# Miata's last gas(p)... build thread!



## RKM (Jun 9, 2008)

Well, its over a year since I first watched "Who Killed the Electric Car". Since then, I've been channeling my anger into planning a conversion! Also cut up my GM Visa card. I've finally pulled the engine and tranny out of my '96 Miata! It's a start at least.

The car will use a Warp9, likely an 800A belktronix controller and kit, dual 120V chargers, no clutch and LFP. We drive alot, the goal is to get a solid 60-80 mile range.

I'm not an EE but have some fabrication skills and an attitude that it can be done. I continue to appreciate the great resources of this forum. The sharing of information/experience/encouragement is priceless! I'm sure I wouldn't be doing this conversion if not for this forum.

I built a car rotisserie for this project. I highly recommend it to anyone!! It is fantastic to have access to the belly of the car while standing up. No road grit falling in the eyes and ears!

I'll update as things progress. Any input is welcome!

Rob


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## slurryguy (Dec 16, 2008)

I'm sure you have an awesome car, but I can't get past that car rotisserie. Sweeeet.

Do you have details about its construction posted online somewhere? I'd like to learn more about it and how you designed/built it.


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## brent.massey (Jul 23, 2008)

To quote the original Batman movie...

"Where does he get those wonderful toys!!"

The car rotisserie is indeed the coolest thing I've seen in a while. Looks like it'll make working on the car a breeze.

Thanks RKM, something ELSE to add to my Harbor Freight list...


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## PatricioIN (Jun 13, 2008)

ok.. seriously dude.. the car rotisserie is freakin' fantastic! Would have made that belly shield I just did a breeze!


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## bblocher (Jul 30, 2008)

Congrats on starting your build. It's by far the most fun I've had over the last 6 months working on mine.

More importantly...I need one of those car rotatormajiggers!!!


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## david85 (Nov 12, 2007)

Yeah, who cares about the car, that rotisserie is saaweeet!

I see the car has rear disk brakes. Is that stock?


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## Qer (May 7, 2008)

brent.massey said:


> "Where does he get those wonderful toys!!"
> 
> The car rotisserie is indeed the coolest thing I've seen in a while. Looks like it'll make working on the car a breeze.


Looks home built to me and surprisingly simplistic too. What I do wonder is, however, how do you attach it securely to the car?

Seriously cool tool though.


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## tj4fa (May 25, 2008)

RKM said:


> I built a car rotisserie for this project. I highly recommend it to anyone!! It is fantastic to have access to the belly of the car while standing up. No road grit falling in the eyes and ears!
> 
> I'll update as things progress. Any input is welcome!
> 
> ...


Cool!!

Can you provide a sketch or plans for your rotisserie in case I...err...some of us here want to build one?


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## RKM (Jun 9, 2008)

I plan to install a full belly pan on the car. That and a knee that's been giving me trouble were my inspiration to put the car on a rotisserie.

I did searches on google for "car tilters" and "car rotisseries". I've seen a tilter in a dealer showroom. They bolt to the rotors and restrict access. I need to remove the rear end to remove the fuel tank. A tilter wouldn't let me do this. There are quite a few sets of rotisserie plans available on line. I won't say mine is better, but I prefer it. Take a look at what others have done as well. 

I'm not a professional engineer, but I do design and build things as my profession. I usually use too much steel rather than too little. So, this is my disclaimer I suppose... feel free to copy the design if you wish. In so doing, you will need to assume the responsibility for ensuring the rotisserie is safe. This design is working well for the Miata (light car with excellent mounting locations). 

Quer, yes is it surprisingly simplistic, much like me. The Miata has four very robust retrival points that are adequate to support the car (I got lucky). The other alternative would be to remove the front/rear bumpers and mount to frame. I wanted the bodywork in place so that I could fit the belly pan properly.

david85, yes the rear discs are stock. Miatas all have discs all round, the 1.8 L has larger brakes than the earlier 1.6 L.

bblocher, buy or build! There is no way I would be without one now! 

I don't have great documentation or instructions on how it is made. I'm a little worried about the liability issue if I provide full details on "how you too can build your very own car rotisserie!" Don't need a lawsuit if someone were to drop a car based on my design! Its too bad we've gotten to this point.

I have incomplete cad drawings (enough that I understand it) and a spreadsheet cutting list that I can make available. Plus I can post more photos. Whatever you do, be very careful. Make sure you stay safe!

Thanks for the positive reinforcement!

Rob


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## slurryguy (Dec 16, 2008)

I have a confession. I have a personal problem.

I get very turned-on by tools. (hangs head sheepishly)

After looking at RKM's rotisserie and reading his suggestion to look at others that people have built, my obssessions got the better of me, and I started Googling through "the internets" looking at Car Rotisserie Porn. (I'm so ashamed. Please don't judge me. I'm not such a bad person except for this one little...okay... BIG problem.)

Admitting I have a problem is the first step in recovery right?

Here are a few of the hot babes I stumbled across in case others also have my terrible mental instablity about tools:






























I could easily fill up this thread with more cute rotisserie babes, but hopefully that will satisfy everyone's "urges." I know I'm feeling very *ahem* better now. (Recovery is going to be a long difficult journey.)


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## RKM (Jun 9, 2008)

Slurry,

Too, too cute!! You must have been up much of the night, managing your "problem". The pursuit of tools is a good and noble thing! Do not be ashamed. And remember you are not alone.

I'm just glad I have a business that helps me justify some purchases. So far as I'm aware, there is no 12 step program that addresses this issue!

Here are a few more photos.

Rob


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## drscoles (Jun 24, 2008)

That is terribly cool. I have two herniated disks in my neck, made me hesitant to tackle a conversion... this could solve the problem! 

How in the hell do you get the car up on the rotisserie???? Love to see a sequence of pics... I'm guessing a series of jacks and a lot of wood/jackstands?


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## RKM (Jun 9, 2008)

drscoles said:


> That is terribly cool. I have two herniated disks in my neck, made me hesitant to tackle a conversion... this could solve the problem!
> 
> How in the hell do you get the car up on the rotisserie???? Love to see a sequence of pics... I'm guessing a series of jacks and a lot of wood/jackstands?


I wouldn't want to do a conversion without it. Should be a solution for you.

Sorry, no photos of the install process. Easier than you would think though.

1. Start off with the caster wheels off, then slide the two sections beneath the car (tires on). Connect the two sections together once your satisfied with the length of the frame (I drilled two 3/8 holes per side and bolted together).

2. Figure out and fab your mounts to the car and connect the rotisserie to the car. Thankfully, the Miata has good connection points. Many cars may have to go to frame.

3. Raise each end, one at a time, with a pry bar so that you can get a floor jack beneath the centre 3X3 bottom frame member. Make sure the lift cable is slack so that you are only lifting the weight of the rotisserie.

4. Use the floor jack to raise the rotisserie frame high enough to install the caster wheels. This is only about 5" in my case. Your done! 

Be careful.

Tip: When you design your rotisserie, make sure that the bottom of the frame is higher than the top of the legs on your engine hoist! Mine is a little too low and I have to jack up the rotisserie and block it to get the hoist in place (oops!).

I have very crude and incomplete cad drawings and a partial (80%) cutting list if you're interested. I figure my parts other than steel are under $200, probably another $200 for steel. For me, the steel was all in stock anyway.

Hope this makes sense to you.

Rob


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## brent.massey (Jul 23, 2008)

slurryguy said:


> I get very turned-on by tools. (hangs head sheepishly)


slurryguy, I laughed so hard at that I almost cried. I think my wife would say the same thing about me... 


Rob, its guys like you (and most others here) that make this forum great. You identify a problem and use sheer ingenuity to overcome it. Gas? We don't need gas! Jack-stands? Who needs those when you've got one of THESE! Bravo on the rotisserie!

Now on to the heart of the matter....we've hit pretty well on the neat rig you're using to build your EV, talk to us about that!


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## RKM (Jun 9, 2008)

Hey Brent...Thanks. I didn't create anything new, just made my own version of a tool that is already out there. My workmanship will be better and I'll be in a much better mood if I can work in a comfortable position!

I'm contiunally impressed by the knowlege, creativity and quality of work that shows up on these posts.

I'll post an update on the car.

Rob


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## RKM (Jun 9, 2008)

Spent 3 hours in the shop on Saturday with my son. We worked at removing more of the unneccessary components. The rear end has to be removed to take out the fuel tank, not too big a job. The fuel lines and filter came off as well. Pulled a few heat shields. Did some clean up work on the rear end and started degreasing the engine compartment.

I hope to use the fuel tank cavity for battery storage. It's not very large but I may cut away some of the original sheet metal and build a batt box.

I'll be using LFP and will make insulated and heated aluminum boxes. There will likely be three (maybe only two) boxes. One in the engine bay, one below the trunk and one in the fuel tank cavity. I'll have to do some figuring for volumes. 

There are a lot of parts we just won't need for the EV! I sure won't miss all the fluids and the inevitable leaks.


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## DC Braveheart (Oct 12, 2008)

RKM said:


> I hope to use the fuel tank cavity for battery storage. It's not very large but I may cut away some of the original sheet metal and build a batt box.
> 
> I'll be using LFP and will make insulated and heated aluminum boxes. There will likely be three (maybe only two) boxes. One in the engine bay, one below the trunk and one in the fuel tank cavity. I'll have to do some figuring for volumes.


Cool project ... and I love the rotiserrie! 

I own a '92 Miata that I've been thinking about converting for over a year now - I really need to bite the bullet - maybe you are the inspiration to get me started at last!

Anyway, in my research I came across the following website for a Miata conversion using 8V batteries - http://home.comcast.net/~aschwarz7/ . If you look at some of the pictures - especially the sections on cutting for the battery boxes and installing the batteries, you'll see he did a MAJOR job on opening up his trunk and gas tank space - enough to fit 15 8V batteries in that space. 

I checked on the sizes of the batteries he used and I figure you can fit 36-38 TS LPF160s in that space, not including the sunken set in the trunk. I like the idea of putting the LPFs there as much of the weight is then forward of the rear wheels rather then being behind them and for a c. 156V system, you'd then put the remaining 12-14 LPFs in the engine compartment. I think that might balance the weight quite nicely.

I'll be watching your conversion with interest.

Stuart


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## DIYguy (Sep 18, 2008)

Hey Rob,

Nice to see you get this post going. There isn't much I can say that hasn't already been said. I knew that spinner would be a hit.. i've thought of it every time junk dropped in my face over the last few months.

As for the rest of you.. this is a guy to watch. (as if you haven't figured that out already) . . . and a real gentleman to boot.

I only wish you had started before me!

Gary


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## RKM (Jun 9, 2008)

DIYguy said:


> Hey Rob,
> 
> I only wish you had started before me!
> 
> Gary


Gary,

It's called strategic planning...or, alternatively... standing on the shoulders of giants! You make me blush and set up unreasonable expectations. I have confidence in the mechanical and fabrication end of things but am way over my head wrt the electrical side of it. I have and will continue to rely on the expertise of others. I'm starting to sound like Scarlett O'Hara... "I have always relied on the kindness of strangers".

