# Planning an EV conversion - 1992 Grand Am GT



## JoshInWV (Oct 8, 2010)

Greetings folks, 

I'm a little new here, so forgive me if I post something .. dumb. I have a 1992 Grand Am that I am going to try to convert into a 100% complete EV. I bought the car in 1998 (it was my first car :3) In 2003 I decided that I wanted to change it's color, so I changed the color from the ugly GM teal to Lemon Ice Yellow. After which I converted the car into a drag racer (yes a uni-body drag racer)

I am an ASE certified mechanic and I have a degree in Computer Engineering (which is 1/2 Electrical Engineering and half computer programming - it makes creating new hardware and developing firmware fun). Realistically, I would like to get a 150 mile range out of the charge. I would be fine with about 75 (that would get me to and from work with about 14 miles to spare).

My whole concept is that I want to do it right the first time so I don't have to do it again. Half a**ing something is just asking for trouble, especially when dealing with electricity.

I actually stumbled upon a site called http://www.electric-cars-are-for-girls.com quite a while ago, and I decided to make the transition over to the EV side of things. Heck I can build full blown dragster engines, why not try my hand in something totally new? I'm not afraid to get dirty, and I'm not afraid to machine or modify certain things if need be.

I'm definitely looking at an AC system over a DC system. I like the idea of regenerative braking and reclaiming power back into the batteries from the wheels. I'm not sure exactly which AC motor I'd use though. I was actually looking at a BRUSA 8-24-10 motor pair for the front end (one per wheel), but that is a steep investment especially for two of them.

I do like the batteries that the guy over at Metric Mind used for his setup. They are KONAM batteries, but other than that, I am still researching things to use. I think the first thing that I really should do is to make my hood and trunk lid out of fiberglass to further reduce some weight. The nice part is that there is ZERO extras on this car. It's an empty shell. No dash nothing. It's already been gutted for weight reduction. I can put a furniture dolly under the front and move the car around, it's that light.

Any ideas, parts info, insight would be most appreciated. Any questions of me will always be answered.

Thanks in advance

- Josh


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## The Toecutter (May 30, 2010)

What kind of budget are you willing to set aside for it?

Is performance/acceleration important to you, and what is the slowest performance you are willing to settle with?

There aren't any 'affordable' AC solutions on the market that exceed about 70 horsepower, and will do so at an RPM of 3000 or less before their power drops off. If you want to haul ass, you're likely stuck with a DC setup(unless you know how to design a control system for the AC motor, which is no small feat).

A lightened Grand Am still leaves a lot to be desired with regard to aerodynamics; with LRR tires, with a manual transmission, this is highly likely to be a conversion that requires around 250 Wh/mile at highway speeds. Are you prepared to buy a 35-40 kWh LiFePO4 battery pack to get 150 miles range?


If money is a concern, I'd recommend choosing a donor that is more aerodynamic with a smaller frontal area. Otherwise, you're going to have to pay up if you're intent on using this donor.


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## JoshInWV (Oct 8, 2010)

The Toecutter said:


> What kind of budget are you willing to set aside for it?
> 
> Is performance/acceleration important to you, and what is the slowest performance you are willing to settle with?
> 
> ...



Thanks for the reply TC,

Well I'd "like" normal acceleration, but who in life get's exactly what they want anyways? I currently drive an F-250 with a V10 Triton, so I am used to very slow starts and long periods of getting to the correct speed. To me that is not an issue. The bigger issue is that I live in West Virginia near Pittsburgh, we have hills and they only get bigger, so my concern is how feasible is something like this around here? So to answer your question, no, performance is not that important to me, but efficiency is.

A budget? I don't really know, I don't want to spend over 20K on the whole car. I have to purchase other things in that as well.

Yes I am prepared to purchase a 35-40 KWh battery to sustain it.

So now for some EV N00b questions:

I found this that might be a good choice for a battery setup: http://www.kokam.com/product/product_pdf/high_power/PL-301_SLPB60460330H_70Ah_Grade.pdf

Can you do a direct drive straight off of the motor to run the wheels minus a transmission? Also what are the best DC and AC motors for this?


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## rillip3 (Jun 19, 2009)

JoshInWV said:


> Thanks for the reply TC,
> 
> Well I'd "like" normal acceleration, but who in life get's exactly what they want anyways? I currently drive an F-250 with a V10 Triton, so I am used to very slow starts and long periods of getting to the correct speed. To me that is not an issue. The bigger issue is that I live in West Virginia near Pittsburgh, we have hills and they only get bigger, so my concern is how feasible is something like this around here? So to answer your question, no, performance is not that important to me, but efficiency is.
> 
> ...


