# Building an EV from the ground up



## Anman (Feb 5, 2010)

Hi,

I have been al following these forums for quite some time. Besides these forums I also frequent forums about locostbuilders and have always been interested in designing my own locost. However I lately I am considering desinging this from the start to be an EV, like the thorr ev. This way I could design room for the batteries and engine from the start. I would like to explain what I envision for this project and would like ask you for a reality check, is it possible and what would be the approximate cost of ev part of this build.

Ok, here is what i came up with so far.
-AC powered, bolting the engine straight on to the diff therefore no gearbox required.
-Top speed, not very important how fast would i want to go in something homemade so 100 mph would be more than enough.
-Acceleration, very important i would like about 6 secs to 60 mph.
-Weight, I think it should be possible to keep the weight below 2000 lbs.
-Range, about 30 miles of spirited driving would be nice, not sure about feasability.

As i see it AC engines are virtually indestuctable therefore investigating in a decent engine will pay off in the long run. 

What are your thoughts about my ideas?

tnx


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## INCONCEIVABLE (Feb 19, 2008)

Nope. Can't be done!


Eric.
http://www.diyelectriccar.com/garage/cars/239


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## Woodsmith (Jun 5, 2008)

Have you a budget in mind?

That will have a big effect on what you are able to achieve.
Have you a particular motor and controller in mind? This and your choice of battery will have the biggest effect on your performance, batteries in particular.

You can get a good idea of the weight of the Locost without the EV components and what its CdA would be for aero drag to work out how much power would be needed to push it to maximum speed and how quickly it will accelerate. You will then also get a good idea of the range possible.


Oh, it's clearer if you use 'engine' to mean an internal combustion engine and 'motor' to mean a DC or AC electric motor.


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## bonewibb (Aug 30, 2009)

I toyed with the building a electric car from ground up for a long time. The biggest issues that I ran into were insurance and titleing. After much research I discovered that the simplest approach was to convert an existing vehicle. 

I do have a set of plans for a VW Bug Prostreet V8 chassis that I am willing to let you have for free if you pay for postage.


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## gsmith191145 (May 1, 2011)

Anman said:


> Hi,
> 
> I have been al following these forums for quite some time. Besides these forums I also frequent forums about locostbuilders and have always been interested in designing my own locost. However I lately I am considering desinging this from the start to be an EV, like the thorr ev. This way I could design room for the batteries and engine from the start. I would like to explain what I envision for this project and would like ask you for a reality check, is it possible and what would be the approximate cost of ev part of this build.
> 
> ...


Top speed: A 343 volt 3 phase induction AC motor will allow you to connect it directly to a 3 to 1 step down transmission, or you can use a Ford 9 inch rear end and find the correct gear ratio for the car. The high voltage will give you a high top speed and fast acceleration. 

Acceleration: This is solved by the high voltage motor and gearing. 

Weight: can be a tube frame chassis with fiberglass body and lexan windows. 

Range: Go lithium to save weight. 

Cost: I will let you be surprised. Believe me it is not cheap for an AC motor that performs like a tesla roadster. 


Look for a Warp 11 with a transmission and lithium batteries and a soliton 1000 amp controller. You can get what you want for much less. more like 15000 or less depending on where you get your parts from. If you want more power piggy back another warp 11 for more power.


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## Duncan (Dec 8, 2008)

Hi Anman

I am aiming for 500Kg - and that's with a 100Kg fork lift motor!

AC would have more than doubled the price for lower performance

http://www.diyelectriccar.com/forum...-dubious-device-44370p2.html?highlight=duncan

This is my car so far - now planning on a small light (44Kg) (cheap) ($2,500) Headway pack - only 4.5Kwhrs -but I only need ~ 20Km
Will give 45Kw continuous and 67 Kw burst


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## Anman (Feb 5, 2010)

Thanks for your replies. 
Eric that looks like a really nice project. 
I understand going the AC route is not very cheap. I recon the engine+controller will set me back about 8000 dollar...?
However because these engine are high voltage i need more batteries to attaim this voltage, which will mean i need a lot of batteries which will probably make my batteries the most expensive part of the build?


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## Anman (Feb 5, 2010)

I thought i needed an AC motor for direct drive but apparently some of the larger DC motors can do eactly the same for lower price. Because they usually run at lower voltages less bateries are required therefore reducing weight and cost.
But DC do have some drawbacks right? They are heavier, require more amps, they cannot spin without load, when something fails they donot stop and they dont have regen.

