# International Harvester Scout 800 conversion



## Tremelune (Dec 8, 2009)

Very doable. One route would be to buy a Nissan Leaf, adapt the motor to the gearbox (tricky/custom), and use the batteries, charger, BMS, and other bits as much as you can. That's probably $10k.

Another route would be to use Chevy Bolt batteries and a Hyper9 or some such. Adaptation would be a lot easier, and the batteries are much better, but you're looking at $20k minues what you could recoup form selling the rest of the Bolt.

I wouldn't mess with the brakes or steering until it seems necessary. With regen, you won't use the brakes much at all, and heavy steering has a lot more to do with tires and castor than weight. The torque from the average electric motor will be more than stock.

That said, building the Bug with a kit will be a lot easier, teach you quite a bit, and would probably have better resale than a home-spun conversion. Still smells like a $20k proposition, if I recall EV West's prices correctly.

No conversion is a weekend project, but any means.


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## eg0n (Feb 3, 2021)

Thanks for the feedback, Tremelune. Totally understand that even a kit conversion is a big project, especially for someone who's not skilled in this area already. I'm in it for the project and learning experience as much as the end result. I'll think more about doing a bug first (also, realistically, if I find it's really not for me, a bug with a partially installed EV West kit is probably a much easier flip than a pile of parts and a gutted Scout).



Tremelune said:


> Another route would be to use Chevy Bolt batteries and a Hyper9 or some such. Adaptation would be a lot easier, and the batteries are much better, but you're looking at $20k minues what you could recoup form selling the rest of the Bolt.


A quick google tells me the Bolt battery packs are 66kWh vs Leaf's 42-62, is that the main difference? I also notice the whole Bolt battery pack is heavier.

Is there likely to be much difference in difficulty/level of customization required to do a full part swap from a Bolt vs Leaf? Is the Leaf just advantageous due to the big used market?



> I wouldn't mess with the brakes or steering until it seems necessary. With regen, you won't use the brakes much at all, and heavy steering has a lot more to do with tires and castor than weight. The torque from the average electric motor will be more than stock.


Gotcha. My only concern was safety on the brakes. I'm guessing though on a truck they'd be already be sufficient for whatever load it's rated for on top of the weight of the vehicle?


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## Tremelune (Dec 8, 2009)

The Leaf has been hacked quite a bit. I believe the current state is that, with a $1,000 controller, you can use the motor, charger, DC/DC converter, and BMS (if you use the full pack in the same configuration). With the Bolt you're looking at figuring out controlling the motor, and then a few grand worth of DC/DC, charger, BMS...I don't think much of the Bolt has been figured out because they're new, but I haven't really been keeping up.

The Bolt batteries are stronger and more dense. You don't need to use all of them, so weight/space is more or less what you can swing. Same with the Leaf, if you buy $1,000 BMS system. Drivable Leafs can be found for near $5k. Most Leaf packs you'll find are 24kW. Batteries lost capacity rapidly until March 2013. They got even better in the 2015 model year.

There's no slam dunk, you just need to choose your compromises.


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## eg0n (Feb 3, 2021)

Right, that makes sense. Appreciate the input. I'll do some more reading with all that in mind.


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## reiderM (Dec 30, 2020)

eg0n said:


> My first questions:
> 
> Ridiculous? Not gonna happen? Too ambitious for someone who’s never pulled the engine out of a car before? Considered starting on something simpler like putting an EV West kit on a bug for my girlfriend, but go big or go home
> Would a Leaf part swap work here or is the Scout gonna be too heavy? The battery box as is (per googling some measurements) would kinda fit in the bed initially (a little wide, so might need to sit on top of the wheel wells and be otherwise supported)
> ...


You can absolutely do a conversion. Anyone can given enough time. I've been learning as I go and it's gone great. As long as you understand basic safety procedures for working with high voltage and don't accidentally short the batteries, it's hard to mess something up that you can't go back and fix. Set a pessimistic timeline (9 months), and try to surprise yourself.

For what it's worth, I started this process having never done anything with cars. Not even changing the oil. But with hands-on experience, I have learned loads about everything related to engines than I thought was possible.

The kinds of conversions that are much more challenging are ones where you're either working on a very tight budget or are programming and building some of your own components (a lot of people build their own inverters for example). Using off-the shelf parts or a leaf motor, its relatively straightforward.

I'm going to echo what Tremelune is saying here. The leaf motor would be more than enough power to get to 75 mph IF you use a gearbox, which I highly recommend. The only challenging bits of the leaf are adapter plates for adapting it to the transmission and the voltage. Nissan leaf inverters require 300-400 volts I believe for full performance (although they will spin with less), which is why I'm not going to use a leaf motor in my conversion, since I need at least 140-150 miles of range and I am using tesla modules for their energy density. If you are going to use a leaf motor, I would just buy an entire salvage leaf (<$10k) and pull the motor and battery pack from it. The leaf motor has a fixed differential bolted on but that can be easily removed if you want to mate it to a manual transmission. This option is the cheapest and would definitely be a good choice.

Another option is to go with a Netgain Hyper9 HV motor, which is a motor designed specifically for conversions. They're $4300 for the motor, inverter, and contactor. You can pair that with 7 Tesla modules ($1000 each about) for 35kwh of battery capacity. This should give you at least 80 or so miles of range, and driving conservatively I'd guess you would get over 100 easily. A total for this option would be somewhere around $20k.

A Tesla motor is unnecessary for your needs and requires a lot of fabrication work.

