# Planning an early Bronco conversion...



## brian_ (Feb 7, 2017)

*Gearing*



Tremelune said:


> *Gearing*
> In stock trim, with a 4.56 final drive and 3.41 first gear, the little six put ~2400 ftlb of torque to the axles. If you look, you can find a Dana 60 or Ford 9" with monstrous 7:1 gearing, but that's still about half the reduction I would need to do direct drive with a single electric motor. I think. I just multiplied torque by the various gear reductions.


Good start, but did you consider the road speed range that would give you? You can't rationally choose gearing without knowing something about what motor you are using, since they have different top speeds and speeds for maximum power output. Specific tire diameter matters too, of course. If you use even 7:1 gearing with a low-speed motor, your top speed will be limited. How much gear reduction you need depends on the motor.


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## brian_ (Feb 7, 2017)

*Batteries*



Tremelune said:


> *Batteries*
> It seems like, and correct me if I'm wrong, the bang-for-buck is to salvage a full pack from a crashed Nissan Leaf or Tesla Model S. How hard is it to take these packs apart and repurpose the individual packs? My napkin numbers:
> 
> Leaf pack - 24 kWh - $4k - 170 $/kWh
> ...


Back to the theme of evolving component choices... 

there are now other salvage options from other EVs (although original Leaf and Tesla Model S/X are the most common) including newer Leaf (40 kWh), and 
you can buy a complete new 60 kWh Chevrolet Bolt battery for less than the price of that used Tesla pack.

All batteries are composed of multiple modules, and modules can usually be reconfigured to change operating voltage. Whether or not this is an issue depends on your combination of battery choice and motor choice.


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## brian_ (Feb 7, 2017)

*Motor*



Tremelune said:


> *Motor*
> I've read that, in 2019, AC is just the way to go. Less compromises. With that in mind, the bang-for-buck that I'm seeing is the NetGain HyPer 9.
> 
> Tesla Model S - $12k - 325 ftlb
> ...


There is no point in comparing torque without considering speed. The production EV motor are intended for much higher voltage than the aftermarket motors, and can produce their torque at higher speeds (more power).

Any motors salvaged from a modern production EV will be used in the original EV with a transaxle containing single-ratio reduction gearing and a differential, and that transaxle is typically included in units for sale. It seems Tesla Model S/X motors always come with the transaxle, because the motor is not readily separated from it. It would be hard to use this sort of transaxle in the Bronco, because the reduction gearing is not in a separate case from the differential. One interesting setup uses the left and right axle outputs of the salvaged drive unit (motor plus transaxle) to drive the shafts to the Bronco's front and rear axles (instead of using the Bronco's transfer case), but the overall gear reduction ratio would be excessive.

Motors salvaged from a modern production EV are all AC, and are commonly available with the controller/inverter, which is often packaged closely with the motor. Aftermarket AC motors (such as the HyPer9 and AC50) may be sold in a package with a controller/inverter, but they are two separate components, usually separately priced.

If you really want a high-torque motor suited for use with only the ring-and-pinion gearsets in the Bronco's axles for reduction gearing, the Chevrolet Spark is an interesting choice: it is designed for use with less than 4:1 reduction (with Spark-sized tires).


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## brian_ (Feb 7, 2017)

Tremelune said:


> *What is the largest thing I'm missing*?


Another $15K


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## brian_ (Feb 7, 2017)

Tremelune said:


> It's likely that I'll begin restoring a 1966-1977 Ford Bronco this year...


Looking good! I assume that the restoration to come is mechanical, rather than body... or that's someone else's Bronco for illustration of the type of vehicle and target look.


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## akseminole (Jan 5, 2014)

Tremelune said:


> It's likely that I'll begin restoring a 1966-1977 Ford Bronco this year. It's increasingly likely that I'll try and put an electric motor in it. Talk me out of it.
> 
> I'm confident in my ability to take the truck apart to the frame and put it back together. I'm not confident in my ability to put a reliable electric drivetrain in it, nor do I know what I'm talking about with regard to components and the complexity involved in installing those components.
> 
> ...




Hello!

