The mauswerkz 300zx EV build

Post up a thread for your EV. Progress pics, description and assorted alliteration
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BigMouse
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The mauswerkz 300zx EV build

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Table of Contents

Receipt and engine removal

Motor coupling and installation to transmission


If you're confused by the name, "mauswerkz" is the name I'm designing my motor controller and BMS under.
Last edited by BigMouse on Mon, 07 Oct 2013, 09:52, edited 1 time in total.
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The mauswerkz 300zx EV build

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Starting a thread for this car since my BMW 318is is on hold for the moment.

Here is the car I am converting:
Image
1993 Nissan 300zx 2+2. Got the 2+2 model so there'd be room for batteries. Will be registering it as a 2-seat after the conversion. The bulk of the batteries will go where the back seats used to be, with the remainder under the bonnet.

Took it for a bit of a joyride to give the petrol engine one last good run in this car before beginning the process of pulling it out.

Up on jacks:
Image

Began pulling off anything that won't be needed after the conversion. Air piping, exhaust, fuel tank, radiator...
Image

Engine...
Image

That's me in the middle, behind the crane.

So the engine is out and gone. The next step is to start taking measurements and designing the battery boxes, motor coupler, transmission adapter, motor mounts, and all the other little things that are needed for the conversion. Does anyone have any tips for taking the measurements? I would have liked to take them off the engine rather than the transmission, but the engine had to go and I don't have a caliper big enough to do it anyway.

But first, I might take it down off the jacks, roll it forward, and give the engine bay a good wash. It'll never be this easy to clean again.

Target specs, post conversion:
130km to a charge
Custom-wound industrial motor from Catavolt (ordered, built, waiting for encoder bearing from SKF)
22kWh CALB CA60FI battery pack (ordered from EV power, waiting for the ship to arrive from China)
Stock manual transmission with clutch intact (aluminium flywheel)
Using my own motor controller and BMS
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Ordered a 300mm and a 500mm digital caliper. Each one is rated to 0.01mm precision. I'll use these to measure up the bell housing mating face and the location of the input shaft. Unfortunately, the engine had to be taken away the same day it was removed, so I'll have to rely on the transmission side of things to get the measurements. Luckily, the input shaft feels solid and has no play in it. I'll document my measurement method and post it here, since I've had no luck finding any details or instructions online for how to do this. I guess I'll have to put my "mechanical engineer" hat on and figure it out myself. I'm planning on using a method of triangulation from various origins, but I'm not sure how to reconcile the error between these measurements as I go and keep it from accumulating. That's one reason for the 500mm caliper!
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The mauswerkz 300zx EV build

Post by Stiive »

I just sold my 300zx about a month ago :( Loved that car.

I actually bought it about 4 years ago planning to do a conversion when the engine gave any sign of trouble (bought it cheap with no service history) - but obviously didn't factor in it being a Nissan as it never ended up missing a beat!
'Thanks' for bringing back memories, now I miss her :(


In terms of measuring, has anyone used the xbox kinect software to 3D render into CAD? I wonder how accurate that is.
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Stiive wrote:In terms of measuring, has anyone used the xbox kinect software to 3D render into CAD? I wonder how accurate that is.


I actually bought a Kinect specifically for this purpose. I plan to use it to plan out my component placement. The difficulty with it is that it outputs a point cloud, no surfaces. Converting that cloud to surfaces is very tricky. I've played with scanning my living room and my BMW with it. It's very hard to keep it from losing track of where it was, even if you get very slow. When it DOES work, it's accurate to maybe 5-10mm (at 2-3m distance). I found some accuracy data for it a while back.

I'll use it to scan the engine bay and the back seat area, but it won't work for the transmission adapter. I DID consider using my 12MP DSLR to take some 'precision' measurements. It takes photos which are 4288pixels wide. If I filled the frame with an object 500mm wide, each pixel would represent about 0.1mm. The problem with this method is lens distortion. If the distortion is known, it can be corrected for in photoshop, but the error between two points on the frame would be unacceptable. The distortion could be calibrated by taking a photo of a large sheet of graph paper at the same distance as the subject being measured, but there's too much source for error in that too (how normal is the camera to the plane being measured? Is this distance the same as it was during calibration? etc).

Might give it a try if I find myself struggling with the calipers.
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Post by Stiive »

BigMouse wrote:
Stiive wrote:When it DOES work, it's accurate to maybe 5-10mm (at 2-3m distance). I found some accuracy data for it a while back.


Wow, okay that accuracy sucks. Maybe your Uni has a proper one then; we do.
Its certainly much more accurate than that.
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Stiive wrote:
BigMouse wrote:
Stiive wrote:When it DOES work, it's accurate to maybe 5-10mm (at 2-3m distance). I found some accuracy data for it a while back.
Wow, okay that accuracy sucks. Maybe your Uni has a proper one then; we do.
Its certainly much more accurate than that.[/quote]

There's probably a laser scanner somewhere at the uni. I'd be more inclined to use the 3D cooridinate measuring "ROMER" arm though. Supposedly it's good to 10um.