Don't go with EV West. They have a 5-year waitlist for conversions they do themselves and they have made it clear to me that they don't want the business of individual enthusiasts from my email exchanges with them.

You probably won't need to upgrade brakes or power steering assuming they are working fine in the current vehicle. All in, post-conversion the car will only weigh a few hundred pounds over what it weighed before I would guess.


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## bronco_zed (Dec 21, 2020)

I'm attempting something very similar with a Bronco, but I'm removing the engine, transmission, and transfer case and replacing them with a Tesla large drive unit mounted at an angle to drive the front and rear axles. I'll gain some efficiency by not running the motor through a gearbox but then I'll lose some by it being full-time four wheel drive, so it may end up being a wash efficiency wise. Mostly I'm doing it this way so I can have more room for batteries.

So far this is what I've purchased:

Tesla LDU with drive shafts and wiring harness - $2400
Quaife 4.5 gearset - $2600 (ouch, I know)

I plan on using the EV Controls drive unit controller - $2700

AEM has also just released a Tesla drive unit controller for about the same price but the EV Controls unit lets you view and change settings in real time with an ipad, so I wont have to buy further instrumentation to gather data.

So right now the damage is $7700 and I still need batteries, BMS, charger, DC-DC converter, accelerator pedal, and a precharge circuit. Plus motor/battery cooling and custom driveshafts.

Overall I think my price and range goals line up with your project but I may end up with less range unless I can find a killer deal on batteries.

Keep us posted! I'd love to see what direction you decide to go.


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## brian_ (Feb 7, 2017)

bronco_zed said:


> I'm attempting something very similar with a Bronco, but I'm removing the engine, transmission, and transfer case and replacing them with a Tesla large drive unit mounted at an angle to drive the front and rear axles....


The angled shaft made necessary by the Broco's centred rear propeller shaft (and the off-to-the-left drive unit output) is a concern, but I recently realized that the Lada Niva has an offset like that in standard form (due to their choice of transfer case and their centred rear axle pinion) so it apparently can work. In this case, even if the offset is okay, the angle is still a concern: if the rear output of the drive unit is not parallel to the pinion shaft of either axle, then the propeller shafts need constant velocity joints (instead of the usual universal joints) to run smoothly... perhaps that's the plan.

The other way to handle this offset issue is to have a rear axle made up with the differential off-centre to match the front. This is the stock configuration of some vehicles (notably the original Land Rover), but is generally not used in vehicles that come in both RWD and 4WD versions. It would require custom-length axle tubes and axle shafts, with the tubes welded into the centre section and end housings welded on to them. Custom-width axle housings are commonly made for custom vehicles, and having different left and right lengths is not a problem. This would be expensive, and would require ensuring that there is room for the rear shaft in that position.


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## bronco_zed (Dec 21, 2020)

brian_ said:


> The angled shaft made necessary by the Broco's centred rear propeller shaft (and the off-to-the-left drive unit output) is a concern, but I recently realized that the Lada Niva has an offset like that in standard form (due to their choice of transfer case and their centred rear axle pinion) so it apparently can work. In this case, even if the offset is okay, the angle is still a concern: if the rear output of the drive unit is not parallel to the pinion shaft of either axle, then the propeller shafts need constant velocity joints (instead of the usual universal joints) to run smoothly... perhaps that's the plan.
> 
> The other way to handle this offset issue is to have a rear axle made up with the differential off-centre to match the front. This is the stock configuration of some vehicles (notably the original Land Rover), but is generally not used in vehicles that come in both RWD and 4WD versions. It would require custom-length axle tubes and axle shafts, with the tubes welded into the centre section and end housings welded on to them. Custom-width axle housings are commonly made for custom vehicles, and having different left and right lengths is not a problem. This would be expensive, and would require ensuring that there is room for the rear shaft in that position.


Yep, both prop shafts will have CV joints. This was the OEM configuration on the Bronco anyway, I'm assuming the reason is to allow large amounts of axle articulation without binding.

The UK company Electric Classic Cars puts Tesla drive units in original Land Rovers using this same setup, but like you mentioned, they don't run into the angle issue because the front an rear differential housings are offset to the same side.


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## eg0n (Feb 3, 2021)

reiderM said:


> For what it's worth, I started this process having never done anything with cars. Not even changing the oil. But with hands-on experience, I have learned loads about everything related to engines than I thought was possible.


That's awesome. The more I read the more I think I can do it, just need to take my time. I'm definitely expecting it to be a 6-12mo project.



> I'm going to echo what Tremelune is saying here. The leaf motor would be more than enough power to get to 75 mph IF you use a gearbox, which I highly recommend. The only challenging bits of the leaf are adapter plates for adapting it to the transmission and the voltage. Nissan leaf inverters require 300-400 volts I believe for full performance (although they will spin with less), which is why I'm not going to use a leaf motor in my conversion, since I need at least 140-150 miles of range and I am using tesla modules for their energy density. If you are going to use a leaf motor, I would just buy an entire salvage leaf (<$10k) and pull the motor and battery pack from it. The leaf motor has a fixed differential bolted on but that can be easily removed if you want to mate it to a manual transmission. This option is the cheapest and would definitely be a good choice.
> 
> Another option is to go with a Netgain Hyper9 HV motor, which is a motor designed specifically for conversions. They're $4300 for the motor, inverter, and contactor. You can pair that with 7 Tesla modules ($1000 each about) for 35kwh of battery capacity. This should give you at least 80 or so miles of range, and driving conservatively I'd guess you would get over 100 easily. A total for this option would be somewhere around $20k.


