Eunos (Mazda) JC Cosmo EV conversion
Eunos (Mazda) JC Cosmo EV conversion
Because my initial plans for this project have changed somewhat since I began researching this I thought I would start a new thread to consolidate my current thinking.
Platform - 1994 Eunos (luxury brand of Mazda) JC Cosmo (4th generation) Type SX
Original engine - 13b twin rotor, twin turbo Wankel engine
Original transmission - electronically controlled 4-speed automatic gearbox to approx 4.3:1 rear axle differential
Original kerb weight - approx 1550kg
Production number - 8,875
Why I chose this car to convert?
Because I had wanted one for a very long time and when one became available I couldn't pass the opportunity. It's a rare car and needed to be saved. The car came to me with no engine (rolling chassis) and when I began looking into the cost of finding and installing an original rotary engine it began to make more sense to convert to full electric instead since it would be a significant investment either way. The pros of restoring to original would be a higher future value in terms of investment due to correct originality. The pros of converting to EV would be use as a daily commuter and gaining EV conversion skills. The cons of restoring to petrol engine is that it would unusable for daily driving due to poor fuel economy. The cons of EV conversion are the complexity of the project and things outside of my ability.
Initially my plan was to use components from a Nissan Leaf: motor, inverter, battery pack and other misc. parts. The logic behind this is due to the availability. There aren't many EVs in this country (New Zealand) and things like Telsa are VERY rare and expensive. Nissan Leaf is by far the most common and most available to get hold of cheap from insurance auctions and the like. Obviously fitting a transverse FWD unit into a RWD platform is not ideal and I was facing the option of retro-fitting a manual gearbox (Cosmos never had a manual transmission) in order to get usable drive ratios, driving the driveshaft directly (which would cause final drive ratio issues as the rear diff of the Cosmo is 4.3:1 and the Leaf runs natively around 8.1:1), or modifying the rear subframe to accept the Leaf in transverse orientation (which would probably require extensive and irreversible engineering work).
My plans changed significantly once I found out about the Lexus GS450H transmission and the potential to chop off the ICE engine and run it completely in electric mode. This has been done successfully before in a 3 Series BMW and others on this forum are also working on their own conversions using this drive unit. The biggest appeal for this transmission in my project is the longitudinal layout which should fit within the drive tunnel of my car without significant work, and also the fact the GS450H transmission (type L110) has a 2 stage ratio in the rear for highway speeds. This transmission is different to the one in the IS350H which is lacking the 2 stage ratio, and different to the LS600H which has an additional transfer case at the rear for 4WD output to the front differential in that car.
The matching inverter from the GS450H would seem an obvious choice to drive the unit but this is where my limitations are. I have very little in the way of electronics ability and so find myself reliant on the continued work of smarter people on this forum to solve the control problems of this type of Toyota/Lexus setup. I'm agnostic about batteries and BMS. I expect to need around 40KWh to cover my daily commute without recharge.
Platform - 1994 Eunos (luxury brand of Mazda) JC Cosmo (4th generation) Type SX
Original engine - 13b twin rotor, twin turbo Wankel engine
Original transmission - electronically controlled 4-speed automatic gearbox to approx 4.3:1 rear axle differential
Original kerb weight - approx 1550kg
Production number - 8,875
Why I chose this car to convert?
Because I had wanted one for a very long time and when one became available I couldn't pass the opportunity. It's a rare car and needed to be saved. The car came to me with no engine (rolling chassis) and when I began looking into the cost of finding and installing an original rotary engine it began to make more sense to convert to full electric instead since it would be a significant investment either way. The pros of restoring to original would be a higher future value in terms of investment due to correct originality. The pros of converting to EV would be use as a daily commuter and gaining EV conversion skills. The cons of restoring to petrol engine is that it would unusable for daily driving due to poor fuel economy. The cons of EV conversion are the complexity of the project and things outside of my ability.
Initially my plan was to use components from a Nissan Leaf: motor, inverter, battery pack and other misc. parts. The logic behind this is due to the availability. There aren't many EVs in this country (New Zealand) and things like Telsa are VERY rare and expensive. Nissan Leaf is by far the most common and most available to get hold of cheap from insurance auctions and the like. Obviously fitting a transverse FWD unit into a RWD platform is not ideal and I was facing the option of retro-fitting a manual gearbox (Cosmos never had a manual transmission) in order to get usable drive ratios, driving the driveshaft directly (which would cause final drive ratio issues as the rear diff of the Cosmo is 4.3:1 and the Leaf runs natively around 8.1:1), or modifying the rear subframe to accept the Leaf in transverse orientation (which would probably require extensive and irreversible engineering work).
My plans changed significantly once I found out about the Lexus GS450H transmission and the potential to chop off the ICE engine and run it completely in electric mode. This has been done successfully before in a 3 Series BMW and others on this forum are also working on their own conversions using this drive unit. The biggest appeal for this transmission in my project is the longitudinal layout which should fit within the drive tunnel of my car without significant work, and also the fact the GS450H transmission (type L110) has a 2 stage ratio in the rear for highway speeds. This transmission is different to the one in the IS350H which is lacking the 2 stage ratio, and different to the LS600H which has an additional transfer case at the rear for 4WD output to the front differential in that car.
