Mazda MX-3 electric

Tell us about the project you do with the open inverter
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arber333
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Mazda MX-3 electric

Post by arber333 »

I came back to roots and decided to remake my first EV.
Mazda MX-3 that i converted back in 2013. Old build log is here: https://mazdamx3ev.wordpress.com/

Well i decided to remove the old air cooled ACIM motor and install Outlander rear motor in place.
I will use OEM inverter and my ESP32 VCU built to control Outlander inverter, charger, heater and JK BMS.

Some photos of Mazda empty space:
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Motor original position:
motorscheme.jpg
I will use ID3 modules 6kW8 modules 12S2P in alu boxes.
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For battery mount i decided to use 3 plate sandwich. I will use two 8mm plates on the outside for stiffness and i will use 5mm plate and cut it simply by jigsaw to a pattern where coolant will flow from one side to the other. Then 5mm plate will be glued between outside plates and bonded by M5 countersunk bolts.
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I will still have to find a TIG welder to weld two 10mm tubes vertically onto one side of the plate for the coolant to enter the channels.
I currently made two 650mm x 460mm plates and put holes for M10 bolts to fit modules from each side of the plate.
arber333
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Re: Mazda MX-3 electric

Post by arber333 »

Some more photos of motor positioning. I need to get good level position with driveshaft well clear of the frame when car is on lift!!
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arber333
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Re: Mazda MX-3 electric

Post by arber333 »

I managed to install Outlander motor. It is a bit offset, to forward axis, like 5deg probably because of my strange bands mounting contraption.
If i dont like it i will correct it by rewelding those forks.
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Next i started to mount inverter and charger. Well the charger mount was already made. I just repositioned it.
For the inverter i made 5mm alu brackets that mount firmly to the chassis. At least 3 mounts to define position in space.
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I also put Outlander heater on the side so i can connect and setup hoses.
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Next i need to fit the front battery box to those transverse beams and make mounts for cell modules inside the rear box.
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Re: Mazda MX-3 electric

Post by arber333 »

I had to make a fitting to fix the charger in place. I simply made a U channel to keep the distance from the front marker.
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I made a simple angle fitting for the coolant header tanks. On the left will be coolant and on the right i will use liquid for the heater system.
I think of making another simple extension fitting to fix the coolant tanks in place by the 3rd point.
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I got the front battery box made from inox 1.5mm. Dimensions 470mm x 700mm x 250mmIn. Idea was to fit 4 of ID3 12S modules inside here. In the end i couldnt get the bonnet closed so i had to cut down the last 50mm to taper down the box. This means i wont be able to fit full 4 ID3 modules but only 3 of them. I will be able to fit complete mount of 4 in the back though.
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tom91
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Re: Mazda MX-3 electric

Post by tom91 »

You looking to reuse OEM bms slaves? Using less then 4 requires some testing to figure out if the balancing works correctly.
Founder Volt Influx https://www.voltinflux.com/
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arber333
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Re: Mazda MX-3 electric

Post by arber333 »

tom91 wrote: Sun Oct 15, 2023 9:31 pm You looking to reuse OEM bms slaves? Using less then 4 requires some testing to figure out if the balancing works correctly.
No i dont have any BMS from VW. I will simply use JK BMS and ESP32 VCU as master control. I already wired 3 12S battery modules to 2 BMS modules but i will have to appropriate another 12S module in the 5th BMS module. This means i will have to program my VCU to modules 4x18S and 1x12S.

I still havent decided if i will need liquid cooling or if the ALU plate will be enough of a heat sink...
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Re: Mazda MX-3 electric

Post by arber333 »

There is a lot of small tasks like make a third mount for coolant headers, cable clamps etc... and i didnt have time to photograph everything.
What i did is take photos of battery mounts within front battery box. I had two inox C profiles made and i drilled holes for M8 bolts to mount those profiles inside the box.
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Later i drilled two moere holes on each side so i can mount the alu plate with battery modules attached. Since i will fit bolts in vertically i needed to weld M8 nuts from the underside of the C profiles. Later i might have to drill large holes in the profile vertical wall to be able to fit cables or sensors...
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That way i will have nut held from the underside and all that will be required would be to torque the M8 bolt.
The arrows drawn on the plate let me assemble the shelf easily as i allways know the direction.
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Re: Mazda MX-3 electric

Post by arber333 »

Another update...
I will add the links to my site here not to spam with photos in dual posting.
I managed to install coolant and heater piping. The idea is to feed both systems from the same header tank. I used a lot of copper piping as i can solder it easily at home. Just need some plummers paste, thick solder and copper piping.
I also salvaged a compact chiller from old Fiat 500 car and fitted 80W cooling fan by its plastic wraps. I still cant belive those plastic things fit into the chiller so efficiently.
This way i will have more compact (less hoses) system in the front of the vehicle.
I am still thinking of fitting the Tesla Gen2 charger to this car for 3phase charging, but it would significantly lengthen the build. I need this project soon so i will settle for 2phase 6kW charging power. Later on i could add fast charging...
https://mazdamx3ev.wordpress.com/2023/1 ... ng-piping/