I had a 71 Bronco that I had been planning to convert (it ended up traded away for work on my house that has yet to happen.. we will see) to electric.

My plan involved changing the transmission out to an *NP435 4 speed because I planned to use an AC motor. The first gear on the tranny was a 6.68 and more importantly the Reverse gear is around 8.26. 
My reasoning here is that an AC motor can be electrically reversed, and the transmission put into reverse as an additional low forward gear. All of my napkin math put the change in low gears as a bump from 51-1 for 1st gear up to 65-1 by shifting in reverse/reverse (assuming stock Dana 20 low range and 4.10 gears). 

*http://www.novak-adapt.com/knowledge/transmissions/manual/np435

To accommodate the NP435 swap, there are conversion kits on https://www.wildhorses4x4.com/product/NP435_T18_to_dana20_Adapter/Bronco_Transmission_Adapters As an example, you can also get them from other Bronco parts retailers, this was just the first one that popped into my head.

To mount the motor to the transmission I would have attached a Small Block Ford Bellhousing to the NP435 and then procured a transmission adapter plate like this one: https://www.evwest.com/catalog/prod...ucts_id=140&osCsid=jblii9b6v2dghov4cb0i7vofn4

My plan for the Power Steering was heading towards something like this connected to the manual steering box:
https://www.evwest.com/catalog/prod...ucts_id=363&osCsid=jblii9b6v2dghov4cb0i7vofn4

I had been looking at the Marine liquid cooled version of the HPEVS dual motors as a potential motor, but now I would probably just go with the Netgain AC motor.

I would encourage you to checkout “Tipover’s” Electric Suzuki Samurai, as it is a very well done AC conversion in the same manner that you want to do. 
He used an HPEVS AC31 motor and Chevy Volt batteries to build a rig that he has taken up the Rubicon. I believe that it is on 33” tires now.

Hopefully, you can just search for his threads here. Also, you can look for his videos on YouTube. And he also has a thread on Pirate 4x4 if you are interested.


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## brian_ (Feb 7, 2017)

Another project which is relevant due to some configuration similarities (compact traditional 4X4):
LandRover lightweight EV conversion


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## Tremelune (Dec 8, 2009)

This is all very helpful.

Current plan is to attach a motor to a transmission and use the whole stock drivetrain. That way, my gearing choices are numerous without much hassle, and would allow for 4WD which is always nice to have in a small monster truck.

The HyPer9 motor (according to a janky image—it's hard to find real specs for this thing) makes peak torque until about 2500rpm after which it dwindles, and then begins a steep decline at about 3500rpm. This is right about the range of an old American truck engine, so I expect ratios would be well within range of what's possible with transmission swaps and aftermarket gears. It's a wild idea to repurpose reverse! That's nifty.

Is there a good resource for comparing OEM drivetrains? Assuming I just need to rig up motor mounts and shaft/bellhousing adapters, would it be better bang for buck to try and go with a salvaged motor...? I don't know my Leaf from my Bolt at this point. I fear some of them require hacking of controllers and emulation of ECUs and what not...I tend to prefer standard components, unless there is real gain in repurposing.

Unfortunately, that image is just a placeholder. I'm beginning my search for a good chassis presently, and it will be uglier.

Out of curiosity, where would the other $15k that I'm not accounting for be spent?

That Samurai is a sweet install:

https://www.pirate4x4.com/forum/general-4x4-discussion/2195009-zookev-electric-suzuki-samurai.html

https://www.diyelectriccar.com/forums/showthread.php/zookev-156817.html

One thing he did that I might was to use cheap lead-acid batteries until he got the thing sorted (after which he went with a Volt battery). That said, it may not be worth trying to procure and then sell a bunch of cheap batteries, so maybe I'll just buy them last...

Time to read through that LandRover three...I wish more pics had survived.


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## akseminole (Jan 5, 2014)

Unless you go with a drivetrain that has already been reverse engineered for DIY conversion, you have a huge uphill battle in repurposing the OEM motors and VFD’s.
Even if you use one of the”kit” DIY AC motor controllers to spin the motor, there is still a lot more technical detail work that you need to do to get them running.