So if I used the components from a Leaf I'd have to use the battery setup in pretty much its exact existing configuration if I wanted to use the Leaf BMS right?

I'm not too concerned about perf, and 75 top speed is probably fine for me, but if I wanted to increase the range to more like 150mi (maybe even 200mi) what would I be looking at? A full set of 14 Tesla battery modules? Is a full Bolt pack likely to meet that requirement with a Hyper9?

I'm still a bit undecided about the requirements. I know what my bare min requirements are, but if I end up spending more on a really nice example of a Scout it seems silly to not go all out on the conversion. I don't have a hard budget requirement, just what I feel like I want to put into it.


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## eg0n (Feb 3, 2021)

bronco_zed said:


> I'm attempting something very similar with a Bronco, but I'm removing the engine, transmission, and transfer case and replacing them with a Tesla large drive unit mounted at an angle to drive the front and rear axles. I'll gain some efficiency by not running the motor through a gearbox but then I'll lose some by it being full-time four wheel drive, so it may end up being a wash efficiency wise. Mostly I'm doing it this way so I can have more room for batteries.
> 
> So far this is what I've purchased:
> 
> ...


This is an awesome design. So you're gonna basically fill the engine bay with batteries?

I understand a lot more about how the 4wd components work now. I'd probably lose a reasonable amount of efficiency in 4wd yeah? I'd consider pulling out the transmission and transfer case for efficiency but I guess that would be a lot of fabrication work like your project, which might be a bit out of my league for now.


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## reiderM (Dec 30, 2020)

eg0n said:


> So if I used the components from a Leaf I'd have to use the battery setup in pretty much its exact existing configuration if I wanted to use the Leaf BMS right?
> 
> I'm not too concerned about perf, and 75 top speed is probably fine for me, but if I wanted to increase the range to more like 150mi (maybe even 200mi) what would I be looking at? A full set of 14 Tesla battery modules? Is a full Bolt pack likely to meet that requirement with a Hyper9?
> 
> I'm still a bit undecided about the requirements. I know what my bare min requirements are, but if I end up spending more on a really nice example of a Scout it seems silly to not go all out on the conversion. I don't have a hard budget requirement, just what I feel like I want to put into it.


For 150 miles you probably want to do almost exactly what I'm doing: a Hyper9 with 10 Tesla modules 5s2p (5 in series, 2 in parallel). Or you could shoot for closer to 200, with a Hyper9 HV and 14 Tesla modules 7s2p. Netgain motors will be a little easier to use since there are pre-made adapter plates available from CanEVs and a few other sellers that can just be bolted on and put right into the car. You do need a BMS for each parallel string though, so keep that in mind as an added expense.

I would go for a leaf system if you don't need more than say 80 miles of range. Above that, something Hyper9 or Hyper9 HV based.

You'll definitely want to do it right the first time though. I personally would reccommend the Tesla and Hyper9 route since Tesla batteries are the best available and will last for at least 8-10 years, if not more. They've come down in price significantly lately too.


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## reiderM (Dec 30, 2020)

eg0n said:


> This is an awesome design. So you're gonna basically fill the engine bay with batteries?
> 
> I understand a lot more about how the 4wd components work now. I'd probably lose a reasonable amount of efficiency in 4wd yeah? I'd consider pulling out the transmission and transfer case for efficiency but I guess that would be a lot of fabrication work like your project, which might be a bit out of my league for now.


4WD won't make a huge difference in efficiency as long as its part-time. Most 4WD cars are part-time, meaning you can change the transfer case from only delivering power to two of the wheels vs all four. Leaving it in essentially 2WD means that the only efficiency lost from having 4WD will be the added weight (no more than a couple hundred pounds). So expect a 4-8% decrease in efficiency and total range by having 4WD. 

Leaving it in 4WD will result in a larger loss in efficiency (possibly over 10%), so I would just keep it in 2WD unless off-roading.

I would say definitely DON'T get rid of the transfer case. You will need to get new shafts and more to get that working, and I think that it's a waste of your time and money to essentially make that car worse. Instead, spend that money in getting 4-8% more battery capacity so that you can still hit your desired range with the added weight.


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## bronco_zed (Dec 21, 2020)

reiderM said:


> For 150 miles you probably want to do almost exactly what I'm doing: a Hyper9 with 10 Tesla modules 5s2p (5 in series, 2 in parallel). Or you could shoot for closer to 200, with a Hyper9 HV and 14 Tesla modules 7s2p. Netgain motors will be a little easier to use since there are pre-made adapter plates available from CanEVs and a few other sellers that can just be bolted on and put right into the car. You do need a BMS for each parallel string though, so keep that in mind as an added expense.
> 
> I would go for a leaf system if you don't need more than say 80 miles of range. Above that, something Hyper9 or Hyper9 HV based.
> 
> You'll definitely want to do it right the first time though. I personally would reccommend the Tesla and Hyper9 route since Tesla batteries are the best available and will last for at least 8-10 years, if not more. They've come down in price significantly lately too.


I agree with reider, the Netgain option has been used by a lot of companies like EV West and ElectricGT so there's already a lot of adapter options and application examples out there for reference. 

Since the Scout and the Bronco are about the same size, I think it's relevant to mention the amount of real estate available for batteries. It's probably possible to fit 10 or even 14 Tesla modules in the Scout, but it will require a lot of fab work and Tetris-ing to pack them out of sight. But, if you are not worried about putting them in the bed then it gets a lot easier.