The other thing is the wiring of systems in front. I made a single CAN line for VCU – CHARGER – INVERTER – HEATER – and leave the last connector for CAN bus termination or to add one Volvo Eltek charger in the end. Of course there will be 12V lines and relays for Enable or charging signaling etc..
The idea is nice and compact wiring up front, something that is now called Full Mux where you only have power supply and digital signals to drive your devices. https://mazdamx3ev.wordpress.com/2023/1 ... omponents/

Next i need to test my CAN lines for messages from VCU and devices.
Stay tuned
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Re: Mazda MX-3 electric

Post by arber333 »

Almost forgot... i cut and welded Mazda and Outlander shafts.
Writeup is here:
https://mazdamx3ev.wordpress.com/2023/1 ... iveshafts/
I will add some photos still...

EDIT: There is a lot of good info on how to splice axles here:
https://www.youtube.com/watch?v=G7iTT-RFfo0
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Re: Mazda MX-3 electric

Post by arber333 »

To connect DC to inverter i used 3d printer and made several DC glands designed by crasbe so thank you :D.
I set this up to fill 75% in PETG. I printed one black gland and one violet - its what i had in PETG - to differentiate DC+ and DC-.
I got a couple O rings 18mm by 3mm thickness to seal the opening. It is quite a tight squeeze because O rings are medium hardness and i cant get any softer version.
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I connected 35mm2 cables in those glands.
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I connected motor cables, yes i luckily got good motor cables with sealed covers.
On the bottom there are two secondary DC connectors that lead to the heater and charger. I like MC4 connectors so i made those connections removable and connected shield to the casing. Every part will be connected to another by grounding 6mm2 cables.
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arber333
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Re: Mazda MX-3 electric

Post by arber333 »

It is alive! I tell you ALIVE!
I managed to drive it up to 100km/h around town. I find acceleration a bit lame up to 20km/h, but then the beast comes out :twisted:.
I need to develop regen effect, but everything else works well. I still have to top up the brake fluid due to messing with clutch lines...
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There are some posts from the build i didnt post before:
Speedo circuit: https://wordpress.com/post/mazdamx3ev.w ... s.com/2466

Battery module repair: https://wordpress.com/post/mazdamx3ev.w ... s.com/2478

Front box build: https://wordpress.com/post/mazdamx3ev.w ... s.com/2504
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Re: Mazda MX-3 electric

Post by Scrappyjoe »

arber333, have you documented your wiring diagrams anywhere? I am currently trying to figure out how to wire up my outlander rear drive unit on the bench and would love to plagiarise it :)
arber333
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Re: Mazda MX-3 electric

Post by arber333 »

Scrappyjoe wrote: Mon Feb 05, 2024 11:13 am arber333, have you documented your wiring diagrams anywhere? I am currently trying to figure out how to wire up my outlander rear drive unit on the bench and would love to plagiarise it :)
Sure... lets see... i am still writing detail posting about my contact box... any day now :).
See here my connector schematic if it will help in the meantime.
Mini-E VCU.jpg
I made a quick schematic of my connections to reflect on...
In the meantime i had to chamge some connections because of the startup logic. I had to start inverter and charger logic BEFORE precharge is complete, but DCDC pin 4 (12V signal) i turn on only after everything is ON. I am missing sense pin 7 (permanent 12V) and charger pin 8 (ignition).
I wired heater start pin so it comes on only when ignition is on, as i also need to power the internal fan. I will capture those in my summary.
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arber333
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Re: Mazda MX-3 electric

Post by arber333 »

After some serious driving with Outlander VCU, for more than 200km stretch... i may share some thought about this VCU.
Teensy works really well when it works inside its loop. That means when VCU is activated and car is in FWD or RWD mode drive is very smooth, no jumps or glitches. Torque is somewhat precise and fairly strong for such a small motor. At lower RPM motor is a bit sluggish but when upwards from 2000rpm i can get off the ramp really quick. I am surprised motor provides great acceleration torque up to 10000rpm.
Regen is marginal (-15A) up to 2000rpm, Good (-35A) up to 8000rpm and really humongous (-70A) upwards of 8000RPM!
I am really pleased with reliable CAN commands while driving. DC cables go really close to CAN lines and once i solved that MCU interrupt overload no such problems occured. Motor - inverter - charger - heater combo tested at 160km/h speed and up to 78kW electrical power.
I still want to install additional battery module for full 96S - 360Vdc nominal. I expect at least 85kW if not closed to 100kW!