The matching inverter from the GS450H would seem an obvious choice to drive the unit but this is where my limitations are. I have very little in the way of electronics ability and so find myself reliant on the continued work of smarter people on this forum to solve the control problems of this type of Toyota/Lexus setup. I'm agnostic about batteries and BMS. I expect to need around 40KWh to cover my daily commute without recharge.
-< Mazda Eunos JC Cosmo rotary -> EV conversion w/ Lexus GS450H gear >-
- Kevin Sharpe
- Posts: 1345
- Joined: Fri Dec 14, 2018 9:24 pm
- Location: Ireland and US
- Been thanked: 8 times
Re: Eunos (Mazda) JC Cosmo EV conversion
Great project
This is a personal post and I disclaim all responsibility for any loss or damage which any person may suffer from reliance on the information and material in this post or any opinion, conclusion or recommendation in the information and material.
Re: Eunos (Mazda) JC Cosmo EV conversion
Another Wellingtonian here and following along with interest. Have you collected any parts yet?
Re: Eunos (Mazda) JC Cosmo EV conversion
What I have so far -
The car itself (minus engine and attached ancillaries like alternator, AC compressor, power steering pump)
I have an electric power steering pump from a Holden Astra.
I have the original gearbox and driveshaft which will be useful for adapting to the new gearbox yoke.
What I still need to collect -
Transmission from a Lexus GS450H
Inverter from a Lexus GS450H or LS600H or possibly RX450H
HV wiring loom from above
Lithium batteries
Battery Management System (haven't looked at this much yet. I know there are good opensource options)
Wiring, plugs, connectors etc.
I have been looking for a cheap crashed donor vehicle but they are rather uncommon so I'm leaning towards sourcing the parts directly from Japan.
Basically doing a lot of reading and planning right now before committing to the hardware but I'm pretty sure I know what I need and have made the right choice in that regard. Due to my lack of electrical engineering I'm hesitant to jump in over my head but rather wait until I see a clear path laid out by others in terms of replacement control logic boards etc.
The car itself (minus engine and attached ancillaries like alternator, AC compressor, power steering pump)
I have an electric power steering pump from a Holden Astra.
I have the original gearbox and driveshaft which will be useful for adapting to the new gearbox yoke.
What I still need to collect -
Transmission from a Lexus GS450H
Inverter from a Lexus GS450H or LS600H or possibly RX450H
HV wiring loom from above
Lithium batteries
Battery Management System (haven't looked at this much yet. I know there are good opensource options)
Wiring, plugs, connectors etc.
I have been looking for a cheap crashed donor vehicle but they are rather uncommon so I'm leaning towards sourcing the parts directly from Japan.
Basically doing a lot of reading and planning right now before committing to the hardware but I'm pretty sure I know what I need and have made the right choice in that regard. Due to my lack of electrical engineering I'm hesitant to jump in over my head but rather wait until I see a clear path laid out by others in terms of replacement control logic boards etc.
-< Mazda Eunos JC Cosmo rotary -> EV conversion w/ Lexus GS450H gear >-
Re: Eunos (Mazda) JC Cosmo EV conversion
I'm probably at a similar stage with my project. I have a car that I want to convert. But for now just spending time lurking and reading in places like this.
It's good to see what others are doing and what's possible. I've learned a lot so far but still have a long way to go.
I'm tempted to buy a salvage Leaf and just go through everything methodically to learn while it's still a complete car. Then re-use the parts with one of the drop in boards.
It's good to see what others are doing and what's possible. I've learned a lot so far but still have a long way to go.
I'm tempted to buy a salvage Leaf and just go through everything methodically to learn while it's still a complete car. Then re-use the parts with one of the drop in boards.
Re: Eunos (Mazda) JC Cosmo EV conversion
The Leaf motor, gear reduction differential and inverter stack is a pretty good option and relatively straightforward for a small-medium sized FWD conversion. VW Touran for example. viewtopic.php?f=11&t=32
Also a reasonable choice for a RWD car if it has or can have fitted a manual gearbox. Though the motor and inverter stack may need to be separated. E46 3 series BMW for example. viewtopic.php?f=11&t=112
I did expect to use this motor myself originally but the lowish power output (80Kw OEM, but there seems scope for "overclocking" that motor) the weight of the car (1550kg ish) and the fact that converting to manual gearbox put me off.
I haven't ruled this out, but the Lexus gearbox seems like a more elegant and powerful option.
What are you planning to convert?
Also a reasonable choice for a RWD car if it has or can have fitted a manual gearbox. Though the motor and inverter stack may need to be separated. E46 3 series BMW for example. viewtopic.php?f=11&t=112
I did expect to use this motor myself originally but the lowish power output (80Kw OEM, but there seems scope for "overclocking" that motor) the weight of the car (1550kg ish) and the fact that converting to manual gearbox put me off.
I haven't ruled this out, but the Lexus gearbox seems like a more elegant and powerful option.
What are you planning to convert?
