George's Suzuki Jimny

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george
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George's Suzuki Jimny

Post by george »

Contents Introduction

Around the start of 2021, I decided to build a "fun, capable 4WD for commuting and adventuring in with my partner, while trying to reduce CO2 emissions". My partner and I fell in love with a 2001 Jimny, so it has been selected as the donor vehicle. I started a thread to discuss the possibility. After a fair bit of throwing ideas around with the wonderful AEVA community, I reached a preliminary design: a direct drive conversion using a Nissan Leaf motor/inverter. Here is a rough breakdown of the decisions made so far and some reasoning:
  • 2001 Suzuki Jimny: light, 4WD, reasonably low (for a 4WD) coefficient of drag of 0.28 according to this 1998 article, not too much difficult electronics to mess around with, and my partner and I love it
  • Direct drive: Easy regenerative braking, less powertrain weight/volume without the gearbox and clutch, lower part count, can get enough gearing from transfer case (modifiable up to 1.63 in high) and differential (can swap for a 4.3) to get a decent performance curve with a final gearing ratio of 7.01, quite close to the factory 8.1 of the Nissan Leaf (credit to @francisco.shi, @jonescg, @T1 Terry, and @seth2012 for talking me gently through this)
  • Nissan Leaf motor/inverter: OEM part = higher quality than a souped up forklift motor, liquid cooled rather than air cooled for more rugged design, comes with a pretty nice liquid cooled inverter (credit to @francisco.shi for the suggestion)
  • Dilithium Leaf VCU: controls the inverter, saves a fair bit of implementation time (yes, the CAN has been cracked on the inverter, but this little box does quite a lot of work on top of talking to the inverter), improves reliability over my own possibly dubious embedded systems skills
The big item that hasn't yet been sketched is the battery. I'm leaning towards a @jonescg style cylindrical cell, end plate cooled module, but I haven't made up my mind yet. I have, so far, followed his advice of not thinking about the battery too much until the drivetrain is all installed and working.

Next Actions
  • Wait for the Leaf motor and the VCU to arrive
  • Perform a bench test with a home made power supply
Last edited by george on Sat, 23 Oct 2021, 13:11, edited 3 times in total.
george
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Re: George's Suzuki Jimny

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Motor Bench Test

The motor arrived in my garage last weekend. Having already taken the time to build a test rig for the motor, the bench test didn't take too much work, all things considered. A home-made 4 A 340 VDC supply, built by a friend, connected through the precharge and primary contactors to the inverter took care of the power stage. A Thunderstruck Vehicle Control Unit took care of CAN communication with the inverter, controlled both of the contactors, and connected to the peripheral throttle and gear select controls.

At first, the motor was "cogging", but with help from a friend, we were able to swap the polarity of a few connections between the inverter and motor (mine was shipped without the harness) until we got smooth acceleration. What a relief! I had been waiting for around 3 months for the motor and inverter to arrive from America, and not only had it arrived, but it worked! Only popped one fuse in the process ;) .

Here is a link to a quick video showing some proof of life.

The vehicle has been weighed at each corner with a home-made rig made of 50 mm square section steel and 4 bathroom scales, taking care to keep the vehicle level. The vehicle's mass distribution:

Code: Select all

Position	Weight (kg)
Front left	307
Front right	297
Back left	238
Back right	264
Total		1106
I've made progress on the battery/BMS/cooling system design, but I'll make a post when some more has been decided. My 20 test batteries (60Ah LiFePO4) have yet to arrive. I will probably try cooling with ambient air, and am considering a mister for occasional hotter weather (not an issue where I live).

Next Actions
  • Take out the ICE components
  • Design the battery/BMS/cooling system
T1 Terry
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Re: George's Suzuki Jimny

Post by T1 Terry »

Hi George, what is the plan with the 20 x 60Ah LFP cells? What costs to date, landed in Australia and released from customs, for the Leaf motor and inverter and the VCU? Did you get the acc kit for the VCU as well?

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george
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Re: George's Suzuki Jimny

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I want to do some testing on the cells, to see if they pull full capacity, and test their current characteristics. I'm thinking that 112 of them in series might do the job for a 80-100 km range vehicle. So, that's 7 modules of 16 cells each. I bought 20 so that I could test 4 cells to destruction, and still have a useful number left to make a module.

The VCU + accessories + shipping was AUD $1641.29. Definitely can save some money here by making your own, but it was certainly convenient, and I don't regret the purchase. The Leaf motor and inverter, plus shipping, was AUD $2309.43. Most of that was shipping cost.
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Re: George's Suzuki Jimny

Post by jonescg »

Great to see some progress George! Where did you buy the Leaf transaxle from? I'm still in the market for one for the CRX...
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george
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Re: George's Suzuki Jimny

Post by george »

Thanks Chris! I bought the motor/inverter (no gearbox or anything else, not even the controller. Bit of a shame not to get any of the wiring harness...) from a scrap-yard in Minnesota, through eBay. There are around 20 or so available in the USA, or at least there were when I documented them all. I had my pick of motors, and was able to pick up a 35000 km 2015 unit that looked like it had been rear ended very gently. Perfect. In terms of shipping, chuck it in a container if you have time and no money, and on a plane if the opposite. At 130 kg, it's just about on the critical threshold for those kinds of logistics decisions.
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Re: George's Suzuki Jimny

Post by jonescg »

Makes sense. I'm keen to get the transaxle too, just cause running it through the manual gearbox is so noisy and inelegant.
I'd probably skip the inverter though. Would rather use something I can control a little more easily.
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george
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Re: George's Suzuki Jimny

Post by george »

I'll be running direct drive, through the transfer case and differential. Should give me a ratio of 1.32*4.09=5.4, which is a fair way off the Leaf's 8.1, but not too bad, and I get to keep 4WD high/low. Agreed that the transaxle is an elegant solution if you're happy with front wheel drive.