Unless things have changed in the year or so that I have been mostly inactive here, the DIY AC controllers were really more of a hobby for electrical engineers with lots of spare time.

You could probably **Buy a commercial Variable Frequency Drive from EV West that will spin an OEM AC motor, but they tend to run around the same price for just the VFD as just buying an HPEVS or Netgain Hyper 9 would cost you.
Then, you still have to figure out how to attach the OEM motor to the transmission.

I “feel” that your time would be more productively spent not reinventing the wheel.

The Hyper 9 and the HPEVS motors have both been engineered around the constraints of the Warp 9 motor for which there is a plethora of transmission attachment plates left over from earlier conversions (I mean in stock at EV conversion supply stores online) which makes the motor attachment phase a bolt on affair. 

This still leaves the motor mounts to the frame to fabricate, but comparatively, that can be a rougher product and still work, whereas adapting the motor to the transmission requires finer tolerances because of the high torque and balance issues. When you are spinning your drivetrain up to 2,500 RPM at 170 ft lbs, you don’t want a micro wobble in between your motor and your transmission while you are driving up a stack of rocks... in my opinion.

I am simply putting forth my own reasons for the design choices that I made, if you are an electrical engineer or rich or both, don’t let me dissuade you from living your life how you want to. 

** https://www.evwest.com/catalog/prod...ucts_id=293&osCsid=1av0k53mlsleqatlp5bm1io986

https://www.evwest.com/catalog/prod...ucts_id=262&osCsid=1av0k53mlsleqatlp5bm1io986

These are simply examples of commercial VFD’s available, I don’t know whether they would run an OEM motor.


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## palmer_md (Jul 22, 2011)

I would look at using the Netgain AC motor package and then put this 2:1 converter behind it connected to the transfer case.


https://www.torquetrends.com/


This should allow you to keep all the stock drivetrain and have a nice AC motor package to drive it that does not break the bank like a Tesla motor solution.


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## Tremelune (Dec 8, 2009)

I'm not looking to build the cheapest EV I can, but I'm also not looking for a high performance monster. I'm trying to ride the wave of bang-for-buck while taking into account my skills (mechanical, electrical, software) and weaknesses (fabrication...specific knowledge of electric automotive drivetrains). I plan for this to be a daily driver in a traffic-ridden city, with occasional overland use for fun.

I'm still at least months out, as I plan to restore as I convert. I migth try to get it going fully electric to make sure I can actually do it, then take everything apart, but I'm not confident I'll _want_ to take anything apart once I have a running machine, so it'll probably be a while before _any_ motor gets back into the truck while I clean things up. I mostly just want to make sure my conversion plans are realistic in terms of cost and effort. I enjoy the research.

I bring up OEM cars, 'cause you can buy entire Leafs for $6-8k. If the fabrication and hacking needs are onerous, it may wind up being more expensive in time and effort. That's what I'd like to figure out. I'm very much down for the well-trod territory. I definitely can't mate a random motor to some or other transmission, but I can certainly buy a kit and bolt things up...

It's smelling like the HyPer 9 is good motor based on price/spec, and going with a 9" or 11" cylindrical motor is well-trod territory. I guess I gotta research what's really involved in getting controllers to work well with an unknown vehicle...

That Torque Trends reduction box looks sweet. Looks like it would be great for a direct-drive application with a custom driveshaft to the rear. At $3k, though, it would be a hard sell vs the several cheap 3-5sp transmissions I could bolt up, and it doesn't seem like it'd be easy to mount to the input side of the transfer case.

Can anyone point me towards a resource for understanding torque, horsepower, and efficiency at various RPM as it relates to electric motors? I understand the difference between torque and power, but I'm uncertain about the "preference" of an electric motor. I always though it was best to run a motor in the "meat" of the torque, but I'm reading that electric motors are more efficient at higher RPM despite having less torque there. How do you know what motor speed to target vs vehicle speed? What are the tradeoffs for higher and lower?