For the situation you describe, direct drive is a bad idea. With a fixed gear you're unable to adjust the RPMs and keep the motor in a good power band. This is particularly important with AC, which has lower starting torque. Also, if you get the direct drive to the point it can climb hills, you'll have to ride your brake the whole way down to keep from over-spinning the motor.

"Best" is a judgment call, but you'll definitely want a largish DC motor, if you decide to go DC. I wouldn't look smaller than 9". If you want regen, you can do a SepEx motor, but I'm not familiar with the pros and cons of this motor construction. Maybe Pete can hop in and clarify, I think he's using one.

For AC, the best one I know of that's in a good price point is the AC 50. There are a few others who are using or building with those right now. It's one of the few AC motors that's readily accessible through retailers to non OEMs.


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## JoshInWV (Oct 8, 2010)

rillip3 said:


> For the situation you describe, direct drive is a bad idea. With a fixed gear you're unable to adjust the RPMs and keep the motor in a good power band. This is particularly important with AC, which has lower starting torque. Also, if you get the direct drive to the point it can climb hills, you'll have to ride your brake the whole way down to keep from over-spinning the motor.
> 
> "Best" is a judgment call, but you'll definitely want a largish DC motor, if you decide to go DC. I wouldn't look smaller than 9". If you want regen, you can do a SepEx motor, but I'm not familiar with the pros and cons of this motor construction. Maybe Pete can hop in and clarify, I think he's using one.
> 
> For AC, the best one I know of that's in a good price point is the AC 50. There are a few others who are using or building with those right now. It's one of the few AC motors that's readily accessible through retailers to non OEMs.


Can the AC-50 be over driven to say 360V? I see the operating voltage is 72/[email protected], am I able to go with a higher voltage overall? I'd like to get one rated slightly higher in HP rating. I followed a link on here to someplace that had converted a BMW to an EV that had what looked to be a huge AC motor. I'll see if I can find the link again. It "looked" like a siemens motor.


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## JRP3 (Mar 7, 2008)

The AC50 cannot go higher than about 120V, controller shuts down at about 130V.

100KW AC induction setup:
http://currentevtech.com/Drive-Systems/100-KW-AC-Drive-System-c45/

80KW BLDC setup:
http://currentevtech.com/Drive-Syst...lers/80KW-BLDC-Motor-and-Controller-p167.html

120KW BLDC setup (very heavy):
http://currentevtech.com/Drive-Syst...ers/120KW-BLDC-Motor-and-Controller-p168.html

I think the 80KW BLDC would give you decent performance at a good price point.


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## JRP3 (Mar 7, 2008)

I would also suggest that Kokams are not a good choice for a basic EV conversion. Look at larger prismatics such as Thundersky or CALB, I'd pick CALB for the higher C rating, and don't try for 150 mile range either if you can easily live with less and are on a budget.


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## The Toecutter (May 30, 2010)

JoshInWV said:


> Thanks for the reply TC,
> 
> Well I'd "like" normal acceleration, but who in life get's exactly what they want anyways? I currently drive an F-250 with a V10 Triton, so I am used to very slow starts and long periods of getting to the correct speed. To me that is not an issue. The bigger issue is that I live in West Virginia near Pittsburgh, we have hills and they only get bigger, so my concern is how feasible is something like this around here? So to answer your question, no, performance is not that important to me, but efficiency is.
> 
> ...


Your budget should get you close to your goal then. If you purchase a Belktronix integrated system(144V/500A controller with DC-DC, LiFePO4 charger, BMS), an ADC 9" motor, and a pack of 40 Thundersky 260AH batteries in series(I assume you can get them for less than $1.50/AH like their smaller 100AH and 160AH models, but I may be wrong on this), plus the cost of all of your wiring, battery boxes, adaptor plate, coupler, ect., you could meet your goals. I don't know how much your car currently weighs, but if the finished conversion weight is 2800 lbs, you would have a 0-60 mph time of around 14 seconds or so, but your 0-30 time would embarrass an 'average' car and it would smoke its tires with ease due to the low end torque(depending on how the ramp function of the controller is set, you could have 100 lb-ft at near 0 rpm).

Of course, there are all sorts of ways to go about this. If you buy used components, you may be able to have a much faster setup for cheaper than the one proposed above(especially if you come across a used auburn Kodiac or DCP Raptor controller).

The Kokam batteries are probably expensive; I'd get an inquiry before seriously considering them. As a general rule of thumb, the Thunderskys more widely available for EV use are $400/kWh and under.

