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Need some suggestions on what to buy for a Leaf motor/inverter/charger build

4684 Views 47 Replies 12 Participants Last post by  darko
I am putting a Leaf motor and gearbox into the rear end of a 1987 Porsche 924S. At least, that's the plan.

I already have a 2015 EM57 Motor, the Leaf inverter (2015 or 2014 I think) and the corresponding Nissan charger. I'm looking to get a bench setup going. But one issue is that I don't have a battery pack selected/purchased yet. Given that the leaf motor needs high voltages, my options are bit more limited on what batteries I can fit in the vehicle. So here are a few questions I'm hoping people can help me with.

  1. Question about nomenclature - when people say "controller", are they referring to the inverter in the leaf stack? I guess in my mind the "controller" would be the brains determining the signals/speed to drive the motor at - like the Thunderstruck EV VCU provides. But in other forums when people talk about "controllers" people suggest using the Leaf inverter with the leaf motor when they are talking about "controllers". Anyhow, just trying to wrap my head around what people call these various components to avoid miscommunication. Perhaps there is a controller built into the leaf inverter they are referring to?
  2. I'm having trouble deciding between the Thunderstruck EV VCU, Resolve EV "controller", or the OpenInverter stuff. I don't know much about all 3 of them, but I've seen folks suggest that if you use the Resolve EV controller then you can use the Leaf battery pack and Leaf BMS as is. So I'm wondering if I need to decide on what batteries and BMS I will use first before I invest in one of those three.
  3. Since I'm having trouble finding a relatively recent Leaf battery pack, I'm thinking about cobbling something together to create the high voltages that it needs (up to 400V). I'm thinking about getting some 80V lawnmower batteries and wiring either 3 or 4 of them in series just to use in a benchtop test where I would be putting very little load on the motor to just test things out. Wondering if anyone has any thoughts on using this to create the high DC voltage I need to run the Leaf inverter. I saw the video with the guy using the rectifier across a 240VAC line but I don't like that approach.

Any other suggestions on how to select the battery pack to buy and the VCU/controller to use would be greatly appreciated.
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1987 Porsche 924S
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Discussion Starter · #21 ·
i think the ResolveEV guy on youtube showed how in his Porsche he reversed the motor direction by swapping two of the lines between the inverter and motor. I think he custom made some copper bars that swap two of the three and I'm pretty sure i saw it briefly in a video of his. I'd have to find it though.
 

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Well this is timely. I was looking at this just yesterday.

If you flip the case upside down, be aware that there is a vent at the top of the case that actually (and strangely) vents to the area between the motor face and the case. Flip it upside down and it's going to start pissing oil into that void. You'll have to epoxy that vent closed and install something else on the new 'top' side.

But flipping the case doesn't seem like a terribly logical solution since the motor would be pointed downwards and then you are looking at relocating the inverter, and none of that makes a ton of sense to me from a packaging standpoint. Maybe I just lack sufficient imagination?

Running the case right side up but in the reverse direction does seem like a common solution and it's what I am planning for my own car too. To reverse the motor you need to swap phases of the power leads into the motor, AND you have to reverse some of the wiring in the resolver. There are videos on how to do that and it seems pretty trivial. I'm not planning to do either of those things, since I am using an Openinverter board I can just set the 'forward' direction to be clockwise.

Now onto lubrication, there is a reservoir that sits above the jackshaft and has a small drip hole in the center. This seems to feed oil to the jack shaft bearing on the motor side. It looks like the differential ring gear slings oil into the reservoir until it is full, then slings oil into a small channel that feeds oil to the back side of the input shaft bearing on the motor side. At this point this is all speculation on my part.

Borrowing a photo from the NKR Motors facebook page so I can mark it up with what I think is going on:
Automotive tire Motor vehicle Automotive design Rim Automotive lighting


The other side of the case is pretty much the same, except bot the input shaft and jack shaft bearings are fed by the oil slung from the ring gear. Another photo from the same source:
Crankset Automotive tire Automotive lighting Motor vehicle Vehicle brake


As you can see from this photo and the level check plug on the left side, the jack shaft bearings should indeed be immersed. Not terribly worried about that one, or the tapered bearings on the differential. (Side note: How the hell do you set preload on the differential bearings? The races seem to be just pressed into the case and when the case is assembled you have no way of checking or adjusting it??)


My concern then is mostly centered around how to lubricate the input shaft bearings, and perhaps a vague concern about the oil getting frothed up by getting slung in the wrong direction with nowhere to really circulate. Could that reservoir have some holes drilles and small tubes added to feed oil to the bearings? Then add a small pump that can supply enough flow to keep the reservoir full. Use the drain plug as a fill line to the pump and tap a hole up top into the reservoir.

As far as pump selection goes, I don't have any great options at the moment. Would this be too small? Would this be too big (and also not rated for continuous duty)?
 

