# Fiero based conversion/ rebuild underway



## CFreeman54 (Jan 14, 2009)

Hello. I'm about halfway through Fiero based conversion/rebuild here in Columbus, Ohio and thought it was about time to join the DIY forums and introduce myself. 

The car is being rebuilt around a WarP 11 motor and Raptor 1200 amp controller, with considerable body lightening and body work. I am working on a hybrid Li / Pb AGM battery system which hopefully will provide 30-40 KWH (depending on how thick my wallet is). The intent is to maximize range while minimizing the cost of the battery system with a slight weight penalty over an all Li Ion pack. 

The project is coming along pretty well thus far, other than for the long wait on getting my transmission/motor adaptor/coupler from Electro Automotive, which I am hoping they will ship to me this week. 

I would love to hear from anyone else working on or who has converted a Pontiac Fiero, or a similar sports car (Toyota MR2, etc.).


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## HighTech (Nov 12, 2008)

Welcome to the forum! Glad we have another Ev'er ready to pass another gas station. Congrats on your build and I hope we see pics soon as well.


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## JRP3 (Mar 7, 2008)

Hi there. I'm doing a Fiero conversion as well, a 1988, using the AC31 motor from HPG. I got my adapter from www.ev-solutions.net and they are working on a coupler for me using my clutch spline. I'll be using a 108 volt 100ah TS lithium pack, prices are getting so low I don't think it's worth bothering with lead any more in the long term. I'm interested in what body mods you're doing to lighten the vehicle.


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## CFreeman54 (Jan 14, 2009)

Hello, HighTech and JRP3. Thanks for the welcome. I will try to get some photos posted soon. 

JRP3, I think you made a wise choice on the tranny adapter. I went with ElectroAutomotive's adapter because they appeared to have the experience (and a Fiero pattern), but they botched the first one they sent me (profile of plate and coupler both wrong), and after telling them about the problem a month ago I am still waiting for the replacement. They have now had my money for 6 months and I'm still waiting for my adapter/coupler. They said they would ship it last week but at this point I'll be happy if it ships this week (or even next). 

Are you buying direct from thunder sky? You are right about going with Lithium in the long run, but for a 40-50 KWH pack now, it is still some big bucks.....like as much as the rest of the rest of the rebuild, roller, motor, controller and all. I'd like to keep the battery pack under $10,000. The hybrid pack allows me to test the design with only partial cash layout first on AGMs, then add KWH's later....and end up with 100-150 mile range. 

I plan to run at 156V. I wanted to run higher voltage than that, but Cafe Electric was already quasi-out of business and other than the Zilla, the Raptor 1200 was the highest voltage, highest amp controller I could find, and it only takes up to 156V. Oh well, I think pushing my WarP above 170V or so without modifying the motor probably isn't a good idea anyway.

On body mods, the first thing I decided was that the rear deck is heavy (about 40 lbs.),and the 90% drop off behind the rear glass is an aerodynamic nightmare. Vacuum big time. So I am fabricating a new rear clip with a hatchback sloped geometry. Made out of carbon fiber and with polycarbonate rear "glass", I will save 30-50 pounds. The hood also, is unecessarily heavy (about 45 lbs.) and can be replaced with a carbon fiber hood for at least a 25-30 pound weight savings (the weight in a c-fiber hood is in the metal attachment plates/latches). The glass sunroof can be replaced with polycarbonate for a substantial weight savings: 1/4" glass weighs about 3.2 lbs. per sq. ft. The pop-up headlights create aero drag and the motors and pop-up assembly adds several pounds a piece. I'm replacing the rear trunk compartment sheet metal with a deeper, composite battery/trunk compartment; this saves about 10 pounds. My 16 lb. OEM flywheel gets replaced with an aluminum one that weighs about half that. Replacing OEM seats with racing seats saves about 20 lbs. per seat (OEMs are almost 40 per). Rotors and wheels may be replaced with Al/Mg alloy if my pockets are deep enough, that saves at least 10 lbs. per wheel/brake. 

The battery boxes are composite set in Aluminum angle frames, epoxy coated to prevent galvanic corrosion....about 1/2 the weight of steel battery racks and uncorrodable. I'm thinking about the side glass and doors. There is possibility for weight savings there but also some complications. 

Anyway, I figure I have saved almost 200 pounds above what you save just by pulling the ICE stuff. Somewhere I read the 2.8L V6 & acoutrements weighed about 350 lbs. , so I figure my car will weigh about 2000 lbs. pre battery pack. If I can limit my battery pack to 800 lbs. I am only 100 pounds over stock Fiero weight when its all said and done. That should be easy to achieve using Lithium.


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## JRP3 (Mar 7, 2008)

CFreeman54 said:


> JRP3, I think you made a wise choice on the tranny adapter. I went with ElectroAutomotive's adapter because they appeared to have the experience (and a Fiero pattern), but they botched the first one they sent me (profile of plate and coupler both wrong), and after telling them about the problem a month ago I am still waiting for the replacement. They have now had my money for 6 months and I'm still waiting for my adapter/coupler. They said they would ship it last week but at this point I'll be happy if it ships this week (or even next).


 Wow, that's too bad, ElectroAuto has been doing this for a while I would have thought they'd know what they are doing by now. Craig at ev-solutions has been working with me because he wasn't sure his S10 adapter would fit the Fiero, so after I sent him a tracing of my transmission face he sent me one to check before charging me a cent! I had to shave just a little off the part right near the CV output shaft, and the lower holes for the starter/flywheel cover are different but they aren't structural so it doesn't matter. He's building a clutchless coupler for me from my clutch hub that I sent him, and still hasn't charged me anything. I fully expect to pay but it seems to be the opposite of your experience.


> Are you buying direct from thunder sky?


 Sort of, I'm getting in on the group buy through www.poweredbydc.com who's getting them from Thundersky. He's charging 1.10 per Ah plus shipping and whatever tariffs are involved.


> You are right about going with Lithium in the long run, but for a 40-50 KWH pack now, it is still some big bucks.....like as much as the rest of the rest of the rebuild, roller, motor, controller and all. I'd like to keep the battery pack under $10,000. The hybrid pack allows me to test the design with only partial cash layout first on AGMs, then add KWH's later....and end up with 100-150 mile range.
> 
> On body mods, the first thing I decided was that the rear deck is heavy (about 40 lbs.),and the 90% drop off behind the rear glass is an aerodynamic nightmare. Vacuum big time. So I am fabricating a new rear clip with a hatchback sloped geometry. Made out of carbon fiber and with polycarbonate rear "glass", I will save 30-50 pounds. The hood also, is unecessarily heavy (about 45 lbs.) and can be replaced with a carbon fiber hood for at least a 25-30 pound weight savings (the weight in a c-fiber hood is in the metal attachment plates/latches). The glass sunroof can be replaced with polycarbonate for a substantial weight savings: 1/4" glass weighs about 3.2 lbs. per sq. ft. The pop-up headlights create aero drag and the motors and pop-up assembly adds several pounds a piece. I'm replacing the rear trunk compartment sheet metal with a deeper, composite battery/trunk compartment; this saves about 10 pounds. My 16 lb. OEM flywheel gets replaced with an aluminum one that weighs about half that. Replacing OEM seats with racing seats saves about 20 lbs. per seat (OEMs are almost 40 per). Rotors and wheels may be replaced with Al/Mg alloy if my pockets are deep enough, that saves at least 10 lbs. per wheel/brake.
> 
> Anyway, I figure I have saved almost 200 pounds above what you save just by pulling the ICE stuff. Somewhere I read the 2.8L V6 & acoutrements weighed about 350 lbs. , so I figure my car will weigh about 2000 lbs. pre battery pack. If I can limit my battery pack to 800 lbs. I am only 100 pounds over stock Fiero weight when its all said and done. That should be easy to achieve using Lithium.


How much are you spending on carbon fiber and other body mods? Since the hood and trunk aren't structural you could use glass cloth instead of carbon and save some cash. While it's good to save weight I wonder if you'd be better off spending the same money on more lithium instead and skipping the lead batteries. You'll save more weight, plus unless you do a lot of stop and go driving the weight is less important than aerodynamics. Another thing, are you sure the chop back has poor aerodynamics? The reason I ask is that I've seen where pickup trucks with an uncovered bed created a "ball" of air in the bed which actually smoothed the air flowing over it. Just some thoughts.


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## CFreeman54 (Jan 14, 2009)

Yes, ElectroAuto has years of experience and from what I have read, good products, but they are SLOW!!!! It took about 10 weeks to get me the adapter the first time. It sat in the box for 2 months due to the feezing Dec.- Feb. cold, then when I could get out in the garage to hook it up, it didn't fit!!!!! It took ElectroAuto two weeks just to answer me what they were going to do about their mistake. I had to send them pictures of the gap between the adapter plate and the tranny bell housing and of the coupler too big to fit the flywheel before they finally agreed to do something about it. Then they said once they got it back they should be able to remachine it in a day or two and would ship it back to me 3 day express....that was more than two weeks ago they got it back.As far as I know it still hasn't shipped. 

They still haven't explained how or why they screwed up in the first place. I told them it was a Muncie M-17, 4 speed transmission that was attached to the "85 Fiero's 2.8L V6, and sent them tracings of the tranny housing, clutch, and flywheel. The adapter plate definitely did not match the tracing I sent! (sent twice actually, they lost the first set of tracings I sent. hmmmm....) And they claim they have a pattern for this transmission adapter...that is why I chose them! My bell housing looks just like the pics in the GM '85 Fiero Service Manual.....nothing odd about it. I don't get it.

Is this the same transmission and engine as yours? If E.A. doesn't send me the adapter soon I may end up in the market for another adapter manufacturer. It sounds like I should try EV-Solutions; It seems I should have bought from them in the first place. Live and learn. Anyway, I'm glad it is not a $10,000 conversion kit I am waiting on! It bothered me that E.A. wanted payment in advance. The other EV dealers I dealt with billed me when the order shipped. KTA & EV of America were great!

I probably will use one layer of fiberglass and one of carbon fiber on the hood & rear clip. I got a good deal on C-fiber, about $30 per yd. so for the hood & rear its only a couple hundred $. If I used only f.g. I would need at least one additional ply and it still wouldn't be as strong. By the time you pay for the extra epoxy to do another layer its not that different.

The weight matters for 0-60 time though; got to keep up with Tesla you know.  As for aero drag, the Fiero supposedly has a Cd= 0.35-0.37 (depending on rear wing - and whose data you trust) . Somewhere I saw wind tunnel modeling of it and the most significant turbulence was behind the rear glass. Pretty much laminar flow elsewhere until you got to the rear end. If you compare that modeling to a car with a "properly" sloped back, like a Porshe 911, you find the Porshe has laminar flow all the way down the back glass to the rear end....and a Cd= 0.28. The only major difference I can see is that big vortex behind the rear glass on the Fiero. Laminar flow is generally thought to promote low Cd. The effect you noted is not entirely unknown though; drag reducing riblets (on fighter jets and missiles) function by creating tiny vortices that reduce boundry layer interaction between air molecules and the surface, but they have to be fractions of a millimeter high to do this....larger and they produce the opposite effect.


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## DavidDymaxion (Dec 1, 2008)

This sounds like an awesome conversion! Two thumbs up on the weight reduction. I used to own a Fiero, and I still miss it.

The year the Fiero was out the EPA rated it as having the lowest highway horsepower requirements of all the cars in its database. Yep, this implies it had the best aerodynamics of any car you could buy that year. Even though I had the iron duke and just a 4 speed, my highway mileage was easily mid-30's, and would top 40 mpg if I kept the speeds down. Another bit of Fiero trivia I read is it is one of the few cars where the rear wing would both produce downforce and improve the aerodynamics (not sure if that was true for the smaller wing, bigger wing, or both). Google on "Kammback Aerodynamics", a sudden truncation is not necessarily as bad aerodynamically as you might think. It would be fun if you got the car running first, tested the stock configuration, and then compared it to a hatchback design.


CFreeman54 said:


> ... the 90% drop off behind the rear glass is an aerodynamic nightmare. Vacuum big time. ...


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## JRP3 (Mar 7, 2008)

CFreeman54 said:


> Is this the same transmission and engine as yours? If E.A. doesn't send me the adapter soon I may end up in the market for another adapter manufacturer. It sounds like I should try EV-Solutions; It seems I should have bought from them in the first place. Live and learn.


I've got the 4 cyl and the 5 speed, I think it's an Isuzu trans? I would think all the bolt patterns would be the same but I'm not sure. This is what my bolt pattern looks like:











> I probably will use one layer of fiberglass and one of carbon fiber on the hood & rear clip. I got a good deal on C-fiber, about $30 per yd. so for the hood & rear its only a couple hundred $.


That's another two 100ah cells 


> If I used only f.g. I would need at least one additional ply and it still wouldn't be as strong. By the time you pay for the extra epoxy to do another layer its not that different.


Well you could use polyester resin if you're not using carbon fiber and save even more, but if you've already got the cf you might as well use it.


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## CFreeman54 (Jan 14, 2009)

Thanks for the compliments DavidDymaxion. Yes, the Fiero Cd is not bad, and compared to the big heavy cars of its day, that had all the aerodynamic styling of a brick driving down the road, it was great, but it can still be improved. Fiero's Cd 0.35 compared to Porshe's Cd 0.28 is not so good, and wind tunnel models show a low pressure area behind the rear glass (fortunately, the glass is small). The idea of a Kammback is to truncate the ideal teardrop form at the boot end after the airflow has been "set" into laminar flow along the length of the car. It still causes some turbulence and a low pressure area behind the car, but is a good compromise between length, space, materials for the car and aerodynamic ideal.My hatchback will follow Kammback aero principles. 

JRP3, your tranny bell housing profile looks the same as mine....at least too similar to see a difference without looking at them side by side....except what are those two "brackets" (outlined in red) sticking out? Mine doesn't have that. 

The cost of another gallon of epoxy to layup an additional fiberglass layer makes it more like one additional 100 ah cell....if the cells only cost $100 a piece. I considered using Polyester resin, but it limits the type of foam you can lay up over (to the expensive kind). Also, I saw some data on tensile strength, modulus, elasticty, etc. , and the epoxy layups are significantly stronger than those done with polyester resin, with vinylester resin falling somewhere in between the two. Since I am using the same resin for the battery boxes, which has to hold 400-500 lbs. of batteries, strength matters. Since the car has no airbags, I would like the body to have some strength as well, so I went with epoxy.


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## JRP3 (Mar 7, 2008)

CFreeman54 said:


> JRP3, your tranny bell housing profile looks the same as mine....at least too similar to see a difference without looking at them side by side....except what are those two "brackets" (outlined in red) sticking out? Mine doesn't have that.


 Those brackets hold the shift cables, different transmissions use different brackets.


> The cost of another gallon of epoxy to layup an additional fiberglass layer makes it more like one additional 100 ah cell....if the cells only cost $100 a piece. I considered using Polyester resin, but it limits the type of foam you can lay up over (to the expensive kind). Also, I saw some data on tensile strength, modulus, elasticty, etc. , and the epoxy layups are significantly stronger than those done with polyester resin, with vinylester resin falling somewhere in between the two. Since I am using the same resin for the battery boxes, which has to hold 400-500 lbs. of batteries, strength matters. Since the car has no airbags, I would like the body to have some strength as well, so I went with epoxy.


You are correct in what you say about epoxy vs polyester etc. but as I understand it Fieros get their strength from the body subframe and did pretty well in crash tests. I don't think the construction of the hood and trunk lid will add much to it. Not that I'm trying to discourage you in anyway, I just hate to see you weighed down with lead, it's so 19th century


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## toddshotrods (Feb 10, 2009)

CFreeman54 said:


> ...The idea of a Kammback is to truncate the ideal teardrop form at the boot end after the airflow has been "set" into laminar flow along the length of the car. It still causes some turbulence and a low pressure area behind the car, but is a good compromise between length, space, materials for the car and aerodynamic ideal...


Isn't that the basic premise behind the Toyota Prius and Honda Insight styling? In profile, they look a little like truncated teadrops - at least much more so than a regular two or three box passenger car design.


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## JRP3 (Mar 7, 2008)

Yup, that's it.


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## Zemmo (Sep 13, 2007)

Hey guys, love what I am reading about here! Would like to see some progress of the Fiero if you have any pictures. 

One thing you haven't mentioned is a belly pan. They are something easily made and can be pretty light weight. It also adds some functionality of debree and water protection. You might also look at covering up any front openings like the turn signals, radiator, etc. I have made some plexi-glass turn signal covers for my car but I haven't installed them yet. I covered up the entire front radiator opening and have 1/2 of a belly pan installed on my car. Every little bit helps.

Again keep up the good work and keep us posted.


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## CFreeman54 (Jan 14, 2009)

JRP3, yes, I know you are right about the primary structural strength of the Fiero coming from the frame/chassis rather than the body panels. If it had not been that I am using the same material for the battery boxes, which are structural, I probably would have gone with a less expensive resin, at least vinylester resin, but since the quantities were not large I didn't want to mess around with ordering two separate materials. Also this way I can familiarize myself with the mixing ratio, drying time, temperature properties of one resin while vacuum bagging and heating it without having to learn the properties of two materials. Anyway, I'm a bit of a perfectionist and If I'm going to spend this much time and money on something I figure I may as well do it in the best way possible.

If I use a small AGM pack, about 40 Ah I can keep the weight around 325 lbs. If I add about 550 lbs. of Lithium ion pack to back that up I can have around a 41.0 KWH pack for under 900 lbs. Not too bad weight wise...but you're right that I could get about 20.0 KWH from that 325 pounds if it was Lithium rather than Pb acid. That would give me about 50 KWH total....almost Tesla like. 

I have some connections in China. I may see what kind of deal I can get on LiFePO4 cells. I'd like to get it running soon though, so may still need AGMs first.


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## DC Braveheart (Oct 12, 2008)

Dunno if someone has posted this link yet but here's a nice Fiero EV build I've read: http://greenplanet3.org/ev/Home.html. 

I loved my '84 Fiero - when I first moved out to the US in '88 I took over the last 6 months of a colleague's lease on his Fiero - it was a sweet drive. If I ever get my Miata done (and I can persuade the wife ) I'd love to convert one of them.


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## Zemmo (Sep 13, 2007)

That Fiero website is the Fiero that I own now. I used the info from his original site and have added on what I have done to the car in the last two years. Thats what the www.ElectricFormula.com website is now.


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## CFreeman54 (Jan 14, 2009)

I need to take some more recent pictures. A lot has been accomplished since I took these pics, but anyway it is a start. Attached is a picture of the newly arrived (last summer) Fiero before any major work. One in the process of pulling the engine, and the front end in the process of removing the radiator, AC components, etc. 

The finished looking cars are the result playing with ideas on the car's picture in a computer aided drawing program. The bubble back one looks a little like an RX7 and the other has a real muscle car look, which wasn't exactly what I had envisioned. 

I may do a 3D model in clay or foam before I execute the new rear clip in full scale.


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## JRP3 (Mar 7, 2008)

If you aren't already aware of it you should check Pennocks Fiero forum for ideas. http://www.fiero.nl


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## DavidDymaxion (Dec 1, 2008)

Thanks for posting the pics! That's awesome seeing someone actually working to improve the aero drag.

I'll admit I don't have a good feel for it, but what is the optimal angle for the rear to slope down? The Prius (one of the few cars designed for good aerodynamics) has an amazingly flat rear window. http://www.toyota.com/sem/prius.html?cid=Google_prius , as does the new Insight http://automobiles.honda.com/2010-i...64:oaJHvNBkOIYAAHPooHIAAAAJ:20090426222003#// .



