how fast it degrades, and how much the IR goes up with cycles. That way we can know for sure, if the only big advantage a123 has over lipo is safety with heat, internal shorts, and puncture.

Of course, this all may change as soon as a123 releases their next gen lifepo4 (if anyone can even get their hands on it). Only time will tell at this point.

 

[voicecoils]

I assume there are various classes for drag racing.

Is there a class where daily drivers (or at least road legal) go head to head?

If so, it could be an area where a slightly scaled back design could still impress.

Surely someone could build an impressive car that could be driven to the track and give Plasma Boy's White Zombie a run for it's money.

In such a package, the A123 vs lico lipoly debate may be minimsed as their would be so many other influencing aspects from the street legal rolling chassis alone (body/frame weight reduction, drivetrain strength, etc).

A lipo version of Luke's Civic would likely crap on many ICE cars even if it sucked compared to the metho powered Civic dragster.

 

[liveforphysics]

My Civic's engine in a the civic chassis can do a 10second run. The same engine setup in a drag chassis could do 8s, and the record for a more built-up version of my engine in a drag chassis has run 7s, and holds the world record for a NA 2L 4cylinder.

If you wana win drag races, a drag chassis is a massive advantage. When my street car runs up against dedicated drag cars, I have to have every thing perfect, and I gotta have about a 50% better power to weight ratio to overcome their awesome ability to put it up on the chip, and let em' hang . Hit the chassis with everything you can throw at it, and it sucks it up and asks for more. That is perfectly suited to taking advantage of the insta-torque hit an electric motor. Streetcar chassis just can't do that. And don't get me started on AWD. Ruins handleing, makes a car boreing, and do nothing to help traction at the drag strip (cause fast stuff with the rear wheels powered will be having no weight on the front tires when they launch, which is why all the fast AWD stuff gets converted to RWD when its gets fast.)

 

[voicecoils]

My Civic's engine in a the civic chassis can do a 10second run. The same engine setup in a drag chassis could do 8s, and the record for a more built-up version of my engine in a drag chassis has run 7s, and holds the world record for a NA 2L 4cylinder.

If you wana win drag races, a drag chassis is a massive advantage. When my street car runs up against dedicated drag cars, I have to have every thing perfect, and I gotta have about a 50% better power to weight ratio to overcome their awesome ability to put it up on the chip, and let em' hang . Hit the chassis with everything you can throw at it, and it sucks it up and asks for more. That is perfectly suited to taking advantage of the insta-torque hit an electric motor. Streetcar chassis just can't do that. And don't get me started on AWD. Ruins handleing, makes a car boreing, and do nothing to help traction at the drag strip (cause fast stuff with the rear wheels powered will be having no weight on the front tires when they launch, which is why all the fast AWD stuff gets converted to RWD when its gets fast.)

Cool, but are their races you do that dedicated drag chassis aren't allowed in? If so, would a non-ICE car be allowed to run?

I understand the inherent advantage to a chassis engineered for a single purpose.

 

[Doctorbass]

Let say you become a winner in EV drag race in your country.... Ex Killacycle, Plasmaboy...

Now you are invited to international event.. wich EV battery do you believe that will be allowed the easyest to cross the border?

400kg of Lipo

or

400kg A123 with that approaved MSDS ?

 

[liveforphysics]

They have class rules. Like the front half of the unibody has to be intact for some classes, and weight minimums depending on the displacement of the engine, and some allow suspension pre-load bars, or wheelie bars, tire size limits etc.

In small tracks in the wild west of racing, you just have open heads-up racing. Slangly named "run what you 'brung' (gotta love the word 'brung' lol). Heads-up open class racing is my favorite type of racing, because its like street races, but the cops don't break it up.

 

[voicecoils]

Let say you become a winner in EV drag race in your country.... Ex Killacycle, Plasmaboy...

Now you are invited to international event.. wich EV battery do you believe that will be allowed the easyest to cross the border?

400kg of Lipo

or

400kg A123 with that approaved MSDS ?

Look at the TTxGP competitors (many on lico lipoly, including US competitors)

How did they do it?

I think there are bigger challenges.

I'm a strong lifepo4 supported but come on, when Wh/kg and W/kg are the greatest concern you simply choose the option with the best of those specs...

 

[liveforphysics]

Let say you become a winner in EV drag race in your country.... Ex Killacycle, Plasmaboy...

Now you are invited to international event.. wich EV battery do you believe that will be allowed the easyest to cross the border?

400kg of Lipo

or

400kg A123 with that approaved MSDS ?

Once the battery is built into the end product, anything can be shipped without issues.