Take care.

Rob


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## david85 (Nov 12, 2007)

Rob, is that a sheet metal break I see in the back? I'm getting more jealous by the minute! Should come in handy to make those aluminum battery boxes. Thats what I'll be doing, except I don't have a break


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## RKM (Jun 9, 2008)

DC Braveheart said:


> Cool project ... and I love the rotiserrie!
> 
> I own a '92 Miata that I've been thinking about converting for over a year now - I really need to bite the bullet - maybe you are the inspiration to get me started at last!
> 
> ...


Braveheart,

Do you mind if I call you Braveheart or would you prefer Stuart? I never get the chance to call anyone Braveheart!

Thanks for the link! I've been doing searches for electric miatas for a long time and had never come accross this one. It's not particularly new either.

He really opened up the trunk/fuel tank area. There is a unibody frame member across the rear of the fuel tank cavity. He cut his out. I was hoping to retain that otherwise I'll need to make the batt box structural. My boxes will not be terribly space efficient due to the insulation space that will be required. LFP should be a breeze to fit compared to Pb miatas out there. Those guys had a real challenge (dimitri et al).

I'm planning a 144V @ 160 Ah pack, so 45 cells will do it. Beyond the volume consideration is weight distribution. I'll want to stay as close to stock distribution as possible. I recorded axle weights but don't have the numbers handy. I agree about trying to keep the weight between the axles as much as is possible.

The Miata is a fun candidate for conversion, so long as you like the car. It isn't the most practical though. Cd of drag is surprisingly poor. The truck guys have the option of affordable batts and range too. I already have a working truck, I've always wanted a Miata. A friend of mine is planning to convert his Miata too. 

I look forward to seeing your build thread start!

Rob


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## RKM (Jun 9, 2008)

david85 said:


> Rob, is that a sheet metal break I see in the back? I'm getting more jealous by the minute! Should come in handy to make those aluminum battery boxes. Thats what I'll be doing, except I don't have a break


David,

Yeah, it's a big old box and pan break. Very old, but works great for us. Weighs about 6000 lbs, 600V 3PH and will handle at least 10 ga on 6 feet. We break 1/4 plate up to 30" without complaint.

Yes, it is very handy. I also plan to build the component box for under the hood. I'll put a large polycarbonate window into the top.

I'll sure be jealous of your LFP batt pack when you get it. I'll need to pick a supplier in a little while so that I can have mine for early summer. Thanks for posting your updates.

Rob


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## PatricioIN (Jun 13, 2008)

the first gen miata (NA) has a near 50/50 weight distribution. I have a '94 and frankly, it's just too damned much fun to beat on to tear the gas guzzler out of it! Nothing like kicking the ass end out on a nice twisty road.. But I will absolutely be watching your build with great interest.

As for the electric part of it, you mentioned that's the part that you think will be a challenge for you. Believe me, it's about the easiest part! The mechanical/fab stuff worried me most and I managed to get through it with little to no experience. You've got that end covered nicely.

Even though I had little to no experience on the electrical end, it just didn't worry me much. And, blown meter problem aside, it wasn't too challenging. After spending a couple of hours really going over the wiring diagrams I had, I felt confident enough to just jump in and start doing it. All ended up well in the end.


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## DC Braveheart (Oct 12, 2008)

RKM said:


> Braveheart,
> 
> Do you mind if I call you Braveheart or would you prefer Stuart? I never get the chance to call anyone Braveheart!
> 
> ...


Rob.

Call me Stuart, "Braveheart" or "hey you" makes no difference - I'll answer to anything.

Yeah, I love my Miata ..... it's known as the "baby car" in my house which is what my youngest christened it when I got it - she was 18 months old at the time ... she's off to college in the Fall. 

One of the reasons (OK the only reason other than picking up the courage to tell my wife I want to drop about $25K for the conversion using AC and TS LPFs) is that, as PatricioIN says, the car, even at nearly 17 years old is too much fun to drive the way it is. Heck as long as there's no rain (roof needs replacing) I'll dirve it even when the temps drop below freezing here in VA.

Go on and get cracking with yours - maybe you'll give me the inspiration (or kick in the butt) I need to start mine!

Stuart


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## RKM (Jun 9, 2008)

PatricioIN said:


> the first gen miata (NA) has a near 50/50 weight distribution. I have a '94 and frankly, it's just too damned much fun to beat on to tear the gas guzzler out of it! Nothing like kicking the ass end out on a nice twisty road.. But I will absolutely be watching your build with great interest.
> 
> As for the electric part of it, you mentioned that's the part that you think will be a challenge for you. Believe me, it's about the easiest part! The mechanical/fab stuff worried me most and I managed to get through it with little to no experience. You've got that end covered nicely.
> 
> Even though I had little to no experience on the electrical end, it just didn't worry me much. And, blown meter problem aside, it wasn't too challenging. After spending a couple of hours really going over the wiring diagrams I had, I felt confident enough to just jump in and start doing it. All ended up well in the end.


 
I probably paid too much for mine. I wanted to get one with a working engine so I'd have a chance to drive it on gas for a season. They are a hoot, not over powered to be sure, but fun none the less.

wrt the electrical... I know I will be able to wire things up in "paint by numbers" fashion. And I have aquired a pretty decent understanding of how things work but it's still a weak link for me. The task of getting the stock tach to work off of a signal from the tail shaft is still a bit beyond me... stuff like that. Trouble shooting problems may be a challenge. Thankfully, there are the good and knowlegable folks on this forum!

Rob


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## bblocher (Jul 30, 2008)

RKM said:


> The task of getting the stock tach to work off of a signal from the tail shaft is still a bit beyond me... stuff like that. Trouble shooting problems may be a challenge. Thankfully, there are the good and knowlegable folks on this forum!
> 
> Rob


The tach isn't bad at all and you may find my blog on that part helpful. If it's like mine the tach is just looking for pulses of 12v. Mine required two pulses per revolution. All I did was ran 12v to a hall effect sensor with a magnet behind it. Then on the output shaft I have two teeth on a collar that rotates past the sensor. The magnet creates a field passing through the sensor as the metal passes near. The sensor detects this change in the magnetic field and sends a 12v pulse out which is connected to your tach. My install is a bit more involved because of my electronic power steering needing this signal and I'm additionally tracking it with a microprocessor but you should be able to ignore any details there I may have added in the blog.

Hope this helps some.


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## RKM (Jun 9, 2008)

Brian,

Thanks for the note. You have one of the best build blogs BTW. Very well documented and helpful for others who will follow. 

I'm familiar with shaft pickups but have been concerned about needing a pulse of a specific quality (voltage or amperage specific range). If it is indeed as simple as a basic 12VDC pulse, it should be no big deal. Gary has nice documentation on his build thread as well.

Can you tell me what model of Gast vacuum pump you are using? Have you found it to be too noisy? If so, do you intend to insulate for sound?

Re. your ceramic heater and heat transfer through the frame... I had wondered if the mounting silicone may have been a sufficient insulator.

I plan on using the same battery pack, 45 @ 160Ah. I hope the performance, cycle and calendar life meet expectations! 

Rob


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## bblocher (Jul 30, 2008)

RKM said:


> Brian,
> 
> Thanks for the note. You have one of the best build blogs BTW. Very well documented and helpful for others who will follow.
> 
> ...


I'll have to check on the model number. I bought it from EV America. It's definately not silent but really isn't too loud inside the car. Luckily it doesn't run much either. I'll have to really wait till I start driving and see if it bothers me.

As for the heater I can't see any problems there. The silicone is rated for 650F but the element itself doesn't get anywhere near that as long as there is air flow. I've run the heater for five minutes or so on full and the frame is barely warm. I've seen a few guys use this silicone to secure their elements in their old heater cores. It better work, I don't want to remove that dash again. 

That battery pack should rock. I'll of course keep updates on the blog as well as an ongoing post here.


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## RKM (Jun 9, 2008)

A little more progress...

I've ordered 6061 aluminum plate for the motor/tranny adapter. Tried to to scrounge around local shops, no luck, only thinner plate. The 5/8" plate will be shipped out of Toronto. I won't need much for spacer plates, so will get material locally.

The coupler will be the same design as Gary's, check his build thread. I've ordered a 6021 taper sprocket (60 series X 21 tooth) with a 1.125 bore taper collar. There will be three draw bolts and the key will engage the sprocket as well as the collar. I'll turn an alignment shaft to ensure that the clutch spline plate is centred on the sprocket collar, then weld a spacer and spline plate to the sprocket. I'll turn down any uneccessary diameter off the sprocket when done. It will be dynamically balanced to make sure there won't be vibration (another fine tip from DIYguy!). Will post pictures when done. 

I've finalized my order for the main components. I'll be using a Belktronix system. It consists of an *800A* controller (YeeHaaw), DC-DC, optical pot box, individual cell LFP BMS, *dual* 120V PFC chargers (2.4KW combined) and a vehicle integration unit. I'll be ordering a Warp9 from Belk as well. Bryan has been very helpful. He is going to integrate motor overspeed protection into the controller. I'll have it set to a max of 5000 rpm. This signal should also be able to run my tach.

http://www.belktronix.com/G2.html

I'm really excited to have committed with a deposit on this system. No more second guessing!

Now I'm waiting for a magical deal to appear on a quality and affordable 144V X 160Ah LFP pack. Technologic has a lead... will this one be for real??

All for now.

Rob


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## RKM (Jun 9, 2008)

Motor coupler complete 

Found a few hours today to get the motor coupler completed. I used a 60 series taper sprocket with 21 teeth and a 1.125 taper collar for the job. There are three draw bolts between the collar and sprocket. There is also a key between the collar and sprocket as well as the .250 key for the motor shaft. I think it is really important to have the key to physically connect the collar and sprocket.

The spline coupler from the clutch plate has an extended side of .355, so I made up a spacer donut out of .375 plate. This is welded to the spline coupler and then the excess coupler is removed and the donut is turned on the lathe to make it true.

The donut and spline are then welded to the sprocket. I made up a step shaft to ensure the spline is centred with the taper collar. Worked well. The excess sprocket diameter was then removed and turned to 3.875. The pilot ring on the Warp9 motor is 4.0, the holes in my adapter plate and spacers will be 4.0, 3.875 will fit through nicely.

I'd like to get it dynamically balanced but will be very surprised if it is off enough to matter. Better to do it right than to regret. I pretty much copied Gary's (DIYguy) method. Pleased with the results, thanks Gary!

Rob


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## DIYguy (Sep 18, 2008)

RKM said:


> Motor coupler complete
> 
> Found a few hours today to get the motor coupler completed. I used a 60 series taper sprocket with 21 teeth and a 1.125 taper collar for the job. There are three draw bolts between the collar and sprocket. There is also a key between the collar and sprocket as well as the .250 key for the motor shaft. I think it is really important to have the key to physically connect the collar and sprocket.
> 
> ...


Nice job Rob, good looking "MIG" welds too! I bought the sprocket that had the taper hub already welded/machined in so...no need for the key there. 