If you want direct drive, an AC setup is basically needed, unless you fancy an expensive DC motor and control system that is oversized for your car; you would need at least a Netgain 11" and a controller that could output 1000A or more, and with a hilly environment, there is still the prospect of running your motor at too high a current for too long. A twin Netgain 9" setup with a controller that could shift between series and parallel could meet this requirement well, but it will cost a lot. 

There aren't any cheaply available off the shelf AC setups with horsepower comparable to the ICE you will be removing; the AC50 is about as close as you will get. AC is very much welcome on hills because it can do regenerative braking, however. If you don't mind a car that will do 0-60 mph in ~17 seconds or worse, the AC50 is the way to go(it's plenty usable; when the turbo stopped working in my Mercedes 300SDL, its 0-60 time increased to 19-20 seconds, but the car was still very drivable).

I'd recommend keeping the transmission(assuming it is a manual transmission), but that's just my preference.


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## JoshInWV (Oct 8, 2010)

The Toecutter said:


> Your budget should get you close to your goal then. If you purchase a Belktronix integrated system(144V/500A controller with DC-DC, LiFePO4 charger, BMS), an ADC 9" motor, and a pack of 40 Thundersky 260AH batteries in series(I assume you can get them for less than $1.50/AH like their smaller 100AH and 160AH models, but I may be wrong on this), plus the cost of all of your wiring, battery boxes, adaptor plate, coupler, ect., you could meet your goals. I don't know how much your car currently weighs, but if the finished conversion weight is 2800 lbs, you would have a 0-60 mph time of around 14 seconds or so, but your 0-30 time would embarrass an 'average' car and it would smoke its tires with ease due to the low end torque(depending on how the ramp function of the controller is set, you could have 100 lb-ft at near 0 rpm).
> 
> Of course, there are all sorts of ways to go about this. If you buy used components, you may be able to have a much faster setup for cheaper than the one proposed above(especially if you come across a used auburn Kodiac or DCP Raptor controller).
> 
> ...


OK for starters right now the barebones chassis weighs Approx 1150 pounds. So by the time I put the doors back on (+ 80lbs each), and the bumper covers, fenders, trunk lid, and hood I'm looking at about < 1500 in total car weight. I'll also have to put on the front suspension. I might have a total of about 1K pounds to play with in total weight. I do need to change some things on the chassis by removing and changing the firewall, the giant hump where the center console was, the rear seat and the trunk space as well. Minor welding and fabricating aside, I am planning on centering the batteries to distribute the weight better. Smoking a car off the line? Maybe, but not high on the priority list. Maybe 10 years ago when I ran with a turbo charged Quad 4 High Output W41 in my car, but now? Not so much.

You mentioned the 11" Netgain motor in DC and running it with too much current? Does that still apply with an AC motor setup? I'm REALLY thinking that I want an AC setup, despite everyone pushing the DC issue. Regen braking is a huge plus for this project. I work about 30-45 minutes away from home depending on traffic. It's mostly flat except for a 1/2 mile hill in the beginning - 10% grade.

With the batteries, I'm looking at a power vs weight ratio to see what is optimal. If I had 40 of the ThunderSky 260AH batteries that is ~735 pounds of weight added just in batteries alone. If I wanted 2 banks running that and connected them in parallel, now I've added a total of 1400 pounds of batteries to the vehicle. 

I'm willing to go with used equipment for now. This is my "tinker" driver, and not even remotely going to be a daily driver for at least a few years. I can bring the range down to 100 miles, but I really don't want much less than that. To my line of thought then it becomes a novelty versus a realistic thing.

The reason I wanted direct drive is I have all of the components for the FWD system. I can have two couplers machined to connect the CV shaft directly to the motors and use the stock CV shafts. I have the old trans (manual) but if I can do a twin AC motor direct drive system, I might be happier. I'm just not quite sure yet. I think I need more info between the two systems to make a well thought through final decision.


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## The Toecutter (May 30, 2010)

JoshInWV said:


> OK for starters right now the barebones chassis weighs Approx 1150 pounds. So by the time I put the doors back on (+ 80lbs each), and the bumper covers, fenders, trunk lid, and hood I'm looking at about < 1500 in total car weight. I'll also have to put on the front suspension. I might have a total of about 1K pounds to play with in total weight.


This is a very good starting point. A pack of LiFePO4 of around 750 lbs would give you about 150 miles range at highway speeds of 60-70 mph. You could fit that without getting too heavy. Maybe my 2800 lbs estimate wasn't far off the mark assuming a 700-750 lbs pack.