And I really like liquid cooling because more heat can be dissipated and overheating is less likely, or am i being to worried?


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## Thumper (Nov 24, 2010)

INCONCEIVABLE said:


> Nope. Can't be done!
> 
> 
> Eric.
> http://www.diyelectriccar.com/garage/cars/239


Yep. Impossible. 

Jan
http://www.szott.com/zot2/zot2.html


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## gsmith191145 (May 1, 2011)

Anman said:


> I thought i needed an AC motor for direct drive but apparently some of the larger DC motors can do eactly the same for lower price.
> But DC do have some drawbacks right?


DC direct coupled motors will limit your top end speed. Do more research on the transwarp 11.

To gear the rear end to get to 100mph with the transwarp you will lose all your low end torque. high gears means slow as a slug on the take off. 

This is why transmissions are used for the different gear ratios.


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## INCONCEIVABLE (Feb 19, 2008)

You'll have a couple of years to decide AC or DC, high voltage or low voltage. Just leave enough room for either motor and lots of little batteries or not so many bigger batteries and get started building!
And most importantly make sure you have room for the controller. My little Curtis 1221 died just before I was gonna take it from my other car. I barely got the new Soliton 1 to fit in my Formula EVee!!!
Be sure you get and save all receipts especially from used car parts, you will probably need them for registration of the car. Last year, I picked the wrong day to get a VIN inspection on my car. Long story short, I ended up a couple days later with a $200 VW beetle with title. So now my car is a "slightly modified" VW Beetle. I probably won't try again unless somebody hassles me about it.
One last thing, Those Lotus 7's are cute, but they were designed for the race track. You might notice my chassis has a lot more triangulated steel, I'm 48 now and have gotten rather used to living, I wanted something that would survive a hit from one of those big boys driving around out there. Just something to consider, that was one of my many compromises, weight for strength.
Eric.


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## INCONCEIVABLE (Feb 19, 2008)

Jan, That's a beautiful Lotus 23!!! 
Indeed, More proof that it can't be done!!!

Even though apparently you posted before my last post, it wasn't showing at the time. 
Wasn't the Lotus 23 originally the "birdcage chassis" car? Never mind, Just looked it up, Maserati built that. That would have been funner to build!!!

Eric.


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## Anman (Feb 5, 2010)

Does for a example a netgain warp 11 engine support regen braking? And what about a reverse?


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## mizlplix (May 1, 2011)

*Car:* Start with something you REALLY like. To make do with something you are not absolutely fond of is the start of failure.

*Weight:* Put it on a diet. Severe.(I really mean severe) You would be suprised with what a normal car can do without.

*Gearing: * An AC50 can use a FORD 8.8" axle, which is strong, but lighter than a 9" and use 6:14-1 gears. With a 30" tall tire at 6,500 RPM, you have 90 MPH.

*Batteries:* Lithiums for sure.

*Tires:* skinny, rock hard 

*Acceleration: *Here is your problem. 0-60 in 8 seconds aint gonna happen. unless you double the price and quality of all components.

*PLAN 2: * 
Get a VW based kit car. strip it down. Lithium it up to the max voltage-300+, Use VW bus 4.88 ring and pinion with a close ratio 3 & 4th gear set. Use a clutch, transmission and short tires. 


*Plan 3:* Most expensive.....LOL

Car: a sports car type car kit. 

Power: 300 volt + system. Lithiums.

Motor: 4 wheel type motors. (Good luck with that.)

Dont mind me, I'm just dreaming...Miz


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## Woodsmith (Jun 5, 2008)

Anman said:


> Does for a example a netgain warp 11 engine support regen braking? And what about a reverse?


The Warp11 is a DC series wound motor. It is complicated to get regen and not worth while. Unless you are planning on driving up and down a lot of hills there is little benefit to be gained for the cost. Many people happily run DC without any regen.

For reverse there are the options of using a conventional gearbox giving you a number of forward gears and a reverse. If you are still aiming at a direct drive then you have two options.

The Nova Racing revese gearbox as used on the Triking.

Reversing contactors, two DPDT contactors wired to reverse the field connections relative to the armature connections on a DC motor. These need to big enough to handle the current that will be flowing through the motor. They should not need to switch under load and so contact wear is not an issue.

