# New to EV, want to go fast.



## DavidDymaxion (Dec 1, 2008)

Sounds awesome! Are you planning to run this summer? Last year on the Salt Flats there were 5 or 6 electrathon vehicles, one of them broke 100 mph in 1 mile with just 67 lbs of lead acid batteries! You can see a bit about that on my web site http://ExplodingDinosaurs.com . I plan to run at this meet: http://www.SaltFlats.com . Bill Dube's team is supposed to be there running an electric motorcycle.

150 mph and 2 miles: Does that mean you are going for the USFRA 150 club? Have you ever run on the Salt Flats before? (or other LSR?)

Too simple scaling for the electrathons:

P ~ v^3 (yes, cubed for power to fight aero drag, it's squared for force)

(150 mph/100 mph)^3 = 3.4 times the power
So an electrathon would need at least 3.4 * 67 lbs ~ 230 lbs of batteries for 150 mph.

But wait... Lead acids probably won't have enough capacity for 2 miles run at the 1 mile power rate, so you'll need even more.

But wait... You'll be fighting alot of aero drag that 2nd mile, so you'll need even more battery...

Can you afford lithium?

Probably your best bet is to try to find specs for streamliner motorcycles, and see how much power they need.

What is the weight of your machine? It would be fun to throw your numbers into my simulator and see a predicted speed for ~300 lbs of batteries. Did you actually measure your 0.2 Cd number? You can see some simulations I did for a full size car on my web site, too, http://ExplodingDinosaurs.com .


Dreamweaver said:


> I'm a total newbie when it comes to EV. Tried reading up on all the forums but having a hard time getting my 57 year old head around watts, amps, current draw blah blah but am trying to learn.
> 
> Ok, on to the big question.
> 
> ...


----------



## Dreamweaver (May 19, 2009)

David,

Thanks for the links to your website and your information.

I have not run on either the salt or the dry lakes but did just get back from the El Mirage dry lakes races as a spectator.

This is all preliminary research as I do not understand the relationships of all the electrical theories involved, so was trying to get some insight into all that on these forums.

The SCTA has an entirely different set of rules than what the folks at WoS events require.

The maximum weight in the class I'm looking at is 1100lbs not including driver.

At this point I'm making some basic assumptions. Vehicle weight of 550 lbs and then 550 lbs for motor, batteries and controllers.

My budget isn't real high maybe $5-10K for the complete project. Just the required firesuit is ~$1000.

Ive researched a lot of streamliners and the really good ones are around a cd of .1-.15, so MAYBE my homegrown one could make it to .2. A well designed car has a cd of about .3-.35.

As to how much horsepower the motorcycle streamliners make, those appear to be racing secrets. Tho I did find one that went ~145 on a 50cc engine.

What I really need to learn is how voltage/amperage relate to horsepower/torque and how long those are available given a set battery pack.

Soooo many questions.

Racing this year, no way, too much to learn and then build.


----------



## DavidDymaxion (Dec 1, 2008)

It sounds like you are going for the 500 kg streamliner record. Good choice, I think that's an open record right now. BYU is building a car for it, and they are projecting their car is capable of over 200 mph. They are using A123 batteries. At the other end, the Singletons ran their Junior dragster a couple of years back, with 144 Volts of small Hawkers. They ran 113 mph on tired, old batteries, but since they ran it in the 130 club it didn't count for the record.

WoS runs mostly SCTA rules, but with some differences. They only run 1 way, which means a record is not an international record, but is nice for spectactors as you can go right up to the starting line. They also have some additional classes, like 130 club, 150 club, barstool, electrathon, and kart. In other words, they are very electric friendly.

Probably the best place to ask electric racing questions is NEDRA:
http://sports.groups.yahoo.com/group/NEDRA/
http://www.NEDRA.com

Enersys (Hawker) Odyssey batteries are favored by some of the of the fast NEDRA guys:
http://www.odysseybattery.com/documents/US-ODY-AM-001_0406.pdf
This doc is really nice in that it has tables for power draw vs. time, so you can start getting some feel for how much power you can draw with 300 lbs of good lead acid batteries for long enough to do a run.



Dreamweaver said:


> David,
> 
> Thanks for the links to your website and your information.
> 
> ...


----------