CFreeman54 said:


> I need to take some more recent pictures. A lot has been accomplished since I took these pics, but anyway it is a start. Attached is a picture of the newly arrived (last summer) Fiero before any major work. One in the process of pulling the engine, and the front end in the process of removing the radiator, AC components, etc.
> 
> The finished looking cars are the result playing with ideas on the car's picture in a computer aided drawing program. The bubble back one looks a little like an RX7 and the other has a real muscle car look, which wasn't exactly what I had envisioned.
> 
> I may do a 3D model in clay or foam before I execute the new rear clip in full scale.


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## CFreeman54 (Jan 14, 2009)

Yes, the Pennock's Fiero Forum is a good resource.

Apparently, according to the aerodynamicists around a 10° slope down the rear glass, boot end is ideal. 

I was excited to get my transmission adapter back from Electroautomotive yesterday....until I saw it. As you recall they botched the first one. After sending it back and waiting 5 weeks I was hoping when it returned everything would go smoothly. No such luck. I removed the coupler hub from the package, fit it to the flywheel; it seems to fit this time. So far so good.

Then I removed the adapter plate and compared it to my tracing of the transmission housing. Unbelievably, it is wrong for the second time!  The profile is nothing like the transmission housing tracing (two sets) I had mailed to Electroautomotive. See the attached picture.

Anyway, I spent my lunch break today looking for an aluminum plate supplier and a machine shop to cut and machine the plate. The one shop I stopped into thought it would be about $300 to cut the profile and drill the holes and another $300 to CNC the channel for the circular motor mount plate to set into. It sounds a little high just for the plate, but then it is a one-off job. 

Post Script:
Ooops! Partly my mistake. It is not as bad as it looks. If you place the adapter plate on the back of the tracing the bolt holes line up. The only problem is a half inch gap near where the axle goes into the transmission. That point is not structural though, so perhaps it can be filled with calk something.


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## CFreeman54 (Jan 14, 2009)

Hey Zemmo, can you tell me what components were used for the front coil over suspension on your car? Are the tubular A-frames racing or custom components? I want to do coil over suspension too. Did you have to weld attachment points for the new A-frames onto the chassis?


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## JRP3 (Mar 7, 2008)

Wow, that really sucks, and it looks as if they didn't press in the two locating bushings. You should really email Craig Dusing from http://www.electricvehiclesolutions.com and see what he can do for you. His S10 adapters fit the Fiero mounting bolt pattern, though as I mentioned the lower non-structural holes are different. You can send him your tracing to double check. Tell him John with the Fiero sent you


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## CFreeman54 (Jan 14, 2009)

Thanks for the suggestion JRP3. This evening I discovered it is not as messed up as I thought; I was being stupid. If you place the adapter plate on the *back* of the tracing the bolt holes line up and the profile almost lines up. The only problem is a half inch gap near where the axle goes into the transmission. Since that is non structural, I think it can be filled with calk or composite or something. I don't think it should be open to road grit and such....don't want rocks in my transmission!


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## JRP3 (Mar 7, 2008)

D'oh! Well at least it's an easy fix, hopefully you figured it out before you called an attorney


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## CFreeman54 (Jan 14, 2009)

Yes, agreed. Oh well, one mistake on their part, and one on mine. I would still like to find a supplier next time that has shorter lead times and better support services. Three to four months is just too long to wait for something you have already paid for.


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## Zemmo (Sep 13, 2007)

CFreeman54 said:


> Hey Zemmo, can you tell me what components were used for the front coil over suspension on your car? Are the tubular A-frames racing or custom components? I want to do coil over suspension too. Did you have to weld attachment points for the new A-frames onto the chassis?


The front was switched out with Racing Tubular A Frames. I didn't build the car, I bought it already converted. But I have pictures on this page of my website if you wanted to see details.

http://www.electricformula.com/Brakes.html


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## electric85 (Apr 10, 2008)

Glad i saw this thread. i'm currently restoring/converting a fiero right now too. its taking way longer then i had planned but its because i just don't have enough time. and i think about the money i've spent in gas since i started my conversion and think of all the batteries i could of bought. I started with a 1985 fiero 2m6 with a 4 speed tranny. i'm using a Advanced DC 9" motor with a Zilla LV. i'm going to put my rad for my Zilla behind the air intake vent behind the drivers door. i plan on making a belly pan and closing the rad vent at the front of the car to help with aero, and i am going to go with TS 200ah cells with a pack voltage of 144. i have everything to convert the car except the batteries and charger...pretty sure i'm going with a zivan NG5. but like i said i havent' had time so i'm still getting the car road ready. i bought most of my stuff from www.canev.com and they had the best adaptor plate i could find. i also found a few other fiero build threads that helped to read over.
http://fiero-ev.blogspot.com/
http://www.elfieroev.blogspot.com/

and there was mention of the pop up headlights not being great for drag, there is a thread about low profile pop ups...i'm going to try an dbuild my own though.
http://www.fiero.nl/forum/Forum4/HTML/035039.html

i hope i get some time to work on the car soon and i can't wait to hear more from your conversions!


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## toddshotrods (Feb 10, 2009)

RCC Specialties has tubular arms, that I believe are bolt-ons.


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## electric85 (Apr 10, 2008)

if your looking for a back end with a sloped window to help with drag you could look at the finale kit on this fiero kit website, even if you could buy a partial kit just for the back end. 

http://www.v8archie.com/v8Archie/home.htm


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## CFreeman54 (Jan 14, 2009)

Zenmo and Toddshotrods...Thanks for the ideas on tubular suspension. That is what I need.

Electric85...nice to know someone else is doing a Fiero conversion now too. Yes, time is problem. Finding enough of my own and waiting for suppliers to send me components. I'm rebuilding the whole front end/hood and the pop-up lights and their heavy motors (well, 5 lbs. per or so) are gone. Flush mounted is the only way to go from an aero point of view. I was thinking of using Mitsubishi eclipse headlights...maybe. I'm redesigning the backend too. The Finale kit is nice, but I want to design something myself. 

I tried to mount my SPEC aluminum flywheel on the weekend only to find it has countersunk bolt holes. The stock Flywheel bolt heads fit so nicely in them there is no room for a socket to tighten the bolts. I thought I'd buy allen head socket cap screws to solve the problem, but finding M10 - 1.0 pitch X 25mm, grade 8 or class 12.9 socket cap screws with low profile head is not so easy. I'm still looking.


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## toddshotrods (Feb 10, 2009)

Try here: http://www.mcmaster.com/

The section for bolts and fasteners is in the right hand column. It takes a bit of patience to sift through all the stuff to find what you want sometimes because they have a lot of stuff! Not sure if they'll have the bolts you need, but there's a good chance.


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## Stunt Driver (May 14, 2009)

Hi, trying to find a good fiero for starting my conversion on it. What should I look for when buying one?


ALso, i think I may have one with AUto tranny nearby, but non with manual... Is there another tranny that fits? Or how difficult it is to find a genuine tranny on scrap yards?


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## JRP3 (Mar 7, 2008)

I think you want to try for a 1988 for the upgraded suspension but I know older ones have been done successfully. I would think you could find manual transmissions fairly easily, either the Isuzu or Getrag, not sure if one is better than the other. Look for rust in the corners of the back trunk area, and under the battery tray, mine is pretty bad there and I need to do some patching.


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## Stunt Driver (May 14, 2009)

I wish there was a lot of choice... but thanks for advice!

How do you get engine out of there?
And if from the bottom - can you roll car after engine been removed?
And is FIero good for conversion overall?

I really like GT body on those! Hope i can find one


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## JRP3 (Mar 7, 2008)

I pulled mine out from the top because I didn't want to deal with brakes and rusted subframe bolts, and I didn't have a good way to get the vehicle 4 feet in the air. It was a tight fit, I had to take off the alternator to get it out, most people drop the whole subframe I think and remove it from the bottom.
Fiero's are fairly popular for conversions, look through the EValbum.com


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## Stunt Driver (May 14, 2009)

Which engine was yours?

I just got mine with 4 cyl 5 spd (corrected). Supposively in good shape, but was parked for last 10 years so can't tell yet.


Do you know if all the engines and transmissions that went on Fiero have same connection plate? 
Reason i'm asking - i'd rather get a cylinder block now and make adapter plate out of it, fix motor and coupling as i don't thinks this is quick.

Im the mean time i'll try to get car back on wheels and drive it for a while. I'm even afraid i'll like it too much to take apart


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## JRP3 (Mar 7, 2008)

I had the 4 cyl. with the Isuzu 5 speed.


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## Stunt Driver (May 14, 2009)

That is pobably what i have, 1985.

Do you have any drawings left that I can borrow to create adapter plate and coupling?


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## JRP3 (Mar 7, 2008)

Here's my adapter, but I didn't make it, I got it from Craig at http://www.electricvehiclesolutions.com









It's one of their S10 adapters, the main mounting bolts line up but not the lower starter cover and shield holes, but they aren't structural. Craig made my coupler as well after I sent him my clutch hub spline.


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## Stunt Driver (May 14, 2009)

Looking very nice! Is it aluminum?
How much was it? (still thinking of milling down cylinder block)
Do you have any pictures of tranny? 
How much does chaft stick out above transmission connection surface?
Do you have pictures of compler and what it is made of?

Reason i'm asking - to start getting drivetrain together before diggin inside of fiero.

Thanks for helping!


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## JRP3 (Mar 7, 2008)

Aluminum. Craig's adapters are around $550.
Here's the tranny, if you have a 4 speed yours will probably look different









Coupler looks like these http://electricvehiclesolutions.com...Path=3&zenid=cc2cbb09ef82643ddfd0ad96ed3f8eae
The transmission shaft does not stick out beyond the face of the transmission, I have the measurement somewhere I'll have to find it. Yours may be a little different since I think you have a different trans.


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## JRP3 (Mar 7, 2008)

The space between the mounting face on the transmission and the end of the output shaft is 11/32 on my transmission.


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## Stunt Driver (May 14, 2009)

Thanks, this gives some to start thinking.

I just checked, and tend to think my transmission is same - 5 speed 
manual, vin mathed to Fiero Sport - 1G2PM37R#FP2#####
I will try to match your pics to my tranny.

Got a little confused by coupler now - so does yours connect to flywheel? I really want to avoid this, as without regen - this is a direct energy loss. And couplers on your link look like those maid out of back part of crankshaft.


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## JRP3 (Mar 7, 2008)

The coupler uses my clutch hub center spline welded into the outer half of a taperlock coupler. The other half of the taperlock is machined to fit over the shaft and keyway of the electric motor. This is a clutchless coupler setup. I'll post some pics of my coupler.


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## JRP3 (Mar 7, 2008)

Clutchless coupler. The hub spline is machined for a press fit and pressed into the taperlock, then welded.


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## electric85 (Apr 10, 2008)

if your looking for a good adaptor plate check out www.canev.com they have a great one that fits great. thats where i got mine. there is a "bump" off each side that would cover where the started would go. you just trim off the one you don't need. its there because this adaptor plate can be used for more ten one tranny. but they also have a nice coupler that keeps the clutch. alot of people complain about the extra weight of the clutch and the flywheel but i've driven an ev clutchless and its not as smooth and you have to wait for the motor to slow down and the car slows down so really you need to use more juice to get back to speed agian after shifting. with a clutch you shift fast, clean, smooth and keep moving along. everyone is different but i think clutch makes for a nicer drive.


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## Stunt Driver (May 14, 2009)

Thanks for a good link! I wish they were also local to save on shipping But those do mount to flywheel, correct? In my project, i don't expect high driving speeds, so probably won't need clutch. But still under uconsideration.
One of main worries - afraid to kill DC motor since there is no push bearing to withstand clutch force.


By now i'd expect to see semi-universal adapters you could buy, so every converter doesn't have to invent a bycicle

Just thought price would be a bit lower....
Well, one of those will work. 
I'll check out local machine shop, see if they can do it, just in case before giving away extra hundreds.


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## Stunt Driver (May 14, 2009)

Another question on Fiero load rating - how many 12v batteries will stock suspention be able to carry with out modifications? 
Is it more in front due to on-shock springs?

I am looking at 5 to start, maybe 6. And want to avoid extra cost for many reasons, including the one that my project ment to be low cost.


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## JRP3 (Mar 7, 2008)

Some people have successfully made their own adapters but they have to be very accurate. One guy here had an adapter made by a shop that didn't do a good job and it ended up breaking his motor shaft due to misalignment. 

Here are some examples of conversions, this guy fit 14 batteries and 2 motors:
http://www.evalbum.com/1396

Here's one with 21:
http://www.evalbum.com/525.html

I think you'll have plenty of room


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## toddshotrods (Feb 10, 2009)

JRP3 said:


> Some people have successfully made their own adapters but they have to be very accurate. One guy here had an adapter made by a shop that didn't do a good job and it ended up breaking his motor shaft due to misalignment...


I'll be doing my own, but it's not going to be cheap. Whether it's manual machining or (in my case) CNC, there's a lot of time involved in getting things perfectly lined up. We'll be using a CMM to plot the motor's drive end and the bellhousing. I have to develop a CAD model from that information. Finally an adapter plate will be cut on a CNC mill from aluminum billet. I could probably purchase an adapter for less than a quarter of what I'll really have in this.

JR3P what did you come up with to address the issue of maintaining concentricity while tightening the taperlock?


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## Stunt Driver (May 14, 2009)

to JRP3 - as i understand, at least one of them upgraded suspension. Other has 88 year model, which supposively a bit stronger to start with.
I'll have to do some test loading to see how low it is.


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## JRP3 (Mar 7, 2008)

toddshotrods said:


> JR3P what did you come up with to address the issue of maintaining concentricity while tightening the taperlock?


All I did was once it started taking up I went around putting a half a turn at a time on each bolt.


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## JRP3 (Mar 7, 2008)

Stunt Driver said:


> to JRP3 - as i understand, at least one of them upgraded suspension. Other has 88 year model, which supposively a bit stronger to start with.
> I'll have to do some test loading to see how low it is.


You can figure once you pull the motor you'll drop about 350lbs right there, plus another 30-50 maybe losing the exhaust system, radiator, coolant, coolant tubes, gas tank, odds and ends, etc.


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## Xerophobic (Jun 10, 2008)

I didnt read every single post here(altho most) but FYI having owned and worked on numerous Fiero's I can tell you with confidence there is no difference in bellhousing bolt patterns for any Fiero transmissions regardless of auto/manual and/or 4/6 cyl. The Iron Duke 4 cyl has the same pattern as the 2.8 V6

I did research some time ago for bolt patterns to do a V8 conversion and found the bolt pattern for the 2.8 V6 online pretty fast, altho I cant find my old file for it at the moment. 

Also dont forget the availability of the never 6 speed trans from the G6. This is a popular conversion for the Fiero and bolts in with some "finess" for the cables etc

Hope this helps, I have an engineless Fiero still and have gotten more and more interested in doing an electric conversion on it 

Cheers


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## electric85 (Apr 10, 2008)

well i think doing a conversion on it would be great. but if you are looking for an engine i have a 2.8 sitting in my shop


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## JRP3 (Mar 7, 2008)

I've got a 2.5 sitting in my shop if you want a 4cyl


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## Stunt Driver (May 14, 2009)

Finally here comes my first dissapointment - transmisison is stuck in neutral, shifter does not move, selector only moves one side. 

Any one seen similar trouble, maybe easy fixer? or that could be anything like broken forks inside transmission?


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## Zemmo (Sep 13, 2007)

I think a common problem with the shifter is the cables. There is a cable rebuild type kit out there for Fiero's. I would make sure that it isn't a cable problem first before tearing anything down. Have someone watch the back shifter while you try and shift gears. Make sure it is pulling and pushing the levers.


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## Stunt Driver (May 14, 2009)

i have already disconnected cables, and disgnosed by applying forse to the gearbox shifter axle itself. Also checked with other tranny, to know how it should be. Looks like something inside presenting from shifting.


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## DavidDymaxion (Dec 1, 2008)

The shifter gives you a lot of leverage, the tranny can be hard to shift just by it's shaft. Not a Fiero, but on my conversion I had to hit the shifter rod with a rubber mallet to get it into gear, and had to spin the axles sometimes to get it into a particular gear. The car shifted easily once the shifter was attached and adjusted.


Stunt Driver said:


> i have already disconnected cables, and disgnosed by applying forse to the gearbox shifter axle itself. Also checked with other tranny, to know how it should be. Looks like something inside presenting from shifting.


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## Stunt Driver (May 14, 2009)

cable end was bend and broken - trust me, there was enough force

as mentioned - other tranny parted out of car shifts easy. I guess replacement it will be. just sad, my tranny is only 59k old..... maybe i'll fix it later.


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## CFreeman54 (Jan 14, 2009)

Well, I finally found the fine thread, non standard socket cap screws for the flywheel and got it mounted. GM's use of non-standard threading cost me almost $60! If the thread pitch had been standard 1.5 they would have only cost like $6.

Last night the SPEC Clutch was mounted, although we had to use the stock throw out bearing because the one SPEC sent with the flywheel wouldn't fit on the transmission. I guess that won't matter. The motor and transmission are now joined! Time to put it back in the car.


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## JRP3 (Mar 7, 2008)

Did you ever consider having the old bolt heads machined into socket heads? If that's even possible, just wondering?


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## CFreeman54 (Jan 14, 2009)

Well, usually custom machining is more expensive. I'm getting back to work on the car after a period of inactivity due to torn biceps tendon surgery. The tranny and motor are joined and the motor was placed in the car last weekend. We had to take it back out due to it being 11/32 too long and riding on the passenger side rail of the engine cradle. Now I have to have the side rail notched and reinforcement welded in...drats! I'm waiting on the welder now. hopefully that will be done in a week or so and we can drop the motor back in.


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## toddshotrods (Feb 10, 2009)

CFreeman54 said:


> Well, usually custom machining is more expensive. I'm getting back to work on the car after a period of inactivity due to torn biceps tendon surgery. The tranny and motor are joined and the motor was placed in the car last weekend. We had to take it back out due to it being 11/32 too long and riding on the passenger side rail of the engine cradle. Now I have to have the side rail notched and reinforcement welded in...drats! I'm waiting on the welder now. hopefully that will be done in a week or so and we can drop the motor back in.


Did he already start? I have a 110v MIG I can bring and do the notch if you want to keep your momentum going. Here's a similar job I did:
http://toddperkinsdesign.com/images/misc/remix18.jpg - http://toddperkinsdesign.com/images/misc/remix20.jpg


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## Stunt Driver (May 14, 2009)

CFreeman54 said:


> . We had to take it back out due to it being 11/32 too long and riding on the passenger side rail of the engine cradle. .


Can you share the measurements needed to avoid this pain? I am about to hit scrapyard for a DC motor for my Fiero, and would like to avoid extra welding if possible.


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## CFreeman54 (Jan 14, 2009)

Stunt Driver,

The WarP 11 is about 17.5" long. Any motor shorter than 17" should be fine. I had forgotten to account for the 2" motor ring between the motor and the transmission adaptor plate (part of the trans. adapter assembly). I figured 3/4" for the adapter plate and thought I had a couple inches to spare, but forgot about the 2" aluminum motor ring. When you add 2 3/4" to the 17.52" WarP 11 it DON'T FIT! 11/32" is about 1/3", so I would not go with a motor longer than 17" unless you are willing to notch the engine cradle rail. Theoretically you could move the whole motor/transmission to the left (driver side) of the car by 1/2" by repositioning the transmission mounts and custom fabricating a new right half axle that is 1/2" longer. This gives you a rear track 1" wider than stock and leaves your frame intact, but unless you own a race car shop, custom fabricating the longer axle would be expensive.


