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Discussion Starter · #1 · (Edited)
Hello all,

I'm a new member, but have been lurking for a few months and have read countless threads. I'm in the process of starting my first conversion and need some input from those with more background than I.

Quick background: I'm an engineer by school and trade and a machinist by hobby. I have a small machine shop in my garage and have friends with just about everything under the sun. I live in a hilly area and want to use the car for a 3 season daily driver.

The conversion:
Car: 1976 Triumph Spitfire 1500 (running!) with 3.89:1 final drive
Motor: AC PM Netgain Hyper9 w/ AC-X1 SME controller from EV West (planned)
Batteries: ~12kwh, ~100v Gen 1 Leaf Modules (planned)
BMS: Orion BMS (very open to others)
Charge: Open to suggestions
Timeline: Driveable by 4/19, drive all summer, rebuild/modify/change/restore next winter.

Questions:
Drivetrain: My biggest question right now is whether or not to use the stock tranny. I really like the idea of direct drive and the advertised Hyper9 specs seem to suggest it would work (as well as several threads on here). Is this reasonable or should just run the stock tranny for the near future? For those that have done direct drive with the Hyper9, how is performance?

BMS: I'm leaning towards the Orion series simply because of proliferation and support. Is there something better out there for a 1st build? I'm pretty comfortable with most aspects of the conversion, but BMS is voodoo.

Batteries: The leaf cells seem very popular and there are good datasheets available online, but I'm still not clear on what sort of discharge I can expect. I'm thinking I'll limit my peak current draw to ~500-600A (for multiple reasons). Can a 4P28S (since they're 2P2S modules) handle 600A peak and ~200A cont.? I've considered building an 18650 pack, but the cost would be more than double.

I think that's enough to get started. Any and all feedback is GREATLY appreciated!

Kilomike
 

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Discussion Starter · #3 ·
From what I've read, I expect that the Hyper9 will fit about 9in back into the transmission tunnel. I haven't removed the old engine/tranny yet, so I can't say for sure. That said, I could easily modify the transmission tunnel if it was worth it.

And I figured as much on the Hyper9 builds. I've seen that several are using them, but I haven't been able to find any actual numbers outside of some calculations.

Thanks for the quick response! Any suggestions on BMS or what I should be looking for?
 

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Discussion Starter · #6 ·
I've seen several of them, but I haven't been through the garage (it not working explains why I haven't found it!). I've read through Molten's thread twice as well several others that showed up when I searched "triumph" or "spitfire".

I've also looked on EVAlbum.com where there are ~12 spitfires. The common trend I've seen is LiFePO4 "brick" batteries and DC motors. I think this is mostly because they were done before AC was common and Lithium was put in production vehicles, but I could be missing something.

Am I correct in thinking that AC is a better option today? Regen seems like a no-brainer and there's a reason all of the big OEMs use them in the production vehicles.

I'm relatively new to all of this, so please correct me if I say anything dumb!
 

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Discussion Starter · #11 ·
Brian, Thank you so much for the guide to other spitfires! I'm very interested in Bottomfeeder's Sparkfire. It looks like the only one that's known to have went direct drive. I just found the thread and hope to get through it tonight.

Thanks again for all of the guidance! Any other nuggets of insight?
 

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Discussion Starter · #13 ·
Thanks for the link to the thread! I probably would have never found that!

As for you comments on the spitfire in general, I completely agree and I think you hit the nail on head about some of my concerns. I chose the spit because of the styling and availability. I paid $2500 for a running spitfire with a clean body. I worry about the rear suspension, but at the same time my only intent is to use this to turn heads and drive the 12 miles each way to work. I'm not looking for crazy performance and I don't ever plan to run autocross with it. I just want it to be fun to scoot around town in. This also lets me get away with an approx 10kwh pack, which at ~250wh/mi, should give me a 30-40mi range.