For reference, the Bronco kit sold by ElectricGT keeps the transmission and transfer case and has 65kWh distributed between the fuel tank area, the engine bay, and the space under the seats. I think that's about the max amount of batteries that can be packed out of sight in a Bronco or Scout-sized vehicle if you keep the transmission and transfer case. That should get you about 130 miles of range.


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## eg0n (Feb 3, 2021)

bronco_zed said:


> I agree with reider, the Netgain option has been used by a lot of companies like EV West and ElectricGT so there's already a lot of adapter options and application examples out there for reference.
> 
> Since the Scout and the Bronco are about the same size, I think it's relevant to mention the amount of real estate available for batteries. It's probably possible to fit 10 or even 14 Tesla modules in the Scout, but it will require a lot of fab work and Tetris-ing to pack them out of sight. But, if you are not worried about putting them in the bed then it gets a lot easier.
> 
> For reference, the Bronco kit sold by ElectricGT keeps the transmission and transfer case and has 65kWh distributed between the fuel tank area, the engine bay, and the space under the seats. I think that's about the max amount of batteries that can be packed out of sight in a Bronco or Scout-sized vehicle if you keep the transmission and transfer case. That should get you about 130 miles of range.


That's a useful data point, thanks. I'll have to read more on what has been done on similar vehicles. I'm fine with batteries taking up the entire bed to begin with, and I'd likely look at improving that over time. I'm currently feeling out if my friends who work at Tesla can get me any sweet deals on batteries 😇


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## brian_ (Feb 7, 2017)

eg0n said:


> So if I used the components from a Leaf I'd have to use the battery setup in pretty much its exact existing configuration if I wanted to use the Leaf BMS right?


If by "existing configuration" you mean 96 sets of cells in series, then likely yes. On the other hand, other than the length of wiring between BMS components and battery modules, the physical arrangement how the modules are stacked up and packaged) doesn't matter to the BMS.


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## eg0n (Feb 3, 2021)

brian_ said:


> If by "existing configuration" you mean 96 sets of cells in series, then likely yes. On the other hand, other than the length of wiring between BMS components and battery modules, the physical arrangement how the modules are stacked up and packaged) doesn't matter to the BMS.


Yeah, I meant if I wanted to use only part of the whole Leaf pack for whatever reason (or additional sets of cells if the other components could handle it) then I'd need a more flexible BMS. Is that correct?


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## eg0n (Feb 3, 2021)

Decided to go with a Scout 800. Rolled this bad boy off the truck this week. First order of business is to clean off all the 🐦  and get it running so I can at least drive it in the interim and don't just let it sit and rust while I faff about being indecisive about the project direction. Pretty good condition overall - most Scouts of this age are well-rusted.


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## Electric Land Cruiser (Dec 30, 2020)

Super excited for your project as it's similar to mine! My buddy has an original Scout SII! He's in the process of restoring it, it's not even completely rusted through! Looks like your truck is a pretty good starting point too! Cool matching hardtop.

Some ideas maybe or maybe you haven't thought of:

-Maintain the stock transfer case but ditch the transmission. It's possible you can find a "doubler" that matches your transfer case. Doublers are used to ultra-low gearing on 4x4 trucks with massive tires and basically "double" the reduction ratio into the transfer case. This is what you want in order to direct drive with the LEAF motor because you can ditch the transmission's dead weight and better utilize the transmission tunnel space possibly even fit the motor there and have an entire engine bay for batteries.

-Keep the stock transfer case so you can shift to Low Range and go offroading or pull trains or whatever sounds most fun to you.

-From my experience driving EVs I expect my 4x4 EV to get 2mi/kwh on a good day. That means to go 100 miles, it needs 50kwh of usable capacity. Something to think about. I plan to use a single LEAF battery to start, and then add more as I go because they are the cheapest option. I do not even know if multiple BMSs can be run independently like that but I think they can.

-Download the CAD file for the adapter plate and wait until the coupler adapter is available for purchase here: For Sale: em57 leaf motor couplers then just need to have a driveshaft shop build a custom shaft to match and build some motor mounts!


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## eg0n (Feb 3, 2021)

Keen to see your cruiser build too, all the rich kids parents had those when I was a teenager in Australia 😂



Electric Land Cruiser said:


> -Maintain the stock transfer case but ditch the transmission. It's possible you can find a "doubler" that matches your transfer case. Doublers are used to ultra-low gearing on 4x4 trucks with massive tires and basically "double" the reduction ratio into the transfer case. This is what you want in order to direct drive with the LEAF motor because you can ditch the transmission's dead weight and better utilize the transmission tunnel space possibly even fit the motor there and have an entire engine bay for batteries.


I thought about this but I talked myself out of it. I wasn't sure how to go about the gear reduction and didn't realize there were good options out there. How do I go about calculating what gear ratio I would need? Are there generic options that would do what I want? Would be amazing if I could fit the whole motor and gearbox assembly further back to make room for batteries. The only down side is I do like the idea of being able to slam on the clutch as a safety measure



Electric Land Cruiser said:


> -Keep the stock transfer case so you can shift to Low Range and go offroading or pull trains or whatever sounds most fun to you.


Yeah def keen to do this!



Electric Land Cruiser said:


> -From my experience driving EVs I expect my 4x4 EV to get 2mi/kwh on a good day. That means to go 100 miles, it needs 50kwh of usable capacity. Something to think about. I plan to use a single LEAF battery to start, and then add more as I go because they are the cheapest option. I do not even know if multiple BMSs can be run independently like that but I think they can.