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## Stunt Driver (May 14, 2009)

Thanks, will use this data!

Is it from end of shaft to back of case?

I am going thru fork lift places looking for motor now, and size obviously is important. 


Main question - how bit of a motor do you really need to push Fiero at 40mph? Would 7" do it?
And what is maximum diameter that will fit?




ps seen nice 12-13" motors @ $500 rebuilt. Must be really powerfull, but don't look like they will fit now....


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## CFreeman54 (Jan 14, 2009)

Stunt Driver,

There is a guy in Indiana who put a 12" GE forklift motor in his Fiero. (http://www.evalbum.com/1735) He told me it just fit. He made his own adapter though...either it is slimmer than mine or the GE motor is less than 17.52" long. I'm not sure which. Anyway, the point is 12" GE forklift motor can be made to work....Mike didn't chop his frame. He's not getting great range with it though.


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## toddshotrods (Feb 10, 2009)

My 11-inch GE motor is 16.3125" long.


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## Stunt Driver (May 14, 2009)

2 CFreeman - want to double check on sizing, as I just got the motor, but have not taken car apart yet. I'll strike a separate thread tomorrow.

My motor is about 9.5" diameter, and about 17" long case to case end.
Now I'm not clear how to measure?

Front shaft is sticking out about 2 inch, may that push motor back more?... Problem?
Back end of shaft is sticking out too - will it be above craddle and cause no pain?

Drawing attached - Zemmo's "Electric Formula". 9" motor ADC. I can't find dimentions yet, but looks like a few spare inch left.
Do I understand correctly that 
Size A (craddle to adapter plate) - 19"
Size B (motor face to motor back) - 17"?


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## Zemmo (Sep 13, 2007)

Mine does have plenty of room there in the engine bay. I could take some measurements so you know how big the plates and spacers are and how much space is really there. I've even thought about putting regen on the tail shaft since there is room.

I wouldn't suggest the center band strap for a sturdy motor mount. Mine has broken and I need to make a tail shaft motor mount that is some how mounted to the cradle. I am still using the car but I put a few pipe straps around it and I only accelerate slowly.


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## Stunt Driver (May 14, 2009)

Would appreciate details. I just hope craddle for Formula and 85 Fiero are the same.


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## Zemmo (Sep 13, 2007)

Starting from the main plate that bolts to the trans is 1/2 inch thick. Then the round spacer that matches the diameter of the motor is 1 3/4 inch thick. The motors outer shell is 15.25 inches long and the tail shaft sticks out an extra 1 3/4 inches from that. From the back of the motor (not counting the tail shaft) the next closest object is the Fiero's frame which is 6 1/2 inches away. If you count from the end of the tail shaft that gap is only 5 3/4 inches but there is still a lot of space there. I don't think there are many difference in the engine compartment but my car has the original 1984 SE model 4 speed transmission in it. Hope this helps you guys.


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## toddshotrods (Feb 10, 2009)

Stunt Driver said:


> Would appreciate details. I just hope craddle for Formula and 85 Fiero are the same.


All 84-87 Fieros all use the same cradle. 88s have a totally different design.


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## Zemmo (Sep 13, 2007)

Is there a lot of difference between the size of the transmission in those years of fiero's? It seems like my EV has lots of space but I have seen other people complain of not enough.


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## Stunt Driver (May 14, 2009)

Which year is your formula?


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## toddshotrods (Feb 10, 2009)

Zemmo said:


> Is there a lot of difference between the size of the transmission in those years of fiero's? It seems like my EV has lots of space but I have seen other people complain of not enough.


As I remember, there were four transmissions available: Getrag (5sp), Isuzu (5spd), Muncie (4spd), TH125 (auto). There shouldn't be any major difference in the distance from bellhousing to the other side cradle rail though because they all had to mount to a four cylinder and still clear the frame and strut tower on the other side of the engine. The Getrag may have only come with V6s, can't remember for sure, but it is interchanged with the Isuzu (even on V8 swaps) so that shouldn't be an issue.

I think the difference in the diameter of the motor. CFreeman54's big 11-inch motor is what caused him to have to notch the cradle for clearance. If you're using a 8-9" motor it will probably ride on top of the cradle. You have a lot more room from the cradle to the frame and strut tower. Remember the engine cradle and the car's frame structure are two different things. The engine cradle bolts to the car, and is narrower than the frame.


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## Zemmo (Sep 13, 2007)

I'm not sure who Stunt Driver is asking for the year of the Formula. But mine is not a formula. My EV is a 1984 SE Model. It came with a 4 cyl 4 spd motor/trans. If your referring to my website, www.ElectricFormula.com, that is referring to a electric formula, you know Amps X Volts = Watts, that type of formula.

toddshotrods, I think your right. The 11" motor is a lot bigger which would use up the extra space. But a 9" motor should leave plenty of space. My motor is higher than all of the motor cradled. So the cradled isn't any problem at all on the space. What is at the height of the motor is the frame rail.


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## Stunt Driver (May 14, 2009)

Sorry, Zemmo, i thought Formula is the car.
Mine is just a year younger than yours, came with 4 cyl/5 spd.
Can you measure distance from adapter plate to back end of motor please? I am starting to do some drawings now, while still driving Fiero


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## Zemmo (Sep 13, 2007)

By going with the measurements I took. From the front of the mount plate (Bell housing) to the back of the motor it is 17 3/4". If you include the tail shaft then it is 19 1/2".


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## Stunt Driver (May 14, 2009)

Thank you, it is a smaller motor!
Mine is 17" front to back (without shaft) Adding adapter plate and extension rings - may bring be trouble... Well, at least i'm prepared now!


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## CFreeman54 (Jan 14, 2009)

Stunt Driver: How is it going? I haven't logged on for a while....been putting every spare minute into working on the car. Lots of people have WarP 9 and Advanced DC 9" diameter motors in Fieros. The WarP 9 is 20.19" from end of tailshaft to end of tailshaft and 15.92" from end of motor case to end of motorcase. If you are in that neighborhood you should have no problem. Dimensions/drawings for the WarP 11 that proved to be 11/32" too long, with the end of the motor case sitting on the cradle rail, can be found here: 
http://www.go-ev.com/images/003_20_00-08311_WarP_11_Eng_Drawing.jpg
The drawings show it as 17.02" long from end of motor case to motor case. If your transmission mounts are in the same place as mine and you use an electroautomotive style adapter you may have a 0.32" problem. Notching the cradle rail is not too big of a problem if you can weld. just don't go down too far on it or you will interfere with the A-arm movement. I hope this helps.


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## Stunt Driver (May 14, 2009)

Thanks, all goes well, even thou one can't notice the progress by looking at the car Have started a separate thread, named Electrofire.
Found out that some fork lift motors have perfect coupler-usable hub parts - should be machining mine together this week.

My motor case is 17", and total spacer between transmission and motor is going to be 2". I think I am on the edge.

HOWever - my motor is only 9" in diameter, and what I can't figure out - will it hit cradle or simply go over it?


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## CFreeman54 (Jan 14, 2009)

Here are some pics to let you all see what I have been working on. You can see: 
The SPEC Stage 3 clutch and Aluminum flywheel installed on the WarP 11. 

Also The WarP 11 and Getrag transmission mating.

Front composite battery boxes test fitted.

The rear clip hatchback modification/ fabrication.

The front fascia modification/fabrication.

The quarter panel and rear clip test fit on the car. 

I don't have pictures yet of the front coil over suspension upgrade. I still need to get the rear coil over bump steer upgrade installed and get some welding/modification to the rear battery boxes so I can get them mounted. Then it is on to batteries and wiring.


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## JRP3 (Mar 7, 2008)

Nice work. I especially like the hatchback. How hard is it to remove the right rear lower body panel in front of the rear wheel? I might need to get into some frame work underneath the old battery location, and having that panel off might make it easier. I might need to take off the whole rear clip though to get full access.


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## DavidDymaxion (Dec 1, 2008)

Wow, body mods, composite battery boxes, massively stripped car -- I bow in your general direction! That's going to be a great EV!


CFreeman54 said:


> Here are some pics to let you all see what I have been working on. You can see:
> The SPEC Stage 3 clutch and Aluminum flywheel installed on the WarP 11.
> 
> Also The WarP 11 and Getrag transmission mating.
> ...


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## CFreeman54 (Jan 14, 2009)

Thanks guys. There's still a lot to do but it is coming together.

JRP: As I recall you need to remove the sidestrip. That quarter panel is held on with a combination of plastic push-fasteners and pop rivets. It is riveted to the "runner" panel that lies under the door. The push fasteners yield to needle nose pliers and a stiff yank. I think the easyist way to deal with the rivets is to drill them out. On mine all the rust from the battery was on the inside though, so think twice before going to the work to remove the body panel. The rear clip also has bolts along the rear taillight area and through the roof (need to remove headliner to get at them). 

I kind of regret not waiting to buy the motor controller though; at the time the Raptor 1200 A was the biggest, baddest I could get, but now the Zilla HV's are available again! Oh well, I see a future upgrade.


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## JRP3 (Mar 7, 2008)

Thanks for the tip. I plan to attack it from the inside if I can.


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## toddshotrods (Feb 10, 2009)

CFreeman54 said:


> ... The push fasteners yield to needle nose pliers and a stiff yank.....


If I recall correctly the plastic fasteners GM used back then have a pin that spreads the "wings" when pushed in. If you pull the center pin out first the fastener comes out easily by hand or pry tool. I busted quite a few before I realized how they were made!


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## CFreeman54 (Jan 14, 2009)

Yes, Todd is correct, a firm yank to the center of the fastener closes the "wings" and allows the fastener to be pulled out. Pulling on the edges doesn't work so well...i.e. they won't come out until you crush/break them. I too learned that the hard way.


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## CFreeman54 (Jan 14, 2009)

Here are some pics of progress on the build, including rear coil over suspension/bump steer, potentiometer install, and headlight modification. Some fiberglass work is needed on the fender around the headlight install, which will be easy as soon as the weather warms enough for resin to set up. 

Also some shots of the rear battery boxes and WarP 11 motor installation.


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## Zemmo (Sep 13, 2007)

Do you happen to have a picture of your back mount plate (back of the motor or tail shaft)? I need to make one for my Fiero, my original mount has broken form the torque. I have an idea, just need to find someone to build it.


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## CFreeman54 (Jan 14, 2009)

I'll take a picture for you Zemmo. It is basically two "L" shaped pieces of quarter inch thick by one inch wide strips of steel welded to a thinner sheet of steel. two bolts go through the "L" shaped pieces into the motor end plate on the left and right, and two more bolts go through the thinner sheet on the top and bottom. This motor mount sits on and is then bolted into the side rail of the engine cradle. A picture will make my description clearer.


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## Zemmo (Sep 13, 2007)

Yeah that sounds really close to what I had pictured in my mind. Below is a quick drawing of what I was thinking.


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## CFreeman54 (Jan 14, 2009)

Here are a couple pics of the motor mount Zemmo. Your drawing is very close to what I did. The main reason I did it this way was I could not bend 1/4" plate steel. The steel bar could be heated for bending with a MAP Gas torch (Thanks Todd). I am concerned that I only have it secured to the side rail by two 3/8" bolts. I recently bought a 1/2" diameter cobalt drill bit and plan to drill holes for 1/2" diameter bolts....hopefully that will withstand the torque.


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## Zemmo (Sep 13, 2007)

Yeah thats great! Almost exactly what I was wanting to make. I should make one out of cardboard or something and find a shop to make me one. I really need to do something with mine, I have been driving it long enough with my band aid fix. Need to do something about it.


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## CFreeman54 (Jan 14, 2009)

Well, I've been busy again! Here are some new pics of the two new battery boxes I decided I need to fit my 50 LiFePO4 and 13 Exide Orbitals into the car (hybrid parallel pack). 

Also a pick of the rear tubular control arm bump steer coil over suspension.


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## CFreeman54 (Jan 14, 2009)

I couldn't resist test fitting some batteries...and discovered I needed to regroup the Thunderskys. 

Re-banding is a real pain in the posterior, and takes a bit of practice and ingenuity to get the tesion on the steel bands right. My advice to Thundersky is "make tougher battery cases"! This end plating/banding is no fun!


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## CFreeman54 (Jan 14, 2009)

I also started working on my dash gauge panel. I decided to replace the stock tachometer with a digital version...thought it would be easier to calibrate to the speed sensor. If my backordered digital speedometer ever comes I will replace that too.

Probably will put a Pack Trackr or E-Vision meter display in the center of the gauge panel.


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## CFreeman54 (Jan 14, 2009)

My Edisonian approach to motor speed sensor wiring resulted in two fried reed switches when I passed 12 V through them.... I now know what doesn't work! 

I made another, tested for continuity with a multi meter, and mounted it to the motor, but have not yet tried passing current through it...don't want to weld another reed switch closed!


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## JRP3 (Mar 7, 2008)

CFreeman54 said:


> Re-banding is a real pain in the posterior, and takes a bit of practice and ingenuity to get the tesion on the steel bands right. My advice to Thundersky is "make tougher battery cases"! This end plating/banding is no fun!


That's why I went with ratcheting cargo straps and turnbuckles. Fast, cheap, and easily adjustable.


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## CFreeman54 (Jan 14, 2009)

Here is an update on the project. I'm doing high voltage wiring now and hope to have it running in a couple weeks.

I bought banding tools from Northern Tool to reband the Thunderskys...well worth the money in saved time and frustration. 

I found I needed more battery space though, since the original plan was for 50 - 160Ah cells....because of the unavailability of the 160Ah or 200Ah cells without waiting two or three months...though I almost ended up waiting two months anyway.... The 100 Ah cells are shorter and don't fill the battery boxes, but make the space above them unusable. I solved the problem by building racks for in front of and behind the motor. 

I also attached a pic of some LiFePO4 samples I bought from China. I plan on testing them to see how they compare to Thundersky and Headway.


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## CFreeman54 (Jan 14, 2009)

Wow, it looks like a lot of Thunderskys around that WarP! The rebuilt trunk is also packed.

I also decided to use the center channel to mount three of the 13 Exide Orbitals. 

I was able to put the 12 Volt battery back almost exactly where the original 12 V battery was!


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## CFreeman54 (Jan 14, 2009)

Well, the batteries are all in and connected and the BMS boards wired, except I can not see the LEDs on the boards for the batteries in the center channel, so I am routing the LED light to a display panel inside the car via fiber optic cable (light pipes). 

Trouble is the boards were not designed with this in mind, so it required a little LED mount adapting. I was able to hand mill a nylon spacing ring with 0.194 inch inner diameter to use as a "foundation" for the LED mount. It would have been easy but a couple of the resister thingys (that's a technical term ) were too close to the LEDs for the ring to sit flush with the board. I used a carbide cutting tool on a dremel to notch the ring to fit over the resisters. The metal cutting disc was then used to cut grooves in the outside of the ring at 180° so that the outer legs of the LED mount fit into them (the inner legs are snipped off with microshears under a dissecting scope). The mount is then superglued into position on the ring, and the ring superglued to the BMS board. See attatched pics. It takes time but is doable for a small number of LEDs.


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## CFreeman54 (Jan 14, 2009)

I tested my power wiring today...and discovered my paltrakr doesn't like like parallel packs. It blew when I connected the Li Ion pack negative into the circuit.

Also, for some reason my pot box is blowing the fuse on the 12 V line it is attached to whenever I activate the Pot box (open the throttle). Anyone have any ideas on this one?


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## CFreeman54 (Jan 14, 2009)

Wiring problems are solved. Paktrakr will be replaced. I backed the car out of the garage yesterday and primed all its body panels. Quarter panels and some windows are not in place yet but here is the picture proof.

The suspension is in serious need of alignment, but I took it for a test run up the driveway today. All seemed well...for the most part....other than sitting on the floor is uncomfortable...need to get some seats in it. I think my Cyberdyne speedometer and tachometer gauges were lit but not displaying anything....need to figure that one out.


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## Zemmo (Sep 13, 2007)

Nice progress with your car! 

I still haven't done anything about my rear motor mount. My band-aid fix finally broke and its back to making that noise again when I take off. Its just a clunking noise from the trans and motor shifting and the motor hitting that broken motor mount (not hard just can hear it, once i'm moving no noise). Nothing is holding/supporting the back of the motor. I think the original motor mount didn't allow for enough play from the transmission/motor and thats why that mid motor strap broke (that and made out of aluminum). I need to get a video camera in there to watch what is going on. How much play do you think is in the trans/motor? You think it is only two directions or do you think it moves in all directions(up, down, side to side, and front to back) when it starts to put pressure onto the trans to start moving?


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## CFreeman54 (Jan 14, 2009)

Thanks Zemmo,

I did a gingerly test run up the driveway on the weekend. My ex took video of it; I need to figure how to post it here. I guess I might have to post to Utube and post the link. I put a seat in it yesterday. I did a couple more aggressive test runs up the driveway today at a fairly brisk acceleration....not pedal to the metal but like normal driving in traffic accelerating from a stop light, or maybe a little more. It goes pretty good...and I was only pulling about 400A. If I give it the full 1200A I can't imagine what it will do.

I don't think my motor/transmission is moving much. I have a battery box about 1/2" in front of the motor/transmission, so if it was moving more than that I would have a crunched battery box. I'm using the stock transmission mounts and a fairly sturdy motor mount bolted to the frame though.


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## JRP3 (Mar 7, 2008)

Zemmo said:


> I think the original motor mount didn't allow for enough play from the transmission/motor and thats why that mid motor strap broke (that and made out of aluminum).


Are you using something similar to the original ICE torque arm? I don't think the motor mounts can handle the torque without it. I moved mine from the original location and bolted it to the top of the transmission and the driver side engine cover hinge mount. Without it the motor and trans rocked back and forth quite a bit during strong acceleration.


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## CFreeman54 (Jan 14, 2009)

I connected the forced air ducting and installed the quarter panel/side skirts. Still needs some detailing in/on the doors, but coming along.


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## CFreeman54 (Jan 14, 2009)

The charger is mounted in the modified center console.


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## crazybry79 (Jun 15, 2010)

Superb build, and great job so far!

I do need to interject though.

By no means am I an experienced EV converter (just started my first build). But, I've been racing for years, and we have discovered one particular fatal mistake.

Normally the transmissions in our cars got swapped out from original, and we simply fabricated a solid mount. We left the engine on its rubber mounts. This led us to constantly break tailshafts / transmissions. After quite a bit of debate, we finally figured out what we did wrong....

The transmission was mounted solid, yet the rubber mounts allowed the engine to move. When the engine moves, but the trans mounts doesn't, something has to give. Kind of the weakest link theory.

I understand that you are not applying the same amount of torque that we were, but you are operating on the same principal here. Your transmission is on rubber mounts, and the motor is mounted solid. That transmission will move around as torque is applied, among other factors. When the trans moves, and the motor can't - eventually something will give.

Just throwin out an idea.


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## toddshotrods (Feb 10, 2009)

crazybry79 said:


> ...The transmission was mounted solid, yet the rubber mounts allowed the engine to move. When the engine moves, but the trans mounts doesn't, something has to give. Kind of the weakest link theory.
> 
> I understand that you are not applying the same amount of torque that we were, but you are operating on the same principal here. Your transmission is on rubber mounts, and the motor is mounted solid. That transmission will move around as torque is applied, among other factors. When the trans moves, and the motor can't - eventually something will give.
> 
> Just throwin out an idea.