-< Mazda Eunos JC Cosmo rotary -> EV conversion w/ Lexus GS450H gear >-
Re: Eunos (Mazda) JC Cosmo EV conversion
1962 Volvo PV544. Just a handful in NZ. Doesn't look it but only weighs about 980kg so the Leaf motor/inverter should be plenty. It's RWD so will have to mount it longitudinally and probably retain the gearbox - it'll need about a 2:1 reduction.
Re: Lexus L110 hybrid ECVT transmission details
I'm going to collate all my research notes about the Lexus L110 transmission here for future reference.
Some of this data is from the Lexus LS600H which uses the L110F transmission which I would guess to be the same as the L110 but with a transfer case added to the end for drive to the front differential (4WD). Although from my research the L110F has a higher rated output (165kW vs 147kW), 300Nm vs 275Nm torque, 300ml greater ATF volume, 5kg extra weight and possibly (unconfirmed) the L110 is lacking water cooling for the transmission fluid.
Sources:
https://slideplayer.com/slide/14432904/
http://www.thecatalystis.com/gears/
http://auto-kat.com/index.php?route=sal ... group=4101
https://youtu.be/6FaUTo5X7Dw thanks Damian
https://info.ornl.gov/sites/publication ... b12996.pdf
Vital statistics L110
Weight = 127kg
DC-link Voltage max = 650Vdc
Boost converter power rating = 36.5kW
MG2 max RPM = 10,230 (not voltage limit)
MG2 motor type = Permanent Magnet Synchronous
18 sec max power @ 4500rpm = 110kW
Power Split Device - (PSD) 1st planetary gear set
ICE Engine drives planetary carrier through inner shaft
MG1 drives sun gear through hollow shaft
Output of gearset is ring gear which is directly linked to output shaft of transmission.
There are no brake packs on any of these elements.
Ring gear teeth = 78
Planet teeth = 22
Number of planets = 4
Sun gear teeth = 34
It is possible to drive vehicle with MG1 alone if ICE input shaft is locked. With no ICE input and planetary carrier thereby locked to housing MG1 drive ratio = 2.294:-1
ie. 2.294 clockwise rotations of the MG1 produces 1 anti-clockwise output of the ring gear. Turning the MG1 motor in reverse will be required to produce forward vehicle speed.
The mechanical trochoid hydraulic ATF oil pump is driven by the planetary carrier. Oil pressure is used in a typical automatic transmission sense that brake packs are actuated by solenoids. This means by locking the ICE input shaft the mechanical oil pump will be disabled thereby relying entirely on the secondary electric oil pump for system pressure. the purpose of the electric pump is to provide pressure when the ICE is off. It may or may not be designed to operate continuously.
There is no disconnect of the MG2 from the drivetrain. When the rear wheels are turning, the MG2 is always spinning. This could be a limiting factor to the top speed of the transmission in regards to running in pure EV mode due to the maximum bearing RPM of MG1.
Ravigneaux 2 speed compound planetary speed reduction
Sits towards the rear of the case after MG2 and before output flange of the transmission.
The output from the PSD prior is connected to the planetary carrier through center shaft.
MG2 is connected to rear sun gear through hollow shaft.
Front sun gear can be locked by brake 1.
Ring gear can be locked by brake 2.
Ring gear teeth = 78
Short planet gear teeth = 28
Number of short planet gears = 3
Long planet gear teeth = 20
Front sun gear teeth = 27
Rear sun gear teeth =30
Brake 1 engaged operates High speed reduction ratio 1.9:1
Brake 2 engaged operates Low speed reduction ratio 3.9:1
There is an integrated parking pawl, an integrated AFT to coolant heat exchanger and resolver.
Final drive ratio of the rear differential GS450H 2006 = 49:15 or 3.266:1. OEM tyres were 255/40ZR18 giving a rolling circumference of 2076mm. At 100kph rear wheels are turning 802rpm which means the driveshaft is turning 2619rpm and MG2 would be spinning 4,976rpm in High gear and 10,214rpm in Low gear.
Some of this data is from the Lexus LS600H which uses the L110F transmission which I would guess to be the same as the L110 but with a transfer case added to the end for drive to the front differential (4WD). Although from my research the L110F has a higher rated output (165kW vs 147kW), 300Nm vs 275Nm torque, 300ml greater ATF volume, 5kg extra weight and possibly (unconfirmed) the L110 is lacking water cooling for the transmission fluid.
Sources:
https://slideplayer.com/slide/14432904/
http://www.thecatalystis.com/gears/
http://auto-kat.com/index.php?route=sal ... group=4101
https://youtu.be/6FaUTo5X7Dw thanks Damian
https://info.ornl.gov/sites/publication ... b12996.pdf
Vital statistics L110
Weight = 127kg
DC-link Voltage max = 650Vdc
Boost converter power rating = 36.5kW
MG2 max RPM = 10,230 (not voltage limit)
MG2 motor type = Permanent Magnet Synchronous
18 sec max power @ 4500rpm = 110kW
Power Split Device - (PSD) 1st planetary gear set
ICE Engine drives planetary carrier through inner shaft
MG1 drives sun gear through hollow shaft
Output of gearset is ring gear which is directly linked to output shaft of transmission.
There are no brake packs on any of these elements.