 

[317537]

Reading a lot of discussion about lipo's and looking at discharge curves, leads me to believe they are much like LiFePo4. The higher charge volatge seems to establish a type of surface charge as this explains the big dip in the initial stages of the discharge cycle. Would be interesting to explore this anomaly using nano tech just to see how far the energy density can be exploited. I think there is much to learn about suface charges in electrochemical applications. Anything over 5c would show the how the two different but similar chemistries inherant behavior are related. Id almost be tempted to add a few more cells with lipo to compensate for the initial steep curve.

Lipos must really fly out of the box when fresh off the charger hey..

 

[liveforphysics]

He is going to be hitting the batteries for 10 seconds or less. That means the top 15% of the pack at 55C discharge. He will be in the fat of the discharge curve

If I had were to do an electric dragster, I would definately pre-heat my battery packs with nitrous bottle heating elements. Those packs see a big drop in Ri, and hold voltage so solidly when you get them around 120degF.

 

[CroDriver]

Have you any pics of that 11" motor??.. Because - or 2 MegaWatts in a motor is .. IS.... ISSSSS... unimaginable...what kind of brush it would use??.. Nirogen presurized motor to blow out the plasma to prolong their life?...

The guy that make the killacycle motor completly need to rebuild them at every event.. or ... race.. for... "only" 0.5 Megawatt..

Doc

I meant to use two such motors in the dragster. Actually, I think we'll make a completely new design but it will go in that direction (two 11" motors X 2)

This motor is in my BMW now

I see one more problem with A123's. It's not easy to make a pack out of them... :? There are a few of them out there...

...but I don't like the idea of welding hunderts of cells with tab welders

 

[Jeff]

 

[CroDriver]

Hah, I nearly pissed myself laughing at the image of those Thunderdie cells installed in a drag car :lol:
All they'll do is sit there and get hot, and maybe even swell a little bit...

I don't intend to sound too pissy, but;
With dual 11" motors, you'll need either a huge LiPo pack wrapped in Nomex with an ejection lever to dump it. Or, something along the lines of twenty five parallel A123 M1 cells, with 80 clusters in series.

And silver plated fine strand copper 00 wire to hook it all together with.

Headway 38120? forget about it.

Either way it's certainly not for the faint of wallet.

Thanks, That was a riot! Jeff

Hi Jeff

I know That ThunderSkys suck, I'll find some other use for them. This BMW was my first "test" build...

Have you sold your A123s?

 

[Jeff]

Hi Jeff

I know That ThunderSkys suck, I'll find some other use for them. This BMW was my first "test" build...

Have you sold your A123s?

Hi Mate!
The A123 cell pack has not been sold yet.
I thought it was. The prospective buyer intended to drop them into a restored GM EV1 electric car, to replace the Panasonic EV1260 VRLA batteries it had originally. These 120 cell A123 modules are an exact dimensional replacement. I wanted to sell them, and not just talk about it. They wanted more romance and support than I was willing to give them. Since it was a "health forces sale" thing, I wanted closure, and try not to give it away.

I decided that your offer was too low, and I'm just not the haggling type.

For those who don't know;
I have an EV battery pack for sale. It is composed of A123 M1 cells in thirty cell parallel clusters, with four series clusters. There are 29 copies.
My investment is $40k (not inclusive of any labor), I'm offering these new assembled batteries for $30k. Yes, you can buy the cells for less. That's only half of it...

My sig line has a link to the pack details.


Regards, Jeff

 

[liveforphysics]

Hah, I nearly pissed myself laughing at the image of those Thunderdie cells installed in a drag car :lol:
All they'll do is sit there and get hot, and maybe even swell a little bit...

I don't intend to sound too pissy, but;
With dual 11" motors, you'll need either a huge LiPo pack wrapped in Nomex with an ejection lever to dump it. Or, something along the lines of twenty five parallel A123 M1 cells, with 80 clusters in series.

And silver plated fine strand copper 00 wire to hook it all together with.

Headway 38120? forget about it.

Either way it's certainly not for the faint of wallet.

Thanks, That was a riot! Jeff

That's not a drag car. That's a roadrace car. Roadraces last +20mins at least, giving average discharge of 3C. TS cells are a pretty economical for a low C rate EV battery.

You laugh at his TS battery choice, I laugh at the suggestion of heavy wimpy A123s, and a pack suggestion that alone would weigh more than a proper dragster should weigh entirely.

 

[vanilla ice]

And I laff at all you bitches not using lead!


JK, btw has to be said.. that GTM is the mutt's nutts! Nice clean simple lines.. lucky guy!

 

[Jeff]

You'se guys are too funny. Lotta talk...

Jeff

 

[vanilla ice]

Your car is flippin awesome as well Jeff.. I'm green as hell at both of you two! Just trying to lighten it up.

You do gotta admit the TS cells are a good price, and of course the larger cap you make the pack, the less an issue the Cmax is.. Like he says even a sprint race lasts at least 20 mins, other types of races are longer.