G


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## tj4fa (May 25, 2008)

bblocher said:


> I'll have to check on the model number. I bought it from EV America. It's definately not silent but really isn't too loud inside the car. Luckily it doesn't run much either. I'll have to really wait till I start driving and see if it bothers me.


I'd recommend putting the vacuum pump somewhere in the back or under the rear somewhere inside a box with maybe some sound attenuation insulation of some kind (I used 2" packing foam under the pump base).

I put my GAST vacuum pump from EVA in a compartment behind the battery box under a tool tray, and when it comes on you have to open a window or strain real hard to hear it. 

In fact, I'm thinking about running a wire from it and have it illuminate a light on the dash panel to show it has power and comes on when the pump is running so I know it's still working.


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## PatricioIN (Jun 13, 2008)

tj4fa said:


> In fact, I'm thinking about running a wire from it and have it illuminate a light on the dash panel to show it has power and comes on when the pump is running so I know it's still working.


I wouldn't worry about that, you'll know immediately if it quits working.. no power to the brakes! I have the same vacuum set up and for some reason, the switch has "stuck" twice now.. had to get out, take the cover off and jiggle it a couple of times to get it working on it's own again. Maybe the cold? dunno...


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## tj4fa (May 25, 2008)

PatricioIN said:


> I wouldn't worry about that, you'll know immediately if it quits working.. no power to the brakes! I have the same vacuum set up and for some reason, the switch has "stuck" twice now.. had to get out, take the cover off and jiggle it a couple of times to get it working on it's own again. Maybe the cold? dunno...


I haven't had any problems with mine sticking (here in Florida) at all but it hasn't got below +20* where I live. 

I wonder if any others have had a problem with the switch sticking? That could be bad especially trying to stop while hauling around all that lead.

Maybe install a vacuum gauge and warning light when the pressure gets too low in the cockpit.


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## PatricioIN (Jun 13, 2008)

tj4fa said:


> I haven't had any problems with mine sticking (here in Florida) at all but it hasn't got below +20* where I live.
> 
> I wonder if any others have had a problem with the switch sticking? That could be bad especially trying to stop while hauling around all that lead.
> 
> Maybe install a vacuum gauge and warning light when the pressure gets too low in the cockpit.


 the only real problem is not working when you expect them to.. I drove around the first couple of weeks or so without the vacuum installed and it was fine, but I've had old cars w/o power brakes and am used to it. Still, once I finally did install the pump, it was nice not to have to do leg presses every time I needed to stop!


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## RKM (Jun 9, 2008)

While we're talking about vacuum... I've come across a couple of kits. Does anyone have experience with either of these?

http://store.summitracing.com/partd...P-12VVCP&N=700+400617+314448+115&autoview=sku

http://www.autoanything.com/brakes/69A3151A0A0.aspx

Both look like they would be suitable.

The miata currently has AC. I wouldn't mind keeping it but it is not a priority and it wouldn't be hooked up again for a long time. Removing it would free up a big chunk of space in the nose. I think this would be a good location for the pump and reservoir. I plan to insulate for noise also.

Rob


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## dtbaker (Jan 5, 2008)

RKM said:


> The miata currently has AC. I wouldn't mind keeping it but it is not a priority


ditch it!
all that weight and extra power.... get a small 12v AC blower right on your feet later if you really can't live without it.


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## notnull (Jul 30, 2008)

I have lurked for a while and haven't had a chance to post pictures of my conversion. I have been driving a converted 1990 Miata for a couple of months now. I did leave the A/C in place and bought a treadmill motor to turn it, but I finally decided to remove it because it takes up so much space. I was then able to layout my batteries the way I wanted to.

Steve


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## PatricioIN (Jun 13, 2008)

RKM said:


> While we're talking about vacuum... I've come across a couple of kits. Does anyone have experience with either of these?
> 
> http://store.summitracing.com/partd...P-12VVCP&N=700+400617+314448+115&autoview=sku
> 
> ...


you'll want a vacuum reservoir as well to hold vacuum so the pump isn't on all the time.. I bought the vacuum kit from KTA for $385 which included literally everything I needed (reservoir as well)..

http://www.kta-ev.com/catalog.html


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## PatricioIN (Jun 13, 2008)

oh and as far as the AC.. that depends on your needs and how you're planning on using the miata EV.. I have a '94 M edition Miata that I frankly never use the AC... but then it isn't my daily driver either, so if I were using it to go back and forth to work everyday (especially when it rains and the top has to be up) I'd probably want to keep the AC.


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## dtbaker (Jan 5, 2008)

PatricioIN said:


> you'll want a vacuum reservoir as well to hold vacuum so the pump isn't on all the time.. I bought the vacuum kit from KTA for $385 which included literally everything I needed (reservoir as well)..
> 
> http://www.kta-ev.com/catalog.html




I used the same kit. works great... only notes are that you want to be SURE not to install the isolation bolt too far into the motor body... it will prevent the motor from working. Only other thing is to know when setting turn on/turn off points is that that the max vacuum is de-rated for elevation at about 1 inHg per 1000' above sea level.

I was thinking my pump was faulty or I had a leak..until the customer support at Gast told me that a max of -15 inHg at 7000' elevation in Santa Fe was to be expected.


----------



## RKM (Jun 9, 2008)

DC Braveheart said:


> Anyway, in my research I came across the following website for a Miata conversion using 8V batteries - http://home.comcast.net/~aschwarz7/ . If you look at some of the pictures - especially the sections on cutting for the battery boxes and installing the batteries, you'll see he did a MAJOR job on opening up his trunk and gas tank space - enough to fit 15 8V batteries in that space.
> 
> I checked on the sizes of the batteries he used and I figure you can fit 36-38 TS LPF160s in that space, not including the sunken set in the trunk. I like the idea of putting the LPFs there as much of the weight is then forward of the rear wheels rather then being behind them and for a c. 156V system, you'd then put the remaining 12-14 LPFs in the engine compartment. I think that might balance the weight quite nicely.
> 
> ...


Braveheart (can't resist),

Started looking at battery placement last night. Know what? Those TS LFP-160AHA are very comparable in volume to Pb. Surprised me a bit. 7.43" X 2.9" X 11.4". Space is a challenge even with LFP! Plus I'll have insulated boxes, adding a bit to the bulk. 

The AC has to go, I need the room. So far, its looking like this three box layout;

Recessed box in trunk floor (17" X 28" X13") to hold 18 cells (2 vertical rows of 9).

Recessed box behind seats in fuel tank cavity (9" X 28") to hold 9 cells (1 vertical row of 9)

"L" box in engine bay to hold 9 cells (1 vertical row of 9) were radiator was located. 9 cells to go above motor (3 horizontal rows of 3). the vertical 9 will actually need to be tilted about 20 degrees off vertical to miss the front torsion bar. It will be a goofy shape, but will hopefully still look good.

The unknown is if I have enough room between the top of the motor and the hood to fit the horizontal set. This arrangement will provide pretty easy access to all boxes and won't require removing structural frame members.

Not sure how this will work out for front/rear weight distribution? I don't have much for options. I expect it will be heavier at the tail and may require heavier rear springs.

It will be a bit of a challenge (what doesn't kill me, makes me stronger (?)).

Rob


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## dimitri (May 16, 2008)

Rob,

I don't think you should mount TS cells horizontally. I asked this question on TS Yahoo group, and everyone was set against it. There is some data indicating that LFP cells will be destroyed internally if mounted horizontally. Something to do with electrolyte eating away internal terminal connections. I can't find any historical data on successful use of TS cells mounted horizontally, so I personally will stay away from it.

You are right about the volume, LFP doesn't have best energy density, the volume is comparable to Lead Acid, but you get twice usable energy at half the weight.

As for 156Volt 160AH pack, I think its an overkill for a small car, sure you get huge range, but at the much higher cost and difficulty to cram all those cells in. With higher voltage I would consider smaller cells, although TS doesn't make 120Ah and 100Ah is probably on a low side. Its a tough choice...

I settled on 40 cells based on these thoughts, but then again I am doing a DC conversion, so YMMV.


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## RKM (Jun 9, 2008)

dimitri said:


> Rob,
> 
> I don't think you should mount TS cells horizontally. I asked this question on TS Yahoo group, and everyone was set against it. There is some data indicating that LFP cells will be destroyed internally if mounted horizontally. Something to do with electrolyte eating away internal terminal connections. I can't find any historical data on successful use of TS cells mounted horizontally, so I personally will stay away from it.
> 
> ...


Dimitri,

Thanks for the heads up re. horizontal installation failure. Was under the impression that they could successfully be installed on their side. I'd hoped to avoid horizontal but hadn't yet figured out how to fit 45.

I believe I can do 44, all vertically. It would mean a "U" shaped box under the hood. Four cells,vertically, on either side of the Warp9. This would leave a nice pocket over the motor for mounting the controller and other hardware. Will need to check dimensions more closely but ought to work!

Are you planning on strapping the pack together and supporting the end plates as some suggest to minimize swelling and plate separation?

Rob


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## dimitri (May 16, 2008)

Rob,

definitely need to use end plates and straps on each group of cells. I will have some groups of 4 and some groups of 5. Apparently they come already strapped in groups of 5, according to Brian who just got his cells from Elite. I will need to restrap some 5s into 4s.


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## david85 (Nov 12, 2007)

Actually, my sales contact at sieden told me that the batteries can be mounted in any position. The rear batteries in my car will be mounted horizontally.

The batteries seem to be a very similar product to thundersky, but maybe they are internally different. They do not require strapping either.


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## dimitri (May 16, 2008)

David,

how much do you trust the sales contact? The damages that could result from not using end plates and improper mounting could become evident 2-3 years into the pack's life, after warranty has expired. Then what?

I would be very cautious about these claims from the sales person. I doubt that prizmatic cells that look almost identical are really much different inside.


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## RKM (Jun 9, 2008)

Dimitri,

What do you intend for the support plate? It's a challenge to have a ridgid plate without adding significant weight or volume. What about an allowance for thermal expansion? How dimensionally stable are these cells with variation in temp?

Rob


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## dimitri (May 16, 2008)

Rob,

look at the pics Brian posted at his Honda S2000 blog, cells came in groups of 5 with nice aluminum plates.

When I re-strap my cells in smaller sub-packs and need additional end plates I plan to use plywood, I can't think of more rigid , light and cost effective material.

There are many strapping kits on Ebay, I plan to buy one of those, they come with nylone strapping band and all the clipping hardware.

Under normal use there should never be any thermal expansion, that is the whole point of strapping, to prevent such expansion. 

I understand that cells are filled with liquid for better thermal conduction, but there is some air at the top, which allows for some amount of venting thru the valve between the terminals. That is another reason not to mount horizontally, if pressure builds up, the liquid could seep thru the valve instead of air.


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## Bottomfeeder (Jun 13, 2008)

A great resource I just came across is http://www.strapworks.com I haven't used them myself, but I've heard good things.