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## Tremelune (Dec 8, 2009)

On a whim, I charted what some of these gears would look like with my janky gearing calculator, Gear Wars (and some Photoshopping):










Red is a typical Jeep/Bronco 5spd with a 4.11 final drive. The blue is direct-drive with a 2:1 torque reduction box. Green is direct-drive. The blue and green cover a "range" of a final drives from 3.00 to 6.50, all of which are readily available for a Ford 9" diff.

Targeting a 3300 rpm max continuous motor speed (which is what I've read the continuous maximum of the HyPer 9 is), it seems like there might be too much compromise. With a top speed of 60-75mph, I suspect 0-40 acceleration would be quite sluggish. A 50mph top speed might work, but it makes highway driving dicey.

It would be nice to lose the weight/complexity of the transmission, transfer case, and front gears, but it would be a bummer to have a car that was both sluggish off the line and low on top speed...all while losing 4WD.

Reduction box is $3-4k plus custom driveshaft. Tranny adapter is $1k.


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## brian_ (Feb 7, 2017)

Tremelune said:


> Reduction box is $3-4k plus custom driveshaft.


Yes, specialty items like the ev-TorqueBox are expensive. That's why the ideal is to buy used, and so let someone else take the hit of buying new and selling at a big loss when they change their mind; for instance, John has a nice motor with an ev-TorqueBox for you:
Huge 1/2 off sale must go; brand new Siemens motor bolted to brand new gear box.

If you are really lucky, the motor and gearbox would fit into the transmission tunnel, leaving underhood space for battery modules, but don't bet on that without detailed measurements.



Tremelune said:


> Out of curiosity, where would the other $15k that I'm not accounting for be spent?


On stuff like an extra multi-thousand-dollar gearbox. 

But seriously, projects just almost always cost more (and take longer) than anticipated, and so the crack about doubling the budget.


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## brian_ (Feb 7, 2017)

Tremelune said:


> On a whim, I charted what some of these gears would look like with my janky gearing calculator, Gear Wars (and some Photoshopping)...


Was "Gear Wars" supposed to be a link? There's no target web address.

The chart is good... now, I suggest leaving off the right-hand half for readability (are you really going to go 80 mph in an EV-converted early Bronco?), extending the transmission gear lines up (to consider what you could do with a higher-speed motor), and maybe marking it up for specific cases (of motor and gearing) to be considered.



Tremelune said:


> Targeting a 3300 rpm max continuous motor speed (which is what I've read the continuous maximum of the HyPer 9 is), it seems like there might be too much compromise. With a top speed of 60-75mph, I suspect 0-40 acceleration would be quite sluggish. A 50mph top speed might work, but it makes highway driving dicey.


Here we see why production EVs don't use <4000 rpm motors. The Chevrolet Spark EV was an oddball exception, running a large 105 kW and 443 Nm (327 lb-ft) motor with tall gearing (overall 3.17:1 initially, 3.87:1 later), but GM didn't continue that approach with the Bolt.

By the way, when I checked the Spark EV motor power Google showed me an ad, which says that the whole Spark EV motor is available for CAD $2849, new! Hilarious, given that there were nearly zero Spark EVs sold in Canada.



Tremelune said:


> It would be nice to lose the weight/complexity of the transmission, transfer case, and front gears, but it would be a bummer to have a car that was both sluggish off the line and low on top speed...all while losing 4WD.


Ah, the importance of understanding what characteristics are important...


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## Tremelune (Dec 8, 2009)

An $8k controller for a $3k motor. That's pretty wild. What does that get me beyond the $4300 HyPer 9 IS setup...? Seems slightly more powerful, with higher max rpm, but I'm not sure I understand where the spend is going.

I'm also not sure I'm ready to start sourcing EV components...but used does seem like the way to go. It's nice that you can get a lot off from retail, but a rather frightening return from resale...

Edit: Whoops...Gear Wars link fixed.


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## brian_ (Feb 7, 2017)

Tremelune said:


> That Torque Trends reduction box looks sweet. Looks like it would be great for a direct-drive application with a custom driveshaft to the rear.


Exactly what it's for, but the "direct drive" terminology makes no sense to me, with a transmission and final drive unit (with a reduction gear and differential) between the motor and axle shafts - there's nothing "direct" about that, it's just single-speed. 