Good point really. Even though Creig isn't building an all-out race car the point is valid because he has a WarP 11, and (I believe) desires somewhat sporty performance. The biggest factor is that the electric motor can deliver *full* torque at 0rpm. That's basically like winding an ICE up and dropping the clutch, or pressing the button on a nitrous system.

Sorry I missed that one Creig. The day we worked on your front mount, I didn't take a good look at the rest of the setup or think through it all. I was more worried about whether there was enough weld to hold. I was probably working that dumb job back then, which would have meant my brain wasn't firing on all cylinders. Over time, you probably will fatigue that front mount, possibly to the point of breaking. You really need a revised design with rubber biscuits between it and the frame.


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## CFreeman54 (Jan 14, 2009)

Thanks for the input guys. I do have rubber grommets on the bolts on the motor mount, but the cushioning they give is much less cushion than the factory motor mount design. I can’t let the motor move too much though…a battery box of 12 Thundrskies is about ½ inch in front of it. Any ideas Todd…or anyone? 

I ran the EV calculator on my motor/controller/car setup. It says I’ll get somewhere between 350-500 ft. lbs. of torque. I think the Fiero with the 2.8L V6 originally had about 170 ft. lbs. of torque.


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## crazybry79 (Jun 15, 2010)

I'm not sure how the Fieros are set up, myself. But, I did run through this in my mind on my convertion already (funny how it ALWAYS works when it's scribbled on a napkin!)

The Metros are set up with the traditional 3 mount setup. One in front of the trans off towards the drivers side, one rear of the trans where the passenger axel exits the trans, and the factory motor mount is forward of the engine.

My plan is to make an endplate to mount on the motor. I will leave the factory mount on the car's chassis. The motor mount happens to be about 12" forward of the motor. I am going to run 2 bars, in a triangle fasshion, to the original rubber mount, and secure to where the ICE conected to the mount.

This design accomplishes 2 things.
1) The original rubber mount will allow for the same movement as the other two mounts.
2) The reason for leaving the original mount so far forward, is that it acts as a lever now.

The reason I am leaning towards a lever set up, when the rotational force is applied to, say, a mount similar to yours, all of the force is being absorbed right there. Whereas the lever concept will multiply the force of the mount.

Picture your friend turning a rusty bolt, while you hold the nut. Either you can hold the socket with your bare hands, or you can put a lever (ratchet) on. Your friend turning the rusty bolt is similar to the motor torque.

BUT, like I said, this applies to my scenerio. I have no clue what your original & current set up is.

Thought I'd throw in my $.02


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## toddshotrods (Feb 10, 2009)

CFreeman54 said:


> ...Any ideas Todd…or anyone?...


I can easily fab a new mount with rubber cushions on the ends. Probably take a couple trips out your way; one to make the patterns, and another to bring/install the new mount. It's not a big deal, I just didn't realize it when I was there before.




CFreeman54 said:


> ...I ran the EV calculator on my motor/controller/car setup. It says I’ll get somewhere between 350-500 ft. lbs. of torque. I think the Fiero with the 2.8L V6 originally had about 170 ft. lbs. of torque.


The 2.8 also had to build it's way up to that number as well. Not any more! You can apply the full 350-500 in a snap!


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## JRP3 (Mar 7, 2008)

CFreeman54 said:


> I can’t let the motor move too much though…a battery box of 12 Thundrskies is about ½ inch in front of it. Any ideas Todd…or anyone?


Yes, you need a torque arm similar to the original dog bone, especially with the torque you'll be producing. I simply relocated the dog bone to the transmission and firewall with a bracket. If you have room you could do the same, though you'll need to reinforce the firewall with all the torque you have.


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## toddshotrods (Feb 10, 2009)

JRP3 said:


> Yes, you need a torque arm similar to the original dog bone, especially with the torque you'll be producing. I simply relocated the dog bone to the transmission and firewall with a bracket. If you have room you could do the same, though you'll need to reinforce the firewall with all the torque you have.


The dog bone is a great idea, but it won't completely eliminate the movement. The issue is he has a mixture of flexible and solid mounts holding the motor/trans assembly in the car. Two allow it to flex and move, while one is solid. That's why I apologized - I know better. You should use the same type of mount at all points of this assembly. It can break cases, mounts, etc. Either let it all move together, or lock it down tight (like mine will be). The dog bone controls the torque reaction, but let's the factory powertrain jiggle around freely. My Honda has one, with rubber engine mounts, and a flex pipe in the exhaust that must be there to not crack exhaust systems like candy canes - ask me how I learned that one.


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## JRP3 (Mar 7, 2008)

Right, I was just addressing his concern about the motor hitting the batteries 1/2 inch in front of it, and I think the torque arm would take care of that. The stock rubber mounts don't seem to allow too much lateral movement but without the dog bone the motor and trans will rotate backwards under load then rotate forwards when off load or in reverse. Originally I had only the stock motor and trans mounts in place and no dog bone


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## toddshotrods (Feb 10, 2009)

JRP3 said:


> ...Originally I had only the stock motor and trans mounts in place and no dog bone


Rock-n-roll! 

Shoot me an email or call Creig. Let's get that puppy ready for burnouts!


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## JRP3 (Mar 7, 2008)

CFreeman54 said:


> I connected the forced air ducting and installed the quarter panel/side skirts. Still needs some detailing in/on the doors, but coming along.


Any concerns with water getting into the engine compartment? I'm trying to waterproof mine yet still allow airflow. I may resort to a blower on the stock inlet and maybe another blowing out the back. I closed off the deck vents and it gets hot in there on a warm day.


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## CFreeman54 (Jan 14, 2009)

JRP3...Thanks, if I understand what you did you stabilized the transmission housing. I was thinking that stabilizing the transmission might solve the problem as well as giving more play to the motor...and is easier to do given my spacial arrangement...or lack of space around/under the motor mount. Actually, the battery rack in front of the motor/transmission may be stabilizing the transmission some...I had to notch the rack in order to fit it...if the tranny moves forward about 1/16" it is against the battery rack. 

I'll give you a call Todd. 

JRP3; I think the slope of the air duct will cause any water drops entering the duct to hit the walls and run back down and out, but I will keep an eye on it. I can add a standard high flow air filter cartridge to block water to the controller if I have to. The duct provides 200 cfm air flow at about 40 mph...not taking into account the effect of the Raptors fan on airflow.


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## JRP3 (Mar 7, 2008)

CFreeman54 said:


> JRP3...Thanks, if I understand what you did you stabilized the transmission housing. I was thinking that stabilizing the transmission might solve the problem as well as giving more play to the motor...and is easier to do given my spacial arrangement...or lack of space around/under the motor mount.


Yes, what I did, since I'm running clutchless, was to use the mounting bracket for the clutch piston, extend a bracket up from that a bit and then went from that to the driver side trunk lid bracket. Maybe I'll just run out and snap a picture. Not a great pic but you get the idea.


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## CFreeman54 (Jan 14, 2009)

Thanks for the pic/info JRP3. I would have to make some modification....my trunk bracket is gone due to the rear clip modification for the hatchback....and I still have the clutch. What did you use for the torque rod? It appears to have new urethane bushings in it.


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## JRP3 (Mar 7, 2008)

It's an after market piece that came with the car. The previous owner was kind enough to put urethane bushings throughout the entire vehicle before he trashed the clutch and sold it  Before I thought of using the clutch bracket I was considering tying into one of the adapter plate/transmission bolts somehow.


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## CFreeman54 (Jan 14, 2009)

Tying a support to an adapter plate bolt would be easy...a few of my bolts are too long anyway.

I got my new digital gauges, that Stuntdriver directed me to (Asia Engineers Rock!) installed in the dash. I haven't connected the ammeter yet because I can't figure out how to give it an isolated power supply. The directions that came with it say it can not share the same 12V power supply as the ammeter. Since I only have one 12V auxiliary battery in the car, unless I run it off the DC-DC convertor I don't know where I will get 12V from. Even the DC-DC shares a common ground with the 12V battery though.

The analog gauges are now somewhat redundant, but I can run battery amps off one and motor amps off the other gauge. Both Voltmeters can display either the AGM or Li Ion voltage. 

I decided I better get my batteries covered. It started to rain when I had the car out of the garage one day. Electrical wiring doesn't like water.


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## CFreeman54 (Jan 14, 2009)

Someone here on the forum suggested the unknown rectangular component that came with the ammeter (Yaohua DY 12S12-1W) may be a mini DC-DC convertor? If it is I am still not sure how to connect it? Any ideas guys?


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## Jimdear2 (Oct 12, 2008)

CFreeman54 said:


> I got my new digital gauges, that Stuntdriver directed me to (Asia Engineers Rock!) installed in the dash. I haven't connected the ammeter yet because I can't figure out how to give it an isolated power supply. The directions that came with it say it can not share the same 12V power supply as the ammeter. Since I only have one 12V auxiliary battery in the car, unless I run it off the DC-DC convertor I don't know where I will get 12V from. Even the DC-DC shares a common ground with the 12V battery though.


Just about every china guage supplier will list (you have to look for it) a isolated power supply for gagues. They cost about $10.00 most of the time. Watch which one you order some are 5 volt and some are 8 to 15 volt. Be sure you order the one needed for your guage, most will want the 8-15 volt one.

A cheaper, simpler way is to power each guage with it's own 9 volt battery. You can control the power throught a relay or a switch. I've heard reports of batteries lasting a year or more if you switch them off when not using the EV.

Take my word for it DO NOT try to run more then one of these china guages from the same power source. In some cases the voltmeters (the really cheap ones) cannot even measure the voltage of the battery it is powered from.

Passing along some expensivly aquired experiance.


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## CFreeman54 (Jan 14, 2009)

Thanks Jimdear2. I seem to have already done something wrong and killed the digital voltmeter. I'm not sure I understand what though.

I installed a Pre-charge resister/relay to balance the voltage of the Li Ion and AGM pack prior to engaging the main contactors, because before when I engaged the Li Ion pack it Killed my Paktrakr (which is only monitoring the AGMs); apparently the Paktrakr did not like the 3-5 volt jump when the Li pack engaged. 

I did make a mistake, and put a 1k-Ohm resister on the line (between the main contactor + terminals) first. This is when the voltmeter died. I corrected my mistake and replaced the 1K-Ohm resister with the correct 1 Ohm resistor, but the digital voltmeter is still dead; it reads 1 V. 

Fortunately, I did not have the much more expensive digital ammeter connected yet. If I replace the voltmeter it means another two days work of tearing the dash apart and putting it back again though...Ahhhhhh!

Why did the resistor kill it though? And more importantly, will the 1 Ohm resistor kill the digital ammeter if I connect it? ...or a new digital voltmeter if I replace the damaged one? Can one of you electrical engineer gurus here explain it to me please? See my control wiring diagram:


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## CFreeman54 (Jan 14, 2009)

It is not too directly relevant to my meter problems (I think), but it seems I never posted my power wiring diagram here, so for anyone interested in my hybrid battery pack arrangement, here it is:


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## CFreeman54 (Jan 14, 2009)

Time to show the new rollcage Todd helped me weld in. He also fabricated a neat little torque bar to stabilize my transmission under acceleration, but I need to crawl under the car to get a pic of it.

Also, here is the new carbon fiber hood freshly pulled from the mold. It weights about 40 pounds less than the factory hood!


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## JRP3 (Mar 7, 2008)

Doing your own carbon fiber, nice. How much did the materials cost?


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## CFreeman54 (Jan 14, 2009)

JRP3: Thanks...its hard to nail down cost because I already had some of the materials I used...some fiberglass/F.G. mat, wax, PVA mold release, plaster/burlap for backing /mother mold, etc. ...all together somewhere in the neighborhood of $300 probably...

Here is what it looks like after a little trimming....and it is so light I can hold it in one hand...with my arm extended. Try that with your factory hood!


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## CFreeman54 (Jan 14, 2009)

I made a carbon fiber tail piece to mount round tail lights in. Here are some pics of it in the vacuum bag and after preliminary trim and test fit. It still needs sanding and finishing. After I buy the lights I will cut the holes in it.


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## CFreeman54 (Jan 14, 2009)

Oops, I forgot to attach the test fit picture. Here it is.


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## clclebaron3 (Sep 6, 2010)

CFreeman54 said:


> I made a carbon fiber tail piece to mount round tail lights in. Here are some pics of it in the vacuum bag and after preliminary trim and test fit. It still needs sanding and finishing. After I buy the lights I will cut the holes in it.


 Hello I have a fiero that I was considering making into an electric build but it seems you have gone into considerable expense and work . I am retired and on a limited income so I am looking for a cheap and not necessarily aesthetic looking vehicle . I am in Medina and just looking to go on 12 mile trips to the store and back. We spend about 240 amonth on gas .


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## CFreeman54 (Jan 14, 2009)

Clclebaron3: Yes, you can do as much or as little as you want with an e-car. Some people have built electric cars for as little as $700 using used and salvaged parts and batteries. On the other hand, you can spend $100,000 if you want to build a race car with custom parts and motor/motor controller. Most people, like me, are somewhere in between these extremes.


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## Crash (Oct 20, 2009)

Wow... What a great build so far. I'm subscribed now.  Looking forward to seeing more progress.


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## RE Farmer (Aug 8, 2009)

That new rear panel would look great with some frenched-in '61 Chevy tail lights.

I'm considering making carbon parts for my MG as well. I have seen CF bonnets available commercially, but not other parts. Did you make a female mold off the original metal?


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## CFreeman54 (Jan 14, 2009)

RE Farmer: I taped the original taillight fixtures together, wrapped the panel in cling wrap plastic (to protect it from resin), then wrapped the carbon fiber around it and spread the resin....no female mold.


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## CFreeman54 (Jan 14, 2009)

Here are the taillights I ended up with.


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## CFreeman54 (Jan 14, 2009)

JRP3: I've been chasing shorts (or something) in my battery regulators/BMS circuits and am about ready to get another charger that doesn't need the regulator/BMS circuit to charge properly. (I can't charge unless I disconnect the control circuit and watch the cell board over voltage LEDS like a hawk). I just had another sparky incident with the low voltage circuit; the inputs on the BMS boards are close together, and if a wire gets away from you....fireworks! You are running a Manzanita Micro charger with no regulators/BMS? Any advice?


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## JRP3 (Mar 7, 2008)

Can you manually top balance the cells so none of them overvolt? They should stay balanced for a while if you don't discharge them deeply.


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## CFreeman54 (Jan 14, 2009)

JRP3: I can't reach about 20 of the Thundersky cells....they are under the main battery box....I know, not an ideal design, but it was a last minute necessity when I couldn't get 160Ah cells from EV Components and had to fill my main battery box with Exide Orbitals. Anyway, the inaccessibility to those cells (and the BMS boards) is what is causing the most difficulty in troubleshooting the BMS too.


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## JRP3 (Mar 7, 2008)

Might be worth getting in there and running remote wires to them.


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## CFreeman54 (Jan 14, 2009)

JRP3: Yes, it appears I may have to get in there either way (with or without the BMS).


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## electric85 (Apr 10, 2008)

CFreeman54 your fiero is looking great! I haven't been on here in a while, nor have i been working on my fiero until just recently. I have found more time to get to the shop and I have been getting alot of work done. still mostly restoration, but its getting closer and closer to the put everything together stage! anyway i was wondering where you bought your Thunder Sky cells. I have been looking at elite power solutions, and ev components.


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## JRP3 (Mar 7, 2008)

Did you not know that ev components has gone out of business?


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## electric85 (Apr 10, 2008)

JRP3 said:


> Did you not know that ev components has gone out of business?


i know that now...i haven't been online doing alot of ev stuff lately, i have all my components just not the batteries, but i'm getting closer to needing them so i'm back online again. so where do you suggest finding TS cells?


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## CFreeman54 (Jan 14, 2009)

Electric85: Thanks. I had visited the Thundersky factory, and was thinking of buying directly from them, but at the time I could get the cells for the same price from EV Components, so I went with them. I wasn't happy with the deal though, and was lucky to get the cells I paid for. I would have been better off to have dealt directly with Thundersky. 

I also bought some samples from a company in Zhuhai I found when I was over there. I sent a couple to Belktronix for testing, and the 100Ah cell tested at 105Ah...pretty good...but of course too small a sample size to form definite conclusions on. 

I'm headed back to China next week and plan to talk with some more battery manufacturers.


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## CFreeman54 (Jan 14, 2009)

I visited the factory that makes batteries for Elite Power Solutions a year ago. It appeared they should be as good as Thundersky (they say better).


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## JRP3 (Mar 7, 2008)

I'd try either http://www.currentevtech.com/ or http://www.lithiumstorage.com/
They both post here on the forums.


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## JRP3 (Mar 7, 2008)

For reference my SE/CALB 100ah cells all came in at 110ah or above, I'd certainly choose them again in the future.


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## electric85 (Apr 10, 2008)

thanks guys, looks like lithium storage has some pretty good prices. i'm heading out to work on the car this afternoon. getting closer and closer to getting this thing together...haha but once it is together i'm sure i'll be looking for help wireing up the car!


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## PatricioIN (Jun 13, 2008)

someone with the best price is not necessarily someone with good business practices. with any battery order of this size, you'll want to have some serious guarantee you'll get what you ordered before you turn over any actual cash.. I wonder if you could escrow it somehow/somewhere - only to be released upon confirmed receipt of product in good condition? Would be worth investigating!

Caveat emptor!


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## helluvaengineer96 (Oct 8, 2010)

CFreeman54,
Great project you have going here. Your EV looks amazing. OK if I add some input on what I plan on doing in the battery area?

I just started down the road of a Fiero conversion with an AC50/Curtis kit. One of my goals is to fit as many batteries in the old gas tank area as possible. I have a really short commute (3 blocks so I really don't need a lot of capacity) but I am tempted to add all the capacity that will fit just in case. I was planning Lead-acid but this comparison and real world constraints really shows the benefits of LiFeO4.

Only have the cradle at my house right now, the rest of the car is sitting in my brother's barn... So I've had to do a bit of the planning without being able to see the car. Luckily someone named, *Andy R. Bujtas, *build a new gas tank for his Fiero and put all of his excellent docs online (there is a picture that you can click on that allows you to down load all of his CAD drawings stored in .doc format.) Thank you Andy! http://www.lambolounge.com/Chassis/Fiero-chassis/Gas-tank/gas-tank.asp 

Don't have access to 3D rendering software (but this is over kill anyway)...Figure a few visio drawing will be close enough until I visit the car with the machined cell carrier. Might be off a little but it does help with a general comparison.. Once I reach a decision I'll take a closer look at actual fit. 

Planning a simple pulley system to raise and lower the batteries. Using bars to bolt carrier into place (Like Andy did with his fuel tank). The Fiero may have to be raised up to actually clear the bottom of the car for removal.

The following is attached:


Table showing expected discharge times for different Ah ratings. Using Peukert's Law. BMP = Discharge rates.
table showing different battery options, weight, discharge time, and ability to fit in Fiero gas tank area. Toying with the idea of going lower voltage 76 or 96V to get more to fit. (bmp = discharge rates)
word doc zipped showing various battery placement options,
Picture showing aluminum cradle bushings
Poly trans mounts.
Picture showing where gas tank use to go....
This is my first time attaching a file............​


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## toddshotrods (Feb 10, 2009)

I had to hook up the emergency disconnect lever cable, and was in the right place, at the right time, to take the first offical ride with Creig yesterday!

You'll have to excuse the horrible video. I just grabbed my Blackberry at the last moment and started recording. It's a bottom of the line Curve, and the windshield was dusty from all Creig's hard work. I also had it resting on my knees, which makes the bumps seem like we're in a Baja truck - it really rode pretty decent.