[ Edited Coulomb: balanced [ quote ] and [ /quote ] tags. ]
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BigMouse wrote: There's probably a laser scanner somewhere at the uni. I'd be more inclined to use the 3D cooridinate measuring "ROMER" arm though. Supposedly it's good to 10um.


If you can get a robot into your engine bay :P

Found this 3d scanner
http://www.nextengine.com/products/scan ... s/accurate

0.005" accuracy - no size limit on object.
Can output to Solidworks (only if you buy software upgrade I think).

You have $5k lying around right?
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Post by BigMouse »

Stiive wrote:You have $5k lying around right?


Looks very cool!

On second thought, I'm pretty good with a caliper ;-)

This is the tool we have at my Uni.
Image

It's maybe 600mm tall articulated as shown in the picture. Would fit easily in the engine bay. I'd likely have to take the transmission out of the car and bring it to the uni to do the measurements though. Both for accuracy (can clamp it to a table) and because they won't let me bring the $20k tool home for the weekend.
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Post by Richo »

I still have the motor so the measurement will be easier for me.
But i'm waiting for 300mm calipers to arrive.

The important ones are the studs to the centre of the shaft.
You can buy dowel pins and put them in the transmission.
You may have to have a piece lathed up to fit on the transmission shaft to take a reading past the flat of the bell housing.

From what I understand these measurements need to be within 0.1mm.
So calipers at 0.01mm should be fine.

Your other option is go to a wrecker and see if they have the motor to take measurements from.
Even if you offer them $20 it's still cheaper than lathing up a piece.
So the short answer is NO but the long answer is YES.
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First test fit of the new motor in the engine bay.

Image
Image

The coupler on the shaft in the photo is an off-the-shelf 3-jaw industrial coupler which I won't be using in this conversion. I'll be shortening the shaft by about 30mm and machining a bore for a pilot bearing in the end of the motor shaft. This should take a total of around 40-45 mm off the length of the motor (and as a result, the transmission adapter). Following that, and adapter will be machined on which the flywheel and clutch assembly will mount. When the custom parts are done and installed on the motor, it will fit on the transmission exactly like the original engine did, only without a starter motor!

The motor mounts will be custom, likely made from laser cut metal plate bent and welded in to shape. It should be possible for each mount to be made from a single piece of steel (or aluminium). The lack of any heavy machining here will keep the cost down. The motor will sit on polyurethane bushings in the stock motor mount locations. This motor is a clever design which has relocatable "feet". This will make it easy to attach to the mounting points already cast in to the motor frame. The mounts will attach to the motor at the sides rather than the bottom. The feet shown in the photos will be removed.

This motor also has a "c-face" mount on the front of it. This is where the transmission adapter will attach. There is a raised lip which will ensure everything is properly centred.

I haven't decided yet how I'll mount the batteries that will be under the bonnet with the motor and controller. They will likely be above the motor just forward of the firewall. The controller will likely be "front and centre" just behind the radiator support. Power steering, aircon, water pump, etc will be hidden down low, probably near their stock locations.

An undertray will be installed to help keep the engine bay clean.
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Post by BigMouse »

Richo wrote:The important ones are the studs to the centre of the shaft.
You can buy dowel pins and put them in the transmission.
You may have to have a piece lathed up to fit on the transmission shaft to take a reading past the flat of the bell housing.

From what I understand these measurements need to be within 0.1mm.
So calipers at 0.01mm should be fine.

Your other option is go to a wrecker and see if they have the motor to take measurements from.
Even if you offer them $20 it's still cheaper than lathing up a piece.


You're correct about the critical dimensions. I hadn't considered that there'd be significantly fewer of them than the number of holes. As long as those are as accurate as possible, the rest of the mounting holes are just for clamping and can be a loose fit.

I can machine an input shaft extension myself pretty easily at uni if I need one.
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Post by Stiive »

Also, you might want to look at this guy from Qld's 300zx conversion.
http://300zxev.blogspot.com.au/


He has updated the blog in over 2 years though - I wonder if he ever completed it
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Post by BigMouse »

Stiive wrote: Also, you might want to look at this guy from Qld's 300zx conversion.
http://300zxev.blogspot.com.au/


He has updated the blog in over 2 years though - I wonder if he ever completed it


Thanks. I've seen that. There's so much about how he's gone about his conversion that I (and apparently his engineer) would have done differently. Battery locations, brittle plastic storage bins, DC system.

I hope he got it fixed up and on the road though.
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Did some work on the motor controller. Milled out some of the fins on the heatsink so I can install plumbing to make it water-cooled. Only the fins under the IGBT modules need that level of cooling, so the water channel is a small 2-pass arrangement with the "turn-around" in the middle of the heatsink. The rest of the fins will remain exposed for additional convective cooling and to help keep the capacitors cool.

Image

The milling was done (in a rush) at my Uni workshop. I wish I had my own machine tools. Someday, when I have room for them!
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Post by BigMouse »

In part-collecting mode:

Electric power steering pump and electric throttle pedal, both from a Holden TS Astra:
Image
(though we'll be using a standard potbox instead of the Astra pedal).