> I do need to change some things on the chassis by removing and changing the firewall, the giant hump where the center console was, the rear seat and the trunk space as well. Minor welding and fabricating aside, I am planning on centering the batteries to distribute the weight better. Smoking a car off the line? Maybe, but not high on the priority list. Maybe 10 years ago when I ran with a turbo charged Quad 4 High Output W41 in my car, but now? Not so much.
> 
> You mentioned the 11" Netgain motor in DC and running it with too much current? Does that still apply with an AC motor setup? I'm REALLY thinking that I want an AC setup, despite everyone pushing the DC issue. Regen braking is a huge plus for this project. I work about 30-45 minutes away from home depending on traffic. It's mostly flat except for a 1/2 mile hill in the beginning - 10% grade.


If performance is not a priority, a liquid cooled AC system would be best if you are 100% intent on direct drive. Liquid cooling is important for this, as it increases your maximum continuous current/torque to two or three times more than an air-cooled DC setup.

But the problem is, there are few AC solutions available, almost none with decent power. Metric Mind does have a few 100+ kW liquid cooled solutions, but they don't seem to provide anything in the way of customer support, at least according to others' reports I have read about them. If you're willing to explore new territory and spend some coin(> $8000 for the drive system), and have a few highly significant issues to troubleshoot, an MES-DEA system from Metric Mind may serve your needs wonderfully.

Otherwise, the only affordable off the shelf AC solutions that are relatively easy to install are also low power and air cooled(although there are discussion topics on this forum that describe how to add liquid cooling to them).

If the hill is only 1/2 mile at 10% grade, a Netgain 11" will probably suit your needs. You won't be able to do regen with it, but you will be able to get fantastic performance with it when matching it to a Soliton 1 or Zilla controller. Like, "blow the doors off of $35000 sports cars" performance... and you'll spend about the same as a 60 horsepower AC setup.



> With the batteries, I'm looking at a power vs weight ratio to see what is optimal. If I had 40 of the ThunderSky 260AH batteries that is ~735 pounds of weight added just in batteries alone. If I wanted 2 banks running that and connected them in parallel, now I've added a total of 1400 pounds of batteries to the vehicle.


One 735 pound bank of Thunderskys would get you that 150 miles range. You probably wouldn't need, and wouldn't want to pay for, twice that pack size. That 735 lb bank is already going to cost a pretty penny(~$12k). The LiFePO4 battery will cost more than all of your other components combined.



> I'm willing to go with used equipment for now. This is my "tinker" driver, and not even remotely going to be a daily driver for at least a few years. I can bring the range down to 100 miles, but I really don't want much less than that. To my line of thought then it becomes a novelty versus a realistic thing.


If you're willing to drop range to about 100 miles, you've just shaved $4000 off of your pack cost and 240 lbs off of your pack weight. Be sure to include enough 'wiggle room' so that you're not discharging your pack more than 80%, unless you're intent on having a BMS.



> The reason I wanted direct drive is I have all of the components for the FWD system. I can have two couplers machined to connect the CV shaft directly to the motors and use the stock CV shafts. I have the old trans (manual) but if I can do a twin AC motor direct drive system, I might be happier. I'm just not quite sure yet. I think I need more info between the two systems to make a well thought through final decision.


There is a Fiero on the evalbum with a twin AC setup.

http://www.evalbum.com/1396

If your machine shop skills are capable, have at it! Twin AC50s would suit this purpose nicely...

http://www.evparts.com/products/str...8-to-96-volt-street-vehicle-motors/mt5615.htm

Twin motors of a smaller size/less expensive variety might also work well. Twin motors go nicely for direct drive systems. t's been done before, and works.

If you want to accelerate like an 'average' car(0-60 mph ~10 seconds), and if your conversion weighs 2800 lbs(including driver/luggage), you're going to need about 100 peak horsepower from the motor(s). A single Netgain 9" motor with a 156V/600A controller retaining a transmission could also do this for much cheaper, but without regen, and it's not as elegant a solution.


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## JRP3 (Mar 7, 2008)

Here's a liquid cooled BLDC motor that might work for you:
http://currentevtech.com/Drive-Syst...lers/80KW-BLDC-Motor-and-Controller-p167.html


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## JoshInWV (Oct 8, 2010)

The Toecutter said:


> Stuff...