There is a third way which is to make a manual reversing switch that does the same job as the reversing contactors but that is a potentially unreliable method, depending on your machining and making skills.


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## Anman (Feb 5, 2010)

Has anyone had contact with EVE about their AC engines? They look ok, but there is no data about for example the AC50. 
http://shop.electro-vehicles.eu/shop/browse.asp?cat=1101&path=1100,1101&tipoprod=AC_Induction_Motors


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## Anman (Feb 5, 2010)

And what about these engines, they look pretty good?
bldc


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## Qer (May 7, 2008)

Anman said:


> I thought i needed an AC motor for direct drive but apparently some of the larger DC motors can do eactly the same for lower price.


No, you need raw power to be able to do direct drive. It doesn't matter if the power comes from DC, AC, BLDC, hamsters in a hamster wheel or whatever, if you go direct drive with a puny motor you'll feel very pathetic when grandma shuffles past you with her permobil at the red lights. Going AC won't automatically turn your car into a Batmobile and the AC-50 is, for example, specified giving a peak power of whopping 50 Hp at 3000 RPM. That won't exactly peel off the paint of the car, especially not if it's direct drive...



Anman said:


> Because they usually run at lower voltages less bateries are required therefore reducing weight and cost.


Less, yes, but not necessarily lighter. What you need to power your car is Watts and what will give you your range is Watt hours. If you decrease the Voltage you'll have to increase the Amps and you'll pretty much end up with the same pack weight just that you will have fewer but bigger cells.



Anman said:


> But DC do have some drawbacks right?


Everything has drawbacks. Well, except Ben & Jerry's ice cream. Still haven't found any drawbacks with those, as long as you stay clear of the cherry flavoured sort. I hate cherry flavour!



Anman said:


> They are heavier,


Are they? A WarP 9 seems to weight about the same as a AC-50.



Anman said:


> require more amps


Because they usually run at lower voltages, yep. See above.



Anman said:


> they cannot spin without load


...huh?



Anman said:


> when something fails they donot stop


So far we haven't had a runaway incident with a Soliton. In fact, all those Solitons that have been tortured until blowing up has died off, not on. But POTENTIALLY a DC-controller can fail on, yes, that's why the Solitons come with built in contactors that can break full current... 



Anman said:


> they dont have regen.


Do you live in an area where you actually can benefit for it enough to be worth the extra cost?



Anman said:


> And I really like liquid cooling because more heat can be dissipated and overheating is less likely, or am i being to worried?


Yes and no. If you drive with a heavy right foot you can melt a DC-motor to scrap, true, but you can melt an AC-motor as well, provided you torture it enough. The water cooling only cools the stator, not the rotor, so even though the water cooling has it's advantages it's definitely not a 100% guarantee against overheating.

I think the main reason we don't see any mentions of melted AC-motors in the forum is because there aren't any high power AC-inverters available for DIYers. It's not very different from that it's rather uncommon for a Curtis 1231C-controller to break motors; it just doesn't have the necessary power to do it. I think it's at least theoretically possible though, but it would mean a very long and deliberate slow torture of the motor at constant full current (probably at so low RPM that the built in fan does a crappy job cooling the motor) until it breaks (we're probably talking hours...).

Why we do see people blowing up DC-motors is simply because there's too powerful controllers (Zilla, Soliton, WarpDrive) which makes it possible to push the DC-motors way out of the safe area and into the "warrant void" terrain where fractions of a second might be the difference between being able to get home again or being stranded at the side of the road.

As far as I know this situation is unique for DC-motors. The advantage is that you can get an awful lot of power for relatively little money. The disadvantage is ... well, *Boom!* 



gsmith191145 said:


> DC direct coupled motors will limit your top end speed. Do more research on the transwarp 11.
> 
> To gear the rear end to get to 100mph with the transwarp you will lose all your low end torque. high gears means slow as a slug on the take off.
> 
> This is why transmissions are used for the different gear ratios.


This is in no way different from any other motor technology. All motors will have a maximum torque and peak power and in a direct drive situations no motor will be able to perform it's best since it will be running in a so wide power band that it can't practically cover the whole RPM-scale without compromises.

My advice would be to use an ordinary gear box unless you're aiming at a no compromise drag racing car. Having a gear box makes things a lot simpler, no matter what motor you choose...