Going with the Hyper 9, I do worry about blowing up the final drive/tranny. I'm almost certain it would destroy the tranny if I let it loose. That's another reason why I'm leaning toward going straight to direct drive. It looks like the final drive should be able to handle the 1:1 ratio torque (173ft-lb advertised peak vs your stated 287ft-lb stock load). Using the tranny may actually be bad in that regard as it would also allow over-stressing of the final drive in lower gears.

I did some more looking at the Hyper 9 specs and I think direct drive should work nicely. I sacrifice a little efficiency at low speed (<~20mph) but that seems to be the only significant detriment.

Hyper 9 curves: http://www.go-ev.com/PDFs/HyPer_9_120V_Performance.pdf
 

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Discussion Starter · #16 ·
Brian,

I plan to keep the stock tires, so it sounds like I shouldn't have too much to worry about with the final drive/rear suspension for the near future. I've been concerned about needing to do a complete rear-suspension replacement, but it sounds like I should be ok. If not then I'll cross that bridge when I get to it. I plan to limit the peak current to somewhere in the 500-600A range, so I think my concerns about the final drive are mostly settled.

As for the RPM range, that was the only reason why I even consider keeping the tranny. I figured I would only use 2nd and 4th or just leave it in 3rd. Realistically, in direct drive I'll probably not get past 4000rpm, which is really under-utilizing the Hyper 9 (and AC in general) capability.

Losing the lower gears means losing the resulting torque multiplication and the ability to keep the motor in a more efficient speed range... which as you say only matters significantly at lower speeds.
This has been my main concern, but looking again at the advertised curves for the motor, once I get to ~20mph I should be up around 87% efficient. I think that's good enough.

I've considered the HV Hyper 9 as well, but I haven't really seen the benefit. since I only want an ~10kwh pack, and the leaf modules are ~60Ah 7.4V each so a 2P14S pack of modules will give me ~104V and 120Ah (~12kwh). I can go higher voltage, but it really just gives me a bigger pack that I don't necessarily need. I am probably going to up to ~120V though just because the only real cost difference to do so is the bare modules.

Real quick on the battery. This is where most my research has focused and it seems like the Leaf modules are both the easiest and most cost effective to work with. I can buy the bare modules for ~$150/kwh which seems to blow everything else out of the water, but I am worried about their peak draw capability. I heavily considered building a custom 18650 pack, but not wanting to use salvage cells puts just the cell cost north of $3k for a barely 10kwh pack. And that doesn't even consider the HUNDREDS of hours to actually build the pack! I haven't looked hard at other production EV packs, but from what I've seen the leaf modules are about the easiest to get and work with.

Lastly, back on trying to match RPM to gearing, I have considered building a custom fixed ratio tail for the motor. Something like 1.25:1 which would let me use a lot more of the Hyper 9 capability. That said, it doesn't do me a ton of benefit at low speed, so I don't think it's worth it. And I have no idea yet what it would cost, just in materials, for me to build such a tail. I've looked at the ev Torque-Box but I think it is both too big and too expensive for this project. Total EV conversion cost I expect to be $8-10k. An additional $3500 just doesn't seem worth it or necessary.

Duncan,

Using a DC forklift motor is actually where I originally started on this project. I was inspired by the super cheap conversions on youtube. But I haven't had much luck finding a usable motor. Local craigslist and such are an empty desert. Ebay has some, but anything under $1k doesn't have any information with it and I'm pretty gun-shy being a first timer. Things like advancing timing and inspecting the coils for over-volting/current capability is just a little out of my wheelhouse. I considered using a Warp 9, but at $2k+ (not counting controller) we're back up in the price range of the Hyper 9 IS package (~$4150 including controller). Plus, I like having regen capability, reverse on a switch (with no extra hardware), and less maintenance than DC. And I can't discount the benefit of having a company I can call if I have to for technical support.

I'm open to going back to DC, but I simply haven't seen enough cost benefit to outweigh what AC offers. And the Hyper 9 seems to just be the best AC package on the market at the moment.
 

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Discussion Starter · #19 ·
Brian,

What you state is all that I've been able to find as well. At best I've been able to dig up a stall torque. Nothing about max RPM, efficiency, etc.

