[DRIVING] Audi A2 /w Prius Gen2 Transaxle & Inverter [FINISHED]

[johu]

Update: due to easier road worthiness checks I will be using matching Prius transaxle & inverter

A friend of mine will attempt to convert his Audi A2.
As recommended by Arber I bought a Renault Twizy Motor for him. It is rated at 12kW but apparently, by raising voltage and current can easily do 40kW. Unfortunately the motor does not have a front bearing, so mounting it to the transmission will be a bit more challenging. The output shaft is rather short, it does not stand out from the motor case. It has inner splines, 19 of them. Might be easier to add a key to the shaft?

Connectorwise it has two KTY84 sensors and a quadrature encoder. Pretty standard, runs off 5V and needs pull-up. Anyone know the part number of these connectors?

I have hooked up the motor to a Gen2 Prius inverter that Damien donated a while ago. It does run though the inverter still behaves rather unique: Small sine amplitudes are not transmitted from gate drive input to IGBT output! So say at 24V if you swing 6000 digits all outputs sit at 50/50 dutycycle. Once you pass 7000 digits it starts to swing as intended. I hope that behaviour is less pronounced at higher DC voltage.

I would also like to use the DC/DC converter and the auxiliary inverter for an A/C compressor. They sit at the bottom of the inverter. Is there any info on these?

Battery-wise he will probably be using my remaining Leaf pack, wired for half voltage (180V).

[MattsAwesomeStuff]

What're you using to repurpose the Prius Gen2 inverter, brain-wise?

I would also like to use the DC/DC converter and the auxiliary inverter for an A/C compressor. They sit at the bottom of the inverter. Is there any info on these?

I haven't heard of anyone tackling the aux inverter yet.

I think you asked a couple months ago about the DC/DC and someone gave you a pinout at least...

*digs around*

viewtopic.php?p=4550#p4550 -- There maybe?

And, I noted there last time that I thought Damien had reverse engineered the DC/DC already as a battery charger. But I haven't seen any details of it or how to replicate that other than his proof of concept.

[muehlpower]

The original gearbox is from comex, the technical data can be downloaded here:
http://www.comexspa.com/index.php/en/pr ... -gearboxes

Fleck sells these motors and gearboxes and matching drive shafts
https://www.fleck-elektroauto.de/shop/elektromotoren/

[Kevin Sharpe]

Fleck sells these motors and gearboxes and matching drive shafts
https://www.fleck-elektroauto.de/shop/elektromotoren/

Seems crazy expensive for such poor performance... wouldn't a Prius transaxle fit in the A2?

[arber333]

Unfortunately the motor does not have a front bearing, so mounting it to the transmission will be a bit more challenging.

Battery-wise he will probably be using my remaining Leaf pack, wired for half voltage (180V).

I dont see a problem with 180V. My Gen3 inverter produced 12Vdc 1kW down to some 120Vdc.

Well i didnt know about the bearing fact. Sorry. I can ask a friend who used that motor to convert his Fiat Punto. How did he do it. Since his punto is operational still. Marjan Bozic, you have met him in Slovenia last time.

I am very interested in making similar AC compressor to work in my Volt inverter. I use Lebowski brain for that since it can run in sensorless mode with light loads. It is using backEMF to find magnet positions. I have inverter PCB built and need to just resolve some of the issues.
Also that code supports CAN bus throttle adress. So you could command the compressor controler through another uC controller.
I will post some design soon since now it pretty much works....

[arber333]

The original gearbox is from comex, the technical data can be downloaded here:
http://www.comexspa.com/index.php/en/pr ... -gearboxes

Fleck sells these motors and gearboxes and matching drive shafts
https://www.fleck-elektroauto.de/shop/elektromotoren/

I am using his 28kW motor rewired for 180Vac in my Mazda. It has some serious torque, i am to be blamed i requested he extends the rotor on his 20kW motor and that 4cm gave it 8kW more continuous power. But with low voltage and hi amps it is air cooled and quickly raises temp to 150°C. This is reason i went to rewire it. Now its best settings are in parameters section with Johannes and Tesla motors .

Yes it was quite expensive at the time, but you have to consider there was nothing else with a propper EN certificate at the time.

[johu]

Thanks for your replies!

So by DC/DC I mean the HV to 12V unit that is in the bottom of the assembly, not the buck/boost converter.

I already bought that motor a few months ago for 280€ so we will make an effort to use it.

I found the splined hub as a replacement part on ebay, so apparently it can be removed and replaced by something fitter.

[GaryClarke]

Seems crazy expensive for such poor performance... wouldn't a Prius transaxle fit in the A2?

I already bought that motor a few months ago for 280 so we will make an effort to use it.

For what it's worth I think the greatest innovation and gift to humanity of this open inverter forum has been the opportunity to recycle and repurpose the Toyota transaxle and inverter as a fulltime EV drive system. It has the potential for a "crate-engine" kit to swap in to millions of front wheel drive diesel cars and vans currently polluting the air of European cities.