Congrats Mr. Freeman on your milestone! 





 
Creig was driving the car like one would drive an ICE with a manual transmission. I noticed him using the clutch pedal from a standing start, and suspect he shifted much more than was necessary with a Warp 11, and five speed transmission. In retrospect, it seems like he could have done that entire trip in one gear. He was upshifting to keep the motor from turning so fast, but spinning a little faster is where the motor would be more efficient. His tach wasn't working, so he couldn't be sure of what the RPM were, so he was probably trying to be safe.

Pack voltage meter never seemed to stray from around 160v. The motor amps peaked at around 600-700 amps when he was pushing on it a little. The car drove like a normal car. I like the big motor/small car format because it has enough guts to keep up with even aggressive city traffic, and some...


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## JRP3 (Mar 7, 2008)

Don't know what speeds you got up to but I'd think if you were under 45 or so the whole drive could have been done in second gear. My lower power but higher revving AC system allows me to do all my driving in second up to 65, including steep hills. The higher RPMs help keep the motor cooler too.


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## helluvaengineer96 (Oct 8, 2010)

Clutch vs no Clutch??


JRP3 and Creig,

Any insight into going with or without clutch?
I've noticed all most all DC motor go clutchless... while some of the AC motor folks go with a clutch.

Looks like Creig went with a clutch... JRP do you have a clutch?


I am having a difficult time picturing the AC motor synchronizing with the transmission that is spinning faster or slower than the motor.
*Pro clutch-less:*

Motor has a lot less rotation mass than the ICE therefore it might be close to the same impact of just the weight of the clutch?
Saves the weight of the clutch and assembly
*Pro Clutch*:

Impact of Regen... How can you downshift without clutch?
AC motor torque curve is much closer to ICE.
Wear and tear on the tranny

This morning I drove my wife's mini without using the clutch.. Some gears OK, others were very rough.



JRP3 said:


> Don't know what speeds you got up to but I'd think if you were under 45 or so the whole drive could have been done in second gear. My lower power but higher revving AC system allows me to do all my driving in second up to 65, including steep hills. The higher RPMs help keep the motor cooler too.


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## JRP3 (Mar 7, 2008)

I went clutchless. With regen shifting is tough because it slows the motor so quickly, if you don't get it just right you get some grinders. On the other hand the higher RPMS and wider torque band of AC means I don't need to shift, I do 99% of my driving in second gear up to about 65 mph at 6500rpm. I could imagine with a higher revving and slightly more powerful motor, (or controller for this motor), running simply a single speed gear reduction as Tesla does. Were I to do it again I might think about keeping the clutch with this setup, but I'm hoping at some point to find a higher power controller to increase the amps for more torque and higher voltage to carry the torque to higher RPMs.


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## toddshotrods (Feb 10, 2009)

JRP3 said:


> Don't know what speeds you got up to but I'd think if you were under 45 or so the whole drive could have been done in second gear. My lower power but higher revving AC system allows me to do all my driving in second up to 65, including steep hills. The higher RPMs help keep the motor cooler too.


If he went over 45mph, it wasn't by much or for long. So he could possibly have shifted one or twice. IIRC, he was using 2nd, 3rd, and 4th. Don't you just use two gears total JRP3?

I'm also kind of surprised by how many amps he was pulling, with a Warp 11, and using the clutch, to start off. He was accelerating from a start fairly aggressively - probably even more so than I normally do in my (ICE)Honda. I'm guessing you must be accelerating pretty easy from a stop JRP3, with a smaller AC motor and 500 amp controller.

If you watch from the traffic light you can see how fast he caught up to the vehicle ahead of him when the light changed, even though it took off sooner and opened a gap between them.


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## JRP3 (Mar 7, 2008)

Mostly I use second for everything unless I really want to get on it, then I'll use first. If I'm doing sustained speeds of 60 and up I'd use third, I used fourth once or twice just to see what it was like, never used fifth. Normal acceleration from 0 in second pulls around 250-300 amps, if I floor it I'll briefly hit 550 amps, my car is 2500lbs.


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## toddshotrods (Feb 10, 2009)

JRP3 said:


> Mostly I use second for everything unless I really want to get on it, then I'll use first. If I'm doing sustained speeds of 60 and up I'd use third, I used fourth once or twice just to see what it was like, never used fifth. Normal acceleration from 0 in second pulls around 250-300 amps, if I floor it I'll briefly hit 550 amps, my car is 2500lbs.


Interesting. I wish I could line you and Creig up and drop the flag!  Maybe his car is a lot heavier than yours. The 600-700 amps of DC torque pull nice, but it's interesting that it uses that much.


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## helluvaengineer96 (Oct 8, 2010)

Thanks for the feedback...

Having a problem finding my clutch and assembly to hand to the machine shop... Figure if I have to buy a new clutch ect... Might as well install it..

However not sure if I want to add the weight / rotating mass (acceleration will be slow enough already)...

Given your input I am leaning towards getting the clutch..If it does not add too much to the bill.. Surprisingly  I am already way over budget.



JRP3 said:


> I went clutchless. With regen shifting is tough because it slows the motor so quickly, if you don't get it just right you get some grinders. On the other hand the higher RPMS and wider torque band of AC means I don't need to shift, I do 99% of my driving in second gear up to about 65 mph at 6500rpm. I could imagine with a higher revving and slightly more powerful motor, (or controller for this motor), running simply a single speed gear reduction as Tesla does. Were I to do it again I might think about keeping the clutch with this setup, but I'm hoping at some point to find a higher power controller to increase the amps for more torque and higher voltage to carry the torque to higher RPMs.


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## CFreeman54 (Jan 14, 2009)

Here are some pics of my car since I got the painting done and windows installed.


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## DavidDymaxion (Dec 1, 2008)

Being able to quickly go down a gear will more than make up for the extra mass of the clutch for acceleration. For a 3000 lb car the clutch effectively makes the car look about 100 lbs heavier (rotational inertia and it's geared weight). Going down from 2nd to 1st gear for acceleration is as if the car is 1000 lbs lighter! Your top usable gear acceleration will be worse, but in any lower gear will be much better than if you had to stick in the high gear. Without a clutch you'll be tempted to lug along in a higher gear, because downshifting is a pain.


helluvaengineer96 said:


> Thanks for the feedback...
> 
> Having a problem finding my clutch and assembly to hand to the machine shop... Figure if I have to buy a new clutch ect... Might as well install it..
> 
> ...


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## helluvaengineer96 (Oct 8, 2010)

David,
That is a great point did not think about down shifting to pass..... Think I'll down shift for Regen a lot more to with the clutch vs not having a clutch as well..

Creig,
Looks great. How much weight did you shave off overall?
Would not recognize it as a Fiero if I saw it on the highway.. The hatch back is a great idea. You should work for Pontiac.. oh wait 



DavidDymaxion said:


> Being able to quickly go down a gear will more than make up for the extra mass of the clutch for acceleration. For a 3000 lb car the clutch effectively makes the car look about 100 lbs heavier (rotational inertia and it's geared weight). Going down from 2nd to 1st gear for acceleration is as if the car is 1000 lbs lighter! Your top usable gear acceleration will be worse, but in any lower gear will be much better than if you had to stick in the high gear. Without a clutch you'll be tempted to lug along in a higher gear, because downshifting is a pain.


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## JRP3 (Mar 7, 2008)

DavidDymaxion said:


> Being able to quickly go down a gear will more than make up for the extra mass of the clutch for acceleration. For a 3000 lb car the clutch effectively makes the car look about 100 lbs heavier (rotational inertia and it's geared weight). Going down from 2nd to 1st gear for acceleration is as if the car is 1000 lbs lighter! Your top usable gear acceleration will be worse, but in any lower gear will be much better than if you had to stick in the high gear. Without a clutch you'll be tempted to lug along in a higher gear, because downshifting is a pain.


Above about 15mph dropping down from 2nd to 1st would not do me any good. I live in an area with many steep long hills and rarely need 1st, actually I never "need" it but sometimes it's more appropriate.


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## JRP3 (Mar 7, 2008)

helluvaengineer96 said:


> David,
> That is a great point did not think about down shifting to pass..... Think I'll down shift for Regen a lot more to with the clutch vs not having a clutch as well..


Actually downshifting to pass would probably be a mistake. Electric motors make their torque at lower RPMs, if you downshift you will increase the RPM of the motor, likely taking it out of it's power band.


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## toddshotrods (Feb 10, 2009)

JRP3 said:


> Actually downshifting to pass would probably be a mistake. Electric motors make their torque at lower RPMs, if you downshift you will increase the RPM of the motor, likely taking it out of it's power band.


I love it! It took me so long to really grasp this. I came in with all my ICE ideas, most of which were completely unnecessary, at best, with an electric motor!  Just stick it in the best gear and drive fellas. If you find yourself needing to shift too much, you probably didn't do your homework in designing it. JRP3 really confirms this because he has a relatively small motor, lives in a hilly area, and rarely finds the need to row through the gears. You can downshift at the traffic lights and stop signs. If you just have to do something, push the gear shift lever into neutral while you're coasting to a stop.


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## helluvaengineer96 (Oct 8, 2010)

I just had to look at the AC50's torque curve again for the 100th time. I keep picturing it as a ICE torque curve... And while the HP curve is close, you are right all the torque is there at low RPMs for the AC50. Just going to take some time getting use to.

Does not elliminate the need for upshifting for higher speeds tho...




JRP3 said:


> Actually downshifting to pass would probably be a mistake. Electric motors make their torque at lower RPMs, if you downshift you will increase the RPM of the motor, likely taking it out of it's power band.


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## CFreeman54 (Jan 14, 2009)

Helluvaengineer96: I removed somewhere between 600-700 pounds. The rear hatch and carbon fiber hood mod alone dropped about 100 pounds. 

Because I currently have a hybrid battery pack LiFePO4 & PbA Exide Orbitals I'm still at least a couple hundred pounds over stock weight, I'm gussing about 2900 pounds. When I drop the Exides and go to all LiFePO4 (200 Ah) the car should be stock weight. I have a couple further weight reduction tricks in mind though. 

JRP3: What charger are you using? I am going to eliminate the BMS when I get back from CHina and just bottom balance and use an programmable charger. I had a BMS wiring/circuitry fire just before I left. It was so hot it burned through the polycarbonate trunk bottom/battery box lid. Most of the heat must have gone up though, because my Thundersky batteries seem undamaged, though the tops of two cell cases are blackened. Fortunately there was no other damage to the car. It took a box of baking soda to extinguish it though!


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## JRP3 (Mar 7, 2008)

I'm using a Manzanita PFC30 charger. It takes some tweaking to set it up properly, and if you charge from different voltages and currents you have to watch it. Example, if you set it to charge at 12 amps from a 120 line it will shut off early if you charge at 20 amps from a 240 line. If set for 20A at 240VAC it will overcharge at 12A 120VAC. Since I mostly charge from 240VAC I set it for that and just watch it if I charge from 120.


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## CFreeman54 (Jan 14, 2009)

Thamks for the info JRP3. I guess that is what Jack Rickard meant when he said a Manzanita micro would work but it required more set-up than a programmable charger. The programmable ones he recommended are about $3000 though...wow!


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## JRP3 (Mar 7, 2008)

Well the PFC30 is about $2500, so not a lot cheaper, the PFC20 is $2000. Nice thing is if you have a problem you can send it back to Rich and he'll fix it quickly, with Brusa, who knows.


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## CFreeman54 (Jan 14, 2009)

I think my garage electric lines could only handle the amp draw of the PFC20 anyway....so that is $1000 savings...fairly significant. Thanks for your info.


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## electric85 (Apr 10, 2008)

CFreeman54 said:


> Tying a support to an adapter plate bolt would be easy...a few of my bolts are too long anyway.
> 
> I got my new digital gauges, that Stuntdriver directed me to (Asia Engineers Rock!) installed in the dash. I haven't connected the ammeter yet because I can't figure out how to give it an isolated power supply. The directions that came with it say it can not share the same 12V power supply as the ammeter. Since I only have one 12V auxiliary battery in the car, unless I run it off the DC-DC convertor I don't know where I will get 12V from. Even the DC-DC shares a common ground with the 12V battery though.
> 
> ...


 
Hey, i know this is an old post but i'm now wiring up my gauges and i have 2 digital panel meters but mine didn't come with any wires...i was wondering if anyone knows what gauge i should use?


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## electric85 (Apr 10, 2008)

hey CFreeman54

How did you end up wiring your gauges, i'm trying to figure out the same thing you were with the isolated power supply and not sharing a common ground...i thought of using 9v batteries on a switch but i'd like to not have to worry about turning those on and replacing them when they wear out.


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## CFreeman54 (Jan 14, 2009)

Electric85: I used 9 volt batteries to power the meters switched on with a relay from the car's 12V system. When the ignition is turned on the relay is activated and the meters light. Radio Shack makes a small relay that will work; if my memory is correct it says it is for 9V DC, but it seems to handle the 12V with no problem. This method insures power isolation to the meters.


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## Jimdear2 (Oct 12, 2008)

electric85 said:


> hey CFreeman54
> 
> How did you end up wiring your gauges, i'm trying to figure out the same thing you were with the isolated power supply and not sharing a common ground...i thought of using 9v batteries on a switch but i'd like to not have to worry about turning those on and replacing them when they wear out.


 
electric85,

These isolated DC to DC units work just great. 

http://www.lightobject.com/1212S-DC...d-Power-Module-Ideal-for-12V-system-P425.aspx

Other sellers offer them as well

You hook the power input of your first meter directly to the vehicle 12 volt source.
Second meter the power input side of the meter is run through one of these units. Put vehicle 12 volt in get and isolated 12 volt out.
Third meter same 
fourth meter same 
and so on.

They do the job with no batteries to change or relays to fuss with.

Jim


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## JRP3 (Mar 7, 2008)

Will the meters that run from a 9 volt battery still work properly with 12V?


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## Jimdear2 (Oct 12, 2008)

JRP3 said:


> Will the meters that run from a 9 volt battery still work properly with 12V?


JRP3,

Most of the meters that run on a 9 volt batterey that I have investigated are rated for 5 to 15 volts operateing voltage. It usually states that i the data sheet for the meter when available. 

There are a few meters I have seen that run only from 5 volts, but there is an isolated volt DC to DC converter for those meters as well. 

I hav run my meters (0 - 200 volts and 0 - 500 amps) for 2 years with no real problems.

Jim


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## electric85 (Apr 10, 2008)

hey everyone thanks for the help. I ended up going with this 


http://cgi.ebay.com/DC-DC-Converter-Isolated-Power-10V-16V-Double-Out-5V-/290547726313?pt=LH_DefaultDomain_0&hash=item43a5fe77e9#ht_2416wt_905

should do the trick. i'm excitied that i am going to start putting the car back together and that i have now started on the electric part of the car. i still need rust work done to the car but if i can get all the gauges and wiring that i need in the interior and get the inside of the car back together so that when the metal work is done i can just put the batteries in and get it on the road!


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## CFreeman54 (Jan 14, 2009)

JRP3: Before you said using the Manzanita micro charger took a little effort to set up for the LiFePO4 batteries. Have you elaborated on that process anywhere? I am trying to decide between going with a Manzanita Micro or a programmable charger like a Brusa, Current Ways, or Elcon. Each seems to have pros and cons, but I like the fact you can change settings on the Manzanita easily, and the price is mid way. I was a little puzzled when Elcon sent me 4 charging curves and asked which one I wanted. I had assumed telling them the battery brand/type, cell number, and max charge voltage/cell (3.65 V) would indicate the charge curve needed.


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## JRP3 (Mar 7, 2008)

The issue with the Manzanita is the voltage clamping is a bit vague and it changes depending on if you're plugged into 120V or 240V. Probably not enough to be an issue if you top balance but it can cause problems if you bottom balance and want to charge your cells above around 95% SOC. There is a bit of voltage drift above your set voltage, and that changes depending on the current you're charging at and the voltage from the wall. For example if you set your charge cutoff when plugged into 120V and pulling 12 amps it will shut off early if charging from 240V and pulling 20 amps. Not a big deal if you are aware of it. The opposite is more of a problem, if you set it when plugged into 240V pulling 20 amps it may overcharge your cells when plugged into 120V pulling 12 amps. I do most of my charging from 240V so I just watch it closely when occasionally plugged into 120V. 
Also since most of the time I don't need the full pack capacity and the cells will last longer undercharged I'm going to experiment with having the charger just shut off after the CC phase and not bother with the CV part. This will undercharge the pack further and avoid the voltage drift during the CV phase.


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## CFreeman54 (Jan 14, 2009)

JRP3: Do the directions that come with the Manzanita Micro charger explain setting it up for the charge curve, etc. or is that something I will need to do more independent research on? I am also considering the Elcon chargers, but it seems the charge curve programming is "hard wired" in with the Elcon's, whereas I like the fact the Manzanita charger can be reset if your battery pack changes.


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## JRP3 (Mar 7, 2008)

I don't think the Manzanita's describe a charge curve as such, you really just set the voltage where you want the charger to go from constant current to constant voltage, and for how long it stays in the constant voltage phase. You select the max amps you want to start charging at and then when it hits the set voltage it will back down on current while holding that voltage. To be honest the "charge curves" are not that complex, CC to set voltage and then CV as current reduces. I've had good luck with charging around 25 amps CC and then just using 15 minutes in CV mode when my smallest capacity cell gets around 3.45V. As I mentioned I think just using the CC phase and shutting off will keep my cells at a lower SOC and still give me plenty of range. I'll compensate for temperature by reducing current when it's cold, otherwise increased internal resistance will push the voltage higher and shut off charging prematurely. This assumes the voltage was set in warmer weather. If I want a higher SOC I can just dial down the current, or switch the timer back on.


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## CFreeman54 (Jan 14, 2009)

Thanks JRP3: I suspected that Elcon was introducing unnecessary complexity with their half dozen different charge curves to choose from.


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## CFreeman54 (Jan 14, 2009)

A few more pics.


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## CFreeman54 (Jan 14, 2009)

Here is what happens when a BMS wire or board shorts out (see pics). In addition to zorching most of the BMS circuit boards it burned through the polycarbonate battery box cover and scorched the tops of two Thundersky batteries, one quite severely. 

It was very exciting when the cabin filled with smoke and with fire visible in the rear view mirror and all; I thought my passenger, auto mechanic/assistant and friend, Russell was going to jump out of the moving car before I could find a place to pull off the road. 

I decided to pull out all the wiring and BMS boards, bottom balance the pack, and monitor it with an EV Display Meter (Thanks Dimitri).

Amazingly the burned batteries were reading normal (3.28 V) and seemed to be functioning when I backed the car out of the garage and drove around the driveway a couple times. I contemplated removing the really blackened cell, but it was reading so normal...and such a shame to throw a way a brand new cell, I decided to leave it. Mistake! 

I was taking someone else for ride and decided to punch it a little. As soon as I pulled some amps from the pack there was a "poof" and a little puff of smoke from the trunk battery box. (no, I don't have a new polycarbonate cover on it yet.) I turned and headed home, which was maybe only a quarter mile away, at a moderate pace. WHen I stopped and opened the rear hatch there was a small candle like flame coming out the top of the blackened battery. I poured some baking soda on it and it immediately went out.

I decided for now to just bypass the bad cell, since removal means removing the banding and rebanding the group of cells the bad one sits in. I added a 100Ah LiFePO4 cell from Zhuhai battery that I had lying around to replace the lost TS cell. Since it is in series with the TS's it is also a good chance to see how it measures up to the TS cells.


