Hot rod EV - looking for advice.

Technical discussion on converting internal combustion to electric
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blwnhr
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Hot rod EV - looking for advice.

Post by blwnhr » Tue, 02 Apr 2019, 17:35

Hi all, new member here.

I'm about to start building a 1951 Ford F1 pickup truck, imported from Oregon, USA. I had planned to use a Holden / Chev LS-series motor, but the lure of EV is strong, especially after seeing this at SEMA.

The fabrication is the easy bit for me, but I know next to nothing about DIY EV's. I'm hoping I can be pointed to some resources on "these are the components of an EV, and this is their order of operation".

My ultimate goal is a performance vehicle with decent range. My build time is likely 5-7 years (young family and all), I will leave the big motor and battery purchases as late as possible to get the latest tech, but I need an understanding of what components are required and approximate sizes so I can masterplan the build and not engineer myself into a corner.

Cheers and thank in advance.

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Re: Hot rod EV - looking for advice.

Post by 4Springs » Tue, 02 Apr 2019, 18:20

Hi blwnhr, and welcome!
That is some machine. It certainly has potential, and your 5-7 years sounds realistic!
The battery and motor/controller are definitely the most pricey parts of a conversion, and they do change with the times. Unfortunately they are also the hardest to leave until last, since so much of your build will depend on the physical dimensions of battery and motor.
Something I always start with (when doing thought-experiment conversions) is the weight. What weight can you carry in your vehicle? That will give you a place to start with working out what is possible with batteries. The more you can carry the further you will go and the more it will cost. Do you have a budget? Or a piece of string?

Have a look at NCOP 14, it has some practical information: https://infrastructure.gov.au/vehicles/ ... _ncop.aspx

It might be useful to know where you are located, as there might be a local AEVA branch with helpful people near you.

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Re: Hot rod EV - looking for advice.

Post by blwnhr » Wed, 03 Apr 2019, 04:13

I'm actually comfortable leaving the motor and batteries further into the build. It is body-on-chassis construction, this offers a number of advantages in strength, packaging flexibility and weight handling. The wheelbase is fixed, as is the cabin, which defines the position of the front sheetmetal. I will be making the cab 6" longer which means a new floor and transmission tunnel. The floor I can leave until last, same with the tray and everything under the bonnet. Based on this I believe the drivetrain can be moved later into the build.

As for weight, it is a 1/2 ton pickup. The original weight was 1,385kg (cast-iron side-valve V8) with a GVM of 2,130kg (745kg payload). I will be running Jaguar front and rear independent suspension from a 1978 Daimler Sovereign which alters the load rating. The Daimler had a kerb weight of 1,750kg without driver, so there is some scope here.

The advantage of being an Australian Street Rod Federation member is a set of standard build guidelines. This does not speak to the use of electric motors, but that is not insurmountable as the guidelines allow for some quite high power and torque V8 engines.

As for budget, not really. There has to be a sweet-spot for cost Vs. performance in there somewhere, happy to pay a premium for performance and range too.

One thing I'm struggling to find is a diagram or description of how the EV setup works, power in -> various boxes, cables and batteries -> electric motor -> differential -> wheels. What happens in the middle?

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Re: Hot rod EV - looking for advice.

Post by brendon_m » Wed, 03 Apr 2019, 07:09

Could try this site
https://www.avnet.com/wps/portal/us/res ... -vehicles/

It doesn't have too much on ancillaries but it goes pretty far into how the main components works. Probably too far for what you're chasing but it does have a layout diagram

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Re: Hot rod EV - looking for advice.

Post by blwnhr » Wed, 03 Apr 2019, 09:22

Thanks Brendon, that was a great start.

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Re: Hot rod EV - looking for advice.

Post by Richo » Wed, 03 Apr 2019, 12:53

blwnhr wrote:
Tue, 02 Apr 2019, 17:35
... after seeing this at SEMA.
Well the details were a bit generic on that link - but I did find this:
https://electrek.co/2018/10/31/1949-mer ... owertrain/
So it runs direct drive - no transmission.

Did you have a target kW?
So the short answer is NO but the long answer is YES.
Help prevent road rage - get outta my way!