Funny, now you've REALLY got my attention. ~240 lbs less weight? From drag racing, every 100 lbs you lightened, you shaved .1s from your 1/4 mile time and changed your top out speed. I assume that in EV's it's like that too, where every bit you lighten, you don't use as much charge with the motors pushing. Oh yeah and saving the $4K is a large plus too.... . Not having a BMS is not an option.

I'm sitting here thinking.... If AC is better efficiency, and for regen braking, BUT the car still has to be plugged in at the end of the day.... at this point.. why bother with it? If I can get 100 Mi / charge out of it, I can plug it in at night during off peak hours and be happy. I live in West Virginia, power is cheap here even during peak hours. Still way cheaper than gas.

With the glycol cooled DC motor that JRP3 linked me to... that's ~180 ft lb of torque per motor * 2 motors. That being said. I can get 2 of the BLDC motors and controllers for the price of MM's single Siemens motor. They are lighter, and looks like they run on lower voltage. It appears to have full brake regen as well?!?! The only two issues I can see are: No mounting plate and no end spline on the shaft. Maybe I'll contact them and see what exactly it has.

Now for the ultimate dumb questions here. With 2 motors, a battery pack, a BMS, and a good charger, what else am I going to need to make this work? 

I'll have to post some pictures of the car as is and as things progress.


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## JoshInWV (Oct 8, 2010)

I know what else I wanted to ask. With 2 motors (DC or AC) will that drain my battery pack twice as fast? And how does a BMS work?


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## JRP3 (Mar 7, 2008)

Yes BLDC motors give you regen. You normally don't want a spline on the motor shaft, you use a taper lock coupler to lock onto the motor shaft and the other end is a spline that fits over the transmission shaft.
Two motors won't drain the pack faster unless you use more power than one motor would put out. So only when you are really getting on it will it draw more than one motor, of course you will be carrying around the extra weight of a second motor which will take more power to move. There may be some slight efficiency losses between two systems versus one.
A BMS has a few functions, some are more basic than others. Basic units monitor cell voltage and can send a signal on a single low cell voltage and high cell voltage. You can use these signals to throttle back the controller on a low cell warning and to shut off the charger on a high cell warning. BMS can also have shunting, which bleeds off charge at a certain level when cells get too high and allows other cell voltage to rise to the same level. This is called top balancing. The only draw back is that when you top balance you end up unbalancing the bottom of the pack. You also don't get any more capacity than your smallest capacity cell.


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## The Toecutter (May 30, 2010)

JoshInWV said:


> Now for the ultimate dumb questions here. With 2 motors, a battery pack, a BMS, and a good charger, what else am I going to need to make this work?


Three things:

1) Money
2) Time
3) Patience

In all seriousness, your ancillary components will include your battery/motor wiring, your low voltage system(for lights, radio, ect. In a series DC conversion, usually done with a DC-DC converter and a small 12V battery as a buffer), motor mount(s), motor coupler, battery racks/boxes, tools... Expect to add about $2-3k to your cost on top of the major components you have listed. This also assumes you make no mistakes while doing the conversion, as those can get expensive.

A good, practical book should be in your library; it's called "Convert It" by Mike Brown. Read it.


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## JoshInWV (Oct 8, 2010)

Where would I get a taper lock coupler at? Does anyone have a picture of one I could take a look at?


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## resago (Sep 28, 2010)

when doing weight calculations, don't forget that gas weighs 6lbs/Gal + the tank that you drop weighs 30-50 lbs.

so if you drop a 12 gallon tank, you're saving 100 - 120 lbs.


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## JRP3 (Mar 7, 2008)

JoshInWV said:


> Where would I get a taper lock coupler at? Does anyone have a picture of one I could take a look at?


Here's an example of what I used for a clutchless setup, had the spline from the clutch pressed and welded into a taperlock hub:


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## JoshInWV (Oct 8, 2010)

JRP3 said:


> Here's an example of what I used for a clutchless setup, had the spline from the clutch pressed and welded into a taperlock hub:


I'll have to see where I can get the internal specs for the CV shafts that I have. They have a snap ring on the inner shaft to "lock" them into the trans. JRP, where did you get the taperlocks at? Also I sent an email out for the 80-kW/h BLDC motor for the shaft and key specs. I'll see if he get's back to me. LOT's of conversions and math to do 

BTW, here are some pictures of the starting point.....


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## JRP3 (Mar 7, 2008)

The guy who built the coupler for me came up with the taperlock, don't know where he got it and he's not in business anymore. He may have machined it himself


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## PatricioIN (Jun 13, 2008)

fyi... grand am 5spd....

http://indianapolis.craigslist.org/cto/2022691848.html


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