Duncan,

How much of an issue is advancing timing and brush maintenance? What other concerns are there with going DC? Saving ~$2k is definitely enticing. It does seem that they are somewhat less efficient than SRIPM AC (~80-85% compared to ~94%). I'm open to the idea, but I'm gun-shy to minimal data and not having the technical background with them.

Where do you find the motors at that price?

Another reason why I've leaned toward the Hyper 9 is it is IP67 rated according to EVWest's page. But now that I look at literature on go-ev.com I'm not seeing any such claim. The only thing I've found is IP54 (limited dust intrusion). If it is in-fact IP67 then that will help a ton, because I am certainly concerned about moisture under the vehicle. It rains almost every day here from late June through late August. The more I look, the more I find wrong on EVWest's page for the Hyper 9. The motor curves they show do not match anything that I've found in other literature.

Kevin (Kilomike)
 

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Discussion Starter · #23 ·
The motor performance graph shown by EVWest appears to be from Netgain, but is for 64.5 volts RMS at the motor or 96 V DC supply, which doesn't match the EVWest package description (of 120 V); it doesn't even look quite like the 96 V grapsh published on Netgain's website. The shape suggests to me that it might be for the HV motor, but it's not labelled that way and Netgain only publishes 120 V and higher for the HV. SME does not publish details for the specific motor which they supply to Netgain.
This is exactly what I'm referring to. I'm not sure where the graph came from, but it makes it seem like high efficiency isn't achieved until almost 3000RPM, whereas all other charts show it around 1200RPM. I can work with low efficiency up to 20mph, but no up to 50mph!

I really appreciate the input! Now I'm itching to get started on the car, but I've got to finish renovating the garage first!

I did just think of one other question on going direct drive. Will I need to allow for axial play between the motor and final drive? If I understand correctly, the TransWarp 9 has a slip-yoke spline for the U-Joint output to allow for some axial play. Will I need to devise something like this? I was hoping to just mount one of these below on the motor shaft and just hook directly to a custom length drive shaft. Allowing axial play will definitely be a challenge, but should be doable if needed. I'm just not sure if it's actually needed!

http://www.evwest.com/catalog/product_info.php?cPath=44&products_id=428
 

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Discussion Starter · #24 ·
Brian,

I totally missed your second post! That's the first curve set I've seen for a DC motor. And yes, the range I really care about (<1000RPM) is completely skipped. That seems like a very important region to neglect, even for mounting up to a tranny.

Matt,

Welcome to the thread! I'll do some looking and make some phone calls this week and let you guys know what I find. I still prefer to go Hyper 9 from a technical point of view, but that much potential savings is hard to pass up...

I usually take the approach of using whatever is cutting-edge technology and somewhat reasonable price wise. Part of my desire for Hyper 9 is somewhat ego driven. Being able to quote high efficiency and point at leading technology is a big plus to me. That said, pointing at an old forklift motor and a homemade controller has it's own ego boost as well. OH THE DECISIONS!!! I'll have to do some serious thinking if I come across a deal on a good DC motor.

On advancing timing real quick. About how much is timing usually advanced? And I'm assuming you just change the rotational location of the commutator end plate? Lastly, by advancing the timing don't you lose the ability to use a reversing contactor for reverse? So therefore I'd need to keep the tranny?
 

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Discussion Starter · #26 ·
A sliding spline drive shaft sounds like the ticket for sure. Axial loading the drive shaft is just going to wear out U-joints. Looking real quick online it looks like some Triumph drive shafts are the sliding-spline type. I'll have to see what mine has when I start pulling it apart. Worst case I think I'll just have to find a sliding spline drive shaft from a different vehicle that is the correct length. I still have no idea where the shaft of my motor is going to end up in the transmission tunnel.
 

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Discussion Starter · #28 ·
I think everyone agrees that the axial load on the half-shafts is a bad idea though. Triumph got it to work in that application, but I wouldn't count on it elsewhere.

I just tried crawling under the car, but I still can't tell what style driveshaft mine has. I'll just have to wait to find out I guess. And yes, when it comes that time I will find a drive-line shop and just have them provide one. Whether it's custom made or an off the shelf I really don't care. I just want it to be professionally done. Last thing I want is my DIY driveshaft vibrating like crazy or separating!
 