Tremelune said:


> ... it doesn't seem like it'd be easy to mount to the input side of the transfer case.


No, it wouldn't, because it's not designed for that. It would be a good match with a divorced transfer case; there are lots of those, but they are much less common than "married" (attached to the transmission) transfer cases. You can even get kits to convert a common transfer case to divorced.

This does raise an issue with any configuration not using the original transmission (or similar), but keeping the transfer case: some custom-built shaft coupler and housing adapter would be needed to mate any motor output to the transfer case input. It's like the situation at the input to the transmission, but with no ready-made components available.


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## brian_ (Feb 7, 2017)

Tremelune said:


> What does that get me beyond the $4300 HyPer 9 IS setup...? Seems slightly more powerful, with higher max rpm, but I'm not sure I understand where the spend is going.


A fair question...
The rated power isn't much different between the HyPer9 and a typical modern EV motor (Spark, Leaf, VW, whatever). The difference is that with it's low operating voltage, the HyPer9 can only produce that power over a narrow range - say 3300 to 6000 rpm - while the production high-voltage setups do that over a broad range (2700 through 9700 rpm for a Leaf). That means that if you have a single-speed transmission, the production motor will out-perform the HyPer9 at most speeds.








(production EV motors such as the Leaf in their stock configuration with 360 V battery and suitable inverter have constant (current-limited) torque output up to a transition speed, just like the HyPer9, but then maintain constant power to nearly their rev limit, instead of starting to drop off only a couple thousand RPM later)


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## brian_ (Feb 7, 2017)

Tremelune said:


> Targeting a 3300 rpm max continuous motor speed (which is what I've read the continuous maximum of the HyPer 9 is)....


I'm puzzled by this. 3300 rpm is just where the HyPer9 reaches its maximum power region. If you gear the vehicle to never run the motor past this speed, you'll literally never get full power from it, and you'll typically have a small fraction of that available.

Why wouldn't you gear for 6000 rpm at the highest desired cruising speed, with the HyPer9? Production EVs are geared for nearly max motor rpm at max allowed speed.


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## Tremelune (Dec 8, 2009)

Interesting. Are there no aftermarket motors that take high voltage and therefore have a broader operating range, or am I just unaware of them (or are they crazy expensive)?

With battery costs dropping every time an EV crashes, seems like higher voltage battery packs will become more and more accessible...

My motor research is limited to like, what EV West publishes on some sale page...It's hard to find specs on this stuff, and I'm already pretty ignorant with regard to the numbers (and terminology, as you've noticed).

Coupling the motor to the rear diff via a reduction box and driveshaft is about as simple as it gets for driving and installation, but I wonder what happens to the cost in motor, batteries, and controllers to run in this configuration with ample acceleration and sustainable highway speeds...


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## Tremelune (Dec 8, 2009)

brian_ said:


> Why wouldn't you gear for 6000 rpm at the highest desired cruising speed, with the HyPer9?


Probably due to my own ignorance. _Can_ this thing be run at high RPM continuously? I see things like "peak" and I assume it can only be run like that for a brief period before heat becomes a concern or some such. Why not aim for the 8k redline instead of 6k?


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## The_Sasquatch (Feb 11, 2018)

This might be helpful to you: 

https://docs.google.com/spreadsheets/d/1lgac0BTILxhe5TTeFWuyruK1MQ2VCn7Nz7HlObfrBOk/edit?usp=sharing

It is a spreadsheet I made for estimating vehicle performance based on an input motor performance curve, vehicle weight, some basic aerodynamic drag estimations, etc. I haven't proven it out yet with an EV but I haven't found any mathematical errors yet...

It is currently set up for my 85 Ramcharger, which is a little bigger than your bronco. You can probably just change the vehicle weight and leave the aerodynamic parameters the same except for the frontal area... both vehicles are pretty much flat faced boxes. 

You can replace the motor curve (see tab labeled "Motor Curve" by copying datapoints off of the charts EV West or other suppliers publish.


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## brian_ (Feb 7, 2017)

Tremelune said:


> Are there no aftermarket motors that take high voltage and therefore have a broader operating range, or am I just unaware of them (or are they crazy expensive)?