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## Anman (Feb 5, 2010)

I would really hate it if i needed to use an entire gearbox. I am looking at some aftermarket gearboxes with maybe two different ratios has that been done before?

thanks


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## bruceme (Dec 10, 2008)

I'm considering making my own monoTracer from the ground up as well. What I need here in the midwest is a vehicle that can drive on the highway with range. Which means aircraft like aerodynamic efficiency.

http://onlocation.consumerreports.org/xprize/x_tracer_e_tracer.html

- cro-moly steal tubing frame, molded fiberglass body, tip-up bubble canopy. (200lbs)
- instead of outriggers, use adjustable pneumatically suspension that lowers the vehicle onto rollers for stability when parked, rolling slowly or backing up.
- 15kwh 120-160v of LifePO4 battery (500lbs)
- 27kw AC hub motor in the rear wheel (200lbs)
- Seats two, but not in a tighter torso to back tandem seat arrangement
- rough target weight of 1000lbs empty (xTracer is 1200 with a lot of amenities and batteries) ... heavy for a bike, light for a car
- Rough perf target: 100wh/[email protected] 150mi @ 50mph range, 100mi @ 70mph top speed

The performance won't be earth shattering and certainly the mono tracer is far superior, but I'd like to keep this build under 15k. I've also built two homebuilt aircraft and converted an EV.


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## Anman (Feb 5, 2010)

Ok, there are a lot of possibilities to consider. I have been dreaming about the following, and am currious about your reactions to the following.
Key in performance for this type if vehicle is weight. Less is more in this case. What if i used this motor. It only weighs about 12 kg's. And because of the low weight less ah batteries can be used to give reasonable range. 200 of these batteries would give 330 V and about 40 Ah. They would weight about 100 kg. Therefore the total weight of the batteries and motor would be only 112 kg. Allowing another 90 kg for the controller(7 kgs), bms and cables would lead to a power pack under 200 kg. Therefore it should be possible to keep the total vehicle weight under 400kg(880 lbs)!
A cheaper alternative might be using 100 of these batteries. Which would increase the weight by about 120 kgs.


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## Anman (Feb 5, 2010)

Ok, so i thought about it some more and i decided it is indeed better to go the tried route of using a warp 9 engine. However I am still stuck on using direct drive, but with this low weight it shouldnt be a problem. However I am a bit stuck about the controllers. As far is i see it there are 3 choices a zilla, a soliton or the netgain controller. What are the pros and cons for each controller?

Thanks


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## gsmith191145 (May 1, 2011)

Anman said:


> Ok, so i thought about it some more and i decided it is indeed better to go the tried route of using a warp 9 engine. However I am still stuck on using direct drive, but with this low weight it shouldnt be a problem. However I am a bit stuck about the controllers. As far is i see it there are 3 choices a zilla, a soliton or the netgain controller. What are the pros and cons for each controller?
> 
> Thanks


There is a thread that is on going thread located here [URL="http://www.diyelectriccar.com/forums/showthread.php/best-controller-and-whyi-62972.html"/URL]


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## Duncan (Dec 8, 2008)

Hi Anman

I have an OpenRevolt controller - 500 amps 150v and $600

I am using 88 off 16Ah Headways - ~ $21 each (less in quantity)

10C continuous (48Kw) - 15C burst (72Kw) 
44Kg

But my car is a bit heavily built - I don't think I can get below 500Kg


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## welder4u (Nov 30, 2010)

Here's a kit car link. They have some good deals at times.

http://www.kitcars.com/


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## Anman (Feb 5, 2010)

Ok, i have taken a look at things and am slowly converging in on using a warp 9 as it is the most common route to go. In combination with the netgain controller. I haven't decided on batteries yet. Lighter is ofcourse better but money is an issue. Maybe a pack of headways or use some 40 aH calb batteries?

One idea is still a bit stuck in my head. Maybe you can make it go away. What if i used two agni 95r's. Each directly attached to one rear way by a belt drive and a suitable reduction gear. If i control these the right way i could end up with an electrical diff, therefore removing weight of an axle and differential. Besides 2 agni's will weight half of a warp 9. So I gain more weight. What are your thoughts about this ?


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## Anman (Feb 5, 2010)

Ok dual agni's might not be a sensible way to go.

Looking at the kostov 9" 220V, it seems cheaper than the warp9 but can spin at higher rpm's. What is the catch?


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