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Re: Hot rod EV - looking for advice.

Post by Richo » Wed, 03 Apr 2019, 12:58

blwnhr wrote:
Wed, 03 Apr 2019, 04:13
What happens in the middle?
Well I expect that is where you are driving :lol:
So the short answer is NO but the long answer is YES.
Help prevent road rage - get outta my way!

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Re: Hot rod EV - looking for advice.

Post by 4Springs » Wed, 03 Apr 2019, 13:51

blwnhr wrote:
Wed, 03 Apr 2019, 04:13
One thing I'm struggling to find is a diagram or description of how the EV setup works, power in -> various boxes, cables and batteries -> electric motor -> differential -> wheels. What happens in the middle?
There isn't very much to it when looking at it from a high level.
Cells have positive and negative terminals. Hook them up in series to make a battery, which can be distributed around the vehicle if you like.
The positive and negative terminals of the battery go to a motor controller.
The controller is connected to the motor via cables.
The motor turns. You'll want a diff to suit the motor RPM.
I think you have it from there.

There is some devilish detail of course:
- you need to connect a throttle to the controller, and perhaps a reversing switch.
- you might need a cooling circuit for the motor and/or controller (water and a radiator).
- you need a charger for your battery. Normally the charger lives in the car and you plug it into the wall with an extension cord.
- you need some safety stuff.
- you need some relays & contactors to turn things on and off how you want them (with the key for instance).
- the battery needs a battery management system.
- you might need heating/aircon for the cabin.
- you might need brake vacuum.
- you might need power steering.
- you probably want some nice instrumentation to see what is going on.

All the components I've mentioned are available off the shelf, in the main you just hook up the boxes as required.

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Re: Hot rod EV - looking for advice.

Post by jonescg » Wed, 03 Apr 2019, 14:35

Yep, the list of little things to do is about 30 km long :)
AEVA National Secretary, WA branch chair.

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Re: Hot rod EV - looking for advice.

Post by blwnhr » Wed, 03 Apr 2019, 16:46

Thanks for the information, it's starting to paint a picture.

For reference I come from a mechanical engineering background, grew up in a hot rodding family and built a supercharged HR Holden as my first car (still have it, about to fabricate an exhaust for it next week). I'm fortunate enough to work with some really clever engineers and scientists, in particular 2 very experienced and enthusiastic mech. eng.'s and an PhD environmental scientist who specialises in energy, including studies into the viability of EV's on a commercial scale. Pooling their knowledge and combining it with that from this forum and the wider internet should hopefully lead to a good result.

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Re: Hot rod EV - looking for advice.

Post by blwnhr » Wed, 03 Apr 2019, 17:00

Richo wrote:
Wed, 03 Apr 2019, 12:53
Did you have a target kW?
Nope, no idea, and no real clue on how to calculate it either. Because of the torque curve I'm guessing power is less of an issue for EV's?
Any tips?


Some questions for the room...
Fearful of starting a thread like this... what's the go with transmissions? I gather there is an optimum band for the motor, how do you determine what that is? From the engine graphs?
I've seen some use a Gear Vendors overdrive, perhaps a Powerglide 2SP auto might also work. Adaption of either of these is no big deal from my end.

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Re: Hot rod EV - looking for advice.

Post by reecho » Wed, 03 Apr 2019, 18:06


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Re: Hot rod EV - looking for advice.

Post by francisco.shi » Wed, 03 Apr 2019, 20:41

I am converting a Pajero which I think is about the same size and weight as your truck.
The Pajero has independent front and rear suspension which makes it easier to connect the motors to the diffs because there is no need for a long tailshaft as the diffs don't move. This leaves more room for batteries. Also 4x4s have lots of room under the body so it is a convenient place to put the batteries.
Most electric motors run between 6k and 10k rpm. The faster you run the motor the more power you will get. The motors only have the rotor and two bearings as moving parts. So the limit of the speed is mostly the bearings and gearbox. The rotor should be balanced to run at those speeds.
In the Pajero the diff ratio is 4.3:1 so the tail shaft spins at about 3k rpm at 100kph. The motors I am using will go to 12k rpm so I have put a gearbox to so the motor will run at about 8k rpm at 100kph. This gives me a top speed of about 150kph.
I am using a single speed gearbox. For a 4x4 a 2 speed gearbox would be better so you can have low range but I decided for the single speed because it was easier and because I have enough torque.
This is the link to my build I hope it helps.
https://forums.aeva.asn.au/viewtopic.php?f=33&t=5721

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Re: Hot rod EV - looking for advice.