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## CFreeman54 (Jan 14, 2009)

Here is a pic of the Zhuhai LiFePO4 100Ah Cell. 

Then I decided to add another three Thundersky Cells...oh, pardon me, Winston Battery Cells, just to make sure my LiFePO4 pack is above the parallel AGM pack voltage wise. I have a few dead AGMs and don't know why. The car had been sitting for seven months while I was in China. The other AGMs are all sitting at about 12.0 V and appear fine...it is very strange!


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## CFreeman54 (Jan 14, 2009)

I also added an inertial switch mounted on the firewall behind my seat to kill the pack voltage in the event of a severe accident. It switches a Kilovac EV200 Contactor that kills the e-'s flowing from both the AGM and LiFePO4 pack. I can manually switch off the emergency contactor by turning the ignition key to off. Later I can add a manual red kill button to the circuit to hang out the back hatch to comply with NEDRA rules when I race.


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## JRP3 (Mar 7, 2008)

That's too bad, another perfectly good cell ruined by a BMS. Which BMS was that?


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## etischer (Jun 16, 2008)

To me it looks like it could have also been due to poor wiring. The wires in this pic (top right) are stripped too far back, and look very close to being shorted out already. There is no insulation on the resistor leads. With that many exposed conductors, and vibration from the road... I am less inclined to blame the BMS. If the BMS board failed, it would simply blow the traces off the board. This fire looks like it had a few more KW feeding it.


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## JRP3 (Mar 7, 2008)

Fair point, but the bare resistor leads are part of the BMS, and just having a BMS introduces a larger number of potential failure points. Certainly no BMS is a better choice than a poorly implemented one.


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## CFreeman54 (Jan 14, 2009)

I am hesitant to name the BMS manufacturer because I do not specifically blame them. As far as I know all the cell level circuit board BMS's are similarly designed. 

Regarding the stripping back on the wires; I tried not stripping back very far when installing, but with shorter leads inserted in the plugs, was having trouble with them pulling out when attaching the wires to the next BMS board. Poorly secured wires would have created an even greater danger of vibrating free and shorting during driving. I am confident that unless the plug end of the wiring became detached those points could not short, because they are held in place by the "screw down" in the plug. Also, the wires in question in the picture above were already partially pulled out of their plugs when I yanked the adjacent burning/burned circuit boards out of the pack. (Yes, I know, not the best way of removal, but when you are afraid your car is going up in a plasma ball and watching successive BMS boards "pop" thinking is a bit unclear.) When they were fully inserted not so much bare wire was exposed.

It is hard to tell for sure what happened, since the evidence is vaporized, but my best guess is that one of the adhesive BMS circuit board mounts let go with road vibration and allowed a BMS board to short on the battery terminals or power leads. The cell vent "hump" makes it hard to secure the boards flat on the top of these cells to begin with. I think if I were to do it again I would mount the BMS boards on a separate panel rather than on the cells themselves, but manufacturer instructions say to mount on the cell top, and no-one else had advised me against it.


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## JRP3 (Mar 7, 2008)

There are a number of differences between BMS designs. For example, Dimitri's MiniBMS, advertised on the side of this page, uses a terminal bolt through the circuit board to secure the board to the cell, not an adhesive patch. He also offers a distributed version which does not mount on the cells. If I were so inclined to use a BMS it would be his.


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## weber (Apr 22, 2009)

Thanks for posting about this, with photos, so others can avoid the same fate, or worse. I believe it highlights the need for a BMS that can raise an alarm if any cell goes over-temperature.

I don't think any of the theories put forward so far have adequately explained the second fire. Here's my guess:

Before the first fire, there was a high resistance joint between the soon-to-be-burned link and its left hand (in the photos) terminal. This could well have been due to the poor wiring practice of clamping fine-stranded copper wire under the head of the bolt instead of using a crimp lug. The strands can slowly creep past each other over time, thereby relaxing the pressure of the bolt holding the link to the terminal.

Under load the terminal to link connection starts to dissipate significant power. At first it just gets a little bit hot, but this speeds up the wire creep and increases the resistance further. This may have been getting worse over several trips.

On the trip of the first fire, it was producing so much heat (which was conducted to the inside of the cell) that the cell was rapidly venting the vapours of its highly flammable electrolyte solvent (a mixture of ethers). All that was missing was a source of ignition.

By now the link would have melted off its own insulation and a spark would have been caused by either 
(a) the high resistance connection going so high it arced over, or
(b) one of the rats-nest of wires that was crossing over the glowing link having its insulation melted and shorting to the link, or
(c) the self-adhesive BMU mountings letting go, as all self-adhesives do once they get a little warm, and the bare resistor leads shorting to the link.

You blamed the BMS (which seems a popular prejudice in some circles at present) and did not suspect the link/terminal connection, so the high resistance remained. So exactly the same thing happened the next time you drew significant current, only this time it happened sooner and there was no cover on the box, so the cell electrolyte vapours could not built up significantly before being ignited. This time, the BMS board or wiring could not have been the source of ignition. It was presumably arcing at the link terminal connection.

It's clear from the photos that when you removed the BMS you just snipped the wires off near the terminal bolts rather than loosening the bolts, removing the wires and retightening the bolts. So this is likely to happen again to a different terminal.


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## JRP3 (Mar 7, 2008)

Good points on the lack of terminal rings.


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## weber (Apr 22, 2009)

I just noticed something else that pretty much clinches the loose-link theory. 

The copper link concerned, spans between two cells that are not banded together. They are banded into separate blocks of cells. This makes it inevitable that the bolts will work loose, even without wire strands under the bolt-head.

Please CFreeman54, as well as removing all the wire ends from under the bolt heads, remove every solid link that spans between separate blocks and replace it with a piece of flexible cable with crimp-lugs. Otherwise it is only a matter of time before it happens again.

And then maybe work on the battery mountings, which at the moment appear best described as "gravity and prayer".


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## CFreeman54 (Jan 14, 2009)

I don't recall blaming the BMS...I simply posted the pictures showing the results of the short. 

Actually, the wires are not clamped under the terminal bolts. They are attached to washers which are clamped under the bolts. Not as neat as terminal rings but secure non-the-less. The bolts could not have vibrated loose and caused resistance; they did not have time to do so... the first fire happened on the third test drive of the car and the car had less than 10 miles of driving on it, mostly at 25 mph in a housing development. Also, the bolt was tight when I removed the copper strap from the burned cell. 

Since the one BMS board was completely vaporized the evidence points strongly toward it as being the point of the short. The adhesive softening on the BMS board mounts allowing it to move with vibration and contact the terminals or copper straps is likely. If the bottom of the board hit a terminal/strap that would do it.


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## CFreeman54 (Jan 14, 2009)

Since the wiring is attached to washers I can not simply loosen the terminal bolt and remove the wires. I have to completely remove the bolt and the washer with the wire attached. I had not done that yet at the time the pictures were taken.


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## CFreeman54 (Jan 14, 2009)

On the second fire, which was rather insignificant compared to the first, the copper strap at the connection with the negative terminal of the burned battery was vaporized. This leads me to believe there was an arc between it and the internal electrode of the battery. Since the top of the battery had been so badly burned in the first fire it is very possible that it was no longer an effective insulator separating the internal electrode from the copper strap above it.


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## CFreeman54 (Jan 14, 2009)

The flexible cable between separate cell blocks is a good idea....easier than banding the blocks together or checking bolt tightness weekly.

The battery hold-downs are in planning. I can't enter the car in NEDRA events without them. As stated the car has only been driven on a few test drives around the neighborhood so far. Any ideas on securing them in composite battery boxes? I hate boring holes through my carbon fiber boxes. It seems the only way to secure hold- downs though.


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## weber (Apr 22, 2009)

CFreeman54 said:


> I don't recall blaming the BMS...I simply posted the pictures showing the results of the short.


You started the post with "Here is what happens when a BMS wire or board shorts out". While I'm thinking "Here is what happens when a joint carrying 600 amps (or more?) goes high resistance".



> Actually, the wires are not clamped under the terminal bolts. They are attached to washers which are clamped under the bolts. Not as neat as terminal rings but secure non-the-less.


OK. How were the wires attached to the washers? Were there any _spring_ washers? 



> The bolts could not have vibrated loose and caused resistance; they did not have time to do so... the first fire happened on the third test drive of the car and the car had less than 10 miles of driving on it, mostly at 25 mph in a housing development.


With the lack of tie downs and the fact that the strap bridged between separate blocks, it would only take one good accelleration or braking.



> Also, the bolt was tight when I removed the copper strap from the burned cell.


That could be due to it having been partly welded in by resistance-heat or arcing. Or it could be because the cause of the high-R in the first place was that the bolt bottomed out in the thread before providing sufficient pressure on the strap. This can happen because the thread was not cut deep enough in the terminal, or the expected combination of flat washer and spring washer was not used, or the bolt was slightly too long, or the strap was thinner than the standard straps.

But OK. We may never know _how_ the high resistance occurred if it did, but I'll spell out what I think is the evidence for it below.



> Since the one BMS board was completely vaporized the evidence points strongly toward it as being the point of the short. The adhesive softening on the BMS board mounts allowing it to move with vibration and contact the terminals or copper straps is likely. If the bottom of the board hit a terminal/strap that would do it.


As someone else mentioned above, if the BMS board had shorted to a terminal or strap, that's at most 3.3 volts across somewhere it shouldn't be and we'd have at most some vapourised tracks on the board.

And I note that the terminal in question is a _negative _terminal and you had fuses in all your _positive _BMS leads as best I can tell. So in fact all that would have happened is a blown fuse.

When a terminal connection goes high resistance, and when we say "high" we're talking maybe 100 milliohms, and you pull 600 amps through it, you end up with 60 volts across it, and therefore 60-3.3 volts across the BMS board. This will cause some piece of silicon on the board to (very briefly) turn into a little highly-conductive molten blob and provide a lower resistance path for much of that 600 amps to flow through the BMS board instead of the bad joint. 600 amps times 60 volts is 36 kW.

What about the fuse in this case? It is probably designed for 32 Vdc max. At 60 V it becomes irrelevant. It will vapourise at about the same time as the blob of silicon on the board and both will be replaced by some now-highly-conductive air, in other words arcs. An established arc is like a mega-powered zener diode. If its voltage threshold of about 1 volt per millimetre is maintained it will take as much current as it can get. Its dynamic resistance is negligible.

But long before this spectacular event, that terminal would have been heating enough, even at low currents, to cause the electrolyte in that cell to boil and be gassing out of the vent, to be later ignited by the vapourising BMS board. Had the BMS board been of a kind that warned of high temperatures or high strap voltages (or preferably both) it would never have got this far. And had the battery box been well ventilated, the electrolyte vapour could not have built up to a high concentration.

Two possible reasons why the second fire was much less spectacular: 1. Most of the electrolyte was already boiled off, and 2. There was no lid on the box.

Now, the evidence for a high-R joint: 

Notice the shape of the pattern of burning on the tops of the cells. It is roughly pair-shaped. It completely surrounds one terminal and follows the strap from that terminal, tapering off toward the other terminal. If the BMS board had been the source of all the heat, I'd expect a different pattern. But then it's pretty hard to tell from the photo and with all the baking soda.

What does the hole in the lid tell us about where the epicentre was?

Also notice the patchy look of the terminal's mating surface after the strap has been removed.


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## weber (Apr 22, 2009)

CFreeman54 said:


> On the second fire, which was rather insignificant compared to the first, the copper strap at the connection with the negative terminal of the burned battery was vaporized. This leads me to believe there was an arc between it and the internal electrode of the battery.


This is of course entirely consistent with a high resistance joint getting worse. The arc may have been from the strap to the negative terminal it was bolted to.

Regarding your hold-down problem. If you have a secure means of attaching the lids to the boxes, can you use some insulating material to transfer that pressure from the underside of the lid to the "shoulders" of the cells. Some glassed-in wood?


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## toddshotrods (Feb 10, 2009)

Wow, this is actually a great discussion! Regardless of the BMS, or not to BMS, debate that inevitably occurs when that acronym is spoken or typed, digging into the possible causes of such a fire is a good thing for everyone. Even if the theories are incorrect, it's food for thought when building a system - all the things that _can_ happen...

Creig, regardless of what caused the fires, the possible causes here are good things to look into and eliminate, over time. If you ever have your packs diassembled, it would be good to check and see if the bolts are bottoming out - on each and every lug. That's a simple matter of screwing a bolt in with no strap or wires and measuring the gap (if there is one) before it begins to tighten. Any suspect lugs could be checked further with a torque wrench to see how tight it gets before the gap is closed properly. In racing, engine-building, and some aspects of customizing, it is common practice to run a tap through critical holes, before final assembly, to be certain that final torque you put on the bolt is actually doing the work you need it to. It's time-consuming but it saves parts and sometimes lives. It would seem to be good practice with 100s of volts of batteries...

Also Creig, I got your messages. As you noted, I have been _extremely_ busy lately. I typically commnunicate by text and email, because finding blocks of available time to chat in person and by phone has been all but impossible. I'm posting this here and will shoot you an email too.


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## Tesseract (Sep 27, 2008)

weber said:


> But OK. We may never know _how_ the high resistance occurred if it did, but I'll spell out what I think is the evidence for it below...


Excellent analysis, weber, and I have to say it certainly looks to be the most likely based on the evidence given, especially since others here have reported incomplete threading of the terminals in, e.g., Thundersky cells.


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## CFreeman54 (Jan 14, 2009)

Weber: I'm not sure how you expected me to head my entry. That a short occurred through the BMS is a fact. Whether resistance is to blame or not is theory or speculation, even if well educated theory/speculation. 

The wire is doubled back around the washer and twist tied tight with needle-nose pliers. I soldered a few of them with a drop of solder where the twist meets the washer, but after comparing the soldered to the non soldered (by pulling on them firmly) I could tell no difference, so gave up on soldering. That washer is secured under a lock (spring) washer with the terminal bolt. None of the other connections are loose and are difficult to remove even when trying. Actually, I can pull the wires out of a terminal ring where only pressure/friction is securing them easier than pull one of these connections free.

_<With the lack of tie downs and the fact that the strap bridged between separate blocks, it would only take one good accelleration or braking.>_ 

But the cells are wedged into the battery box so tightly they are difficult to install or pull out; they can not move. It is not like they are sliding around in the bottom of the battery box. On sides where the cells were not a tight fit foam is wedged between the cells and the battery box walls. Also, the copper plated busbar that was there was a "U' shaped link made of three thinner layers; it has spring. It probably has almost as much play as my 4/0 welding cable does, at least along the east-west plane.

Weber: Your explanation sounds plausible for the first BMS board perhaps, but I stood behind the car and watched the short travel through the BMS popping successive boards (my passenger did too). As this occurred, there appeared to be “lightning” (like a Tesla coil emission) traveling through (around/between the boards) the BMS circuit. (It was rather spectacular actually; I would have thought it was cool had it not been burning up my car/BMS). There was no 600 amps flowing through the power circuit then; The contactors were open and I already had the manual disconnect pulled. Where was the voltage coming from? Why didn’t the amperage vaporize the 22 gauge wire connecting the boards and act like a fuse saving the other boards? I have a lot of questions but I am not convinced by any of the answers.

The fire appeared to be mostly the boards and wire/wire insulation that were burning. They looked like a Fourth of July sparkler at first, then de-intensified to a more normal looking fire. They were located above the scorched cells during the fire. Of course the polycarbonate lid was burned through above the fire (the lid was not airtight). The burning boards and wires were sitting on the battery tops that are scorched, so the burn pattern may be more evidence of where the fire was than of what caused it. 

<_The arc may have been from the strap to the negative terminal it was bolted to._> 

I am not sure I see how you can get an arc from a battery terminal to a copper strap bolted tightly to it. On the second incident I am absolutely positive the strap was tight. I had just bolted it on securely and had not driven more than 200 yards out of the driveway. (I have seen no signs of short or poorly tapped bolt holes in the Thundersky batteries I have. )

<_Also notice the patchy look of the terminal's mating surface after the strap has been removed._>

Yes, but that look is a result of the second incident, in which there definitely was an arc between the strap and something….I think the battery’s internal electrode (the copper strap is discolored from the heat of the arc too, just adjacent to where it is vaporized). My reason for thinking that is that the battery top is sufficiently damaged to act like a wick and allow electrolyte to burn like a kerosene lamp at the battery top. With essentially no insulator between the strap and the electrode, they are in close proximity and an arc between them seems likely. 

If pressure is an acceptable way of holding down batteries, then the lateral pressure from the battery box sides should meet the requirements to prevent lateral movement of the batteries. Where they are not wedged immobile by the battery box sides there is foam tightly wedged between them and the box wall. While not sufficient in event of a roll over, nor sufficient to meet NEDRA regulations, cells can not shift about under normal driving conditions. For a test drive around the neighborhood this should not be the source of a problem.

If people want to use a BMS I have no problem with that; I obviously thought it was a good idea or I wouldn’t have had it in my car. I didn’t find installing the 504 fine gauge wire connections particularly fun though, and after this incident do not plan to go to the expense and time to replace it if there is a simpler way. Those of you who feel you can install something like this perfectly with no error, go for it. Just be aware small mistakes can be costly.


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## weber (Apr 22, 2009)

CFreeman54 said:


> Weber: I'm not sure how you expected me to head my entry. That a short occurred through the BMS is a fact. Whether resistance is to blame or not is theory or speculation, even if well educated theory/speculation.


Fair enough. I guess I'm a little sensitive, having seen some kneejerk blaming of BMS for other fires, without any evidence. There are definitely some badly designed BMS out there, that are definitely worse than no BMS. Yours was one of them. But that doesn't mean we should tar them all with the same brush. And it doesn't mean it actually _started _the fire in this case.



> Weber: Your explanation sounds plausible for the first BMS board perhaps, but I stood behind the car and watched the short travel through the BMS popping successive boards (my passenger did too). ...


Let me guess. Your 156 V traction pack has one side connected to chassis potential and half of the BMS signalling wires draped all over the terminals were also at chassis potential. Let me also guess that these signalling wires did not have an insulation voltage rating anywhere near 156 V. Let me also guess that the BMS wire/board arcing travelled only in the direction of _increasing_ potential above chassis.

It takes 3000 V per mm to get an arc started, but once it's started it only takes 1 V per mm to keep it going, provided it can pull at least 10 amps.



> I am not sure I see how you can get an arc from a battery terminal to a copper strap bolted tightly to it.


You can, and will, if the joint has high enough resistance and you try to pull a large enough current through it. A significant fraction of the pack voltage can appear across the resistance, which may be a thin oxide layer.

If it was 60 volts and the gap was 0.02 mm, there's your 3 kV/mm to get it started.

If the joint under the strap was good, why would it arc from the _strap _to anythinginside the cell? If the joint was good the negative electrodes inside the cell would be at the same potential as the strap and they are much closer to the positive electrodes, so any such arcing would just happen _inside_ the cell.



> On the second incident I am absolutely positive the strap was tight. I had just bolted it on securely and had not driven more than 200 yards out of the driveway.


Did you remove the link completely, examine the mating surfaces, clean them, and reinstall it? Or did you just tighten the bolts?


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## CFreeman54 (Jan 14, 2009)

Weber: 

It may well be an error in my installation method that caused the short in the BMS. I still suspect the place to point blame is at my cell mounts though. I know that I had trouble getting them to stay secured over the cell vents. I had some pull loose while “daisy chaining” the adjacent boards. I even added industrial strength Velcro because I felt the adhesive clip mounts were not sufficient alone. If you look at the pics you can see some of it still attached to the cells after I removed the BMS. I know that the burned boards (the couple that burned and were not vaporized) were dangling loose in the fire. That leads me to believe vibration knocked them loose and they touched the strap carrying 160V. 