Yeah I think if I decide on the Leaf part swap I'd just use whatever pack I got with the donor vehicle and explore other battery options later - maybe flip the whole leaf pack and BMS



Electric Land Cruiser said:


> -Download the CAD file for the adapter plate and wait until the coupler adapter is available for purchase here: For Sale: em57 leaf motor couplers then just need to have a driveshaft shop build a custom shaft to match and build some motor mounts!


THIS is what I've been looking for. So what exactly would I need to connect this coupler to the gearbox/doubler?


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## brian_ (Feb 7, 2017)

eg0n said:


> How do I go about calculating what gear ratio I would need?



From the tire outside diameter (or circumference, or rolling radius) and the highest road speed you ever want to be able to go, work out the axle speed (in RPM) at that road speed.
Multiply the axle speed by the axle ratio to get the propeller shaft (driveshaft) speed.
Divide the motor's maximum speed by that highest driveshaft speed.
Use that ratio or less (taller gearing) so that the motor never goes too fast; the higher ratio (shorter gearing) that you use, the more torque you have to the wheels at low speed, and the lower the speed where you start into getting full motor power available.
For example, with 235/75R15 (29x9.25R15) tires, 130 km/h (81 MPH) top speed, 4.27:1 axle ratio and 10,500 RPM Leaf motor...

speed divided by circumference is about 975 RPM at the wheel/axle
axle speed times 4.27 is about 4160 RPM for the driveshaft
max motor speed divided by driveshaft speed is about 2.5
... so you can use up to 2.5:1 reduction gearing.



eg0n said:


> The only down side is I do like the idea of being able to slam on the clutch as a safety measure


You can slam a big red STOP button to kill high voltage power for the same effect. You can even attach the switch to a clutch-style pedal if you like that.


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## Electric Land Cruiser (Dec 30, 2020)

eg0n said:


> Keen to see your cruiser build too, all the rich kids parents had those when I was a teenager in Australia 😂
> 
> I thought about this but I talked myself out of it. I wasn't sure how to go about the gear reduction and didn't realize there were good options out there. How do I go about calculating what gear ratio I would need? Are there generic options that would do what I want? Would be amazing if I could fit the whole motor and gearbox assembly further back to make room for batteries. The only down side is I do like the idea of being able to slam on the clutch as a safety measure


You can make it complicated or not complicated. The Nissan LEAF has a total ratio of 8.2:1. My Land Cruiser has a final drive of 4.1:1 so if I want to match the LEAF's top speed of 95MPH at 10,000RPM then it's just a simple 2:1 reduction (4.1 x 2 = 8.2:1). But since it's a heavy truck and 95MPH is way faster than I need I decided on a 2.7:1 reduction which gives me 2.7 x 4.1 = 11.07:1 and a top speed of 70MPH with stock size tires.

You can also just cross multiply using the LEAF's numbers:
95MPH/8.2 x 11.07 = 70 MPH

You'll likely be limited by what is available to bolt on to your truck but anything from 2.5:1 and 3:1 additional reduction should work for you. Also depends on your truck's differential ratios.

I do like the safety aspect of a clutch, with a transfer case you can simply shift to neutral, also. Not as natural or fast but just as effective.



> THIS is what I've been looking for. So what exactly would I need to connect this coupler to the gearbox/doubler?


You would need to have a custom driveshaft built. Also that coupler is only halfway made, it's designed to be drilled out to bolt on a specific drive coupling but instead of that my plan was to have a machine shop weld or bolt on a common sized driveshaft yoke.


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## brian_ (Feb 7, 2017)

Electric Land Cruiser said:


> You can make it complicated or not complicated. The Nissan LEAF has a total ratio of 8.2:1. My Land Cruiser has a final drive of 4.1:1 so if I want to match the LEAF's top speed of 95MPH at 10,000RPM then it's just a simple 2:1 reduction (4.1 x 2 = 8.2:1). But since it's a heavy truck and 95MPH is way faster than I need I decided on a 2.7:1 reduction which gives me 2.7 x 4.1 = 11.07:1 and a top speed of 70MPH with stock size tires.


That works, but by the time you've considered the target speed adjustment your calculation is just as complex as doing it from the fundamentals, and you still haven't accounted for any possible difference in tire size between the Leaf and the vehicle being converted.


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## eg0n (Feb 3, 2021)

Ah this is helpful, thanks folks. I appreciate the fundamentals because I'm pretty new to this aspect (I mean, and all aspects of how cars actually work). So, I need to get underneath and confirm exactly what I have on this truck but say the rear axle is a Dana 44 with a gear ratio of 3.71, and I'm using 235/75R15 tires with a 130km/hr top speed as in Brian's example:

Tire circumference is 2304mm, so 1 rotation is 2304mm.
Speed in m/min: 130 * 1000 / 60 = 2167m/min
RPM at the axle going 130km/hr: 2167 / 2.304 = 940RPM (this is slightly off from your example Brian, did I do this wrong?)

Driveshaft RPM: 940 * 3.71 = 3487

Maximum ratio: 10500 / 3487 = 3.0

So 3:1 gear reduction. Does that seem about right?



brian_ said:


> Use that ratio or less (taller gearing) so that the motor never goes too fast; the higher ratio (shorter gearing) that you use, the more torque you have to the wheels at low speed, and the lower the speed where you start into getting full motor power available.


Reading this it sounds like ideally I want to be as close to that maximum ratio as possible, without going over. Is that right?


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## eg0n (Feb 3, 2021)

Electric Land Cruiser said:


> You would need to have a custom driveshaft built. Also that coupler is only halfway made, it's designed to be drilled out to bolt on a specific drive coupling but instead of that my plan was to have a machine shop weld or bolt on a common sized driveshaft yoke.