Post by Adverse Effects » Wed, 03 Apr 2019, 21:48

you sure you want to go with the suspention you have for it?

i was just thinking 2 of the bigger Tesla drive units (4WD) hmmmm LOTS of ommphhh!!!

and this is just 1 drive unit

Tesla Electric Motor Swap In Lotus Evora Puts Out 440 Whp On Dyno

Image
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Re: Hot rod EV - looking for advice.

Post by blwnhr » Thu, 04 Apr 2019, 04:41

Francisco, thank you, everything there is very helpful. I too will be running independent rear, the simplicity of running a splined coupling in place of a tail shaft will be a big advantage for packaging. I hadn't thought of that.

Adverse Effects, the Tesla drive unit would be the ultimate, but the track width is a mile too wide. A change like that is too great for even my ambition. Stock the truck is 1,524mm, the Jag rear is about spot on (many are using this conversion) at 1,485mm, this allows a good looking wheel with some offset. By comparison the Model S is 1,700mm (+215mm)! Even the Model 3 is 1,580mm (+95mm).

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Re: Hot rod EV - looking for advice.

Post by Richo » Thu, 04 Apr 2019, 12:53

blwnhr wrote:
Wed, 03 Apr 2019, 17:00
... I'm guessing power is less of an issue for EV's?
Well no power is power weather its from electrons or petrol.
You could put in a 60kW electric motor direct drive and it would drive ok be simple and reliable.
You know all show and no go...
But if you want to drag a Tesla off down the strip you'll probably need a bit more.

Perhaps I should have said how do you want to use your car?

blwnhr wrote:
Wed, 03 Apr 2019, 17:00
... what's the go with transmissions?
I gather there is an optimum band for the motor, how do you determine what that is? From the engine graphs?
In a RWD the gearbox is optional.
Normally if you get a big enough motor you wont need the gearbox.
The power band of the motor is also related to the batteries you have.
Perhaps a fair comparison between vehicles/motors is to look at the torque curve rather than the power curve.
In many cases the torque is 100% up to a nominal RPM then it drops off.

Image

blwnhr wrote:
Wed, 03 Apr 2019, 17:00
I've seen some use an ..overdrive.. perhaps a Powerglide...
Using one of those will complicate the build.
Really would only want one if the power is going to be quite high.
But once again "high" is subjective.

I'm sure we could suggest an example system if you had a ball park of peak power or what you want to do with it.
So the short answer is NO but the long answer is YES.
Help prevent road rage - get outta my way!

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Re: Hot rod EV - looking for advice.

Post by francisco.shi » Thu, 04 Apr 2019, 14:02

What is your maximum. Desirable speed and what time do you want it to do 0 to 100kph.
This will determine how much power you need.

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Re: Hot rod EV - looking for advice.

Post by Adverse Effects » Thu, 04 Apr 2019, 16:05

blwnhr wrote:
Thu, 04 Apr 2019, 04:41
but the track width is a mile too wide. (+215mm)!
there halfshafts very easy to take 107.5mm out of each shaft

you dont have to use there frames i have see a vid of a VW combi with 1 in it
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Re: Hot rod EV - looking for advice.

Post by blwnhr » Thu, 04 Apr 2019, 17:07

Richo wrote:
Thu, 04 Apr 2019, 12:53
Perhaps a fair comparison between vehicles/motors is to look at the torque curve rather than the power curve.
This is what I was getting at, power not really a useful comparative tool for EV to ICE. (Jason @ EE's video is really handy about this.)

To answer the power and performance question, I was going to run an LS-series V8 so would be looking for performance similar to a VF SS Commodore. They are 304kW / 570Nm with 0-100 of 4.5sec. They are heavy, 1750kg, meaning 5.75kg/kW and 3.07kg/Nm.