Similar to this Transition one project https://www.digitaltrends.com/cars/fren ... esel-cars/

The supply of Twingo parts seems much more limited and therefore the benefit less than could be achieved by using the plentiful toyota parts.

I would be prepared to fund the purchase of a Toyota transaxle for this project. may be others would chip as well? I could even contribute an A2 but as you're in Europe that may not be practical in view of current events.

If you wish I could organise a crowd fund for the entire project.

[arber333]

Hi Johannes

I made some inqiries into how many cars are here in Slovenia running on that motor. It seems they are 4 Fiat Punto cars, 3 Fiat Panda and several Smart for two cars with semi auto transmission converted by Andrej Pecjak.
All this conversion have in common that there were debates what to do with the axial load from the clutch. It can be like 40kg load when shifting etc... My first reaction was then you simply not use the clutch and shift like i do here... https://mazdamx3ev.wordpress.com/2018/0 ... lopka-ven/
The motor i was discussing has two ball bearings and they support weight of the shaft radially, but that kind of bearing also supports some load from the axial side. So it should not be a problem to ask a machinist to get you bearings with good seat to ward of some axial loads.
Did you dissassemble the motor yet? Can you send me some photo of bearing retention system in the front?
I also asked some of those cars drivers and their reply was to just use the plate on transmission housing and mount the motor to it. No bearing needs to be adapted. Make good effort to allign the center, but really clutch remains.

Well today i had conversation with Marjan and he said you need to keep the clutch. When at low RPM motor does not have enough pull and if you remain in 2nd gear some steep hill may be against your torque. Then you need to shift to 1st gear and go... If not you are stuck an have to stop since most 1st gears are not synchronised to be used from 2nd to 1st. Basically from his experience you ned to drive it with high RPM.

My motor has enough torque to pull from 5th, so i dont have that problem.

He absolutely advocates to mackine out the flywheel so you remove its countertorque when in regen.

[RetroZero]

Yes, Transition One has big plans, as long as they leave the nice prius transaxles for the moment, I'm happy.....

[johu]

Thanks for offering to fund this project. The need to change down to 1st gear on inclines really makes me think twice whether this motor is a good choice.

I found a Prius transaxle here: https://www.ebay.de/itm/Toyota-Prius-II ... SwIZJd7A8-

It is actually just 30km away from my friends place.

EDIT: the same guy even has a Gen3 Prius inverter: https://www.ebay.de/itm/Spannungswandle ... Sw6zhd62YJ

Thats the one that runs on Damiens board, right?

Forgive my ignorance, does the Prius transaxle also have two motors and do you need to run both? Or should the stronger one be sufficient for small cars?

[SciroccoEV]

Remember the Gen 2 Prius IPM had deadtime generation built in, so if you don't have deadtime set to zero, that may cause no PWM at low amplitude.

DC/DC is just a enable and voltage control lines (float/boost).

[arber333]

Forgive my ignorance, does the Prius transaxle also have two motors and do you need to run both? Or should the stronger one be sufficient for small cars?

I have Auris and Yaris inverters at home and i will try to get them working as charger and as MG2 drive.

I think that large MG2 should be able to run A2 up to some 90km/h. Maybe 100km/h?
MG1 usually does not contribute to wheel torque. But if you weld up the PSD like Damien did you can transfer additional torque for more speed.

I think you should take gen 3 prius transaxle then. Its MG1 / MG2 speed ratio seems to be much better.

[jnsaff]

I found a Prius transaxle here: https://www.ebay.de/itm/Toyota-Prius-II ... SwIZJd7A8-

It is actually just 30km away from my friends place.

EDIT: the same guy even has a Gen3 Prius inverter: https://www.ebay.de/itm/Spannungswandle ... Sw6zhd62YJ

These are crazy prices. Ge2 transaxle can be had for 100 EUR and there's a really good Gen3 with all the wiring still attached for 355EUR here https://dalys.lt/en/autoparts/lexus/ct- ... ox/1146927 the shipping for sure won't be that bad.

Also Auris/Yaris (Gen3) inverters are as low as 100EUR as well: https://www.xdalys.lt/en/search?q=toyot ... ter&page=1

[GaryClarke]

Thanks for offering to fund this project. The need to change down to 1st gear on inclines really makes me think twice whether this motor is a good choice.

I found a Prius transaxle here: https://www.ebay.de/itm/Toyota-Prius-II ... SwIZJd7A8-

Excellent. I'm taking that as a yes to crowdfund the whole project. I will start putting things together to whip up some interest and raise the cash. I think the more people involved and following progress the better.

I will follow progress and document. The aim being to produce a how-to-guide to converting an A2 using Toyota hybrid parts.

The first objective to fund will be sourcing the parts. My initial search was for Generation 3 components.

Trans axle : https://www.ebay.co.uk/sch/i.html?_osac ... x&_sacat=0

Transaxle mounts? : https://www.ebay.co.uk/sch/i.html?_osac ... s&_sacat=0

Inverter : https://www.ebay.co.uk/sch/i.html?_osac ... r&_sacat=0

Drive shafts : https://www.ebay.co.uk/sch/i.html?_osac ... s&_sacat=0

Throttle pedal? : https://www.ebay.co.uk/sch/i.html?_osac ... l&_sacat=0

HV wiring; https://www.ebay.co.uk/sch/i.html?_osac ... g&_sacat=0

What else is needed?