Ring gear teeth = 78
Planet teeth = 22
Number of planets = 4
Sun gear teeth = 34
It is possible to drive vehicle with MG1 alone if ICE input shaft is locked. With no ICE input and planetary carrier thereby locked to housing MG1 drive ratio = 2.294:-1
ie. 2.294 clockwise rotations of the MG1 produces 1 anti-clockwise output of the ring gear. Turning the MG1 motor in reverse will be required to produce forward vehicle speed.
The mechanical trochoid hydraulic ATF oil pump is driven by the planetary carrier. Oil pressure is used in a typical automatic transmission sense that brake packs are actuated by solenoids. This means by locking the ICE input shaft the mechanical oil pump will be disabled thereby relying entirely on the secondary electric oil pump for system pressure. the purpose of the electric pump is to provide pressure when the ICE is off. It may or may not be designed to operate continuously.
There is no disconnect of the MG2 from the drivetrain. When the rear wheels are turning, the MG2 is always spinning. This could be a limiting factor to the top speed of the transmission in regards to running in pure EV mode due to the maximum bearing RPM of MG1.
Ravigneaux 2 speed compound planetary speed reduction
Sits towards the rear of the case after MG2 and before output flange of the transmission.
The output from the PSD prior is connected to the planetary carrier through center shaft.
MG2 is connected to rear sun gear through hollow shaft.
Front sun gear can be locked by brake 1.
Ring gear can be locked by brake 2.
Ring gear teeth = 78
Short planet gear teeth = 28
Number of short planet gears = 3
Long planet gear teeth = 20
Front sun gear teeth = 27
Rear sun gear teeth =30
Brake 1 engaged operates High speed reduction ratio 1.9:1
Brake 2 engaged operates Low speed reduction ratio 3.9:1
There is an integrated parking pawl, an integrated AFT to coolant heat exchanger and resolver.
Final drive ratio of the rear differential GS450H 2006 = 49:15 or 3.266:1. OEM tyres were 255/40ZR18 giving a rolling circumference of 2076mm. At 100kph rear wheels are turning 802rpm which means the driveshaft is turning 2619rpm and MG2 would be spinning 4,976rpm in High gear and 10,214rpm in Low gear.
-< Mazda Eunos JC Cosmo rotary -> EV conversion w/ Lexus GS450H gear >-
Re: Eunos (Mazda) JC Cosmo EV conversion
My Organ Recipient continues to wait for a Donor.
I've pretty much given up hope finding a Lexus GS450h in this country (New Zealand). They are rather uncommon to see on the roads here. Probably because they were fairly expensive to buy new and even when imported used from Japan they are still pretty expensive to buy. $12K for a 12 year old Lexus??
So it's not a matter of being able to find one, there are many in used car yards around the country, but just not a lot of them being sold and thus not a lot of them being crashed.
They are available from private sellers for a few thousand dollars less but it just doesn't feel like a great idea to take a working and road legal car and break it to pieces. A bit irresponsibly wasteful even.
So I've been looking to import parts from Japan. And the cost of freight has made my eyes bleed.
If you look on Yahoo Auctions there is plenty of great gear at bargain prices, but you need a Yahoo Auctions account, probably a Japanese bank account, and it would help to speak Japanese. Then you still have the issue of receiving the parts (most won't send overseas, especially bulky things like transmissions). There are Proxy Bid services that take care of the bidding, and receiving problem, and also sending overseas, but not bulky items, and their handling fees can get excessive.
I enquired with a logistics company here in NZ about using them as an agent to handle all the pickup, packaging, customs and freight. They wanted NZ$2200. Considering the gearboxes are around NZ$500 that really jacks the price up.
Recently I found a forwarding company in Japan that seem to have access to all the same parts I've found on Yahoo Auctions. A bit parts consortium is called Used Parts Japan. They have the same gear listed in many places. I recognize the same photos in different places and similar prices. Generally they airfreight parts using DHL. But this is where it gets a bit complicated. I can have an entire GS450h transmission air freighted to me within 10 day for NZ$863 but a smaller lighter inverter is NZ$1156?? A rear differential which is 1/5 size of the trans cannot be air freighted and has to go by sea for 1-2 month and cost NZ$1567.
Then I noticed if I had the inverter on my list and added the transmission the freight cost stayed the same. And if I had anything that required sea freight, I could create a big list of items and have it shipped for 1 price. It seems that you're paying for what must be a cubic meter and as soon as you go beyond the limits the cost of another cubic meter is added to the freight.
I need to check with the company that these freight charges are legit and not erroneously calculated by computer. I don't want to have unexpected charges part way through the transaction. And I suspect customs charges at my end are not part of that price, nor transport from the South Island to the North Island (the only destination port available as an option is Timaru). I suspect only a little port like this is willing to handle odd small volume cargo like this.
I've pretty much given up hope finding a Lexus GS450h in this country (New Zealand). They are rather uncommon to see on the roads here. Probably because they were fairly expensive to buy new and even when imported used from Japan they are still pretty expensive to buy. $12K for a 12 year old Lexus??
So it's not a matter of being able to find one, there are many in used car yards around the country, but just not a lot of them being sold and thus not a lot of them being crashed.
They are available from private sellers for a few thousand dollars less but it just doesn't feel like a great idea to take a working and road legal car and break it to pieces. A bit irresponsibly wasteful even.