And we want to make sure this thing can rev, and handle the torque, so a Fidanza flywheel and stage 3 clutch kit have been acquired:
Image
The ring-gear will be removed. No need for it anymore. Could even remove some more material from it at the same time, but I don't think it'll make much difference or be worth the cost of machining.

I also bought an aluminium clutch kit for my BMW at the same time (to save on shipping from the US) so that I'm ready to go with that conversion when the time comes.
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Post by Renard »

BigMouse, with a fairly heavy car -- 1350 or 1400kg? -- the current you need to get it up a long hill means that you need to allow adequate space for a decent sized cooling fan.
Just something to bear in mind.
For myself, I may have to increase the cooling of my motor. More tests will tell.
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Renard wrote:you need to allow adequate space for a decent sized cooling fan.
Yeah, I'm already considering ways to accomplish cooling on this motor. The integral fan will be removed as I'm going to be driving the aircon compressor from a pulley at the front of the motor (owner's request). I'll either duct in a squirrel-cage "blower" fan for cooling, or experiment with a water cooling jacket on the motor.
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Post by BigMouse »

Big day for the EV conversion. Batteries have arrived!

Image

60Ah CALB grey cells. 120 of them.

I'm always impressed when I hold an EV battery. They've got a certain "heft" to them.
Image

About half the pack will sit in the back seat area. Here's a 3D model showing a rough arrangement. One of several possibilities.

Image

I'm hoping to fit a bit more than half the pack here as I want to keep the engine bay relatively open so the motor is visible. This is going to be a demonstration car after all. Elcon charger nestled in the middle straddling the drive shaft tunnel. This may be relocated though as I'm planning on installing the J1772 socket in the nose rather than the stock fuel filler location (a 10a connection will go there, perhaps an IEC computer power supply style connector).
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Post by Renard »

Happy day!
It's an exciting moment isn't it.

The smallness of those cells should make it easier to fit them in the spaces available. I assume you're going to fit cells in front up to the weight of the original motor.
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Renard wrote: Happy day!
It's an exciting moment isn't it.

The smallness of those cells should make it easier to fit them in the spaces available. I assume you're going to fit cells in front up to the weight of the original motor.


Very exciting!

I want no more than about 40 or so cells up front. With 60 in the back, and 40 up front, I need to find room for 14. Maybe 2 more rows of 7 in the back seat area somehow.

If I can squeeze one more cell on the end of each side of the back seat pack, that's 6, then maybe 4 more end-to-end along the width of each half. That'd make up my 14. I'll figure it out.

For the record, 114 cells will be installed. The elcon tops out at 417v output, which is 3.65v per cell (the datasheet charging limit). This also gives a nominal 364.8v on the pack. I'm curious to see if a 240vac compatible SMPS (for the DC-DC) will work on this pack at full charge. I'll check the component ratings first of course.
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Post by Renard »

With my 112 cells, I'm often driving with a pack voltage in the low 370's when the pack is fully charged. As to how the SMPS responds to this slight over-spec voltage, I don't know.

Because my SMPS is in a hard-to-get-at position, I didn't risk it; I put a 30V active zener in series with the converter, but which is bypassed with a FET for pack voltages less than 360V.
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Post by weber »

Congrats BigMouse. We designed for two strings of 114 cells originally too (but have cut back to 109 now for weight reasons) and we use the Meanwell HLG series SMPS from Mouser as they are rated to 431 Vdc.
http://au.mouser.com/new/meanwell/meanwellhlg/. They are designed to operate from one of the many strange AC supplies used in US industry -- one where they have 480V 3-phase for motors and use the neutral to phase voltage of 277 V for lighting. These SMPS are intended to power LED lighting from that 277 Vac. We are using two of the HLG-240H-15 (15A 15V adjustable). A single HLG-320H-15 might suit you.
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weber wrote: Congrats BigMouse. We designed for two strings of 114 cells originally too (but have cut back to 109 now for weight reasons) and we use the Meanwell HLG series SMPS from Mouser as they are rated to 431 Vdc.
http://au.mouser.com/new/meanwell/meanwellhlg/. They are designed to operate from one of the many strange AC supplies used in US industry -- one where they have 480V 3-phase for motors and use the neutral to phase voltage of 277 V for lighting. These SMPS are intended to power LED lighting from that 277 Vac. We are using two of the HLG-240H-15 (15A 15V adjustable). A single HLG-320H-15 might suit you.
I looked at those power supplies when you guys discussed them in your MX-5 thread. They seem very nice and suitable except they're only available in fairly low powers. I'm using an electric power steering pump which supposedly can draw around 50a at full lock. Ideally, I'd like at least 500w from my DC-DC. Considering designing and building my own (heck I'm doing it with the inverter, why not the DC-DC). Seems like there's a market for them!

Or I could just use two of the supplies you suggest in the interest of expedience.
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Post by weber »

We have electric power steering too. It shouldn't spend very long at full lock, so in theory the 12 V battery can make up the difference during that time. But did you see where we added a current-limited PWM speed control to our power steering pump so now at full lock it just stalls and doesn't pull anywhere near as much current from the 12 V supply.
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