I'm thinking an initial budget for a kit of parts is £1000 is achievable . plus batteries and open inverter components.

A catchy initial target for the project would be 60 miles at 60 mph of range for £6000. Or in metric 100 km at 100 kmh for 6000 euros.

[jnsaff]

For the A2 I would consider the MGR. 50kw (which you were aiming for?) directly to front drive shafts. This is my plan for a 2003 Mini.

[Kevin Sharpe]

A catchy initial target for the project would be 60 miles at 60 mph of range for £6000. Or in metric 100 km at 100 kmh for 6000 euros.

I think the proposed performance figures and price are unacceptable today given you can buy a good second hand Leaf for £5000.

My suggested target would be 100 mile range, 100 mph top speed, £1000 in parts.

This would be achievable if you subsidise the battery by buying a wrecked Leaf and selling the unwanted parts. One of our course participants is doing just that, they paid £2000 for a wrecked Leaf and are selling everything except the battery.

[Kevin Sharpe]

For the A2 I would consider the MGR. 50kw (which you were aiming for?) directly to front drive shafts. This is my plan for a 2003 Mini.

That's a great suggestion

[Jack Bauer]

I'm happy to donate a gen3 prius inverter board to the project.

[Jack Bauer]

Do not use a Yaris or Auris gearbox. Unlike the prius or lexus ct200 version they do not have any liquid cooling.

[GaryClarke]

A catchy initial target for the project would be 60 miles at 60 mph of range for £6000. Or in metric 100 km at 100 kmh for 6000 euros.

I think the proposed performance figures and price are unacceptable today given you can buy a good second hand Leaf for £5000.

My suggested target would be 100 mile range, 100 mph top speed, £1000 in parts.

This would be achievable if you subsidise the battery by buying a wrecked Leaf and selling the unwanted parts. One of our course participants is doing just that, they paid £2000 for a wrecked Leaf and are selling everything except the battery.

I don’t think our performance aspirations are so very far apart. We have just expressed them differently. An A2 EV capable of 60 miles of range AT 60 miles per hour could well also achieve a top speed of 100mph and, if more soberly driven, in a city and regen braking, a maximum range of 100 miles.

A budget of £1000 for parts excluding batteries using from “off the shelf” parts, seems reliably reproduceable in significant numbers. There seems to be greater potential supply of Prius transaxle parts. With Gen 3 having capability for EV propulsion without internal modification.

Batteries will be the most expensive item. In time at least, if not in cash. It may well be possible for a few individuals to reduce the headline cost. They could perhaps justify time spent off the main objective of the conversion.They could get lucky with a one-off bargain price on a battery pack. My feel is that those people would be the exception rather than the rule. Therefore, I think a budget that reflects off-the-shelf prices.

Personally I think it’s more worth only converting interesting cars. Future classics. For me that’s the A2 along with A4 cabriolets and TTs from the same era. I want to see as many buzzing around as can be done. £6000 conversion cost seems great to me. I’m looking to support a project that can be used as a template for a great number of conversions. The more conversions, the more of Damiens and Johannes boards get bought.

[Kevin Sharpe]

£6000 conversion cost seems great to me. I’m looking to support a project that can be used as a template for a great number of conversions. The more conversions, the more of Damiens and Johannes boards get bought.

Damien converted a 40 mile range car for €1000 two years ago. Obviously it's your money but I really don't think we want to be promoting the idea that it costs £6000 to convert a car today

If you're serious about mass conversions then take a look at project LEXI (here) which will demonstrate what you can so with €1000 today

Also recommend you take a look at the Toyota MGR which are readily available for under £100 (here).

[GaryClarke]

£6000 conversion cost seems great to me. I’m looking to support a project that can be used as a template for a great number of conversions. The more conversions, the more of Damiens and Johannes boards get bought.

...Obviously it's your money but I really don't think we want to be promoting the idea that it costs £6000 to convert a car today

This seems like a distraction from the main business. Lets keep the contributions positive.

Damian has offered up a gen 3 inverter. My offer still stands to supply a transaxle. The Prius Gen 3 suits my purposes best, but I am open-minded. I will get behind what ever choice gets the project moving. If the project needs further funding, I will help.

[arber333]

Johannes i got an offer from a friend who is driving a converted A2. It uses an old 30kW motor and inverter of Slovenian design. Aleš an Me made my inverter according to this design. System is 210Vdc.
Audi A2 is a pain because you need a host of CAN data to send so that main column knows that you are "running gas guzzler".

He is offering for me to listen on his CAN adapter that is sending that info over CAN so we can replicate its signals. I bet this will save you or anyone else a ton of trouble. I just need to go to him and make this work now with COVID19....

A

[MattsAwesomeStuff]

Damian has offered up a gen 3 inverter.

Err, I think Damien offered a Gen3 Inverter control board. I.E. The thing he designed and had fabricated. Not the whole inverter.