Crazy expensive. Borg-Warner (formerly Remy) HVH, YASA, etc are all available for roughly 400 V (and higher) applications, and in each case a single barely-adequate-to-run-a-car motor costs about as much as the entire conversion budget for many projects in this forum. Small-scale motor producers have high unit cost due to their low production, and mass producers can't reasonably sell to individuals so their products go through multiple high-markup intermediaries, if you can get them at all.



Tremelune said:


> My motor research is limited to like, what EV West publishes on some sale page...It's hard to find specs on this stuff, and I'm already pretty ignorant with regard to the numbers (and terminology, as you've noticed).


EV West has a strange selection, apparently consisting of what they can find in salvage, or make a deal for in some sort of oddball new purchase. They make things available that DIYers couldn't otherwise get, which is good, but after all the middlemen between the manufacturer and the end customer the price can be shocking.


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## brian_ (Feb 7, 2017)

Tremelune said:


> _Can_ this thing be run at high RPM continuously? I see things like "peak" and I assume it can only be run like that for a brief period before heat becomes a concern or some such.


An electric motor is mechanically simple and can spin fast with minimal consequence... unless of course it's a brushed DC motor. It's still more efficient to run at an optimal speed, but in production EVs essentially all manufacturers have decided that the efficiency improvement of keeping the motor speed lower when cruising at steady high speed is not worth the cost, weight, and complication of a multiple-ratio transmission. This is in contrast to the trend for an ever-increasing number of ratios in transmissions for use with engines (currently at 10 ratios for the leading edge).

Heat would be a concern at high power (or current), not so much high speed.



Tremelune said:


> Why not aim for the 8k redline instead of 6k?


Because there won't be enough power at 8,000 rpm to make the car go at the corresponding road speed. You may not have noticed this, but most production cars (with gasoline engines) do not reach their highest speed in their top gear - they need to be in a lower gear to make enough power; the top gear exists for better economy, less engine wear, and quieter operation than spinning the engine continuously at high speed.


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## Tremelune (Dec 8, 2009)

I've been toying with the Leaf motor and reducer approach...It seems someone has made an adapter to the Warp 9 bolt pattern, which then could bolt to the CanEV adapter, which would bolt to the Ford Ranger bellhousing, which would bolt to the Bronco transmission...

Decent torque, high RPM. $500-1000 for the motor, $500-1000 for each adapter...and then figuring out about the shaft and software...I'd love to see more charts and specs for this motor (like a torque/efficiency chart), but I'm finding conflicting data.

This would require more research, I think, but it might really be good bang-for-buck for a car that tops out at 60mph and has many gearing possibilities...


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## brian_ (Feb 7, 2017)

Going back to the HyPer 9 for a moment...
A solution to the power dropping off at about 6,000 rpm might be the higher voltage version, the HyPer 9HV
... although NetGain's goofy testing methods make any of their data suspect.


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## brian_ (Feb 7, 2017)

Tremelune said:


> I've been toying with the Leaf motor and reducer approach...
> ...I'd love to see more charts and specs for this motor (like a torque/efficiency chart), but I'm finding conflicting data.


Really? This - for the pre-2018 Leaf - is probably the most widely and consistently published motor/controller system output and efficiency chart in existence. Torque is constant (limited by current, which in turn is limited by the controller programming) until the output climbs to 80 kW, then power output is constant to nearly the top speed. The efficiency is shown by colour coding, so look for any of the graphs with the colours:
Google image search for "Nissan Leaf torque efficiency curve"

The inconsistency would be in what people say the motor can do if the controller programming is changed. Until the 2018 model, the current and power were limited to these levels to protect the battery (and they're still limited, but at a higher power level); the motor can do more, but its efficiency would be the same for the conditions within what is currently allowed.


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## natalizumab (Jul 9, 2019)

coupla thoughts (subjective & anecdotal) 

I'm not familiar with the hyper-9, but the ac-51 is a little higher torque that the ac-50. It propels my cj-5 much more quickly (with stock gears/trans/axles/transfer case) than the original 258 I6. (I do not have oversize tires) The power curve "feels" pretty flat from dead stop up to 7500 rpm. The stock trans is only 3 speed, so that is the most limiting factor for top speed. Although 45-50 feels plenty fast in a 70's cj. Your vehicle will be heavier however.