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Discussion Starter · #30 · (Edited)
Baratong,

Thanks for the input on direct-drive vs. tranny. I'm still torn. I'm not terribly concerned about performance, so I think Direct with the Hyper 9 will work. If i go that route then my backup plan is to make a small single speed "transmission" that will bolt onto the face of the motor. AC will allow 6-8k peak RPM, and going direct drive only lets me realistically use about 4k rpm. A ~1.25 ratio at the motor would be very helpful....

On your thread, I started reading it last week, but actually just finished tonight. I'm amazed by your BMS system. Your electronics skills are lightyears ahead of mine. That said, I'm leaning towards an Orion for the simplicity. In your experience, is this a good option? Or what else should I consider?

Also, on your batteries, what drove you to use LiFePO4 bricks? It looks like you started in 2014. Were there production lithiums available at the time or were the bricks the only real option? I'm planning to use Gen1 Leaf Modules because they're about $150/kwh and a lot more energy dense than LiFePO4. What are your thoughts on Li-Ion vs LiFePO4?

Kevin
 

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Discussion Starter · #31 ·
Well, no luck on finding a forklift motor locally. I looked around and could only find one shop that actually repaired/serviced forklifts within 2 hours of here. I talked to them for a few minutes over the phone, told them what I was looking for and why. They said that they hardly ever get any electric fork trucks in and it's once in a blue moon that it would actually be scrapped out. He couldn't even remember the last time they had an electric one in. He did say that they sometimes will have the smaller walk-behind style, but it's my understanding that the motor on those is a little too small.

Anyways, I'll still keep my eye out for a good deal, but I'm just going to stick with the Hyper 9 plan.

On another note, I'm about halfway done renovating my garage, so I'm getting closer to actually starting on the Spit!

Kevin
 

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Discussion Starter · #33 ·
Molten,

Thanks for all of the feedback. I absolutely agree with 1, 2, and 3. For the batteries I'm planning to use Gen 1 modules from a Leaf. That may change to Gen 2s depending on price when I go to buy. BMS if a definite (planning to use an Orion BMS since I'm rather ignorant on the topic). And I'm certain that the Hyper 9 would destroy the tranny and probably the final drive if I left the Tranny.

On the talk of the tranny, I'm still torn about using one or not. RPM wise, direct drive works out very well (~3400 rpm at 60 mph). Being an SRIPM motor, the Hyper 9 has near full torque at ~0 rpm all the way up to ~3600 rpm. Correct me if I'm wrong, but I believe that DC motors don't get full torque until ~100 rpm (can't remember where I read/heard that). If that's true, then I can see needing a tranny to get off the line with a DC motor (or pure inductance AC), but maybe not with the Hyper 9.

A 2 speed transmission seems like it would be ideal, but I'm not willing to pay $3-5k for a powerglide (or similar). I've kicked around the idea of building my own ~1.25:1 single speed transmission and pushing the motor RPMs up into the 6000 rpm range at highway speeds. If I go that route then I'll definitely have to do forced air or liquid cooling on the motor though, as it's continuous rating is only 3300 rpm.

It all really depends on what performance is going to be like and what I think I need (which I have no idea...). The car currently has the week 1500cc motor in (with problems), and I'm not very good on stick and it still seems to scoot about with plenty of pep (when the carb actually feeds fuel :p).

On making a custom drive shaft or adapter plates. I have a full size mill and lathe as well as welders, grinders, etc. I think I can make just about anything I need, although I'll probably pay to have a proper drive shaft made. I'm really excited to get started. Just have to finish renovating the garage first! Almost done wiring, next up is insulation....

P.S. I didn't mean to put the angry face on the subject line...
 

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Discussion Starter · #36 ·
Duncan,

I assume that's with a transmission and in first or second? Either way, impressive! I am hoping to avoid that though. Prefer to not break the wheels loose... It would be cool to be able to for showing off, but nowhere near a design goal.