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Discussion Starter · #23 ·
silly question for @Zieg or anyone else considering running these backwards... what is the primary reason you have to run them backward? My simple brain says you could just turn the motor around the other way to have forward be forward (however it was in the leaf). Is the issue that mounting the motor like that in the rear pushes something too far into the rear or something like that? We haven't started the process of seeing how this stuff might fit in our car so I'm not really sure what the primary reason for having to run in reverse is.
 

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Looks like it's splash lubricated and uses the large ring gear as a slinger to lube the gears. Most of the bearings appear to be immersed other than the input bearing, which has a lube catcher feature built into the case that then drip lubes the upper bearings.

Flipping the case pretty much immerses those bearings.

The possible issue I see in this is not lubrication; with the input shaft immersed, sealing the 10,000 RPM shaft to keep lube out of the motor might be a long term problem. So oil level will be critical - arguably would reach its own happy point.

My $0.02.
he decided against flipping the motor over and rather turned it around with the gearbox in front of the motor as opposed to behind the motor as it would sit in the original leaf..

Not to hijack this thread.. But in my project i need to turn the motor parallel to the drive shaft and keep the weight centered on the chassis. So I need to find out if it is doable or not.
 

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silly question for @Zieg or anyone else considering running these backwards... what is the primary reason you have to run them backward? My simple brain says you could just turn the motor around the other way to have forward be forward (however it was in the leaf). Is the issue that mounting the motor like that in the rear pushes something too far into the rear or something like that? We haven't started the process of seeing how this stuff might fit in our car so I'm not really sure what the primary reason for having to run in reverse is.
i need to turn the motor and gearbox 90 degrees to get 4x4 drive capabilities. with the rotation clockwise turning it in the direction I need to changes that rotation direction. The change in the rotation is the same that would be needed to run in a 911 or VW bug. I just haven't heard or seen it done to know it will work..
 

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silly question for @Zieg or anyone else considering running these backwards... what is the primary reason you have to run them backward? My simple brain says you could just turn the motor around the other way to have forward be forward (however it was in the leaf). Is the issue that mounting the motor like that in the rear pushes something too far into the rear or something like that? We haven't started the process of seeing how this stuff might fit in our car so I'm not really sure what the primary reason for having to run in reverse is.
That's it exactly. In the leaf, the motor sits ahead of the wheels, but my rear wheels are way too close to the rear firewall. I did briefly consider mounting it facing forward but the axles would be swept forward at quite a sharp angle when viewed from above. The outer joint can handle angles like that to accomodate the front wheels steering, but the inner joint is much more simplistic and probably not capable of such an extreme working angle.

I've never seen the under side of a 944 but I'm hoping you won't have to worry about it due to the transaxle leaving more space for the motor to sit ahead of the wheel centerline.
 

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Discussion Starter · #28 ·
That's it exactly. In the leaf, the motor sits ahead of the wheels, but my rear wheels are way too close to the rear firewall. I did briefly consider mounting it facing forward but the axles would be swept forward at quite a sharp angle when viewed from above. The outer joint can handle angles like that to accomodate the front wheels steering, but the inner joint is much more simplistic and probably not capable of such an extreme working angle.

I've never seen the under side of a 944 but I'm hoping you won't have to worry about it due to the transaxle leaving more space for the motor to sit ahead of the wheel centerline.
ahh i see... so if we get luck and can either and fit the motor in front of the axle in the 924S (or cut an acceptable amount of metal into the rear seats area) then perhaps we can still have it drive forward? If so, that would leave more room for batteries in the rear and put the weight more towards the center of the vehicle which would be nice anyways. I'll guess we'll cross that bridge when we get there.
 

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924S, sorry. Brainfart. But yeah, that'd be the hope. If it comes down to it, I'd probably even be willing to mount the inverter remotely if it made the difference between running the transmission forwards instead of backwards.
 

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Discussion Starter · #30 ·
924S, sorry. Brainfart. But yeah, that'd be the hope. If it comes down to it, I'd probably even be willing to mount the inverter remotely if it made the difference between running the transmission forwards instead of backwards.
totally agree. just three wires to interface them I believe so that's a good trade IMO
 

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I, too, had looked for a way to mount in reverse. Resolve-EV Wiring Diagram and Fun Facts has good, quick explanation.

I've been exchanging some email with #InductiveAutoworks. It sounds like their EX-8 project rotated the motor/gear reduction a bit, but not flipped over. They did recommend the EM61 motor over the EM57 as it's a little smaller and easier to relocate the inverter. Food for thought...
 