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## DC Braveheart (Oct 12, 2008)

RKM said:


> Braveheart (can't resist),
> 
> Started looking at battery placement last night. Know what? Those TS LFP-160AHA are very comparable in volume to Pb. Surprised me a bit. 7.43" X 2.9" X 11.4". Space is a challenge even with LFP! Plus I'll have insulated boxes, adding a bit to the bulk.
> 
> ...


The numbers I figured were for non-insulated boxes so that sounds right. I figured out the sizes from the specs of the PbA batteries on Andrew Schwarz's website - your measurements confirm.

To echo what Dimitri said, I've read that the Thundersky cells have problems when installed horizontally - I think it might have been in one of Viktor's MetricMind conversion blogs.

You've not ordered your cells yet have you? 

I also noticed that you were planning on using just a monitoring system for the cells (from Elite Power) rather than a true management system. Did you investigate a true BMS? I'm not sure if MetricMind's BMS is actually available (it sounds really good but no mention of ordering info on the website). I thinking about asking for a quote for the BMS from EV Power in Australia that Ian Hooper's conversion (ZEVA) refers to.

Stuart


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## david85 (Nov 12, 2007)

dimitri said:


> David,
> 
> how much do you trust the sales contact? The damages that could result from not using end plates and improper mounting could become evident 2-3 years into the pack's life, after warranty has expired. Then what?
> 
> I would be very cautious about these claims from the sales person. I doubt that prizmatic cells that look almost identical are really much different inside.


I'll be honest with you, I might be taking a risk but their actions so far have been at least as good as businesses that I have delt with in canada and the states. Indeed, they seem to even be more prompt with information and shipping after payment.

I also highly doubt that any liquid or paste that is inside the case would actually stay on the bottom of the case if held upright over the years. Corrosion simply should not happen inside no matter what position the battery is in.

If there is a problem I would like to know more about what you heard. Do you have any more info or links?


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## RKM (Jun 9, 2008)

DC Braveheart said:


> The numbers I figured were for non-insulated boxes so that sounds right. I figured out the sizes from the specs of the PbA batteries on Andrew Schwarz's website - your measurements confirm.
> 
> To echo what Dimitri said, I've read that the Thundersky cells have problems when installed horizontally - I think it might have been in one of Viktor's MetricMind conversion blogs.
> 
> ...


Stuart,

All the more reason to install vertically if possible, one less thing to worry about. Thanks for passing on the info.

No, I haven't ordered cells yet. I'm waiting for one of two things to happen. LFP prices to drop substantially or the Canadian dollar to rally relative to the USD. If neither of these happen in the next two months, I'll have to bite the bullet a little harder and close my eyes while I write the cheque, but I won't be happy. Group buy anyone?

You must have me confused with someone else re the Elite BMS. I will be using a Belktronix system (controller, pot, tandem chargers, vehicle integration unit and "proper" BMS). The BMS does monitor each cell independently and will shut down to protect from over charge or discharge of any cell. Should do the job (I hope!!). I'm not an EE but the Belktronix hardware looks very good and Bryan has been very helpful, he has a good reputation too. www.belktronix.com

Rob


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## dimitri (May 16, 2008)

> If there is a problem I would like to know more about what you heard. Do you have any more info or links?


Since I have no first hand experience with LFP yet, everything I say was learned from forums and Thundersky Yahoo group. I asked the question about horizontal mount on Yahoo recently and got few replies from experienced TS owners and some quotes from a guy who is considered an expert with TS products.

It is possible that some of this relates to earlier productions of TS cells and perhaps their design has improved. Its also possible that HI Power cells are different inside and not prone to same issues as TS, but personally I will not be risking my investment and will mount all cells vertically and well strapped, YMMV.


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## RKM (Jun 9, 2008)

Motor adapter plate and spacer plate...

The adapter plate and spacer plate are complete except for some finishing touches.

The adapter plate is 5/8 Aluminum plate, curiously it measures nearly 11/16 thick. I used the steel gasket from between the engine and tranny to transfer hole locations. The only holes that are really critical are for the two dowel pins and for the motor mount. The other six bolt holes use 1/2 bolts but are oversized in the tranny. I made up a quick cad drawing of the motor mount and positioned this onto the plate with spray adhesive, then centre marked the holes for drilling. The system worked great, but for an error on my part. The tranny shaft is equidistant between the pair of dowel holes and the lower four bolt holes (symmetry is good). It appears, to the naked eye, that the shaft is on a straight line between the dowel holes. I should have taken a more accurate measure. Turns out that the shaft centre is about .030 lower than the line between the dowels. RATS . I've elongated the four motor mount holes to compensate. Lesson learned.

My plasma didn't like cutting Al plate this thick. My old wood bandsaw did the trick but very slowly.

The spacer plate is made out of mild steel, because Al is expensive and I had steel in stock. I removed some extra weight with a hole saw. The four corners will eventually be removed to match the radius of the motor. It's not as light or pretty as Al, but it will be painted to match the motor.

All for now

Rob


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## RKM (Jun 9, 2008)

Well, it's been a while since my last update and it will be longer still before I'll be able to work on the car again.

Work has gotten very busy, a spring rush. I plan to join a group buy of lithium batts that Techno has been working on. Will be ordering a Cycle Analyst. Should have the motor, controller, charger, BMS, pot box, DC-DC, etc. by the end of May. I should be able to focus completely on the car later in May and June. Hope to be rolling by the end of June. 

The car has been covered and moved outside to make room for paying work. The photo was taken today during a spring snow storm. Looks pretty sad.

Later.

Rob


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## RKM (Jun 9, 2008)

Finally, back at it!

Most of the parts are on their way now...

Picked up the WarP 9 on Monday.
Misc Miata parts from Blake at isellmiataparts.
Vacuum kit from Brian.
Cycle Analyst from Renaissance Bicycle Co.
Controller and other stuff from Belktonix
45 X 180Ah cells from EVcomponents
MR2 electric/hydraulic power steering pump
SS strapping for securing batts

Need to make decisions re.

Fluid for tranny and diff (Redline?)
Main breaker (Airpax JLE-1-1-53-3-B4-250 ?)
Rear suspension upgrade?

Have installed the motor on the tranny. It spins very nicely at 12V. Hopefully it will at 5000 rpm!


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## tj4fa (May 25, 2008)

RKM said:


> Need to make decisions re.
> 
> Fluid for tranny and diff (Redline?)


I got caught up in trying to use a synthetic blend gear oil in my transmission listening to other people.

The truck was hard to shift between gears and when I read up on it in the maintenance book, the manual transmission actually called for Mercon automatic transmission fluid.

Once I changed it out to the transmission fluid, the transmission shifted much smoother and haven't had any problems.

I'd recommend going with the lubricant that the transmission originally called for.


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## RKM (Jun 9, 2008)

tj4fa,

Thanks for the comment re oil selection. All I'd heard is rave reviews over synthetics. Did the synthetic you'd put in your manual have a different viscosity than the auto trans fluid that was recommended? It sounds like it did.

Is the superior performance of synthetic oil a bit of a myth?

Rob


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## dimitri (May 16, 2008)

I put Redline in Miata and it was awesome, smooth shifting and excellent coasting. Redline was recommended by many people at Miata forums.


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## dtbaker (Jan 5, 2008)

RKM said:


> Did the synthetic you'd put in your manual have a different viscosity than the auto trans fluid that was recommended?


some transmissions spec ATF, some spec gear oil.... they are quite different, and will affect shifting and wear if you use the wrong one. redline is good stuff, just don't stray too far from spec.


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## RKM (Jun 9, 2008)

Thanks guys. Redline it will be.

Any suggestions re. main breaker or rear suspension upgrades for a Miata?

The motor and tranny are back under the hood, but still hanging from the hoist. I'll get it positioned properly and work on the motor mount tomorrow. Opinions on solid versus rubber mount? I plan to use 1/2" of neoprene between the motor mount and frame unless someone convinces me that it is a bad idea. 

Next, I can get serious about batt box design/fabrication and ceramic heater installation. 

Rob


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## RKM (Jun 9, 2008)

Motor mount complete and motor installed.

Finally got the motor installed. Much of the work for the ceramic heater core is done. Working on the motor cover for the forced cooling. I'll be using a fan to draw air through the aftermarket engine air filter to cool the motor Time to start at the batt boxes next.


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## DIYguy (Sep 18, 2008)

RKM said:


> Motor mount complete and motor installed.
> 
> Finally got the motor installed. Much of the work for the ceramic heater core is done. Working on the motor cover for the forced cooling. I'll be using a fan to draw air through the aftermarket engine air filter to cool the motor Time to start at the batt boxes next.


Nice job on the motor mount Rob. Those fabrication skills are coming in handy. 

Gary


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## dtbaker (Jan 5, 2008)

pretty!

hard to tell what is holding the motor/tranny from spinning... just clamping force, or also the lift-bolt in shear? I found that there is a suprising amount of torque running thru these suckers! Are there more mounts on the transmission ?


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## notnull (Jul 30, 2008)

Looks great. Very similar to my mount but no tab for the lift bolt. I have had no issues with the assembly wanting to twist.

There is no transmission mount for the Miata. They have what they call a power plant frame (PPF) that bolts to the differential and the transmission. It looks like a ladder brace that surrounds the drive shaft on one side.

Again, no issues for me and I have the ADC 9in and a 750A controller.

Steve


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## RKM (Jun 9, 2008)

Steve,

Thanks for the note regarding torque not causing a problem, even without the tab. I'm pretty confident this should be fine.

The PPF may reduce torque twist of the tranny a bit as it is connected to the diff.

Dan,

Yes, there is a tab (top right photo) that has a 1/2" bolt into the motor. Should hold down a 9" okay.

Gary,

Thanks. I have a really old roller that worked very well for rolling the 3" X 1/4" straps. I'm pleased with the result.

Rob


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## dimitri (May 16, 2008)

Rob,

awesome job so far!

Are you going to paint batteries red to match with the rest?


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## kittydog42 (Sep 18, 2007)

I recently converted a Miata. My pictures can be found here:

http://www.flickr.com/photos/ev-supply/sets/72157608659516504/

I have a lot more yet to upload. I put two batteries in the area formerly occupied by the gas tank, and I removed the stock access cover to get to the wiring. The only place I cut away was the bottom of the trunk for a drop-in box. I had all my metal work powder coated red after I was finished.


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## RKM (Jun 9, 2008)

dimitri said:


> Rob,
> 
> awesome job so far!
> 
> Are you going to paint batteries red to match with the rest?


Dimitri,

Thanks. Your Miata conversion has been an inspiration for me (and many others I'm sure). I won't get mine put together in the three weeks you took to complete yours! I'm hoping that I'll be done by mid July.

Yellow or Blue will have to do for battery colour! Just hope it won't clash with the red! I will be having transparent tops on the batt boxes. I think it will look good, be convenient for people to see what the cells look like and will allow me to see the LEDs on the BMS modules without removing the tops.