You can actually modify the inverter using some open source hardware to get 140 kW, if you so wish. It involves a bit of surgery, but it doesn't look too hard. Quite nice to have a liquid cooled inverter, and even nicer to have complete control over all the code inside it. Nicer yet with the OTA WiFi software updates: https://openinverter.org/shop/index.php ... rch=nissan. This might only work for the newer inverters though. I get really confused with the Gen 1/2 and Z0/Z1 and EM57/EM61 stuff.
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Re: George's Suzuki Jimny

Post by T1 Terry »

george wrote: Sat, 16 Oct 2021, 12:21 I want to do some testing on the cells, to see if they pull full capacity, and test their current characteristics. I'm thinking that 112 of them in series might do the job for a 80-100 km range vehicle. So, that's 7 modules of 16 cells each. I bought 20 so that I could test 4 cells to destruction, and still have a useful number left to make a module.

The VCU + accessories + shipping was AUD $1641.29. Definitely can save some money here by making your own, but it was certainly convenient, and I don't regret the purchase. The Leaf motor and inverter, plus shipping, was AUD $2309.43. Most of that was shipping cost.
Thank you George, so roughly $4,000 buys a motor, inverter and interface controller with the wiring harness, sounds like great value to me.

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Re: George's Suzuki Jimny

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T1 Terry wrote: Tue, 19 Oct 2021, 09:38 Thank you George, so roughly $4,000 buys a motor, inverter and interface controller with the wiring harness, sounds like great value to me.
Yeah, roughly. You'll still end up needing a coupling machined (see https://www.diyelectriccar.com/threads/ ... st-1074154 for those who are interested) for another few hundred incl. shipping, but that will get you a spinning motor on a bench.
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Re: George's Suzuki Jimny

Post by brunohill »

I really like the Idea of this project and the direction it is taking. Should I follow and get my old Suzuki back on the road, or buy a Rivian? Perhaps I should check with my wife first.
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Re: George's Suzuki Jimny

Post by T1 Terry »

george wrote: Tue, 19 Oct 2021, 14:13
T1 Terry wrote: Tue, 19 Oct 2021, 09:38 Thank you George, so roughly $4,000 buys a motor, inverter and interface controller with the wiring harness, sounds like great value to me.
Yeah, roughly. You'll still end up needing a coupling machined (see https://www.diyelectriccar.com/threads/ ... st-1074154 for those who are interested) for another few hundred incl. shipping, but that will get you a spinning motor on a bench.
I see there is a local Ebay importer selling the motor, transaxle and inverter with driveshafts from Japanese half cuts, but up around the $6.500 mark, a bit rich for my blood at the moment.

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george
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Re: George's Suzuki Jimny

Post by george »

brunohill wrote: Wed, 20 Oct 2021, 00:30 Should I follow and get my old Suzuki back on the road, or buy a Rivian?
Depends if you want a project, or if you want to go 4WDing in an electric car ;)
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Re: George's Suzuki Jimny

Post by george »

Engine and Transmission Removal

Yesterday, a mate and I removed the engine and transmission. Took all day, so I was glad to have bought an engine hoist for the job.

Here's a link to a timelapse video of the process.

Next Actions
  • Design the coupling between the motor and transfer case
  • Design the battery/BMS/cooling system
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Re: George's Suzuki Jimny

Post by Bukes »

This is brilliant. Put a smile on my face thinking how excited you must have been to get the motor spinning in the test rig! Congrats on getting the engine and transmission out, can’t wait to see more
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Re: George's Suzuki Jimny

Post by rhills »

Hey @george,

Did you manage to finish your Suzuki Jimny project?

I found an ABC News update about it from early last year, but nothing since that time.
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george
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Re: George's Suzuki Jimny

Post by george »

Hi @rhills,

Unfortunately, it's on hold. I got married and bought a house, and have another project currently using most of my spare time. Trying to save up for a Kona at the moment.

I can't WAIT to get back into it. https://www.bigweibattery.com.au/produc ... tery-cell/ looks like a great battery: 112 of them would weigh 134.4kg, give me the full voltage range, and 14 kWh or so usable capacity. Might be getting around 100 km range for $8000, assuming 140 Wh/km town driving.

So, this project is waiting, but not forgotten. No substantial progress since removing the old engine/trans, last I worked on this I was having difficulty working out a mounting solution.
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Re: George's Suzuki Jimny

Post by jonescg »

Keen to help keep this mad project on the go. I reckon the house battery trailer idea is a winner.
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george
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Re: George's Suzuki Jimny

Post by george »

Thanks Chris. A few people have been asking questions and offering support, so I might have to get working on this sooner rather than later. My big blocker at the moment is the motor mounting. I may just need to fail forward with that one.
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Re: George's Suzuki Jimny

Post by T1 Terry »

I was keen on getying the engine and trans out and motor driving the transfer case input in my Jimny .... till the workshop fire, then the serious projects turned to getting the easiest/quickest/fuel affordable vehicle on the road ... that turned out to be the Silver Prius that was damaged with a battery fire many moons back .... but I'm keen to see how your project goes so I can show the wife to get her on board to letting me do a conversion on our Junior Jeep

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Re: George's Suzuki Jimny

Post by necrogt4 »

I know it's going back a wee bit, but I'd love to see any photos of your corner scales setup you might have? I'm looking at ideas for my own setup right now.

And where did you manage to find scales that could cope with 300kg? They sound like serious heavy duty bathroom scales!
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