I’m sure no perfectly executed BMS ever starts a fire, even a poorly designed one. (I am not saying mine was poorly designed). I mean, who designs a BMS to start fires? The point is who can perfectly execute one? I touched an OVP (over voltage protection) or UVP (undervoltage protection) wire (can’t remember which- UVP I think) to an adjacent port while installing the BMS and blew three boards in the short. The ports on the boards are only a couple mm apart. (I mounted Micro- Hymenoptera under a dissecting scope (microscope) for several years as my job, so I don’t think I have particularly unsteady hands.) Wiring something on a bench in front of you at good height/angle/distance and with good lighting is completely different than than wiring something in the installed battery box of a car, in a garage where your light, reach and position are all unfavorable and you have high voltage /amperage power cables right next to your hands/tools. 

If you have 500 and some of these wiring connections to make under these unfavorable conditions the *probability *of an error greatly increases. An *error *involving 22 ga wire and circuit boards attached to 1000A cells will result in fireworks.

The traction pack is completely isolated from the chassis, or at least it is supposed to be. While removing the BMS I found a ground fault when my arm touched the trunk latch while unscrewing a battery terminal. It has voltage but apparently very little current; it will not light a 100W light bulb. I followed it back to the most positive Li ion cell, but still can not see any location of contact with the chassis. Someone suggested unplugging the charger to see if it is coming from it. If it is coming from the charger the short may have occurred a few days ago when I attempted to charge the parallel AGM pack which had a dead battery in the circuit (no continuity in the circuit). I have read this can damage a charger. The initial BMS fire occurred a few months ago. 


Quote:
I am not sure I see how you can get an arc from a battery terminal to a copper strap bolted tightly to it. 

_<You can, and will, if the joint has high enough resistance and you try to pull a large enough current through it. A significant fraction of the pack voltage can appear across the resistance, which may be a thin oxide layer.

If it was 60 volts and the gap was 0.02 mm, there's your 3 kV/mm to get it started.

If the joint under the strap was good, why would it arc from the strap to anythinginside the cell? If the joint was good the negative electrodes inside the cell would be at the same potential as the strap and they are much closer to the positive electrodes, so any such arcing would just happen inside the cell.>_

But the terminal appeared clean and shiny, and the strap was new, just fabricated from copper pipe, with the connection freshly drilled and filed, so if the joint under the strap was good, there should have been no resistance to begin with.

Quote:
On the second incident I am absolutely positive the strap was tight. I had just bolted it on securely and had not driven more than 200 yards out of the driveway. 

_<Did you remove the link completely, examine the mating surfaces, clean them, and reinstall it? Or did you just tighten the bolts?>_

See above. The old link was damaged in the initial fire and was removed. 

I wonder why some E.E. can’t design a BMS that infers voltage/current/SOC from Hall Effect sensors placed on the cable or straps between cells and two wires to the most + and – battery in the pack? Other than for the two wires to the most + and -, the whole system would be isolated and no small gauge wires would be needed.


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## Anaerin (Feb 4, 2009)

CFreeman54 said:


> I wonder why some E.E. can’t design a BMS that infers voltage/current/SOC from Hall Effect sensors placed on the cable or straps between cells and two wires to the most + and – battery in the pack? Other than for the two wires to the most + and -, the whole system would be isolated and no small gauge wires would be needed.


That's actually quite simple. Hall Effect sensors can only measure current (Amperage), not Voltage. As a BMS needs to monitor Over-Voltage and Under-Voltage, current sensing isn't of much use. You could count amps in to/out of each cell, but this wouldn't be much help as you would have no way of controlling where the power goes, and as LiPo cells don't increase resistance as they fill there is no self-balancing tendencies, so you would just get a sudden cut as the lowest cell approached empty (or the highest cell approached full, if charging).

The best kind of BMS would be one where all power goes through the BMS directly, each cell's power in and power out being strictly controlled (So a pair of FETs on the + side to control the amount of current to each individual cell, or to short around it). Then, each cell receives only the amount of power it can take when charging, and switched out and receives no power whatsoever when full, and as each cell approaches empty, the FET limits the amount drawn out of the cell to only what the cell can provide. Of course, this would severely impact the efficiency of the system, and be extremely expensive and complicated to create.


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## weber (Apr 22, 2009)

CFreeman54 said:


> I still suspect the place to point blame is at my cell mounts though. ... That leads me to believe vibration knocked them loose and they touched the strap carrying 160V.


What strap carrying 160 V? 160 V with respect to what? 

Sorry to be pedantic, but can't be too careful with safety issues like this. A strap can't really be said to "carry" a voltage. It carries a current, analogous to a flow rate. A voltage, analogous to a pressure difference, exists between two points. Although we do sometimes talk of a voltage at one point when the second point is understood to be something like the ground or the car chassis. But only a terminal at one end of the string of cells could be at 160 V relative to chassis, and then only if the terminal at the other end is connected to chassis.

Make no mistake, I think self-adhesive pads or velcro are utterly ridiculous means for attaching BMUs (battery monitoring units) to cells. The slightest warmth will soften it and it will let go. And to have a ratsnest of fine wires crossing over each other and over cell terminals and straps, and to have resistors with long bare leads, is a recipe for disaster. But in this case, as I've explained, the evidence points to major heat generation _preceding _the BMS failure. And BMS failure certainly doesn't explain the second fire, since the BMS had been removed. 

I'm trying to come up with another explanation of the melted spot on the new strap after the second fire, other than a high-R joint between it and the terminal below it. Is there no obvious arc burn on the terminal or terminal nut below where the burn on the strap was?



> I touched an OVP (over voltage protection) or UVP (undervoltage protection) wire (can’t remember which- UVP I think) to an adjacent port while installing the BMS and blew three boards in the short.


This makes it blatantly obvious that there has been a connection between your traction pack and chassis (or whatever supply your BMS master runs off) since before you started installing the BMS.



> An *error *involving 22 ga wire and circuit boards attached to 1000A cells will result in fireworks.


Not if the cells are floating w.r.t. the BMS master. I think any traction pack over 36 volts nominal should be floating. And if they are intended to be floating then they should have a contactor at both ends. And over 96 volts nominal they should have an alarm for if a fault causes them to no longer be floating. And even if it's floating, there should not be thin wires or parts of circuit boards at chassis (or chassis-referenced) potential inside the battery box, unless they are insulated to withstand the full pack voltage (in case of a fault to chassis).



> The traction pack is completely isolated from the chassis, or at least it is supposed to be. While removing the BMS I found a ground fault when my arm touched the trunk latch while unscrewing a battery terminal.


Not the best way to find out.  I shouldn't smile. 120 Vdc is considered lethal (at least in Australia) and much lower voltages can be lethal if you're wet or have a large area of contact. Cardiac fibrillation is the main danger. I hope you never work on this stuff alone. And insulating gloves would be a good idea.



> It has voltage but apparently very little current; it will not light a 100W light bulb. I followed it back to the most positive Li ion cell, but still can not see any location of contact with the chassis.


Do you mean that the most positive cell measured zero volts w.r.t. chassis? 



> But the terminal appeared clean and shiny, and the strap was new, just fabricated from copper pipe, with the connection freshly drilled and filed, so if the joint under the strap was good, there should have been no resistance to begin with.


Would you humour me and screw a bolt into that terminal now and see if it bottoms out early? Otherwise I'm at a complete loss to explain the evidence of arcing you describe on that new strap. Unless perhaps if the cell was now so dried out that _it _presented the high resistance (a hundred milliohms or so) and there was a carbon (soot) track from the terminal in question to a near neighbour (to the left or below it in the photo). Any evidence of arcing on any of those?

Yes, all soot should be completely removed from insulating surfaces after an event like that, by sand-papering or grinding or completely cutting away the surface if necessary.


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## CFreeman54 (Jan 14, 2009)

Anaerin: My Physics is a little rusty, but isn't the magnetic field intensity around a wire a result of the voltage x current? If the voltage does indeed have some influence on the field intensity, and the pack voltage is known, then the Hall Effect Sensor could be used with the proper computer chip and equation to infer voltage and current. That was what I was thinking.


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## steven4601 (Nov 11, 2010)

Physics has not changed since 2005 as far as I know.
This applies for DC upto 1/15th..1/10th wavelength for cables:

The voltage across a conductor has nothing to do with the magnetic field produced by the current running through the conductor. Voltage will be induced across an conductor due to current but it is not where the magnetic field is induced by.


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## CFreeman54 (Jan 14, 2009)

Weber: OK, I should have said "touched a cable with a potential of 160 V" . 160V (Ok, maybe not exactly 160 V, but > 100 V) .....relative to the other end of the daisy chain of BMS boards. 

The arc burn on the new strap is on the end of the strap just back to the outer edge of the terminal hole; the tip of the strap is vaporised. A picture is easier than words...I'll try to get a photo for the next post. 

Quote:
I touched an OVP (over voltage protection) or UVP (undervoltage protection) wire (can’t remember which- UVP I think) to an adjacent port while installing the BMS and blew three boards in the short. 
_<This makes it blatantly obvious that there has been a connection between your traction pack and chassis (or whatever supply your BMS master runs off) since before you started installing the BMS.>

_Well, the BMS manufacturer E.E. said it was because the BMS ground is referenced to the battery pack. As I said, there is no (known) connection between the traction pack and the chassis. Only the pack and the BMS._

<Do you mean that the most positive cell measured zero volts w.r.t. chassis?> _

Yes, the most positive cell measures 0 volts with respect to the chassis. 

_<Would you humour me and screw a bolt into that terminal now and see if it bottoms out early? Otherwise I'm at a complete loss to explain the evidence of arcing you describe on that new strap. Unless perhaps if the cell was now so dried out that it presented the high resistance (a hundred milliohms or so) and there was a carbon (soot) track from the terminal in question to a near neighbour (to the left or below it in the photo). Any evidence of arcing on any of those?

Yes, all soot should be completely removed from insulating surfaces after an event like that, by sand-papering or grinding or completely cutting away the surface if necessary. >
_
There was plenty of carbon soot from the event. Even the window above (the rear hatch) was covered in black soot. It makes sense that an arc could have formed from the strap to the carbon to something, but the only thing other than the strap I see damaged is the already damaged battery, which was directly below the strap of course. 

It sounds like I should even now do some more cleaning up of the battery tops and the trunk compartment if arcs can form that easily. ( I think I'll wear the rubber gloves for that job! A damp rag and electricity doesn't sound like a good combination!) I thought that at 160-170 V the distance an arc could jump was only about 1/8 of an inch or so? I guess if there is a carbon track making a connection it really isn't jumping though.


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## CFreeman54 (Jan 14, 2009)

Steven4601: It was a little before 2005 when I had to study physics. 

I'm a little confused by what you wrote. I think the just of your meaning is that a 10A current at 160V will produce the same magnetic field as a 10A current at 1 V ? Is that right?

I really need to go read a physics text.


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## steven4601 (Nov 11, 2010)

Yes.
Pushing 10A through a super cooled conductor will give the same magnetic field as through a glowing piece of tungsten yes 

Something interesting :
Can you measure current through vacuum? 
If you'd imagen an evacuated glass bulb with a plate capacitor inside. If you'd place your current measuring apparatus (a current probe in this case) over the bulb and at the hight where the two plates are placed. And you'd run an current through the capacitor to charge it. (AC works too, irrilevent in this example though) then you'll measure the same current as was going through the wire to the capacitor as it was going through air.....


Recently I saw an video also describing this phenomena or physics fact and was quite entertaining. He sounds surprising a lot like a Dutchman speaking English. 

ah here it is:

http://www.youtube.com/watch?v=FGaSeSP0tCM


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## Coulomb (Apr 22, 2009)

CFreeman54 said:


> I thought that at 160-170 V the distance an arc could jump was only about 1/8 of an inch or so?


In dry air, it takes 3000 V to jump just 1 mm. But the problem is that once an arc starts, and has more than 10 amps flowing, you have plasma, not ordinary air, and plasma behaves very differently. Once a 160 V plasma starts, it can keep going over 160 mm (3000 times further than air).

Also, once you have plasma starting, it shoots metal snot everywhere, starting daughter plasmas. I believe that this is what you saw with the bright light (the plasma of the arc) jumping from place to place across your pack.

That's one reason that all those bare resistor wires are such a bad thing.


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## CFreeman54 (Jan 14, 2009)

Wow! if a plasma arc can jump that far it sounds like an emergency disconnect could have a hard time breaking the circuit. When I pull my emergency lever the Anderson Disconnect separates only about two inches.

During the onset of the initial event I probably was seeing plasma arcs. When I was standing behind the car watching it travel across the BMS wires/boards I'm not sure though. That "lightning" was traveling across the panel mounted BMS boards/wires that could not go directly on the cells mounted "down under" the main battery box. It looked like a blue lightning bolt. 

I guess one solution to getting rid of the exposed resistor wires, if one were to use this kind of BMS would be to shrink wrap the resistor wires.


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## CFreeman54 (Jan 14, 2009)

I've been hunting the source of my ground fault for two days now. I can't find the source of the battery pack short to the chassis. Everything looks well insulated, no contacts touching the chassis, most wire also inside corrugated plastic tube. I'm going to check the line going to the ceramic heater core tomorrow. If I find nothing there I am at a loss. If any of you Electrical Engineers have any suggestions on tracking it down please don't be shy. Suggestions on this one are most welcome.


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## EVfun (Mar 14, 2010)

Anaerin said:


> That's actually quite simple. Hall Effect sensors can only measure current (Amperage), not Voltage. As a BMS needs to monitor Over-Voltage and Under-Voltage, current sensing isn't of much use.


Do they make Hall Effect sensors that are designed to measure milliamps or (even better) microamps? With that you could measure cell voltage by measuring the current through a high value resistor across the cell. That would provide the much coveted isolated voltage measurement of cell in the traction pack.


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## CFreeman54 (Jan 14, 2009)

EVFun: Using a resistor/Hall Effect sensor combination sounds easy enough. I wonder why no one has made such an isolated BMS?


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## weber (Apr 22, 2009)

EVfun said:


> Do they make Hall Effect sensors that are designed to measure milliamps or (even better) microamps?


No. I'm afraid they do not. Here's the most precise I can find and it has a typical error of +-75 mA, and that's _before _you put it in an environment with stray magnetic fields all over the place.
http://www.allegromicro.com/en/Products/Part_Numbers/0714/0714.pdf



> With that you could measure cell voltage by measuring the current through a high value resistor across the cell. That would provide the much coveted isolated voltage measurement of cell in the traction pack.


It wouldn't eliminate an arc-over via the voltage-sensing resistor if one of the cell terminal connections is high-R and a high current is drawn from the pack. And you would still have to bring a foreign potential inside the battery pack to power the hall effect device.

Isolated voltage measurement is easy. You just have to isolate the _signals _as they enter and leave the pack, and as they pass from one BMU to the next (if they do).

Coulomb and I are trying to design the world's safest open-source cell-top battery monitoring units, with help from other members of the Australian Electric Vehicle Association forum. We plan to eventually run them in our MX-5/Miata EV on a pack with 228 LiFePO4 cells in series. That's 830 Vdc when on full charge. We will be taking signals in and out of each battery box via low-cost optic fibre. Signals between BMUs in the same box are opto isolated. There are almost no wires used in the system. The boards have "wings" that bolt to the terminals, on top of the straps. Signals are transferred between BMUs by flexible pieces of printed circuit board (PCB). Thanks to James Kennedy of Tritium for that idea. The only wires are some very short jumpers to connect the signals between BMUs when one PCB ends and the next one starts.


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## Coulomb (Apr 22, 2009)

CFreeman54 said:


> Wow! if a plasma arc can jump that far it sounds like an emergency disconnect could have a hard time breaking the circuit. When I pull my emergency lever the Anderson Disconnect separates only about two inches.


Yes. That's why emergency disconnects should be designed for breaking high DC currents. That usually means vacuum contactors with magnetic blowouts. Even then, something like an EV200 can only disconnect under load a dozen times before wearing out. In an extreme case it might be guaranteed to open only once. So you have to throw it away after it saves your vehicle from a disaster. Indeed you may also have to replace it after you make a mistake and disconnect under heavy load when you didn't mean to.

Interrupting high DC currents especially with inductive loads is quite a difficult thing.


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## CFreeman54 (Jan 14, 2009)

Well, I am glad I designed my car with both Anderson disconnects and a Kilovac EV200 contactor as emergency disconnects then.


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## CFreeman54 (Jan 14, 2009)

Weber: I see your interest in BMS's is not entirely academic. Anyway, I hope you design a good short proof BMS that simplifies installation and use. 

I wish you could be as helpful in suggesting how to find the battery pack short as you were vocal in asserting it existed. It is not proving easy to track down.


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## CFreeman54 (Jan 14, 2009)

I made sure all battery terminal extensions are encased in corrugated plastic tube. If the insulation voltage rating was too low and there was leakage to the chassis this should have solved the problem. Unfortunately, I am still getting a voltage reading between the chassis and the negative terminal of the batteries. 

I can see nothing touching the chassis, and everything but the batteries is disconnected. I am out of ideas where to look.


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## toddshotrods (Feb 10, 2009)

How many sub-packs do you have? I know you have at least two, LiFePo and Pb. Can you disconnect the sub-packs one by one to isolate the source? _E.g._, if you disconnect the Pb sub-pack and it goes away you've found the source. Then, you can break that pack down to find out where it's happening.


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## Coulomb (Apr 22, 2009)

toddshotrods said:


> Then, you can break that pack down to find out where it's happening.


Exactly. Use binary search.

First, disconnect a battery stap or connecting cable about the middle of the leaky pack (let's say it's the LiFe pack with all those wires). Hopefully, only one half has the leakage. In the pack with the leakage (or pick one at random if both are leaky) and disconnect a link or cable half way through that. It should take about 6 disconnects to get to one cell of a less than 64-cell pack. Once you have the leaky cell isolated, take it out and examine it carefully, and clean off any carbon, dirt, dust, water condensation, and so on. If the case is cracked, you might attempt to repair it, or replace it. While waiting for a replacement, it may be possible to run without that cell. It may well not be a cell; it could be charred wiring or wiring that has had carbon soot deposited on it.

If you repair a cell (e.g. with epoxy resin glue) and it has lost some electrolyte, it will likely be lower capacity than the others, so keep an eye on it. Ideally, measure its capacity, and remember that the capacity of the pack will be equal to the capacity of the worst cell.

But my guess is that it will be some carbon muck from the fire, either on a battery case or on some of the wiring.


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## CFreeman54 (Jan 14, 2009)

Todd: It is definitely in the LiFePo4 pack. The AGMs are disconnected. I tried homing in on where the voltage reading goes to zero, but it took me back to the most positive cell; still see no source of a short though. It is very puzzling...and annoying!


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## CFreeman54 (Jan 14, 2009)

Thanks Coulomb. I was starting to think it must be a battery leaking or carbon soot trail, because I can find no place a wire or cable is touching the chassis. The leak seems to be in the cells around the motor. Yesterday I disconnected the fuse, which connects between the trunk cells and the motor compartment cells, and the voltage on the chassis dropped to less than 11V, which maybe could be from the 12 volt agm accessory battery being grounded to it? 