Rob


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## RKM (Jun 9, 2008)

kittydog42 said:


> I recently converted a Miata. My pictures can be found here:
> 
> http://www.flickr.com/photos/ev-supply/sets/72157608659516504/
> 
> I have a lot more yet to upload. I put two batteries in the area formerly occupied by the gas tank, and I removed the stock access cover to get to the wiring. The only place I cut away was the bottom of the trunk for a drop-in box. I had all my metal work powder coated red after I was finished.


Rick,

Beautiful conversion! Powder coat would be great. For reasons of time and convenience, I'm just using three coats of a quality spray paint.

Great photos. They raise a lot of questions. What plastic material did you use for the belly pan? What sensor (?) did you put on the tailshaft? What kind of conduit did you use to protect your wire runs? How did you address the rear suspension upgrade to handle the extra weight?

Rob


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## kittydog42 (Sep 18, 2007)

Rob,

Rick was my customer for this conversion. Unfortunately, he passed away in December, so the project was on hold for a short while, but his wife ended up giving me the go ahead to finish. She will be the main driver now, with me taking it to car shows as Rick had intended to do himself.

The plastic that I used is just regular ABS. I buy it is 4'x8' sheets and cut it to size. That ABS is 1/8" thick. 

I used non-metallic liquid tight conduit. I ran 4 total, 2 for the high voltage 2/0 cable, 1 for the high voltage charger and DC/DC wires, and 1 for all the low voltage control wiring. For the 2/0, I pre ran it into the conduit, and for the others, I installed the conduit first and then ran a fish tape through it and pulled the wires I needed.

The Valence batteries that I used did not seem to have a tremendous effect on the level of the car, so nothing has been done on the suspension yet. All 7 rear batteries only weigh about 290 pounds. The fuel tank full was approaching 100, and the spare tire was sacrificed due to the problem of there being no place to put it, so those things probably weighed around 120, so I am not over by too much.

I used the standard Zolox type sensor most people use. http://www.evsource.com/tls_speedsensor.php. They also sell an adapter for the WarP on the "Motor Accesories" page.

Feel free to ask any other questions, I don't mind answering.

Carlo


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## RKM (Jun 9, 2008)

Carlo,

Sorry for the mix up with the name. Thanks for the information.

The fuel tank from my car weighed only 45 pounds. I had expected it to be heavier. I'm anticipating gaining at least 300-350 pounds at the back (18 X 5.6 kg cells in trunk floor plus another 9 behind the seats).

Sorry about the death of your customer. Its nice that the car will be completed.

Rob


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## RKM (Jun 9, 2008)

Ceramic heater installed

I went the traditional route and tore apart a 120VAC heater to get my ceramic element. The heater was about $21 CAD from Rona. I hope there is some durability to it. The box is 18 ga steel built slightly smaller than the original heater core. Weather stripping makes for a nice seal and friction fit into the heater chamber. High temp silicone seals and isolates the element inside the steel box.

I've removed the AC to make room for a batt box. I'll use the AC clutch relay to close the contactor to turn on the ceramic heater. No extra switch or wiring will be required in the dash. There is even a small indicator light beneath the switch for a visual reminder that the heater is turned on.


Rob


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## RKM (Jun 9, 2008)

Motor cooling fan/filter and retractable cord reels

Have made some progress with the motor cooling. I've decided to filter the air into the WarP 9. We will be driving on two miles of gravel everytime we leave the yard. I'm using the cylindrical engine air filter that came with the car, coupled to a 5 speed cabin fan from a Miata. The cover band on the motor has a pair of 1.5" OD tubes attaced to the lower brush ports of the motor. I have a pair of 1.5" ID helix hoses connected between the fan and the band. The photos are a work in progress. I need to paint and silicone seal the parts and make one hose a bit longer. 

I'm hoping to use a thermal switch to turn the fan on when needed. I've chosen the second lowest fan speed but can change to a higher speed if neccessary.

I'm using a dual 120V 2400W charger. I can plug in one or both chargers to get either 1200W or 2400W of charge. For convenience, I wanted to have retractable cords extending from the front air scoop of the car. The cords extend up to 18' and have build in 13 amp breakers. I plan to fill the air scoop with a clear polycarbonate and have the cord ends extend out through the polycarb. The cord ends light when they have power.

I've bolted a 1.5X1.5X.100 wall square tubing to the front torsion bar bolts to serve as a mount for the reels and the fan. This tube will also support the weight of the front batt box (9 LFP cells).

All for now.

Rob


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## DIYguy (Sep 18, 2008)

Hey Rob,

hmmm, I never thought about bringing cooling air to the motor from the bottom. I shall have to look to see if I have room. Good idea!
I will have one battery right between the frame rails down low though....so, I dunno...we'll see.

Retractable cord reels is a nice idea too..... should be handy!

G


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## RKM (Jun 9, 2008)

Main breaker safety trip

Can't believe its almost 2 months since my last post on this thread! Progress is being made, though not as quickly as I'd like. When asked, I say that the car is 2-3 weeks away from being done. I've been saying that for 6 weeks now!

I'm using the clutch pedal as a safety trip for the main breaker. The pedal will be moved higher 3-4 inches so that no one will mistakenly trip the breaker out of habit (going for the clutch). The photos show the trip mechanism.

Rob


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## RKM (Jun 9, 2008)

Battery box frames

I've made skeleton frames out of 1X1X.125 angle. These will be lined with polypropylene and .375 foam insulation where space permits. Each of the 5 box sections will have a small 12 volt fan (two fans in the largest box). These will be controlled with a thermal switch that starts at about 80 F.

The TS cells will be restrapped into groups of nine (one five and one four grouping) and will be strapped vertically down in the boxes with SS strapping.

Each box has a clear polycarbonate lid with an Al frame. The lid is oversized to allow ventilation.

Rob


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## bblocher (Jul 30, 2008)

Really looking good. Can't wait to see you get it on the road!


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## RKM (Jun 9, 2008)

Brian,

Thanks. Even though progress has been slower than I'd like, I'm happy with the results so far. Now to get it done! 95% of the fabrication is complete. I'll be assembling from here out, close to wiring.

Once again, your beautiful S2000 conversion has been an inspiration.

Rob


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## RKM (Jun 9, 2008)

Rear suspension upgrade

Thanks to those who suggested options for the rear suspension upgrade. I finally went with what is likely the most expensive and hopefully the best option.

I estimate that the rear end will be about 325 pounds heavier than stock. I contacted the good folks at Flyin' Miata for higher spring rate springs and new shocks. They did the calculations and provided the hardware (I hope they are right!).

The springs rest on adjustable height perches, so I should be able to set the ride height where I want it. Strange that the new higher spring rate springs have a smaller cross section, smaller diameter and shorter uncompressed length. They are definately a stiffer rate though.

I made up a quickie spring compressor to make the swap. It worked well, no one got hurt!

We brushed off the dirt and surface rust from the front and rear end, then painted with "Rust Mort" and finally black paint. "Rust Mort", as the name implies, kills rust.

Can't get photos to upload right now, will post photos later.

Rob


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## RKM (Jun 9, 2008)

Motor overspeed protection

Bryan (from Belktronix) has developed a motor overspeed protection system (OSP). Mine is set to limit the motor to 5000 rpm. At 5000, the system reduces power to the controller. At 6000, the contactor is opened. The OSP also provides a signal to the tach. I've made up a two lobe cam for the tailshaft. 

Rob


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## DIYguy (Sep 18, 2008)

Looking nice Rob!

Some questions for you....

Is the coverband with inlets for forced air to the motor made of SS? (I have to do this part still....was thinking of getting some light wall SS tubing from an specialty exhaust shop.)

What kind of prox are u using for the tach/motor overspeed?

Did you ever sort out the battery Ah question?

I like the look of those bat boxes...have you picked something for heating?

This whole thing does take a while.... I think it's cause we don't want to do a hack job... at least that's my excuse...lol 

Cheers.


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## DIYguy (Sep 18, 2008)

Now u got stars!!!!!!!!!! lol


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## RKM (Jun 9, 2008)

DIYguy said:


> Looking nice Rob!
> 
> Some questions for you....
> 
> ...


Gary,

The coverband and ports look like stainless, but are not. 18 ga cold rolled sheet. It's been painted since the photo. I've been using stock material as much as possible.

I can't give you much information on the proximity sensor. Brian put that system together. Some of the specs show up from the photo. The cam lobe is made to provide equal length pulses of on and off (square wave).

Re. the Ah question... I'll pm you on that.

I've opted to do without a heating system for the bat boxes. TS LiFePO4 cells are rated down to -25 C. The car will be parked in my house garage which, while not heated, seldom freezes. I'm adding .375 foil foam insulation where space allows in the boxes. I don't think heating will be worth the effort.

I'm more concerned about cooling. Each box will have at least one 12V fan for ventilation. A thermal switch (thanks again) will turn them on and off.

I've been away 9 of the last 12 days. Expecting to make good progress now! Must make good progress now!!!

Take care.

Rob


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## RKM (Jun 9, 2008)

More progress...

Motor cooling fan and retractable cord reels installed. Thermoswitch controlled, batt box cooling fans installed.


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## RKM (Jun 9, 2008)

More progress...

Circuit breaker, with clutch pedal safety trip, main contactor, shunt, potbox installed.

Trying to source the remaining wiring parts. Have make up a mount for the charger/DCDC next.


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## PatricioIN (Jun 13, 2008)

This is all amazingly good work. Even those of us with "clean" conversions are jealous! All the little details on the batt boxes show a tremendous amount of forethought. Very good job so far!


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## RKM (Jun 9, 2008)

PatricioIN,

Thanks for the kind words. I'm just trying to keep up with the rest of you! Build it right, build it once is the philosophy I suppose. I've had lots of help from forum folks along the way.

It's taking way too long, but like Gary has said "don't want to do a hack job". I'm getting to the point where I just want it done. I need my shop back for paid work! How in the world did dimitri do his quality conversion in 3 weeks?!

Getting the last of the wiring supplies lined up. Really looking forward to finishing the wiring, turning the key, and having everything work the first time! Wishful thinking?

Take care.

Rob


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## Woodsmith (Jun 5, 2008)

It certainly looks very well thought out with no obvious bodges, and very clean and tidy. I'm impressed.

I hope to do like wise with the 'build it right, build it once' but I am also impatient.
I do like the clean and tidy approach, it makes things so much easier to check and service later on.


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## DIYguy (Sep 18, 2008)

Woodsmith makes a good point, few consider. Service-ability. Its one thing to cram in the necessary components, quite another to do it in such a way that things can be serviced with minimal heartache. This is actually engineering. It doesn't have to be documented, (something I'm not always patient engough to do) but "time in thought" is engineering. In europe, engineers must be tradesmen first ... thoughts of repairing...creep into the minds of those who are journeymen ....while "thinking". (I mean journeyman in the most common way....those who are DIY'ers of course... 

Nice job Rob.... unlike some, I'm not surprised...


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## EV-propulsion.com (Jun 1, 2009)

Here's yet another miata conversion....seems the miata crowd is dedicated to clean looking conversions! http://www.ev-propulsion.com/projects.html
mike
www.EV-propulsion.com


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## RKM (Jun 9, 2008)

Mike,

Thanks for the link. I've admired your conversion before. There are quite a few similarities between your conversion and my own. I had originally intended Al boxes but opted to go with steel skeleton frames and poly liners (cost, equipment and familiarity). 

