Locost EV ?

A few months back I noticed how cheap a Chevy Bolt sold  on the insurance site. 
The body was totaled  but it was claimed it ran and drove.  
     If I separated  the charging unit and kept only enough batteries to run an autocross. Stuffed the result in a locost chassis. With the instant acceleration of EV's wouldn't I have a winner?  
    Would I be better using a Tesla?   Wait for the Ford F-150 with it's 439 horsepower?  
 I'm thinking of  trailering to the site. Not  running the whole day just enough batteries  to run a lap or two and either recharge them or  do a quick change.  

I'm looking forward to seeing this.

One thing to know - batteries aren't like gas. If you run just enough battery to make it through a run, you won't be able to deliver power as quickly so you'll be down on acceleration. To be able to deliver a big slug of power at once, you need a lot of battery. Balancing that against weight would be a good challenge and it may have a different solution for different tracks.

Two things that the Teslas have that will be difficult to beat with this approach are big honkin' batteries and very good torque vectoring. Will light weight and small size be enough? Let's find out!

I've had random thoughts of an EV Locost from time to time. Doesn't seem it would be *too* difficult. These thoughts usually happen after watching Vintage Voltage and seeing them electrify something. Electric motor up front, battery packs in the boot, bam, done (lol). With just an electric motor up front there'd be TONS of space left over. Could probably land some battery packs in the nose too.

I have had similar thoughts about an electric autocross vehicle, and I would guess lots of other GRMers have too. I could make everything mechanical work out, but I always get stuck when trying to think through how to make the software work with a stripped down electrical system. 

For example, would the stock software run with a reduced number of batteries? Would the stock battery charging system work when connected up to only half the batteries? Would the stock software work without the rest of the car's electrical system (body modules, abs, door locks, etc.)?

My guess is that you would need to transplant the entire electrical system from the Bolt (or whichever) into the locost chassis. And then it would weigh too much and be too complex to be much fun.

What would be nice would be an aftermarket MicroSquirt type ECM set up to control the stock EV system. Until some really smart EEs (and I know you are out there) develop a GRM controller, I am going to have to stick with ICEs.

I think I see the problem now.  Knowledge.  The physical stuff is very straight forward.  The integrated  systems workarounds aren't as simple.  
With an ICE  if A/C isn't needed, it's unbolted and disconnected. Cruise control? The same, power brakes, ditto. 
    

In reply to Yourself :

If you're serious about this, I'd recommend looking at EV West and their product solutions. 

AEM and Motec also make standalone EV controllers.

Keith Tanner said:

I'm looking forward to seeing this.

One thing to know - batteries aren't like gas. If you run just enough battery to make it through a run, you won't be able to deliver power as quickly so you'll be down on acceleration. To be able to deliver a big slug of power at once, you need a lot of battery. Balancing that against weight would be a good challenge and it may have a different solution for different tracks.

Two things that the Teslas have that will be difficult to beat with this approach are big honkin' batteries and very good torque vectoring. Will light weight and small size be enough? Let's find out!

The question is how much of that battery power is used in a full scale acceleration of the stock vehicle and how much is used to get range?  
Once we have that formula  then we can do a quick weight reduction formula to find out how much battery is needed for a full scale 1 minute autocross.  Add whatever for the unanticipated and we've figured out our battery pack size. 

In reply to frenchyd :

The problem is that you can only get so much current into or out of a battery cell so fast.  Tesla has been making a lot of strides in this field but it's all been incremental upgrades.

Because of that, if you want to get a lot of current moved quickly, as in "fast charging", you need a lot of battery cells, which results in longer range... and faster acceleration.

It's a little weird to wrap your head around.  In a gasoline analogy, it would be like if every gallon of fuel had its own container with a tiny feed hose.  If you want to make a lot of power, you have to add more gallons of fuel capacity.

Another approach would be to keep the original batteries and driveline intact and build a Kart. Since I have a BMW i3 sitting in my garage, I often wonder how you could increase performance and reduce weight. An early i3 BEV (currently about $12k with a clean title) is around 2900 lbs. I think you could strip off much of the bodywork and interior (and recoup some $$) and still have a running driving car. If you could take out 400-500 lbs, lower it on some coilovers and get wider (anything is wider than stock!) sticky tires, I think it would get interesting. They come with a carbon passenger cell, so you shouldn't have to build a cage. With a little luck, there's probably not much 'building' or expertise involved aside from suspension setup.

In reply to hunter47 :

Thanks! I had looked into EV West before, but stopped looking when I saw the prices. I did not know about AEM and Motec. The stand alone controllers along with a wrecked EV might just be the answer. I need to learn a lot more - one more trip down the rabbit hole! Need to wrap my mechanical engineering brain around electronics again - maybe it will stick this time?

Maisgelb:

I had not thought about an EV Kart. This might be the easy button for learning on and having fun!