So I've been looking to import parts from Japan. And the cost of freight has made my eyes bleed.
If you look on Yahoo Auctions there is plenty of great gear at bargain prices, but you need a Yahoo Auctions account, probably a Japanese bank account, and it would help to speak Japanese. Then you still have the issue of receiving the parts (most won't send overseas, especially bulky things like transmissions). There are Proxy Bid services that take care of the bidding, and receiving problem, and also sending overseas, but not bulky items, and their handling fees can get excessive.
I enquired with a logistics company here in NZ about using them as an agent to handle all the pickup, packaging, customs and freight. They wanted NZ$2200. Considering the gearboxes are around NZ$500 that really jacks the price up.
Recently I found a forwarding company in Japan that seem to have access to all the same parts I've found on Yahoo Auctions. A bit parts consortium is called Used Parts Japan. They have the same gear listed in many places. I recognize the same photos in different places and similar prices. Generally they airfreight parts using DHL. But this is where it gets a bit complicated. I can have an entire GS450h transmission air freighted to me within 10 day for NZ$863 but a smaller lighter inverter is NZ$1156?? A rear differential which is 1/5 size of the trans cannot be air freighted and has to go by sea for 1-2 month and cost NZ$1567.
Then I noticed if I had the inverter on my list and added the transmission the freight cost stayed the same. And if I had anything that required sea freight, I could create a big list of items and have it shipped for 1 price. It seems that you're paying for what must be a cubic meter and as soon as you go beyond the limits the cost of another cubic meter is added to the freight.
I need to check with the company that these freight charges are legit and not erroneously calculated by computer. I don't want to have unexpected charges part way through the transaction. And I suspect customs charges at my end are not part of that price, nor transport from the South Island to the North Island (the only destination port available as an option is Timaru). I suspect only a little port like this is willing to handle odd small volume cargo like this.
-< Mazda Eunos JC Cosmo rotary -> EV conversion w/ Lexus GS450H gear >-
-
- Posts: 437
- Joined: Sat Jul 27, 2019 10:53 am
- Location: UK
- Has thanked: 1 time
- Been thanked: 13 times
Re: Eunos (Mazda) JC Cosmo EV conversion
HTM and MTH data packets are different on the RX450h (it has a third motor). I believe the MG1 and MG2 are less powerful in this car as well, making it unsuitable for the GS450h motors.
Can't comment on the LS600h, you may get lucky with the control, you probably won't.
Nice car, I've always wanted one (but with a 20B, of course!)
Re: Eunos (Mazda) JC Cosmo EV conversion
Just an update to confirm this project isn't dead.
Still looking for an affordable donor for this project.
Missed out on a Toyota Crown hybrid last week. Went through insurance auctions as a write-off due to hail damage. We had a massive hail storm in one particular region of the South Island a few months ago which resulted in thousands of perfectly good cars being replaced. The car I was interested in was a 2012 and only had about 100,000kms on it. Fine apart from golfball divots on the upward facing surfaces. Was a popular lot in the auction and I chased it up to $6,750nzd which was still a good price for a working car. Would have a value around $15,000nzd in undamaged condition. But since I was intending to break it for the gearbox (and a few other supporting bits no doubt) it seemed like a bad idea.
So the search continues. My fallback plan is to just import the parts from Japan and hope I get what I need.
Fortunately I have other projects to keep me occupied while I play the waiting game. An upside is that all of this great development you guys are doing continues and keeps getting better so starting late will benefit me in the long-run.
I just wanted to say that I read all the threads on the forums but refrain from adding trivial comments to the threads to avoid forum clutter. I think many people read and follow your open source projects and are greatly appreciative.
Thank you!
Still looking for an affordable donor for this project.
Missed out on a Toyota Crown hybrid last week. Went through insurance auctions as a write-off due to hail damage. We had a massive hail storm in one particular region of the South Island a few months ago which resulted in thousands of perfectly good cars being replaced. The car I was interested in was a 2012 and only had about 100,000kms on it. Fine apart from golfball divots on the upward facing surfaces. Was a popular lot in the auction and I chased it up to $6,750nzd which was still a good price for a working car. Would have a value around $15,000nzd in undamaged condition. But since I was intending to break it for the gearbox (and a few other supporting bits no doubt) it seemed like a bad idea.
So the search continues. My fallback plan is to just import the parts from Japan and hope I get what I need.
Fortunately I have other projects to keep me occupied while I play the waiting game. An upside is that all of this great development you guys are doing continues and keeps getting better so starting late will benefit me in the long-run.
I just wanted to say that I read all the threads on the forums but refrain from adding trivial comments to the threads to avoid forum clutter. I think many people read and follow your open source projects and are greatly appreciative.
Thank you!
-< Mazda Eunos JC Cosmo rotary -> EV conversion w/ Lexus GS450H gear >-
Re: Eunos (Mazda) JC Cosmo EV conversion
Well I have a working, driving and road legal Lexus GS450h now and have been using it as my daily driver while evaluating it's performance, considering things I like about it and things I would change.