Looks very impressive.

Rob


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## DIYguy (Sep 18, 2008)

OK I wanna know who did the rotisserie first! ? lol


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## RKM (Jun 9, 2008)

Over due updates...

Clean up of brakes

My rear brakes had been dragging a bit and the right rear seized up altogether while the car was parked. I took the brakes apart and cleaned everything up. Drag is gone. In a weak moment at Canadian Tire, I broke down and bought a can of high temp caliper paint!


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## RKM (Jun 9, 2008)

Spray on body undercoat

A previous owner had done some damage to the lower frame rails. I boxed them with 18 ga. on three sides and riveted the reinforcement in place. Also added short sections of 2 X 2 X .125 square steel for routing the cables through. Then, put on a coating of body undercoat.


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## RKM (Jun 9, 2008)

Installing four conduits, front to back

The dual charger is installed in the trunk, so there are alot of wires to go front to back. The bat box cooling fans are set up to run off 12V when charging or when driving. The result is 11 light gauge wires, a pair of 14/3 AC cords and another pair of 12 AWG wires. These are divided between two poly conduits, one on either side of the frame.

The 4/0 cables are protected in Sealtite (metal sheath with outer poly) conduit. This seems to be a very tough armor to protect the cable and the metal should reduce EMI. The two cables are run on either side of the frame.


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## RKM (Jun 9, 2008)

Cycle Analyst speed pickup

The CA has a speed pickup that is installed at the differential.


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## RKM (Jun 9, 2008)

Thermal switch for auxiliary motor cooling fan

The WarP 9 has an internal fan that will draw air through the auxiliary fan and filter. I've added a thermal switch (thanks Gary) that will turn on the aux fan at about 100 F. I had thought of running the fan all the time, but thought it would be nice to have the car quiet until the extra cooling became necessary.


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## RKM (Jun 9, 2008)

Belly pan in progress

The belly pan is about 3/4 complete. The back end has to wait until the car comes off the rotisserie. It is a poly pan, PVC IIRC, and is in three parts. I have to give credit to Murray, who works with/for me, for most of the work fitting the pan in place. IMO, he does nice work.


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## RKM (Jun 9, 2008)

Repacking TS cells and assembling BMS

The TS cells came stapped in groups of 5. I need 4 groups of 9, one 5 and one 4. It takes alot of time to reassemble the packs. I understand that it may be possible to have TS group to individual needs. Make sure you ask if this is possible.

The Belktronix BMS boards are installed on polycarbonate strips that I have attached to the packs with velcro. This allowed me to do most of the board wiring on a bench then remove the strips for stapping the cells into the bat boxes. There is still a resistor to install once everything is in place.

Thanks to my 11 year old daughter for cutting, twisting and bending the wires!


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## RKM (Jun 9, 2008)

Strapping the cells in

SS strapping (a la KIWIEV) is used to strap down the cells. I had to buy the strapping tool for this job, but I'm sure I'll continue to use it for other projects. I have clear poly tube over the strap where it brakes around the top edge of the cells and to protect against shorting on the terminals. Have also put heat shrink over the buckle.

I have welded short pieces of 5/16 round on the bottom of the bat boxes to ease the radius of the lower corners of the strapping. So far, so good, we'll see how it stands up to road use.


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## DIYguy (Sep 18, 2008)

Hey Rob,

Nice and tidy! I really like your workmanship. Most of your BMS boards will be pretty well protected from the elements I take it? Still planning covers over the boxes? 

I'm a little concerned about leaving mine mounted on top of the batteries without something else to protect. I can see water getting up there and causing issues. Was thinking of putting them in boxes and running wires. Either that or will come up with some suitable covers although there isn't a lot of room in places.

Is that your dual charger in the trunk? Looks like you have a lot of the wiring done. Did you read the blurb on the soil heating wires? Seems like a good option for heat since they maintain 75 deg F, which is just right I think. Ideally though, it would go under the batteries...and mine are in already...argh. Not sure how good it would work to snake it on top....with top insulation of course....

Are you planning to get yours on the road before winter sets in... or will you nurse it till spring?


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## gdirwin (Apr 7, 2009)

Nice job Rob - almost there!

I had the pleasure of a guided tour of Rob's car about a month ago (thanks Rob!). It looks even better in person - definitely not the "rush to see the wheels turn" kind of job - lots of attention to detail...

I will be starting my own build thread shortly, and have already learned lots from Rob's Miata...


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## RKM (Jun 9, 2008)

DIYguy said:


> Hey Rob,
> 
> Nice and tidy! I really like your workmanship. Most of your BMS boards will be pretty well protected from the elements I take it? Still planning covers over the boxes?
> 
> ...


Gary,

Yes, I have already made Al and Polycarbonate covers for each of the five bat boxes. I need to remove a bit of Al to allow the cable interconnects into and out of the boxes, no big deal. The BMS boards will be protected from the elements but still visible for monitoring LEDs. I think you're wise to get some kind of protection from the elements.

Yes, you can see the dual charger in one of the photos. It is mostly wired, still need to connect the Over Voltage Protection signal wires. There is a polycarb and Al shield for this also. The top fan is partially exposed and I wanted to protect the connections from cargo and fingers.

I'd originally intended to have heat for the boxes, ended up deciding against it. LiFePO4 is more forgiving of the cold (I keep telling myself) and the car will be in the garage (seldom freezes). If I had gone with heat, I'd have opted for the heating wires you suggest beneath the cells and above the insulation. My bottom layer of insulation had to go as well as the BMS required more height than I had originally thought. I'm sure you'll agree that the heat on top of the batts will be much less effective. Is it worth it to remove your batts thought?

Don't even suggest holding the project over till spring. I'm so close now, I'm going to see it through. I've got a hardtop for the car and will get winter tires. We're going to drive it year round.

You'll be done soon too?

Rob


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## RKM (Jun 9, 2008)

gdirwin said:


> Nice job Rob - almost there!
> 
> I had the pleasure of a guided tour of Rob's car about a month ago (thanks Rob!). It looks even better in person - definitely not the "rush to see the wheels turn" kind of job - lots of attention to detail...
> 
> I will be starting my own build thread shortly, and have already learned lots from Rob's Miata...


I look forward to seeing your conversion. Your's will make mine look like a soapbox racer by comparison! I'm envious of your EE ability and have appreciated the help you've offered. That's one of the great things about this kind of project... getting to know some great people.

Take care.

Rob


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## RKM (Jun 9, 2008)

TEST DRIVE 

The EV grin is REAL and completely involuntary, it can't be stopped!! I'll show you what it looks like >  . Wow, it is an amazing rush. I hate to make this comparison but the closest feeling I can compare it to is the birth of a child. Both projects take about nine months!

The car is not done. Wiring to tidy up, some reassembly of the interior is left. Some belly pan to complete. Need to sort out a glitch with the charger. Heater relay circuit to trouble shoot. Seat heaters to install yet. Need to figure out the Cycle Analyst. Body work and paint to come. BUT, I HAVE DRIVEN IT AND IT IS GOOD!

Here's some of the good stuff...

The motor Over Speed Protection circuit and tach signal work great. It revs to just over 5000 rpm then limits speed. The factory tach seems right on.

Inflated the tires to the max rated of 44 psi. I'm able to pull the car on flat concrete with my little finger. I know that's not quantified, but I think it's pretty good! 

Clutchless shifting is much easier than I had expected. I've been reading horror stories of waiting 10+ seconds between gears. Upshifting and downshifting is surprisingly smooth and quiet. No argument, crunch or effort required. Very little delay, only 2-3 seconds. Really pleased about this as I had imagined I'd be regretting the clutchless decision and would be putting it back in sometime.

I'd say the car is much quicker at the bottom end. The low rpm torque on tap is a real hoot. The ice Miata was fun, but it wouldn't push you back in your seat the way it does now. Starting in 1st gear is nothing but tire spin. 2nd is easy to break the tires free. Starting in 3rd is quite acceptable. 4th was a bit sluggish from zero. Bear in mind that I was only driving around my yard (big yard) and the road is wet gravel. Still, I was thrilled by how the car will take off!

The toyota power electric/hydraulic power steering is perfect. Thanks to dimitri!

Brian's vacuum brake kit seems good so far, will need to add a vacuum gauge and increase the vacuum level for a bit more boost.

Bryan of Belktronix has provided excellent support and trouble shooting assistance. He really stands behind his product and supports his customers (a pleasent change from many vendors). 

No emissions. I put about 8 km on the car while it was still in the air in the shop. Not a hint of exhaust!

The rear suspension upgrade (higher spring rate and new shocks) seem to be right on the money. It has adjustable height spring perches, but is good right as it is. The front stock hardware are about right also.

Sorry for the lengthy and maudlin post. It's been a long road with some yet to go, but I'm very, very pleased with the results. 

Rob


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## JRP3 (Mar 7, 2008)

Congratulations on the new member of the family  She's a beauty.


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## DIYguy (Sep 18, 2008)

WOW!!!!! That is awesome Rob! Congratulations! I'm very happy for you! It really looks great. You did an awesome job and your selection of components has shown great decisions. 

I just came in from working on mine, just after 10 pm here, and thought I would check the blackberry to see what I had missed. I was very surprised to read your post.  I knew you were close, but didn't think you were this close! Very kewl. 

Now you have me all excited to get mine out. Maybe I'll take her for a spin this weekend... hehehe.... 

I'm EV-smiling here in Ontario ... for you...


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## tj4fa (May 25, 2008)

Very cool!! Congrats!!


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## david85 (Nov 12, 2007)

I probably shouldn't be naming favorites, but this is a hands down show car from what I've seen so far. Love the belly pan. Can't wait to see you chime in on the freeway distance thread


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## gdirwin (Apr 7, 2009)

Congrats! Glad your "pre EV Grin" fears about shifting etc... were for not.

Your post was like a little kid who just got his first red bike!

Rightfully so - well done!

Did you take video? Long parallel ruts in your road would be good for show...


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## paker (Jun 20, 2008)

This is exactly the car I'm looking forward to converting, even the same color . I'm quite interested in seeing what the highway performance, 70MPH +-, will be as that will be 11 miles of my work week commute.


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## RKM (Jun 9, 2008)

paker said:


> This is exactly the car I'm looking forward to converting, even the same color . I'm quite interested in seeing what the highway performance, 70MPH +-, will be as that will be 11 miles of my work week commute.


Paker,

I've got no regrets over the choice of car. Mazda has done a great job with the Miata at creating a fun to drive, good looking little roadster (IMO). The only downside is that space is sooo tight! If the TS cells were 5 mm larger in any dimension, I couldn't have fit them in as I did.

I'm completely confident it will cruise at 70 mph. The question is, how many amps will it pull? How efficient will it be? I'd be thrilled to draw 250Wh per mile at 60 mph.