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  1. Question about nomenclature - when people say "controller", are they referring to the inverter in the leaf stack? I guess in my mind the "controller" would be the brains determining the signals/speed to drive the motor at - like the Thunderstruck EV VCU provides. But in other forums when people talk about "controllers" people suggest using the Leaf inverter with the leaf motor when they are talking about "controllers". Anyhow, just trying to wrap my head around what people call these various components to avoid miscommunication. Perhaps there is a controller built into the leaf inverter they are referring to?
  2. I'm having trouble deciding between the Thunderstruck EV VCU, Resolve EV "controller", or the OpenInverter stuff. I don't know much about all 3 of them, but I've seen folks suggest that if you use the Resolve EV controller then you can use the Leaf battery pack and Leaf BMS as is. So I'm wondering if I need to decide on what batteries and BMS I will use first before I invest in one of those three.
  3. Since I'm having trouble finding a relatively recent Leaf battery pack, I'm thinking about cobbling something together to create the high voltages that it needs (up to 400V). I'm thinking about getting some 80V lawnmower batteries and wiring either 3 or 4 of them in series just to use in a benchtop test where I would be putting very little load on the motor to just test things out. Wondering if anyone has any thoughts on using this to create the high DC voltage I need to run the Leaf inverter. I saw the video with the guy using the rectifier across a 240VAC line but I don't like that approach.
I used a Thunderstruck VCU, BMS, charger, and controller in my project, and I have been very happy with all of it. I would've been happier to save $2k and use the Leaf BMS and charger, but hey. I wound up using 22 of the 24 modules, and if Resolve can't handle that, that's a bummer...That said...if everything else is as smooth and friendly as the Thunderstruck VCU, they cost about the same...

Since you don't have batteries yet, I'd probably buy a power supply or device that can output a dozen amps at 200V or some such. The inverter is alleged to function as low as 140V, but 400V is ideal...Pandemics notwithstanding, the longer you wait to buy batteries the more EVs will been built and crashed...
 

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Discussion Starter · #34 ·
I used a Thunderstruck VCU, BMS, charger, and controller in my project, and I have been very happy with all of it. I would've been happier to save $2k and use the Leaf BMS and charger, but hey. I wound up using 22 of the 24 modules, and if Resolve can't handle that, that's a bummer...That said...if everything else is as smooth and friendly as the Thunderstruck VCU, they cost about the same...

Since you don't have batteries yet, I'd probably buy a power supply or device that can output a dozen amps at 200V or some such. The inverter is alleged to function as low as 140V, but 400V is ideal...Pandemics notwithstanding, the longer you wait to buy batteries the more EVs will been built and crashed...
that's really great info. What we wound up doing for our testbed was using 3 of the 80V batteries used for lawn equipment in series and that is working good so far for testing (video on that coming soon on our channel). We are also using the Thunderstruck VCU as of now.

I'm thinking about going with new batteries rather than something used... perhaps like 13 of the LG Chem 7S modules from EV west in series. I just don't know what exactly I need for a charger and a BMS. I see that Thunderstruck offers the BMS and charger (or even their new "Master Control Unit" product), but I see that the max voltage you can configure their TSM2500 for is 312V and my 13 modules will go up to around 380V-390V... i'm just not sure if it all works out or not. I'm also not sure how I can create some bus bars for those LG Chem 7S modules... or even if I should switch to some other battery. But so far, I haven't really found any new battery modules that I could put together to get the really high voltages the Leaf motor/inverter needs and still be able to fit it in the car and not cost a bazillion dollars. Would love any and all suggestions!
 

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Not much written about these batteries (they came on the market last year), but the specs and price are comparable to used Model S modules:


The packaging and configuration options are nice.
 

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Discussion Starter · #36 ·
Not much written about these batteries (they came on the market last year), but the specs and price are comparable to used Model S modules:


The packaging and configuration options are nice.
Man, those are really nice. I would be interested but any of the configurations I can come up with that has a 380-400V voltage I need for the leaf battery puts me at somewhere between $18k - $24k (!). That's too much for our project. I love the size and configuration they have.
 

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Well again, if your minimum voltage condition is 140V, you might still be able to use less of them. High voltage seems most beneficial from a wiring and/or charging standpoint...I think (like I don't know) that sag and what not has more to do with the battery chemistry than total pack voltage.
 

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how I can create some bus bars for those LG Chem 7S modules... or even if I should switch to some other battery.
Super cell jh3 modules? They are hooked in series via heavy gauge wire. I suspect You could make copper bus bars out of 1/8- 1/16 inch copper stock.
Have you looked at battery hookup? There are many options there most at under $200 kwh from 2s to a complete Volvo 96s battery pack.
 

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I see that the max voltage you can configure their TSM2500 for is 312V and my 13 modules will go up to around 380V-390V
Remember, 312V is just the nominal voltage. Their chart gives a range of 200-420V for that configuration.

I visited ElectricGT a few months ago. I really liked their battery configurations. They seemed willing to sell for DIY, but that might have been with their motor packages. Can't remember :rolleyes:

And I'm also eyeing that Volvo pack from Battery Hookup. Just gotta find out if they'll ship to Hawaii!
 
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