The motor compartment was completely isolated from the fire though, so that eliminates soot I think. Since all the cells are in insulated boxes I am not sure I understand how anything can be getting to the chassis, unless a cell leaked a lot of electrolyte maybe...even then I think only the box in front of the motor may not be completely water(electrolyte)-proof. I have one inexplicably dead cell back there though...maybe that is a good place to suspect.


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## CFreeman54 (Jan 14, 2009)

Since those cells in front of the motor are strapped together, it will be a lot of fun trying to get the one out of the box!


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## weber (Apr 22, 2009)

CFreeman54 said:


> Weber: ... I wish you could be as helpful in suggesting how to find the battery pack short as you were vocal in asserting it existed. It is not proving easy to track down.


Sorry CFreeman54. The DIY forum failed to email me about this post, so I didn't read it until now (when it emailed me about your latest post).

It would be good to have a schematic or wiring diagram of your system that has better resolution than the one you posted earlier in this thread. There is much text I can't read. Maybe you have to post it in two parts or convert it to a black & white GIF (or at least one with fewer colours/shades-of-grey) to keep it under the forum limit while making it readable.

I think I see that you have a separate contactor in the positive lead from each subpack. Is that correct?

Correct me if I'm wrong:
With a voltmeter you read a steady voltage of about 160 V between the negative lead from either subpack and the chassis, with the negative lead being negative with respect to the chassis. And this 160 V is there, no matter whether the contactors are open or closed. But the resistance of this apparent fault from positive to chassis is not low enough to light a 12 V headlamp bulb when connected between negative lead and chassis.

Can you easily measure the current through that bulb at the same time as measuring the voltage across it? If not, don't worry.

You measure zero volts from positive terminal to chassis. I assume this is when the contactors are off. Do you measure zero volts on the LiFePO4 positive, but a volt or two on the Pb positive (wrt chassis) or the other way 'round?

Whichever one reads closest to zero volts, can you then switch your multimeter to read resistance and tell us how many ohms the fault is? Don't do this if there is more than a volt or two there as it may damage the meter. If there is any voltage there at all it will make the ohms reading inaccurate, but you can check that by reversing the direction of the meter to ensure the ohms reading stays much the same.

Since you have carefully checked and double-insulated cables, it may be that the fault is inside some component such as the motor, controller, contactor etc. It may even have been deliberately designed into that component.

I guess the first one to check is the positive contactor for the subpack that has the zero volt positive. Unbolt the battery lead from the contactor and insulate it, and with your meter on volts first, and then if that's zero, go to ohms, see if the fault is on the battery side or the contactor side of the disconnection. If it's on the contactor side, then try disconnecting the lead on the other side of the contactor and see which side of /that/ disconnection the fault is on. 

Like toddshotrods says. You just have to keep disconnecting things and seeing which side the fault is on. Divide and conquer.


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## weber (Apr 22, 2009)

I was a little surprised to see those LiFePO4 cells with BMS wires still coming off them. I somehow imagined you'd removed that BMS entirely. So does this use the same BMS boards but this time they are somwhere other than on top of the cells?

If you're going to take skinny wires away from every terminal like that, the fuses need to be inside the battery box, in fact the fuses need to be as close to the terminals as possible. But unless the fuses are rated to interrupt a DC arc at the fully battery voltage they are almost a waste of time. Such fuses are sand-filled ceramic cylindrical fuses at least 10 x 38 mm and are not cheap.

That's why it makes more sense to have the BMS boards bolted to the terminals and only have optically isolated alarm signals or monitoring signals entering or leaving the battery boxes. Such BMS are already readily available. While ours remains incomplete and untested, my favourite is Rod Dilkes' EVPower BMS.
http://www.evworks.com.au/tech/EVPowerBMS/ 

Rod's is always going to beat ours on price (although ours is open source so you can build it yourself). The only reason we're not using his in our Miata/MX-5 conversion is that we have very high voltage requirements and wanted individual cell voltage monitoring.

I'm wondering if your battery to chassis fault is due to the design of your BMS. If you pull all the BMS fuses does the fault go away?
http://www.evworks.com.au/tech/EVPowerBMS/


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## CFreeman54 (Jan 14, 2009)

Weber & Coulomb: Thanks for the help in tracking down the problem. Sorry for the slow response. I have not been on the forum for a while....putting all my time into working on the car and into career issues. 

Weber: The wires you mention are the terminal extensions I wired so I can monitor the batteries around the motor that are under another battery box and inaccessible. (Yes, I know it is a bad design. The original plan called for 160 or 180 Ah LiFePO4 cells in the "above board" battery boxes. Those cells were not available at the time thanks to EV Components Co. and I had to settle with 100Ah LiFePO4s and a parallel string of AGMs for current. The extra , large AGMs necessitated adding last minute, unplanned battery boxes under the rear compartment main battery box to give sufficient room for the extra batteries.)

After tearing half the car apart and going through the batteries and wires one by one, I finally found the source of the ground fault in the most unlikely place. It was the only place left to look at that point. The terminal extensions that I have in the trunk for the inaccessible batteries around the motor were the only remaining place to look. The positive terminals are covered by the rubber flap of the trunk seal, which I intentionally left in place to act as a sort of terminal cover. Somehow, that rubber was conducting voltage to the chassis....almost no current but almost full pack voltage. When the "flap" was lifted off the terminals the voltage disappeared. When it was replaced the voltage returned. A layer of electrical tape lining the underside of the rubber flap that comes in contact with the terminals eliminated the voltage on the chassis. I still don't get it, because a couple kinds of rubber are semi-conductors, but rubber almost has to be engineered to conduct electricity. It is strange that a piece designed as a trunk seal would be conductive.

Anyway, I have the car back together again. I am dealing with some charger issues.


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## CFreeman54 (Jan 14, 2009)

The charger I had in the car was designed to work only with the BMS. The BMS throttles the charger down in current as the over voltage LEDs come on on each cell BMS board. 

Since the charger is installed in the center console between the seats, and was working OK on the AGMs, I decided to keep it and use it to charge the AGM batteries and get another programmable charger to charge the lithium pack that lost its BMS boards to the short. 

Unfortunately, I had to replace three AGM batteries due to me being in CHina for half a year and forgetting to disconnect the packtrakr remotes from the AGMs before I left. One of those batteries was in the center channel battery box where the gas tank used to be....a very inconvenient and unpleasant place to have to work if you don't have a hydraulic lift to get the car up overhead. A few days of crawling around under the car jacked up on jack stands finally got the new cell in and wired up. 

The new cells are at about 13.0 V and the "older" cells at about 12.3 to 12.6 V. I was trying to drop the new batteries down to similar voltage with a couple 30W resistors paralleled to the battery, but it was taking forever...and making me even hotter than the 95°F weather today. 

I don't entirely trust the BMS to bring the old batteries up to 13.0 V without cooking the new bats that are already at 13.0V. 

The new charger, a Manzanita Micro PCF-20, is sent back to the manufacturer for repair. During the initial setup on the first charge with it, the volts trim screw would not turn down to match the pack voltage. I am not sure if the screw was stuck or there was a problem with the screw head, or the insulated screw driver Manzanita gives you does not fit the screw head, but in any case, it would not turn down, and in the process of trying to turn it down the potentiometer screw FELL OFF into the charger ! Apparently the potentiometer fell completely off! I guess I should of gotten an Elcon and saved myself a thousand dollars and some frustration.


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## CFreeman54 (Jan 14, 2009)

Here is a photo of where the ground fault problem was originating. 

The black rubber trunk seal that is partially covering the positive terminals was the culprit. After coating the inside of it with electrical tape my ground fault is gone! Yeah!


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## RE Farmer (Aug 8, 2009)

CFreeman54 said:


> ... The positive terminals are covered by the rubber flap of the trunk seal, which I intentionally left in place to act as a sort of terminal cover. Somehow, that rubber was conducting voltage to the chassis....almost no current but almost full pack voltage. When the "flap" was lifted off the terminals the voltage disappeared. When it was replaced the voltage returned. A layer of electrical tape lining the underside of the rubber flap that comes in contact with the terminals eliminated the voltage on the chassis. I still don't get it, because a couple kinds of rubber are semi-conductors, but rubber almost has to be engineered to conduct electricity. It is strange that a piece designed as a trunk seal would be conductive. ...


"rubber" these days is usually a synthetic made from oil with carbon black (the stuff T. Edison added to the filaments of his first light bulbs to make them work) added for strength, UV protection and to make it black. Perhaps there's enough carbon or a coating that's conductive at 160V.


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## CFreeman54 (Jan 14, 2009)

Yes, apparently there is enough carbon in the foam rubber stuff to make it conductive.


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## CFreeman54 (Jan 14, 2009)

I've been getting some interesting results from the The EV Display monitoring my LiFePO4 pack and Paktrakr monitoring my parallel AGM pack. 

When I connect the two packs with the main contactors, the Paktrakr quickly starts to show the increased voltage in the AGM pack, which normally sits about 10 V below the Li pack. voltage rises until it is close to that of the Li pack voltage. The SOC gauge on the Paktrakr also increases to 100% from whatever state of charge it previously was. 

After a few minutes of driving however, the Li pack SOC indicated on the EV Display drops from 100% (when the Li pack is freshly charged) to near zero SOC. 

I know driving a couple miles can not be sucking 17 KWH out of my Thunderskys, and recharging the Li pack to full confirms only a couple of KWH have been removed from it. My first thought was that the energy was being transferred to the AGM pack, but I don't see how a 50 AH (@20 Hr rate) AGM can hold 100 AH of Li ion battery energy....also, the Paktrakr indicates that the AGMs are still at about 60% SOC even though the EV Display is saying the Lithiums are empty! 

Something about the interaction of these parallel packs is obviously confusing my monitoring equipment, but I can't figure out exactly how and what is going on. Any thoughts guys?

I am considering hooking some Cellog 8s up to the Lithiums to try to get a better handle on the situation, but need to make the wiring harnesses for them. Soldering those wires to the tiny plugs plug connectors should be a lot of fun!


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## JRP3 (Mar 7, 2008)

Can you put a clamp on meter between the two packs when you hook them up to see how much current is actually flowing?


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## CFreeman54 (Jan 14, 2009)

JRP3: You mean put the shunt for an ammeter between the two packs? I guess I would need one between the packs and one on the Li contactor line, and subtract the contactor current from the "to AGM" battery current. The line going to the AGM pack also leads to the contactor so if I put it there I could not distinguish whether it was going to the controller or to the AGM pack. 

I know I can not be "burning" 6 KWH per mile, but I also don't see how 18 KWH of energy from the Li pack can fit into a 8.2 KWH AGM pack...especially when the AGM pack is already 70% full????


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## JRP3 (Mar 7, 2008)

I was thinking using a clamp on meter when you initially hook up the packs. You say the AGM pack is normally 10V below the Lithiums, so that means when you hook them up current will flow from the lithiums to the AGMs to keep their voltage equal, I was just wondering how much. Putting a shunt between the packs to monitor while driving should also be informative. I'm not sure how your mixed pack is actually interacting, obviously something unusual is going on.


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## toddshotrods (Feb 10, 2009)

Is the SOC real-time, or an average based on how the vehicle is being used? The way Creig drives that thing, he's probably pulling a lot of current out of the AGMs and the Li pack is constantly dumping its energy into the Pb pack to bring it back up. If the SOC is giving an estimation, it could be saying if you keep pulling this much current (from the Li) you're basically done.

Just a thought, based on the fact that Pb can dish out and take decent amounts of current, and also sag considerably more when pushed on. I was thinking about David dumping massive current back in his Porshe's pack with SepEx regen at Bonneville, and the difference in stiffness with the drag racers from Pb to Li (regarding sag). If the condition for the Li to dump into the Pb pack is based on voltage, and the Pb starts out 10v down, then he hammers it, wouldn't the effect be that much more?

Creig you were pulling 800 (motor) amps consistently the days I rode with you, maybe 500-600 when you were "taking it easy". Perhaps figure out the sag on your Pb pack under those conditions and see what the difference would be?

Then again, I may be out in left field chasing a pop-up behind home plate.


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## JRP3 (Mar 7, 2008)

I had similar thoughts, LA sag pulling current from the Li pack.


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## toddshotrods (Feb 10, 2009)

If it is, you really need to find how much it's pulling - how JRP3 suggested. Could it possibly pull more than your max c-rate, and damage your Li cells?


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## CFreeman54 (Jan 14, 2009)

JRP3: Where can I find such a clamp on meter? It is not so easy to find ammeters that can handle 500-1000 A of current. 

Todd: I would think until the Li pack starts to sag there isn't much current draw from the AGMs, since they are at lower voltage. I have been trying to "take it easy" on the batteries until I figure out what is going on...still I am probably pulling 400-500A on acceleration. The digital voltmeter is showing momentary sag of 10V or so, but the analog ammeter is not really showing much sag at all under acceleration.


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## CFreeman54 (Jan 14, 2009)

If surge from the Li pack to the AGMs were pulling more than the max C rate for the Li ions, I would think I would see a dip in individual cell voltage down below 2.5 volts. I put a multimeter on one of the lowest Li cells and set it to voltage reading and so far I have never seen it drop below 3.1 volts, even when I am accelerating.


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## CFreeman54 (Jan 14, 2009)

When I check the individual Li cells after a drive they are all resting at about 3.28 volts, even though the EV Display says they are empty. It only takes a couple KWH from the charger to bring them back up to 3.65 volts.


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## JRP3 (Mar 7, 2008)

CFreeman54 said:


> JRP3: Where can I find such a clamp on meter? It is not so easy to find ammeters that can handle 500-1000 A of current.


Yeah once you start going above 500 amps DC or so they get expensive.


> Todd: I would think until the Li pack starts to sag there isn't much current draw from the AGMs, since they are at lower voltage.


But with the AGMs sagging to a lower voltage they will be pulling current from the lithiums to try and equalize voltage with the lithiums.


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## JRP3 (Mar 7, 2008)

CFreeman54 said:


> When I check the individual Li cells after a drive they are all resting at about 3.28 volts, even though the EV Display says they are empty. It only takes a couple KWH from the charger to bring them back up to 3.65 volts.


3.28V resting, after a good amount of time, half an hour or more, should be about 50% discharged.


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## JRP3 (Mar 7, 2008)

CFreeman54 said:


> If surge from the Li pack to the AGMs were pulling more than the max C rate for the Li ions, I would think I would see a dip in individual cell voltage down below 2.5 volts. I put a multimeter on one of the lowest Li cells and set it to voltage reading and so far I have never seen it drop below 3.1 volts, even when I am accelerating.


I've pulled 5.5C from my CALB cells and they don't get anywhere near 2.5 unless they are almost empty.


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## CFreeman54 (Jan 14, 2009)

Thanks JRP3: That info is helpful. I think I will try driving a bit with just the Lithium pack contactor engaged after charging and see if the EV Display still goes to zero in a minute or if it really is the interaction of the parallel packs that is causing this. 

I don't want to routinely drive that way because acceleration pulls more than 3 C out of them without the AGMs to buffer the current, but it will tell me if the EV Display problem has to do with current pull from the other pack or not.


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## CFreeman54 (Jan 14, 2009)

JRP3: What kind of voltage spread do you get at the top on a full charge? I know you are bottom balanced. 

I think mine are out of whack from the BMS that was on them. I am getting a spread at the top from about 3.4 to 4.0 volts when I charge. I am still trying to get the high ones pulled down enough I can charge most to 3.65 V.


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## JRP3 (Mar 7, 2008)

After my first bottom balance they were between 3.43 and 3.50 volts, but they are closer now since I don't charge to such a high SOC, so the smallest cells don't get as far into the curve. I haven't checked them all lately but I think they are between 3.40 and 3.45. Next time I do a full charge I'll check more closely. I'm also not using the CV phase any more in order to further undercharge them.


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## CFreeman54 (Jan 14, 2009)

It took 7.1 KWH to recharge the Lithium pack after 10 miles of driving on the weekend. I don't believe the driving can be using that much energy. I was pulling around 400-500A on acceleration and cruising at about 150A. The AGM pack must be sucking off some of the Li pack charge. I can't figure why the AGM pack Paktrakr still only says 68% full though.


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## CFreeman54 (Jan 14, 2009)

JRP3: So you are charging to 3.5V max? Is that the recommended charge Vmax for Calib cells or are you undercharging in hopes of extending cell life? 

I am thinking of aiming for 3.60 V on charge since I have some cells shooting up to 4.0 V while others are still at 3.4 ....that may give me a little safety at the top....at least until I can get them balanced better. I'm not sure yet what they are going to look like at the bottom though. I haven't taken them down below 3.15 or so yet.


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## JRP3 (Mar 7, 2008)

CALB uses 3.6V as their max. I keep mine under 3.45 most of the time, and I'm actually trying 3.40 now since I don't need full range normally and shallow cycling in the middle of SOC seems to increase cycle life. A123 has shown dramatic cycle life testing in the middle range of SOC.


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## CFreeman54 (Jan 14, 2009)

It sounds like I had better get my higher cells that are hitting 4.0 V on charge pulled down so I can keep them all under 3.65V.


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## JRP3 (Mar 7, 2008)

Just remember if you balance at the top you are unbalanced at the bottom. It sounds as if your cells are not well matched for capacity, or maybe they are marched but are not balanced either top or bottom. If you don't know the capacity of the cells I would first bottom balance them to around 2.900V each, then charge and monitor them during charging. That way you'll find which fill up first and are the smallest capacity, plus you'll see how much they vary. Then you can decide if you want to top or bottom balance. It's time consuming but it's the only way to really know.


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## CFreeman54 (Jan 14, 2009)

The BMS I had top balanced my cells before...supposedly. I didn't know what state of charge the cells were in. They had been charged (with the BMS) once before, driven about 10 miles, then sat for seven months while I was in China. I was afraid I would discharge them below 2.5 V if I just blindly started driving to pull them down to 2.90 V, so I decided to charge them full, then use the SOC meter/(EV Display) to tell me when I was getting near empty. The EV Display has to be calibrated with the cells fully charged. Now at least I have a good idea of when the cells are approaching empty.....if I can get the EV Display to stop going to zero SOC every time I drive (with the packs connected). Once I know they are near empty I can monitor them with a multimeter/voltmeter to get them to 2.90V and bottom balance. That was the plan anyway, but the false empty readings I am getting from the SOC meter is making this harder than it should be.


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## CFreeman54 (Jan 14, 2009)

I was having trouble getting my headlight focus and pattern right and decided the easiest fix was to install a different headlight assembly. Here are some pics with the new headlights.

I will finish the body work and give it a new paint job next summer.


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## JRP3 (Mar 7, 2008)

Looks like a pretty decent contour, what are they from?


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## CFreeman54 (Jan 14, 2009)

The new lights are from a Toyota Celica.


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## CFreeman54 (Jan 14, 2009)

New carbon fiber body planned for the 2.0 model build. Thanks Todd for the CAD help.


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## JRP3 (Mar 7, 2008)

The entire body out of CF?  That would be impressive. How did you end up with the large rear end, just for looks or was there some aerodynamic modeling?


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## CFreeman54 (Jan 14, 2009)

Slope angles of rear hatches have been aerodynamically studied extensively by companies like Porshe. Raising the rear end decreased the slope to a better angle for Cd. I don't recall the details off the top of my head, but back a couple years ago I had taken notes on wind tunnel studies done by Porshe. You see this decreased slope on cars like Prius and Insight also due to the improved Cd. It so happens it also gives the car a more contemporary look (I think). We may tweek the fender contours a bit yet too.


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## JRP3 (Mar 7, 2008)

I have been contemplating a Prius type rear slope as well, which actually curves down more than your drawing, which is why I asked.


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