Rob


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## dimitri (May 16, 2008)

Rob,

congratulations!!! This is easily the best DIY Miata EV build ever! 

I wish I had your patience.....

Good luck with testing and tuning, now the real fun begins....


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## RKM (Jun 9, 2008)

DIYguy said:


> WOW!!!!! That is awesome Rob! Congratulations! I'm very happy for you! It really looks great. You did an awesome job and your selection of components has shown great decisions.
> 
> I just came in from working on mine, just after 10 pm here, and thought I would check the blackberry to see what I had missed. I was very surprised to read your post.  I knew you were close, but didn't think you were this close! Very kewl.
> 
> ...


Hey Gary,

Thanks! I'm still on a high, even though there is still some finishing to do. For the most part, I've been following your lead on this job. Your build design has been top notch and you've had the creativity and resources to get the job done without laying out nearly so much cash. 

You're one of the people on this forum who is blessed with an abundance of intelligence, imagination and common sense, who also has the skills to see the plan through. This applies to many of you out there, but Gary has been particularly helpful to me.

Get er done, feel the grin!

Rob


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## dtbaker (Jan 5, 2008)

very nice to see this up and running!

can you summarize your final battery/bms/charger setup and costs if you don't mind? I am trying to decide if it is time for me to dive into the world of Li with my next conversion.....


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## RKM (Jun 9, 2008)

dimitri said:


> Rob,
> 
> congratulations!!! This is easily the best DIY Miata EV build ever!
> 
> ...


dimitri,

High praise from one of the true conversion gods! I won't agree with you on that assessment, there are alot of very nice Miatas out there, but thanks.

You don't know how many times I've said to myself and to others... How in the world did dimitri do his conversion in 3 weeks?!? It took me longer than that to decide on a controller! I wish I had your speed!

Rob


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## RKM (Jun 9, 2008)

JRP2, tj4fa, David, Garth...

Thanks so much for the affirmation! There have been challenges along the way, but it has been sooo worth it. Still more to be done.

There are at least two main benefits to doing a conversion. The first is self serving, to bask in the glory of a job well done, the sense of personal achievement. The second benefit is more altruistic. The more reliable, capable and fun EVs we put out on the roads, the closer we get to a mass alternative to gas powered personal transportation. This is good for the planet and everything on it. Sermon finished.

I've said it before and I'll say it again. I would not and could not have done this conversion if not for this forum and the great people who are members. 

I'm not really a video kind of guy, I prefer to be behind the lens of an SLR. I'll get some video of the car after it has fresh paint. 

Rob


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## EV-propulsion.com (Jun 1, 2009)

yes, very nice job! My miata draws 240wh per mile at 60mph,(with a full voltage pack) but the drivetrain is somewhat different (120 volts,warp9, curtis controller) so yours should be less than mine being a higher voltage.
And you are 100% right about everything being tight- there is no extra space anywhere-if you get 1/4" between things you got lucky!
Good job, and a very nice thread to document all the work you did-we appreciate all the time _that_ took to do-
what's your next project we have to look forward to seeing on DIY ?
Mike
www.Ev-propulsion.com


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## RKM (Jun 9, 2008)

dtbaker said:


> very nice to see this up and running!
> 
> can you summarize your final battery/bms/charger setup and costs if you don't mind? I am trying to decide if it is time for me to dive into the world of Li with my next conversion.....


Dan,

I purchased 45 TS 180Ah cells from EVcomponents at their price of $1.10/Ah USD. I'm in the centre of the continent so had ocean freight to Vancouver and truck freight to Manitoba (combined freight cost was about $425 USD). The cells were duty free but there was brokerage (about $100 CAD).

I don't have separate pricing on the Belktronix BMS and charger, it was priced as a package with the controller, potbox, etc. I felt that the package price was good value, still do.

Yes, lithium is expensive. If it delivers on the projected life expectancy, I'll have no regrets. It was the only way for me to get the kind of range I need to make the car useful. The other huge advantage is that it helps keep the weight down. The car isn't overloaded and it's a hoot to drive (though I've driven very little so far). That is worth an awful lot to me. 

Rob


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## dtbaker (Jan 5, 2008)

thanks for run-down....



RKM said:


> Dan,
> I purchased 45 TS 180Ah cells from EVcomponents at there price of $1.10/Ah USD. I'm in the centre of the continent so had ocean freight to Vancouver and truck freight to Manitoba (combined freight cost was about $425 USD). The cells were duty free but there was brokerage (about $100 CAD).


ok, so that adds up to $8910 for the batteries for your setup, plus freight, right? I would probably only need the 100AH size, and to compare with my current FLA pack that is 96v, I'd only need 32 cells... about $3200, versus the $1500 for FLA; but have to buy the BMS in addition for another $25 per cell for a minimum BMS volt-blocher totals to $800... so $4000 for Li batteries and BMS versus $1500 for FLA. Hhhhhmmmmm starting to look better in cost per cycle than it did 2 years ago!




RKM said:


> Yes, lithium is expensive. If it delivers on the projected life expectancy, I'll have no regrets.


I wish we didn't have to WAIT to find out!


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## Bottomfeeder (Jun 13, 2008)

Congratulations on a great looking car! You've got a lot to be proud of. It's great to see another EV on the road.


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## DC Braveheart (Oct 12, 2008)

RKM said:


> Motor adapter plate and spacer plate...
> 
> The adapter plate and spacer plate are complete except for some finishing touches.
> 
> ...


Rob,

Been a while since I posted - great build! 

It's also been a while since I made progress on my car - I've been waiting for parts. Now they are rolling in I'm about to kick off again. First up will be attaching the motor to the tranny using the adaptor I bought from EV-Propulsion. In their instructions, they mention the location dowels you refer to above ... hmmmm - I don't seem to have those ... arghhhhh! I assume that they are still connected to the engine block which was sold long ago sold. You wouldn't happen to know what size those dowels are (dia and length)?

Regards,


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## DC Braveheart (Oct 12, 2008)

DC Braveheart said:


> Rob,
> 
> Been a while since I posted - great build!
> 
> ...


Ah, never mind - I found the part number for these (99234-1916) and ordered a couple from my local dealership.


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## RKM (Jun 9, 2008)

Stuart,

My pins stuck to the engine side as well, easily pulled out though. Too bad your's got away. Not too expensive I hope.

Glad to hear the build is on again!

I'm patiently waiting for the paint shop to finish up, taking much longer than expected. I tell myself it will be worth the wait (what else can I do??).

Still have a couple small issues to resolve around the BMS and DC-DC, but it can be driven. 

The good news is that the car is licensed and insured again, will be legal to drive away from the paint shop. Yee Haaw! My only choice for vehicle insurance in Manitoba is public insurance. EV conversions are still very rare in MB, I may be the first. Manitoba Public Insurance has no policy for EVs. I simply re-registered the car. They are aware it is an EV conversion, but they have no other listing than "gas" or "diesel". Therefore, it is listed as gas. No inspection, no nothing, could not have been easier.

I know of at least 3 other conversions to be completed in Manitoba in the near future. Will be interesting to see if MPI figures out a way to handle EVs.

Have fun with your project! Take care.

Rob


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## DC Braveheart (Oct 12, 2008)

RKM said:


> My pins stuck to the engine side as well, easily pulled out though. Too bad your's got away. Not too expensive I hope.


Didn't cost more than a couple of beers.


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## dimitri (May 16, 2008)

Hey Rob,

you went quiet for a month, what gives? That EV grin gets in a way of forum posting? 

How's Miata handling the cold?


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## RKM (Jun 9, 2008)

dimitri said:


> Hey Rob,
> 
> you went quiet for a month, what gives? That EV grin gets in a way of forum posting?
> 
> How's Miata handling the cold?


dimitri,

Thanks for the concern! Trust that I'd be reporting, if I could. Here's the deal... I took the car in for bodywork and paint on Nov. 5, the job was to have taken two weeks. With a little luck, I'll bring it home on Christmas Eve!! Yes, two weeks has turned into seven. I had chosen a small, local shop to support a small, local business. The bright side is that he does very good work. The down side is that my job will be less profitable than insurance work and so has been bumped several times. Didn't know this would happen when I took it in. It has been trying my patience as you can imagine. I tell myself it will be worth the wait.

Regarding cold weather performance.... I'm getting a bit concerned now reading about the diminished performance of lithium in the cold, better than lead but still diminished. Space is so tight in the little car that I wasn't able to insulate as much as I would have liked. Heat cable beneath the cells would have been nice as well. The car will be in an attached garage where it will freeze under occasional extreme conditions.

The intention is to drive the car 12 months a year, hopefully that will still be the case. I'll be putting a set of winter tires on before I bring it home for Christmas. Depending on how it handles -25 C, we may have to drive it on warmer days, to be determined. Then again, the theoretical range should be around 80+ miles, so if the range were cut in half by cold, it will still manage our round trip to town (20 miles) very well.

I'm getting anxious to find out. Manitoba winter will be a great test for lithium. I predict insulation and a heating system will be the recommendation.

Will update on my real world experiences when I can.

Take care and have a great Holiday season.

Rob


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## RKM (Jun 9, 2008)

Home from paint shop!

It's been a while since I've had much to add to the thread. Seven weeks to the day, the car was brought home from the paint shop. I'm tired of whining about it, so I won't say any more about the wait! Got it home for Christmas Eve... pretty nice present.

Got a few replacement parts today and installed them. The car is running again, hopefully to stay. Still need to tidy up a bit.

Here are some photos. I'm really pleased with how it turned out. Note the missing fuel filler door on the left rear fender and the polycarbonate air scoop filler plate (work in progress). The new Nokian snow tires have a very low RR.

A safe, happy, healthy and electric New Year to all.

Rob


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## JRP3 (Mar 7, 2008)

Looks too pretty to drive in the snow. Do you have caps for the plugs in the front? I'd be worried about moisture and road salt corroding them.


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## tomofreno (Mar 3, 2009)

Nice! Shame to get that slush and road grime on that shiny new paint!


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## david85 (Nov 12, 2007)

Car looks great!


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## RKM (Jun 9, 2008)

JRP3 said:


> Looks too pretty to drive in the snow. Do you have caps for the plugs in the front? I'd be worried about moisture and road salt corroding them.


Good point about protecting the plugs from moisture and other road debris. I'll find some caps.

So long as the batts and electronics work well enough in the cold, we plan to drive the car through the winter, with the exception of really ugly weather. I want this car to demonstrate that EVs can be used in real world conditions and are not just fair weather toys. The more this car is driven, the more it will pay for itself and offset our "gas" miles.

I agree, it is a pretty car! It will wash!

Take care.

Rob


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## DIYguy (Sep 18, 2008)

Season's greetings Rob! 

I haven't been online for a while.... car looks great! I like the look of those tires! BTW... as for driving in the snow....gor for it!  I bet the car is better balanced than original....perhaps??