Gotcha, so I'd need a custom driveshaft with this coupler bolted/welded to one side, that can bolt onto the input shaft of the doubler on the other side.


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## brian_ (Feb 7, 2017)

eg0n said:


> Tire circumference is 2304mm, so 1 rotation is 2304mm.
> Speed in m/min: 130 * 1000 / 60 = 2167m/min
> RPM at the axle going 130km/hr: 2167 / 2.304 = 940RPM (this is slightly off from your example Brian, did I do this wrong?)


Nothing wrong , the exact tire size depends on brand, and the tire squishes a bit under load so it effectively has a smaller diameter than it does without load so you get different numbers depending on specifically what is measured... the difference isn't important.



eg0n said:


> ...
> Maximum ratio: 10500 / 3487 = 3.0
> 
> So 3:1 gear reduction. Does that seem about right?


Yes, that seems reasonable.



eg0n said:


> Reading this it sounds like ideally I want to be as close to that maximum ratio as possible, without going over. Is that right?


Yes, for best performance.


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## eg0n (Feb 3, 2021)

What are the considerations for a minimum reduction ratio? Amount of torque available from the motor at the low RPM end?

I'm wondering if I could just skip the doubler and mate the motor directly with the Dana 20 t-case already in the Scout and run it in its 2:1 mode. Obviously wouldn't provide any higher reduction if I wanted to actually use it for crawling or anything, but that's not a primary goal. Thoughts?


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## brian_ (Feb 7, 2017)

eg0n said:


> What are the considerations for a minimum reduction ratio? Amount of torque available from the motor at the low RPM end?


Yes, torque to the wheels, which depends on gearing and motor torque. And that "low end" extends well up into the motor's possible speed range.



eg0n said:


> I'm wondering if I could just skip the doubler and mate the motor directly with the Dana 20 t-case already in the Scout and run it in its 2:1 mode. Obviously wouldn't provide any higher reduction if I wanted to actually use it for crawling or anything, but that's not a primary goal. Thoughts?


Yes, but then

you wouldn't have an even lower gearing option for crawling off-road (as you realize),
the input speed to the transfer case is limited,
low range in some transfer cases use straight-cut gears which are noisier than the helical-cut gears (or no gears, depending on design) used for high range, and
most transfer cases don't easily shift between ranges when moving a significant speed.
I haven't taken the time to review the Dana 20 design to see how many of these apply.


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## eg0n (Feb 3, 2021)

Thanks Brian, I'll explore those caveats.


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## brian_ (Feb 7, 2017)

I should have mentioned that most transfer cases do not allow the use of low range in 2WD, so unless it has a centre differential the low range would not be usable on pavement. In the case of the Dana 20, according to Novak:
"There is an interlock pin between the shifter rails. Removal of this interlock allows for the added function of 2wd/Low and front-wheel-drive High or Low to the 20 - if you have the "twin-stick" version (see below) of the 20."​If leaving the transfer permanently in low range, this could presumably be arranged even if you don't have the ideal version. If you defeat the interlocks, be careful, since it become possible to engage one output in high and the other in low at the same time, binding all of the shafts.

The Dana 20 (and 18) is an all-gear design, described in a Ford manual for the Dana 20 on a Bronco enthusiast site.
In the *high range*, power goes directly through from _input shaft_ to _rear output shaft_ (no transmission through gears), and via helical parallel gears including the _main drive gear_, an _idler shaft drive gear, and high speed gear _from _input shaft_ to _front output shaft_ - no chain, and only helical gears, so that's good.
In *low range*, power flows through the first pair of those helical gears (_main drive gear_ and _idler shaft drive gear_) to the intermediate ("idler") shaft, then by straight-cut gears (_idler shaft low-speed gear_ and the _sliding gears_) to rear and front output shafts - that's going to be noisy.

With any luck you can follow the power flow in this image from that manual, and the manual also includes a longer version of the power flow descriptions:









To get *2WD low range*, it appears that you would need to engage the _rear output sliding gear_ with the_ idler shaft low-speed gear_ (using one lever), but leave the _front output sliding gear_ in neutral (not back to engage with the _idler shaft low-speed gear_, and not forward to couple the _front output shaft_ to the _high-speed gear_). The sliding gears actually slide in and out of mesh with the _idler shaft low-speed gear_; there are no synchros anywhere, so this is not practical to shift on the fly... okay if you want to leave it in low range all of the time, but that will be loud on the highway due to the straight-cut gears.

I think the Dana 20 is a brilliant design, but it is not intended to be an auxiliary transmission to reduce the speed of a high-speed drive motor.

Other discussions in this forum have considered this sort of "leave it in low range" approach, and some discussions have included the Dana 20, but in a few minutes of searching I haven't found anyone who has gone ahead and left a Dana 20 in low range.


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## eg0n (Feb 3, 2021)

Thanks for the detailed analysis, Brian. Sounds like leaving the Dana 20 in low range isn't a great plan. It seems like the best path forward is either finding/building a 2.5-3:1ish doubler or just proceeding with the original plan of retaining the transmission and clutch. I've read a bit about building doublers from other transfer cases and I'll do some more investigation. I'm not sure it's worth the weight reduction if I have to spend multiple thousands on a special purpose doubler, but if there's the possibility of building something out of a common transfer case then it might be worthwhile.