I plan to collect a complete library of CANbus events for future analysis and reference including -
- AC system operation
- regen/braking events
- radar cruise control
- steering angle sensor
- engine/motor RPM/torque/temp
- battery statistics
I plan to collect a complete library of CANbus events for future analysis and reference including -
- AC system operation
- regen/braking events
- radar cruise control
- steering angle sensor
- engine/motor RPM/torque/temp
- battery statistics
-< Mazda Eunos JC Cosmo rotary -> EV conversion w/ Lexus GS450H gear >-
Re: Eunos (Mazda) JC Cosmo EV conversion
-< Mazda Eunos JC Cosmo rotary -> EV conversion w/ Lexus GS450H gear >-
Re: Eunos (Mazda) JC Cosmo EV conversion
Good luck! This looks like a great project car and definitely has more personality than the 450h that is donating its organs for the good of a classic car.
Re: Eunos (Mazda) JC Cosmo EV conversion
I have been driving my GS450h over the past few months and there are only a few occasions when it will allow electric only operation and it's not always obvious when. I do a 160km round trip to work and back. Mostly highway speeds but a few reduced speed zones, some stop/start traffic in town and a slow climb up with rapid downward run going in to work and the opposite on the way home.
I car's display reports an average of 8L per 100Km which has been confirmed with my own fuel economy calculations from fuel refills and odometer readings. There are no warnings on the dashboard and from the battery test I did there are 2 cells (out of 40) that are a bit weaker than the others but not bad enough to cause errors. However, I can't say how these effect the performance of the car.
From my observation the GS450h will use full EV mode when -
- the battery is above 50%
- the KW consumption is below 10KW (according to the dashboard KW usage gauge)
- generally not above 60kph (driving at this speed requires more than 10KW on the flat)
Travelling at 100kph on a level road with AC and heated seats on consumes around 25KW so I assume this car would consume 25KW/h travelling 100km distance. Which makes me assume it would require approx 50Kw/h battery pack to achieve the daily range I need. Less if it was lighter.
If the car has been running previously and still warm and there is a reasonable charge in the battery and you go easy with the throttle and keep your speed down, it will drive in electric mode. As soon as you want to go a bit faster, or the battery gets a bit low, or you start to climb an incline, the engine will kick in.
My car won't do more than about 500m on pure electric mode. These cars only have about 1.2KWh batteries in them, and the car won't allow the voltage to get very low before recharging again with the petrol engine. The recharge will stop when the battery pack gets to about 60% to ensure there is a bit of capacity to capture regen braking energy. I'm not sure if this is about as far as you can expect to go in EV mode as I can't really say what condition the battery pack is in. Car has done 135,000km so not new.
When I get home and stop at my gate the car will do my 500m driveway in EV mode in low speed. Next morning the battery pack will be too depleted to go any further so the engine will start and stay running until it is up to operating temperature.
The engine is never not running on the motorway at 100kph. It's always sending power to the rear wheels according to the power consumption diagram in the display, but also sending power to the battery pack (which I assume is for running the accessories). There is a short level stretch of road at reduced speed. It's about 2km long and the car will do about 500m in EV mode at 60kph on the flat before engine has to start again. There is also an extended downhill run with decent grade of about 2km. The car goes into full regen and the battery capacity is maxed out halfway down the hill, thus wasting any further energy recovery.
I car's display reports an average of 8L per 100Km which has been confirmed with my own fuel economy calculations from fuel refills and odometer readings. There are no warnings on the dashboard and from the battery test I did there are 2 cells (out of 40) that are a bit weaker than the others but not bad enough to cause errors. However, I can't say how these effect the performance of the car.
From my observation the GS450h will use full EV mode when -
- the battery is above 50%
- the KW consumption is below 10KW (according to the dashboard KW usage gauge)
- generally not above 60kph (driving at this speed requires more than 10KW on the flat)
Travelling at 100kph on a level road with AC and heated seats on consumes around 25KW so I assume this car would consume 25KW/h travelling 100km distance. Which makes me assume it would require approx 50Kw/h battery pack to achieve the daily range I need. Less if it was lighter.
If the car has been running previously and still warm and there is a reasonable charge in the battery and you go easy with the throttle and keep your speed down, it will drive in electric mode. As soon as you want to go a bit faster, or the battery gets a bit low, or you start to climb an incline, the engine will kick in.
My car won't do more than about 500m on pure electric mode. These cars only have about 1.2KWh batteries in them, and the car won't allow the voltage to get very low before recharging again with the petrol engine. The recharge will stop when the battery pack gets to about 60% to ensure there is a bit of capacity to capture regen braking energy. I'm not sure if this is about as far as you can expect to go in EV mode as I can't really say what condition the battery pack is in. Car has done 135,000km so not new.
When I get home and stop at my gate the car will do my 500m driveway in EV mode in low speed. Next morning the battery pack will be too depleted to go any further so the engine will start and stay running until it is up to operating temperature.
The engine is never not running on the motorway at 100kph. It's always sending power to the rear wheels according to the power consumption diagram in the display, but also sending power to the battery pack (which I assume is for running the accessories). There is a short level stretch of road at reduced speed. It's about 2km long and the car will do about 500m in EV mode at 60kph on the flat before engine has to start again. There is also an extended downhill run with decent grade of about 2km. The car goes into full regen and the battery capacity is maxed out halfway down the hill, thus wasting any further energy recovery.