Interested to hear how the battery performance is. Hope you keep some notes and can compare as the temps vary.... would be great for a lot of folks. (maybe even me...  )

Cheers,
Gary


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## RKM (Jun 9, 2008)

DIYguy said:


> Season's greetings Rob!
> 
> I haven't been online for a while.... car looks great! I like the look of those tires! BTW... as for driving in the snow....gor for it!  I bet the car is better balanced than original....perhaps??
> 
> ...


Gary,

Took the car on its maiden voyage into town today. The Cycle Analyst isn't properly set up yet, so I can't quantify energy use. Its COLD here in the prairies, -20C. The car started out at about freezing and performance was far more sluggish than at plus temps. I had changed out the controller yesterday, so that is another wildcard. I attribute the difference in performance to the cold. It improved as we drove (battery internal heating?), top speed was only about 65 mph, which is adequate. A far cry from my experience in warmer weather.

The 20 mile round trip went very well. The car is particularly fun to drive in town. Had a big grin on my face when I drove to the gas station to buy sparkling water. Great feeling to know that car will never use gas again! 

The Nokian winter tires are great, have been using them on our other car for years. Ground clearance is minimal in the Miata, but the increased rear weight and good tires grip really well. 

My early assessment for cold climates is to insulate and heat the batts if at all possible (surprise, surprise)!

Happy New Year Gary. You've been a great help through this entire project!

Rob


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## gdirwin (Apr 7, 2009)

Looks like it was worth the wait Rob - awesome shiny red!

Congrats on the maiden voyage!


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## DC Braveheart (Oct 12, 2008)

RKM said:


> Battery box frames
> 
> I've made skeleton frames out of 1X1X.125 angle. These will be lined with polypropylene and .375 foam insulation where space permits. Each of the 5 box sections will have a small 12 volt fan (two fans in the largest box). These will be controlled with a thermal switch that starts at about 80 F.
> 
> ...


Hey Rob,

I hope things are going well with the car. My progress has been 'slow' ... but things are finally coming together and I've completed the boxes for 36 of my 45 TS cells - 18 in the old gas tank space and 18 up front - funnily enough my front box bears a remarkable resemblance to yours  Still gotta cut into the trunk for the last 9.

I have a question if you are still around on the forum ... how did you fasten your boxes down to the chassis? I can see from your pictures that the fornt of the front box is simply bolted throufh the front cross member - but what about the support at the rear of the box? That (in my case at least) sits over the frame rails on both sides. I'm reluctant to run a long bolt through the entire rail (scared I'll crush the rail when I tighten things down. I was thinking of welding a stud made from cut down threaded rod to the top of the rail and bolting down to that. Does that sound like a plan? How did you do it?

Regards,
Stuart


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## dtbaker (Jan 5, 2008)

DC Braveheart said:


> how did you fasten your boxes down to the chassis?


I used heavy duty 'rivet nuts' or 'jack nuts' which are basically industrial strength molybolts intended to provide a threaded nut in blind installations through sheet metal. My general construction page for rear rack is at 
http://www.envirokarma.org/ev/09.RearRack.shtml

with some detailed photos and whatnot in the photo gallery around here:
http://www.envirokarma.org/ev/gallery/090114_rivnut02.preinstall.htm


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## RKM (Jun 9, 2008)

Stuart,

Good to hear you're making progress. I can certainly relate to slow progress.

It's been so long now since I'd installed the boxes, I've forgotten how it was done. I believe I used existing bolt mounting locations (nuts factory welded into frame) on either side of the engine bay. The five front boxes are a unit. The front portion (nine cells) is supported on the front ledge above the radiator location. I added a 1.5" X 1.5" tube under the front portion to support it from beneath. This tube is bolted to the torsion bar mounting bolts. The tube is also used to mount the pair of retracting cord reels. The photo shows that there are a pair of 1/4" X 2" flat irons that span the engine bay. The first is between the front portion and the second is at the rear. Small angle iron tabs are welded to the flats. The angle tabs have holes to align with the bolt locations. The photo shows the painted boxes upside down. Confused yet?

Rivet nuts would be a good option too. I didn't have the tool and was able to make exiting nuts work. 

I hope this helps.

Rob


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## EV-propulsion.com (Jun 1, 2009)

Welcome back!
Nutserts are a similar option, most good hardware stores have them
 or 
 

also called rivet nuts, they are pulled tight by a bolt in the threads, no rivet gun required. Different styles for different metal thicknesses.
Mike
www.EV-propulsion.com


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## dtbaker (Jan 5, 2008)

RKM said:


> My early assessment for cold climates is to insulate and heat the batts if at all possible (surprise, surprise)!


I am in the process of converting my battery boxes from FLA to install my new TS cells... and will be adding a product called heat-line in the bottom (from http://heatline.com/length.htm ) in lieu of the typical Farnum heater pads because the heat-line is sort of self limiting without needing a thermostat and relay. The other thing about the line is that it can be plugged into AC while parked, or DC (120vDC) direct while driving. The plan is to line the inside of my battery boxes with space-blanket rather than thicker insulation, so we'll see how that works.

My QUESTION for Ray is that with the closed insulated boxes whether heat build-up in the summer actually was a problem requiring ventilation, or really not a problem? i.e. if you were to do it again, would you include the fans, or forget'em? Can you describe your 'usual' summer temps and whether you are doing extended highway miles or urban stop and go?


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## RKM (Jun 9, 2008)

One more thing I should mention... it's not related to battery box installation, but to motor coupler design.

I have a clutchless coupler and the first design failed after about 5000 miles. The female spline had been welded directly to a taper coupler. I wouldn't recommend this! It seems the temper was lost during welding. The softened splines did not last.

For the replacement, I kept the springs of the clutch plate and kept the assembly cooler while I welded. FYI, DIYguy had his first coupler fail, so I'm in good company! The new design should be more forgiving of any misalignment as well. So far, so good.

Picture on left good, right bad.

Rob


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## JohnnyLinux (Nov 16, 2010)

Rob,

What a fantastic build; I can't help but gawk at the meticulous work you've done on this machine! I hope to get a chance to see this in person sometime.

I'd love to do a Miata build myself, however I'm not certain my 6'4" frame will fit in all that well! It's looking more and more like I'll be doing a small pickup conversion, however there's still time to make a decision on that.

Thank you for a very well written thread on this build; I've been making notes based on your experiences (especially the battery heating/insulation issues).

Cheers,

John


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## RKM (Jun 9, 2008)

Hey John,

Thanks for the kind words... always nice to have someone appreciate your work. I think I've done the best I'm able to with the mechanical/steel work. I'm a little embarrassed of some of the wiring. It's not nearly as neat and organized as some other conversions I've seen. I stand in awe of gdirwin, DIYguy and others.

Yes, the Miata is very tight for components and bodies. I'm about 6' on a good day and my head brushes the roof. If I were any taller or wider, it would have been a non starter. Depends on how you are proportioned though, try one on for size.

Rob


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## RKM (Jun 9, 2008)

dtbaker said:


> I am in the process of converting my battery boxes from FLA to install my new TS cells... and will be adding a product called heat-line in the bottom (from http://heatline.com/length.htm ) in lieu of the typical Farnum heater pads because the heat-line is sort of self limiting without needing a thermostat and relay. The other thing about the line is that it can be plugged into AC while parked, or DC (120vDC) direct while driving. The plan is to line the inside of my battery boxes with space-blanket rather than thicker insulation, so we'll see how that works.
> 
> My QUESTION for Ray is that with the closed insulated boxes whether heat build-up in the summer actually was a problem requiring ventilation, or really not a problem? i.e. if you were to do it again, would you include the fans, or forget'em? Can you describe your 'usual' summer temps and whether you are doing extended highway miles or urban stop and go?


Dan,

Good question re. to fan or not to fan. The top covers on my boxes are not a tight fit, they are able to breath. I can't honestly say that the fans run very often. I have no indicator light to say that they are running. They are quite quiet as well and would be difficult to hear over the controller cooling fan. All five fans are activated by a small thermal switch located in the largest, best insulated box. They should all come on when that box reaches 25C. Our typical drive is usually 9 miles pulling about 140A, then home again. I haven't checked the temp of the batts after a run, but should. I think the greatest heat build up is if the car is parked in the sun for several hours, then driven. I have heard the fans run under these conditions. Usually, the car is parked in the shade, in the garage.

I would do it again, as insurance if nothing else. It was a bit time consuming to put five fans on five boxes, but not very expensive ($20 for all the fans, $10 for thermal switch, wire and fuse). Bear in mind that this is just my opinion and I don't really know what I am doing!

Rob


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## dtbaker (Jan 5, 2008)

RKM said:


> I haven't checked the temp of the batts after a run, but should.


I got a cheap thermometer that can show three wireless location temps... I think I am going to try WITH heatline and space blanket in enclosed box for winter, no fans, and probably one 'removable' panel or plug to allow convection in summer and see how it goes....

My garage drops to about 45 overnight in the winter which is not bad but DOES affect capacity, so that is the larger issue right now.



RKM said:


> $10 for thermal switch,


could you post a link to the switch, and source for purchase you used... just in case.


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## RKM (Jun 9, 2008)

Dan,

The photo shows the switch, it is normally open and closes at about 25C. I don't have quick access to the part number. It is similar to the switches I've used to control the Farnam heaters. I picked all these up at Active Electronics.

Rob


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## dtbaker (Jan 5, 2008)

RKM said:


> Dan,
> 
> The photo shows the switch, it is normally open and closes at about 25C. I don't have quick access to the part number. It is similar to the switches I've used to control the Farnam heaters. I picked all these up at Active Electronics.
> 
> Rob


hhhmmm, I poked around for a minute and found some of the Stancor disc thermostats online... they are cheap enough, but look to be rated for AC (not DC). do they hold up for ya?

They also look like they need to have a significant change outside the operating range before they 'reset'. Got me curious about how well they will hold up!


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## DC Braveheart (Oct 12, 2008)

dtbaker said:


> I used heavy duty 'rivet nuts' or 'jack nuts' which are basically industrial strength molybolts intended to provide a threaded nut in blind installations through sheet metal. My general construction page for rear rack is at
> http://www.envirokarma.org/ev/09.RearRack.shtml
> 
> with some detailed photos and whatnot in the photo gallery around here:
> http://www.envirokarma.org/ev/gallery/090114_rivnut02.preinstall.htm


Thanks Dan!


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## DC Braveheart (Oct 12, 2008)

RKM said:


> Stuart,
> 
> Good to hear you're making progress. I can certainly relate to slow progress.
> 
> ...


Rob,

Thanks (esp on the note about the reinforcement under the front cross member - I'll have to look at that).

Apologies for hi-jacking your thread!

Regards,


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## DC Braveheart (Oct 12, 2008)

RKM said:


> One more thing I should mention... it's not related to battery box installation, but to motor coupler design.
> 
> I have a clutchless coupler and the first design failed after about 5000 miles. The female spline had been welded directly to a taper coupler. I wouldn't recommend this! It seems the temper was lost during welding. The softened splines did not last.
> 
> ...


Thanks. I got my coupler from Mike at EV-Propulsion (who as you can see above is posting here) so I'm sure all will be will with mine (won't it Mike?  )


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