I would definitely agree with the "extra 15k" comment, for sure 5-10k, plus things you may want to add along the way- along with a good coupler/adapter plate, there are myriad contactors, relays, wiring, instruments... it doesn't seem like much individually but it will add into thousands before you know it. (not saying this at all to dissuade you) Especially if you are rebuilding an old vehicle as you go, which I did. Just rebuilding axles & brakes and such was a huge task and expensive. Of course, afterwards you'll have a better vehicle then when it was originally built. 
I would say that the itemized list was close to 2x what I had estimated initially just looking at the motor/controller and batteries.

I understand the idea of going partial pack etc, with the intent to rebuild later. I had the same thoughts, still do. But after all the time and hassle, by the time you are done, it may be better to save up and get what you will want to drive. The motor/controller/gears/range etc all fit together as a package, and it may be harder to patch in more later on, than it might appear initially. Like for me, I would like to go to a tesla pack later, but that may mean an entire rebuild for the following: will my motor take the add'l power? very likely my controller will not. then, the drive train connections, the custom & labor intensive battery boxes & motor mounts, the instrumentation, the controls, the weight balance ratio (suspension)... etc etc. The more I think about it, the less likely it seems unless I can just get a partial leaf/tesla pack at the voltage/amp size I need, the main benefit being weight reduction, maybe a slight increase in voltage.

If you start working on the vehicle body & mechanics, the used production stuff will just continue to come down in price. It's amazing the options now from when I started a couple of years ago.

I hope you (slowly) go forward with your project!


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## natalizumab (Jul 9, 2019)

I take back the part about upgrading later- just read the post about the suzuki going from lead acid to volt batteries...


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## brian_ (Feb 7, 2017)

natalizumab said:


> I understand the idea of going partial pack etc, with the intent to rebuild later. I had the same thoughts, still do. But after all the time and hassle, by the time you are done, it may be better to save up and get what you will want to drive. The motor/controller/gears/range etc all fit together as a package, and it may be harder to patch in more later on, than it might appear initially. Like for me, I would like to go to a tesla pack later, but that may mean an entire rebuild for the following: will my motor take the add'l power? very likely my controller will not. then, the drive train connections, the custom & labor intensive battery boxes & motor mounts, the instrumentation, the controls, the weight balance ratio (suspension)... etc etc. The more I think about it, the less likely it seems unless I can just get a partial leaf/tesla pack at the voltage/amp size I need, the main benefit being weight reduction, maybe a slight increase in voltage.


I think this is a good point. If anyone plans to upgrade the battery pack later, they should plan all of the other components to handle the voltage and current of the eventual pack, not just the initial pack.



natalizumab said:


> coupla thoughts (subjective & anecdotal)
> 
> I'm not familiar with the hyper-9, but the ac-51 is a little higher torque that the ac-50. It propels my cj-5 much more quickly (with stock gears/trans/axles/transfer case) than the original 258 I6. (I do not have oversize tires) The power curve "feels" pretty flat from dead stop up to 7500 rpm.


I appreciate that this is a subjective observation, but it is quite far from true that the power curve is flat. From minimal speed to the transition point, torque is limited to a constant value by current, and torque is what the driver feels. The transition point depends on voltage; it is about 2500 RPM in the HPEVS published data for 96 volts, and about 5000 RPM for 144 volts. Above that transition, modern high-voltage EV drive systems do have approximately constant power (so torque drops off in proportion to speed), again due to protective controller programming, but the HPEVS systems don't have the voltage to sustain power at high speed, so the power drops off and the torque drops off sharply. This is apparent in the performance curves published by HPEVS.

The NetGain HyPer9 (which NetGain just buys and re-brands) is a permanent magnet synchronous motor (rather than induction as with the AC- series), but it is designed for a similar voltage range (to fit easily into the same applications as NetGain's old brushed motors), so performance is not much different from the HPEVS motors.


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