There some downsides however...
1. After lengthy VCU inactivity CAN bus comes out of sync and causes all kinds of rock and roll on starting. To resolve this i need to cut the 12V power (disconnect cable harness) and then VCU starts a new. I tried to use WDT reset function and it didnt work. Only hard power reset helped with this.
My plan to resolve this is to change VCU wiring so ignition will provide power to VCU when only when active and a separate relay will turn VCU on when charger is connected. Some work to do still.

EDIT: On the 1st point it seems now if i cycle the direction switch in F N R and then R N F direction for several times, then i come to FWD the VCU would be in sync again. I still have to confirm this by multiple confirmed instances though.
EDIT2: Nope! I still get twitches from keeping VCU connected and at idle for extended time. I will have to implement VCU ignition starting.

2. I noticed motor does not provide much torque at driveoff from 0km/h. its late for about 0.5s even if i floor it. Like a giant rubber string. I dont know what the issue is but this happens no matter how i set up throttle map.

3. Flimsy Teensy :). Really delicate Teensy pins really require care when assembling and inpurs need to be secured by opto coupler. I had to replace analog input to different pin as i caused damage from 5V input. To combat this i use resistor divider and 3.6V zener diode reversed towards GND so if more than 3.6V shows it is drained to GND. Throttle pedal is 5V and its signals can go up to 4.2V...

4. Trouble with PP signal and charger activation. I am using PP signal from L2 EVSE port which is pulled down inside cable by 680R or 220R resistor to PE. This allowed me to attach 2K7 resistor from 5V to opto input. This means that in code PP pin is signalled as active when nothing is connected and will be seen as inactive if i connect EVSE. I had to invert PP reading for CAN to transmitt and VCU to disable the car when charging. I think for this to work propperly it would require a change of VCU board. If i do this i will also add a buzzer and use its function in case of errors.

5. I seem to leak gearbox oil from LH driveshaft socket, but that seems to be my bad, probably i damaged the seal on that side, have to investigate...
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Re: Mazda MX-3 electric

Post by arber333 »

Rear box will remains much the same.
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My idea was to fit 4 battery modules in sandwich on 8mm thick Alu sheet. They will be supported by two C inox sections bolted into the box from underside.

Each lower module is bolted to upper module by M10 x 180 bolts. Those bolts incidentally join together complete assembly of Alu plate.
image.png
Electrical connection is established via cables to and from the modules on the right side where i left space for Pb Aux battery and cable routing.

I made a simple alu sheet metal fixture for individual BMS modules. This will fix modules in place and provide connections to CAN lines. Modules are set by numbers from the most negative terminal towards positive terminal. So Module no. 1 is one which connect to the negative line cable. Module no. 7 is the last one with terminal at the positive most cable.

CAN twisted pair runs from the rear box towards front box and connects all modules onto 250kbaud network,

Furthermost + cable exit from the box and under the rear seats into the box that is under the seats. I cut a hole into the alu cover which will house battery service disconnect. If i would need to service the HV system i simply remove the top part of disconnect and i can safely work on the HV system.
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arber333
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Re: Mazda MX-3 electric

Post by arber333 »

I decide to connect additional 12S module, 8 in total together.

This last module will live under the rear seats. I cut an underside plate from 5mm Alu which will help fix the module in place and dissipate the heat.
To fix it in place i used 100mm M10 bolts that i fit from the underside and carefully torqued not to damage the module.

BMS module is connected directly in 12S connection and i connect CAN wires to the main strain.
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arber333
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Re: Mazda MX-3 electric

Post by arber333 »

I am now trying to install 3phase Tesla Gen2 charger despite the fact that the last 12S battery module occupies its space under the rear seats now.
I asked my friend to cut and weld me a flat mount where Tesla charger will fit behind the rear seats in the trunk area.
I will use rear seat belt bolts to firmly fix the mount.
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When thinking on how to route cooling hoses i decided to use 18mm copper tubes. They can be soldered and i tried to form straight lines whenever possible. Small mixing bottle will serve to remove air from the system and i will release it from the top valve.
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Whenever tube was routed throught car casing - sheet metal i used small piece of coolant hose which i cut in the middle. This middle part would caught on the hole in the metal and form a sort of grommet. This is so that i dont get metal on metal contact...

Underneath the car i mounted a small radiator. I used reducers to bring 18mm tube to 10mm hose which will connect to the computer alu radiator. I hope radiator and one fan will be enough.
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Now i need to test the system by filling water and circulating the pump. I have that wired so when charger is active it will automaticaly power the pump and the fan.
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Re: Mazda MX-3 electric

Post by arber333 »

My daughter asked me if i could mount a rear camera to Mazda. I thought what to use best and i decided to buy a radio with 3.2in LCD display.
That display has a connection to plug in vide input from camera.
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I bought a small 8 LED camera and mounted it above the licence plate.
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I routed the cable from the dash under the carpet to the rear. Then i connected the power to the rear light and used an old hole to the bumper side.
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Now when i switch to RWD i get a good shot of the rear on the radio!
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