In reply to Pete. (l33t FS) :

Interesting analogy. Easy for me to grasp.  Thank you. 
   Now to figure out how to cheat.  Quick change battery pack? Would the motor overheat?  Could I cool it down with a refrigerant of some kind?, dry Ice?  

From what I have read battery construction techniques give tradeoffs between max capacity and max instataneous current values.  You don't get both, you have to compromise, and that means there are different ideal batteries for different purposes.  You can see this in lead-acid batteries by comparing car starting batteries (high current) vs deep cycle (high storage capacity), and the same thing is true of different types of lithium batteries too.

So ideally in an autox or drag race car you'd want lithium batteries that sacrifice max capacity for higher current than might be chosen for a road car.  I have no idea if there's an easy/cheap source for such batteries, though.

There have been people fiddling around with electric drag cars for some time now, they seem to have worked out the problem of high current draw for a short period of time.  I would imagine what they've done could be applied to autocross.

Most EVs are a fully-tied in system, though the Nissan LEAF uses standard CANBUS for it's parts so alternate battery packs and things can actually be pretty easily added into it's system. Tesla's I think use a version of Unbutu Linux to run the car.

This guy on the DIY Electric Car Forums made an EV Locost. His build used a brushed DC motor, so his electronics were minimal but he lacks regen and can only air-cool his parts.

I can go into wild detail about motors to look for but we'd have to get specific.

CAN bus is just a networking protocol, it's not the language. You can use a variety of things to send CAN messages, you just have to know what those messages should be and what they mean. I suspect Tesla uses it as well but nobody has decoded the messages yet.

If you want to see battery variety on a small scale, take a look at the RC world. I think they use a rating called C that denotes the speed of discharge. But if you're dealing with junkyard parts, you're pretty much stuck with the discharge rate of an individual cell, so the only way to increase it is to add more cells.

https://www.youtube.com/watch?v=DxxaHYlCuN8&list=PLoTU9_iCGa6i_C38pwQyg0pBGoov76NNv

SuperfastMatt on Youtube is electrifying an old Jag, and seems to be an ex Tesla engineer/designer, so he has loads of useful info

Scca rules also currently hate ev drivetrains.

I'm not sure you'd be able to run it in scca autox, but maybe if the drivetrain is all from current road going vehicles.

I should mention, that I really do want to do this. Regardless of scca rules.

Rigante said:

https://www.youtube.com/watch?v=DxxaHYlCuN8&list=PLoTU9_iCGa6i_C38pwQyg0pBGoov76NNv

 

SuperfastMatt on Youtube is electrifying an old Jag, and seems to be an ex Tesla engineer/designer, so he has loads of useful info

His videos are worth watching even if you aren't into EVs - he's an interesting guy.

For an autocross car you really need to use lithium titanate batteries.  They have a low power capacity (you won't go far) but they have great power density (low weight for the volts), can discharge at 10C or more and can recharge very quickly.  They are also very safe like lithium iron phosphate (no fires... good thing).

As far as SCCA, you are at the mercy of the local region.  I considered swapping my Fmod to electric back when I worked for an EV manufacturer and emailed back and forth with someone at National.  Unfortunately, all that was on my old work email and it disappeared with the company.  The gist of the conversation was this, approach your local region, offer to educate them on the safety aspects of your car re course workers not getting electrocuted, car not bursting into flames, etc. AND make sure your car is built to a standard that supports your claims.  Get familiar with the Amod rules because that's where you'll probably be.

Good luck!

One thing to be aware of with the Bolt?  They have a stability system that you can't defeat that ruins all of the fun when you start flogging the ride.

So you'll have to divorce the drive and control system from all of that, which will be tricky.

In reply to triumph7 :

If A Mod is the class you're in that means it has the potential to be the fastest car.  
In other words,  if you do your homework  you shouldn't have to spend a great deal of money to be a winner. 

In reply to Stefan (Forum Supporter) :

I don't intend to use very much of the actual car.  The charging engine will stay in the trailer.  I need to figure out how to divorce the EV portion from the rest of the car.   
     The actual top speed of the Bolt needs to reflect the track driven on.  I think the easy way is to change the diameter of the tires.  Looking at tires of Legions cars as well as various formula cars. I may try to delete  the regen function in order to provide a more linear braking. 
    In short the biggest motor I can find, a simple throttle and just enough battery to do a lap.   

Robbie (Forum Supporter) said:

I should mention, that I really do want to do this. Regardless of scca rules.

So do I. I think there is a window for creativity.  

stuart in mn said:

Rigante said:

https://www.youtube.com/watch?v=DxxaHYlCuN8&list=PLoTU9_iCGa6i_C38pwQyg0pBGoov76NNv

 

SuperfastMatt on Youtube is electrifying an old Jag, and seems to be an ex Tesla engineer/designer, so he has loads of useful info

His videos are worth watching even if you aren't into EVs - he's an interesting guy.

Yeah, I didn't know about that build (thanks for posting!), but I think he has posted on here at least a few times and also has a bike engined Honda roadster that was on with Jay Leno.