-< Mazda Eunos JC Cosmo rotary -> EV conversion w/ Lexus GS450H gear >-
-
- Posts: 3427
- Joined: Mon Dec 24, 2018 1:37 pm
- Location: Slovenia
- Has thanked: 98 times
- Been thanked: 304 times
- Contact:
Re: Eunos (Mazda) JC Cosmo EV conversion
Really nice analisys!
I wonder if it would be possible to connect a VW 8kW battery in paralell with your NiMh. At least comparative cell count to allways have NiMh higher than 60% SOC. What would the ECU do then?
I have connected 9kWh battery in parallel with Ampera battery in our hybrid. After a few unsuccessful tryouts i found the connection was reliable enough so that BMS functioned without major issues.
There was one issue with both batteries inequality when i had to stop after a short drive and restart again soon. Then BMS would throw an error when it saw current flow from main pack back to aux pack and the car was off. I had to reset errors via Torque pro app. I decided to rectify this in future by adding one contactor and one power diode (or transistor) in direction of the aux pack. This will even allow current flow with original charger in place.
A
I wonder if it would be possible to connect a VW 8kW battery in paralell with your NiMh. At least comparative cell count to allways have NiMh higher than 60% SOC. What would the ECU do then?
I have connected 9kWh battery in parallel with Ampera battery in our hybrid. After a few unsuccessful tryouts i found the connection was reliable enough so that BMS functioned without major issues.
There was one issue with both batteries inequality when i had to stop after a short drive and restart again soon. Then BMS would throw an error when it saw current flow from main pack back to aux pack and the car was off. I had to reset errors via Torque pro app. I decided to rectify this in future by adding one contactor and one power diode (or transistor) in direction of the aux pack. This will even allow current flow with original charger in place.
A
- ggeter
- Posts: 133
- Joined: Wed Nov 18, 2020 1:56 pm
- Location: Houston, TX
- Has thanked: 4 times
- Been thanked: 15 times
Re: Eunos (Mazda) JC Cosmo EV conversion
I've got my 450h parts on the way for my MG project. Will follow your project for ideas and inspiration.
Houston, Texas, USA
EV Newbie
1979 MG Midget + GS450h = "Mexus?"
IT Consultant
EV Newbie
1979 MG Midget + GS450h = "Mexus?"
IT Consultant
Re: Eunos (Mazda) JC Cosmo EV conversion
I have spent some time thinking about this problem. Specifically how to replace the NiMh pack with a larger LiFePo pack and then "trick" the car by mapping the voltage ranges from lithium to nickel values. The obvious danger here would be differences in charge/discharge between the dissimilar chemistries. Would the car's hybrid drive systems allow too much energy into or out of a lithium pack and cause a fire hazard for example?
I guess if technically feasible the easiest way to achieve this upgrade would be to install a CANbus "man in the middle" device between the BMS and car powertrain ECU to catch, interpret and modify the data communications between the two. This is assuming the BMS can operate with values outside it's normal operating ranges (different voltage ranges per cell for example). Otherwise it might be necessary to intercept the values from each cell before they get to the BMS. This would be more robust and allow different numbers of cells than original configuration.
But now we're talking about modifying the original car rather than using it as a donor. But this could apply if one was to use the entire hybrid drive from a GS450h and try to transplant into another car along with an upgraded battery (which I have also been thinking about)...
-< Mazda Eunos JC Cosmo rotary -> EV conversion w/ Lexus GS450H gear >-
-
- Posts: 3427
- Joined: Mon Dec 24, 2018 1:37 pm
- Location: Slovenia
- Has thanked: 98 times
- Been thanked: 304 times
- Contact:
Re: Eunos (Mazda) JC Cosmo EV conversion
No i just thought about connecting a Li ion battery in parallel with enough overhead so NiMh would run higher than 60% for longer time. I am sure you could put such battery in the back of the car and observe result in a controled way. NiMhs have such higher Ri that you would be pulling amost all energy from Liions for some time. That is only to prove a concept.sfk wrote: ↑Wed Dec 09, 2020 7:11 pm But now we're talking about modifying the original car rather than using it as a donor. But this could apply if one was to use the entire hybrid drive from a GS450h and try to transplant into another car along with an upgraded battery (which I have also been thinking about)...
So 240S NiMh at 1.4V full is 336Vdc and 1V empty is at 240Vdc. You could just use a complete Outlander pack in the back and run it to about 3.2V per cell. 80S should give you range from 320Vdc to 256Vdc which is still acceptable. All you need is to connect paralell DC lines.
Re: Eunos (Mazda) JC Cosmo EV conversion
Well this sounds quite interesting then. Are you saying that it shouldn't be any more difficult than simply finding and Outlander pack and connecting the DC lines in parallel to the existing GS450h pack? Does the Outlander pack have an integrated BMS that would manage itself in this situation?arber333 wrote: ↑Wed Dec 09, 2020 8:03 pm No i just thought about connecting a Li ion battery in parallel with enough overhead so NiMh would run higher than 60% for longer time. I am sure you could put such battery in the back of the car and observe result in a controled way. NiMhs have such higher Ri that you would be pulling amost all energy from Liions for some time. That is only to prove a concept.