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## eg0n (Feb 3, 2021)

Quick update: Got the 152 running well, done the shocks, brakes, shoes and put some Corbeau seats in. Decided to go the Leaf swap route. Coupler for the Leaf em57 motor is en route courtesy of user Bratitude, and I’m on the hunt for a salvage Leaf. Hopefully will have a breaking down the Leaf update soon!


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## eg0n (Feb 3, 2021)

Hey folks, I’d like to get some feedback on my current plan. As I mentioned above I’ve got my Scout up and running and I’m ready to buy a Leaf to cannibalize.

I’m planning to buy a whole salvage Nissan Leaf >2014, preferably with the Plus trim for the 62kWh battery. I’ll use the following components from the Leaf in my build: motor, inverter, battery pack, BMS, contactor/precharge circuit, PDM (slow and fast chargers, DC-DC), with an aftermarket controller.

After some discussion with the folks from Thunderstruck and Resolve-EV I think Resolve is the better option for the controller (though I’m open to input here). Their focus seems to be more on full vehicle swaps rather than just running the motor and inverter. They support comms managing the PDM, and say it should work with the gen3 battery pack with a little additional reverse engineering.

I’ve got a coupler on the way from user Bratitude. After chatting to them I think a clutchless design is going to be the way to go. My desire to retain the clutch was primarily to have a simple mechanical way to disengage the motor in an emergency (I work on software security for a living - I don’t trust software), but Bratitude pointed out that I can just pull the stick into neutral in that case. I’m not too concerned about shifting as I should be able to get close to top speed in 2nd (tho I need to do the accurate math on the gear ratios here), and it’s not expected to be a speed demon anyway. I’m sure I’ll figure out clutchless shifting. Bratitude also suggested an electrical cutoff on the PWM input to the motor controller (similar to Brian’s suggestion upthread). So I think between these I’m pretty satisfied with the non-software safety aspects with a clutchless design.

The motor and transmission will be joined directly by the coupler, with an aluminium adapter plate mating the transmission bellhousing to the motor (I'll likely buy one from user: Electric Land Cruiser over here once I figure out if that will have enough metal to mate with the bellhousing on the Scout's trans, otherwise I’ll have one fabbed).

The coupler has internal splines for the Leaf output shaft on one side, and blank metal on the other. My options are:

Find a machine shop that can mill internal splines matching the Scout’s transmission
Cut down a clutch disc and weld it onto the end (this seems super janky and tough to get right)
Find some other hub that matches the scout trans spline and attach it somehow?
For my initial proof-of-concept the whole Leaf battery pack will sit in the tray of the Scout, and I’ll figure out where they can go once I get everything going. I’d like to have a rear seat, so there’s a few options for batteries:

Under the hood
On top of the long, flat wheel wells that span the entire length of the tray
Behind the rear seat
Under the rear seat
Between 2, 3 and maybe 4 I can possibly fit the whole broken down pack without needing multiple BMSes. We’ll see when I get there.

Concerns, challenges and opens:

Best way to get the Scout trans connected to the coupler
Unknowns with using the 62kWh battery
If I get a gen3 Leaf, the Resolve folks haven't had much experience there yet so I might be doing a bit of reverse engineering of the BMS comms. I'm comfortable with that, but it's something that's going to add some time. From chatting with Isak I think I'll probably have some support getting it to work, and I'll gladly feed back information from my own reversing. Alternatively I can focus on getting a gen2 Leaf with low miles, but it’s somewhat dependent on what I can find.
I believe the Leaf inverter and PDM require liquid cooling
Any feedback? I’m particularly interested in any huge flaws in my reasoning, or big things I might have missed that I need to make a decision on before I commit to this plan, and definitely experienced input on the best way to approach the coupler situation -- bladesmithing experience has not prepared me for designing things involving real torque.

The next steps for me are:

Buy a leaf and strip it down
Decide on and buy a controller
Get the motor/inverter/batteries/basic charging running on the bench with the new controller
Pull the transmission out of the Scout (the point of no return [not really, but the Scout will sit in the carport until it's drivable from here, unless I buy another transmission or something])
Get the coupler machined to fit the Scout trans
Buy or get an adapter plate made
Get the motor and trans mated on the bench
Put it all together
Then it's phase 2: polish. Stashing batteries and figuring out whether I need another BMS, getting fast charging working, instrument panel, etc. At some point in there when it makes sense I'm probably gonna have the Scout painted (frame off), clean up and POR-15 the axles, etc. I'm loath to strip it all back down once it's built, but I also don't wanna get sidetracked with general restoration stuff and focus on the EV conversion. I also don't wanna have a nicely painted and restored Scout body that I then have to cut up to fit stuff into, so we'll see. There's some other stuff I wanna do like disc brake conversion, maybe improve the steering, etc. But that can probably come later. Anyway, lmk what you reckon! Thanks, as always for the collective wisdom!


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## cricketo (Oct 4, 2018)

I think one big line item should be figuring out how to accommodate the battery. 62kWh is not a joke, and this vehicle doesn't seem to offer a lot of room without having to break the thing down and rewire. Maybe do some CAD modelling first. You called it out as an "unknown", but it should be specifically itemized in terms of questions/problems to solve.


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## eg0n (Feb 3, 2021)

Good advice -- I'll do some more research and check the dimensions before I go with the 62kWh battery.


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## cricketo (Oct 4, 2018)

eg0n said:


> Good advice -- I'll do some more research and check the dimensions before I go with the 62kWh battery.


 Gen2 battery is significantly smaller, but I don't think it will get you to the desired range with the boxy aerodynamics of this vehicle. Leaf itself can barely make the range. Though of course I don't think you specifically stated at what speeds you're planning to commute for that distance.