EVSpitfire,

Sounds like you'll have quite the setup! A quick search on that motor shows some impressive specs. 221 lb-ft of peak torque, 80 HP continuous. Far better than the 173 lb-ft peak and ~50hp continuous of the Hyper 9. Alas, the cost and voltage is prohibitive for me though. Looks like ~$6500 and 300+VDC compared to the Hyper 9's ~$4200 and ~100VDC. I don't need a huge battery pack,so getting that kind of voltage would be tough for me. Either way I can't wait to see how yours works out! Your 0-100kmh should be impressive!

I am very interested in your subaru diff swap! That ratio would be perfect for what I'm wanting and word on the street seems to be that they can actually handle the instant torque of electric. Is it a direct sub for the diff, or do you also have to make major suspension mods? Any info you can share or point me to would be great. I'm already betting 50/50 that my diff will implode in the first year.

I can't wait to see your build thread/site!
 

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Discussion Starter · #38 ·
WOW!! I didn't expect that could be a direct drive. Do you know what kind of torque it puts out at low rpm? I wonder how much more it is than the Hyper 9.

And how difficult was the subaru diff swap? Rough math suggests the triumph diff **should** be able to handle the torque of the Hyper 9, but I don't have that much confidence.

Kevin
 

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Discussion Starter · #40 ·
I am feeding my Hitachi with 1200 amps and 340 volts
That has to be ridiculous amount of torque!!!! I'm planning for 100-120 volts and ~700A peak. I'm doubting mine would break the tires loose if I go direct drive...

Where are you finding such motors for so cheap? I tried the 'local' forklift place (closest one is 2 hours away) with no luck. Said they almost never work on electrics anymore. I see motors that look like they could work on ebay for ~$1k (maybe $600ish), but I don't know enough about them to confidently buy. I'm also not thrilled with the idea of a reversing contactor for reverse (assuming I go direct drive).
 

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Discussion Starter · #45 ·
I really appreciate all the feed back. I'll look around again for a forklift rebuild shop. Los Alamos definitely does not have a forklift shop, and from what I've heard Santa Fe doesn't either. I talked on the phone to the only one I could find online, which is down in Albuquerque. I'll look around again though. Phoenix is 8 hours away....

I still hesitate to go DC though as I sort of fancy the idea of direct drive. DC, and the limitation of advancing brushes and such, concerns me. I mean, there's a reason that all of the OEMs use some kind of AC correct?

Molten, I can definitely agree with your assessment of Direct Drive with the AC50. But I think the Hyper 9 will be in a better position to handle it. The Peak torque is 44% higher and power is ~90kw (~120hp) at the same rpm point as the AC50's peak power (~71hp at ~3500 rpm). As long as I can take off at a stoplight at a rate similar to normal driving of an ICE, then I'll be happy. From there I'm confident I can get the speeds I'll need for my drive to and from work.

Technical question: I know back EMF is a big issue for DC, is it for AC though? I'm not an electrical engineer, but my understanding of how the motors work would suggest that it isn't as much of an issue since the field is in constant flux instead of discrete steps field-to-field of DC.

Wife and I are going on a mini vacation, so I may be off for a few days. Again, thank all of you for the input and awesome discussion.
 

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Discussion Starter · #51 ·
EVSpitfire,

That is some invaluable information about the diff for sure. At least for this first pass I'm going to try to use the stock final drive. I would like a 4.11 or higher ratio offered by some R180 configurations, but I think I need to stay as simple as I can on my build. If I blow up the stock diff then I will definitely be coming back to these posts, but hopefully I can save some time and money in this first year!

On the hardware, do you have design files you'd be willing to share? I'm a design engineer and hobby machinist. Would love to have them just in case, and if people in the US are interested I could go about getting a small production run made.


In other news, I'm closer to getting the garage ready for the Spitfire! Wiring and plumbing is done. Should be insulating this weekend and putting up walls soon after. With any luck I'll be ready to start disassembling the Spitfire in November! Now the question of when to start ordering hardware comes to mind....
 
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