I will be doing a lot of highway cruising so want it to be comfortable at 110km/h.

The original engine + gearbox is around 300kg, less fuel tank and ICE support systems (85kg nom.) the weight is around 1,000kg. It has a GVM of 2,130kg so less passengers and manditory chassis alterations I've got probably 850kg for the full EV system. (Remembering this will never be used as a ute, nor will it ever tow a trailer.)

Adverse Effects wrote:
Thu, 04 Apr 2019, 16:05
there halfshafts very easy to take 107.5mm out of each shaft

you dont have to use there frames i have see a vid of a VW combi with 1 in it
I'm not worried about making the axles more narrow, rather the impact that has on suspension geometry. I haven't seen enough good photos of a Model S drive unit to determine if the motor could be moved back so the suspension arm mounts could be brought closer together. It looks like they perhaps could, but I'm not 100%.

EDIT:
Looking at these two photos - one - two - it looks like the top arms could be moved in while maintaining the motor position. Still not sure on the bottom arm.

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Re: Hot rod EV - looking for advice.

Post by blwnhr » Fri, 05 Apr 2019, 04:51

I found a CAD model of a Tesla Model S chassis, I can't speak to its accuracy but the geometry looks about right. Based on this I think it would be possible to narrow the track while maintaining the stock suspension geometry.
This is really exciting, I like the idea of using the Tesla power unit, the packaging is just so neat, but dismissed it based on track width. Thanks @Adverse Effects for pushing that line of thought.
I'll play with the 3D model a bit more to prove the concept, but it looks promising.

Below is a plan view and a section through the suspension arms. The rearmost top arm would clear the motor, it looks to be in alignment with the half-shaft. The bottom arm fits under the motor so this is no big deal. The chassis framing to pick up all those mounts would be hard to get looking good, but not insurmountable.

Image

Image

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Re: Hot rod EV - looking for advice.

Post by francisco.shi » Fri, 05 Apr 2019, 06:59

Where did you get the model from?
Do you have a link?

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Re: Hot rod EV - looking for advice.

Post by Adverse Effects » Fri, 05 Apr 2019, 07:26

you dont even have to use there frames

have a look around this channel about 1 year ago

there is a LOT of what they did with a DOKA

i made a play list of some of his videos

Tesla powered DOKA
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Re: Hot rod EV - looking for advice.

Post by blwnhr » Fri, 05 Apr 2019, 09:24

@francisco.shi GrabCAD; whole Model S chassis (dimensionally questionable perhaps) and Model S drive unit (dimensionally accurate, corrected 3D scan).

@Adverse Effects I wouldn't use their frame, but I do like their suspension design as it's proven reliable. Using the Tesla arms etc. would make spares easy to source, no good reinventing the wheel. Thanks for the DOKA link, I've found some good write-ups and videos.

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Re: Hot rod EV - looking for advice.

Post by Richo » Fri, 05 Apr 2019, 12:35

blwnhr wrote:
Thu, 04 Apr 2019, 17:07
... I was going to run an LS-series V8 so would be looking for performance similar to a VF SS Commodore.
They are 304kW / 570Nm with 0-100 of 4.5sec. They are heavy, 1750kg, meaning 5.75kg/kW and 3.07kg/Nm.
Excellent - that is something I can work towards.
Any ideas what your car might weigh stock or as it is now? Ball park is fine.
So the short answer is NO but the long answer is YES.
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Re: Hot rod EV - looking for advice.

Post by Richo » Fri, 05 Apr 2019, 12:37

blwnhr wrote:
Thu, 04 Apr 2019, 17:07

The original engine + gearbox is around 300kg, less fuel tank and ICE support systems (85kg nom.) the weight is around 1,000kg. It has a GVM of 2,130kg so less passengers and manditory chassis alterations I've got probably 850kg for the full EV system. (Remembering this will never be used as a ute, nor will it ever tow a trailer.)
Ah I should have read on...
So stock it was about 1.4T
So the short answer is NO but the long answer is YES.
Help prevent road rage - get outta my way!

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