So 240S NiMh at 1.4V full is 336Vdc and 1V empty is at 240Vdc. You could just use a complete Outlander pack in the back and run it to about 3.2V per cell. 80S should give you range from 320Vdc to 256Vdc which is still acceptable. All you need is to connect paralell DC lines.
In the GS the battery pack is reasonably small and sits above the boot floor pan behind the rear seats. This reduces the boot space somewhat. Adding the Outlander pack would mean pretty much giving up the boot space entirely I imagine. Not a big issue for me but worth considering.
-< Mazda Eunos JC Cosmo rotary -> EV conversion w/ Lexus GS450H gear >-
-
- Posts: 3427
- Joined: Mon Dec 24, 2018 1:37 pm
- Location: Slovenia
- Has thanked: 98 times
- Been thanked: 304 times
- Contact:
Re: Eunos (Mazda) JC Cosmo EV conversion
You would need to make the modules fit in your boot but yes TomDB made BMS module that can talk to original Mitsubishi BMS. Definitely usable.sfk wrote: ↑Wed Dec 09, 2020 8:14 pm Well this sounds quite interesting then. Are you saying that it shouldn't be any more difficult than simply finding and Outlander pack and connecting the DC lines in parallel to the existing GS450h pack? Does the Outlander pack have an integrated BMS that would manage itself in this situation?
In the GS the battery pack is reasonably small and sits above the boot floor pan behind the rear seats. This reduces the boot space somewhat. Adding the Outlander pack would mean pretty much giving up the boot space entirely I imagine. Not a big issue for me but worth considering.
viewtopic.php?f=13&t=131
Hm... if this works you could cut up the boot and put a box in the rear wheel well area and fit all your cells there. No need of MOT if your car is already an EV...sort of...
Also you could use the main contactor and fuse to be able to split the packs for servicing. You could also connect Outlander charger. It is charger and DCDC unit all in one... Or you could use one low profile Eltek charger... Put the charge plug on the rear bumper . That would be my plan.
Maybe you would also need to put some spacers to your rear springs to keep the car level then...
Re: Eunos (Mazda) JC Cosmo EV conversion
Thought I would add some observations about regen braking in the GS that I forgot to mention above.
It seems there is a fairly hard limit to the amount of regenerative braking energy the car can deal with.
When you take your foot off the accelerator after getting up to speed the car enters a mild state of regen. According to the Power Meter in the instrument cluster, it's generating about 10kW as it coasts down in speed. Eventually it will come to a stop. It doesn't seem there is any way to simply coast with zero resistance; there is always some regen when you have no accelerator or brake input.
The first part of the brake pedal engages regenerative braking. From my experiments it seems the maximum about of regen is about 35kW before regen is completely disabled and the braking switches over to manual traditional brake pads and rotors.
It seems to me that the regen and standard braking systems do not operate in concurrently. Or at least the hand-over transition between the 2 is quite rapid. It takes a bit of practice to get the brake pedal pressure just right to maximize regen without pushing a bit hard and tripping standard brakes, thus losing all regen.
Because all power in and out of the battery pack must go through the buck/boost converter, is this a limiting factor? I would prefer if there was no regen on accelerator lift and regen more aggressive right up until disc brakes are added in to assist when even more braking is required. Something to consider is that the front brakes usually do most of the work and regen is only possible on the rear for the GS.
It seems there is a fairly hard limit to the amount of regenerative braking energy the car can deal with.
When you take your foot off the accelerator after getting up to speed the car enters a mild state of regen. According to the Power Meter in the instrument cluster, it's generating about 10kW as it coasts down in speed. Eventually it will come to a stop. It doesn't seem there is any way to simply coast with zero resistance; there is always some regen when you have no accelerator or brake input.
The first part of the brake pedal engages regenerative braking. From my experiments it seems the maximum about of regen is about 35kW before regen is completely disabled and the braking switches over to manual traditional brake pads and rotors.
It seems to me that the regen and standard braking systems do not operate in concurrently. Or at least the hand-over transition between the 2 is quite rapid. It takes a bit of practice to get the brake pedal pressure just right to maximize regen without pushing a bit hard and tripping standard brakes, thus losing all regen.
Because all power in and out of the battery pack must go through the buck/boost converter, is this a limiting factor? I would prefer if there was no regen on accelerator lift and regen more aggressive right up until disc brakes are added in to assist when even more braking is required. Something to consider is that the front brakes usually do most of the work and regen is only possible on the rear for the GS.
-< Mazda Eunos JC Cosmo rotary -> EV conversion w/ Lexus GS450H gear >-
Re: Eunos (Mazda) JC Cosmo EV conversion
I have noticed that you can sort of increase the regen by using the gear select (the + -) to manually select a lower gear (CVTs don't have real gears as you know). This creates a stronger engine braking effect. The kW gauge on the cluster shows a higher level of negative energy (regen) but the RPM of the engine goes right up also. It's a bit hard to tell if the regen is really electrical energy recovered or just more mechanical engine braking but works quite well to control speeds while descending steep grades.
-< Mazda Eunos JC Cosmo rotary -> EV conversion w/ Lexus GS450H gear >-