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## eg0n (Feb 3, 2021)

cricketo said:


> Gen2 battery is significantly smaller, but I don't think it will get you to the desired range with the boxy aerodynamics of this vehicle. Leaf itself can barely make the range. Though of course I don't think you specifically stated at what speeds you're planning to commute for that distance.


Yeah I didn't really factor the increased pack size in. The 24kWh pack will (just) fit unmodified in the back, but I'll have to find some dimensions on the 62kWh one.


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## eg0n (Feb 3, 2021)

Re: the range, 55-65mph top speed but it's hilly so probably not gonna get that range. I can charge at both ends. Honestly I'm less concerned now about commuting in it - it'll probably be a fun local runabout in the end. I forgot how rough old trucks are 😂


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## eg0n (Feb 3, 2021)

Looks like the new packs are actually about the same size. Slightly taller, some lumps and bumps (e.g. BMS on top) and a lot less free space inside the case.


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## cricketo (Oct 4, 2018)

eg0n said:


> Looks like the new packs are actually about the same size. Slightly taller, some lumps and bumps (e.g. BMS on top) and a lot less free space inside the case.


The other thing is weight. I think Gen 2 was about 440lb, Gen 3 62kWh is 900lb.


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## eg0n (Feb 3, 2021)

Woof, yeah that's a bit of a difference


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## cricketo (Oct 4, 2018)

Not super crazy on absolute scale, but poor weight distribution may have side-effects.


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## brian_ (Feb 7, 2017)

cricketo said:


> Gen2 battery is significantly smaller...


What do you mean by "Gen2"? If you mean the 40 kWh packs... yes, like the 24 kWh and 30 kWh packs, they are smaller in physical volume and weight than the 62 kWh pack. The 24 kWh, 30 kWh, and 40 kWh packs and modules are all the same size and about the same weight.



eg0n said:


> Looks like the new packs are actually about the same size. Slightly taller, some lumps and bumps (e.g. BMS on top) and a lot less free space inside the case.


Yes, the 62 kWh pack is basically the same on top (fits against the same vehicle floor), but the case is deeper. The closer packaging and deeper case accommodate the almost 50% increase in module volume resulting from 50% more cells of essentially the same size.



cricketo said:


> The other thing is weight. I think Gen 2 was about 440lb, Gen 3 62kWh is 900lb.


There shouldn't be nearly that much difference. The 62 kWh pack has 50% more cells of essentially the same size and weight each. The current (40 kWh and 62 kWh) packs use essentially (or maybe exactly) the same cells, so 50% more of them means 50% more capacity. The weight increase should be less than 50%, because the 62 kWh pack's modules are more efficiently packaged (they don't have end covers for every eight cells).

For the purpose of minimizing weight for the same energy storage, modules from either the 40 kWh or 62 kWh packs should be used (because they have the same cells, each containing much more energy than the older cells).

This project used, and showed in detail, both the older (24 kWh, 30 kWh, 40 kWh) and newer (62 kWh) styles of modules:
*Toyota 4Runner 4x4 Race truck Leaf conversion*


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## cricketo (Oct 4, 2018)

I was comparing 24kWh to 62kWh weight wise.


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## brian_ (Feb 7, 2017)

cricketo said:


> I was comparing 24kWh to 62kWh weight wise.


The 24 kWh, 30 kWh, and 40 kWh should all weigh roughly the same, because they have the same cell volume of similar materials (about 914 g/cell). Apparently the cells of the 40 kWh pack are a bit thicker or denser, but packaging changes made the later modules slightly lighter than the cells would suggest; Marklines reports:
24 kWh pack: 225 kg (a bit more than 440 lb) {3.8 kg per module, as per GreenTecAuto}​40 kWh pack: 303 kg {8.7 kg per bonded pair of modules, or 4.35 kg each}​This is more difference between the 24 kWh and 40 kWh packs than I expected.
With the 40 kWh pack at 303 kg and 50% more of the same cells in lighter packaging, the 62 kWh should be less than 450 kg (less than 900 lb) - PushEVs estimated 410 kg.


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## cricketo (Oct 4, 2018)

brian_ said:


> With the 40 kWh pack at 303 kg and 50% more of the same cells in lighter packaging, the 62 kWh should be less than 450 kg (less than 900 lb) - PushEVs estimated 410 kg.


450kg is 1000lb, while 410kg is 904lb.

Also note that among the DIYers the "gen X" terminology refers to the battery module design. So like sardine cans is gen1, then the symmetrical design of the same capacity (newer) is gen2, and the final one is gen3. Not a reference to the vehicle itself.


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## brian_ (Feb 7, 2017)

cricketo said:


> Also note that among the DIYers the "gen X" terminology refers to the battery module design. So like sardine cans is gen1, then the symmetrical design of the same capacity (newer) is gen2, and the final one is gen3. Not a reference to the vehicle itself.


Or the single modules in cans are gen1, the doubles are gen2, and the 62 kWh type are gen3. And what would you call the 62 kWh, since they don't replace the 40 kWh? Since Nissan doesn't define the generations, the generation naming is unclear. Of course, if Nissan has authoritatively defined them somewhere, I'll happily follow and refer to that.


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## cricketo (Oct 4, 2018)

I think Nissan's definition is somewhat irrelevant for practical purposes when there is a secondary market for these with its own rules. Either way, not the most important data point for the OP. Difference in weight between smallest Leaf pack and largest pack is what I was trying to highlight.


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## robertwa (Dec 16, 2011)

Any updates on this build? Considering something similar on a Scout 80


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