Lead Wing's BMW E30

Post up a thread for your EV. Progress pics, description and assorted alliteration
User avatar
leadwings
Groupie
Posts: 34
Joined: Wed, 19 Nov 2008, 13:44
Real Name: Malcolm Reeson
Location: Perth

Lead Wing's BMW E30

Post by leadwings » Fri, 14 Jan 2011, 00:06

About 4 years ago I began thinking about making an EV. The reasons for this were many and varied – environmental reasons, energy security, had a friend working on one, my car had just been hit and needed replacing and, well, I love a good project and challenge!

The first step for me was lots of research – what was involved technically, what sort of car to convert, what it would cost. My objective was a “100/100/10” car – that is it could go a minimum of 100 km on a charge, minimum of 100 km/h and a 0-100 km/h time of 10 seconds or better.

During this time I decided that the critical part of choosing which car to convert was that it had to be a car that I would still want to be driving in 10 years – there was not point putting all this effort and expense into something and then not enjoy driving it.

I considered a number of donor cars, and decided to target a BMW E30 Bauer cabriolet. The reasons for this were many – I had had an E30 before and they are a great little car and fun to drive, parts are readily available, they are a decent size (I’m quite tall), they are well built, and the Bauer convertibles have the advantage of a 2-part removable roof so you can still have shade in summer with the back part down, and they have a built in roll bar. They also avoid a lot of the leak paths that many convertibles suffer.

I was luck enough to find a car in Victoria on the internet that was being sold unlicensed as the owner didn’t want to fix what would be required for a roadworthy. I had it inspected and no major issues were found, so I picked it up site unseen for $2000. Luckily when it arrived I found out it was in excellent condition inside and out, but with a tired motor. It took all of $300 to get the car register in WA, and I proceeded to try and wear the tyres out before the conversion started.

The next big decision was EV drive train configuration to use. I laboured long and hard about whether to keep the gearbox or not, but at this point I met Rob Mason who had just converted another BMW E30. One drive told me that a direct drive system worked fine, so that made all the pieces fall together. This also gave me the ability to copy Rob’s design and layout, and gave me confidence that everything would fit.

The final EV system consists of an Advanced DC FB-4001 motor direct drive, 45 x 160 Ah LiFePO4 Thundersky battery pack, Rod Dilkes Battery Management System (BMS), Zilla 1K LV controller and Zivan charger.

Next came the grunt work of the conversion. I drove the car to the EV Works workshop, and pulled out 280 kg of junk – motor, gearbox, muffler, fuel tank, radiator etc, then left the car with them to mount the motor and build the battery racks. I then took the car home on a trailer, where it spent months sitting there as I slowly added all the smaller components (vacuum pump etc) and cabling etc.

Just as the car was ready to be completed, work asked me to go to Houston for 6 months (which became 9 months…). Damn frustrating to be so close and not be able to finish it off, but within 2 weeks of my return to Perth the car was running.

Overall it has been a great project, and I’m really happy with how the car has worked out. The car easily makes the “100/100/10” objectives, and is a hoot to drive. Many thanks to my patient wife, and all the great and help and advice along the way particularly from Rob and Ian at EV Works.

User avatar
leadwings
Groupie
Posts: 34
Joined: Wed, 19 Nov 2008, 13:44
Real Name: Malcolm Reeson
Location: Perth

Lead Wing's BMW E30

Post by leadwings » Fri, 14 Jan 2011, 00:15

ImageImageImageImage

User avatar
leadwings
Groupie
Posts: 34
Joined: Wed, 19 Nov 2008, 13:44
Real Name: Malcolm Reeson
Location: Perth

Lead Wing's BMW E30

Post by leadwings » Fri, 14 Jan 2011, 00:16

ImageImageImageImage

User avatar
leadwings
Groupie
Posts: 34
Joined: Wed, 19 Nov 2008, 13:44
Real Name: Malcolm Reeson
Location: Perth

Lead Wing's BMW E30

Post by leadwings » Fri, 14 Jan 2011, 00:18

ImageImageImageImageImage

User avatar
leadwings
Groupie
Posts: 34
Joined: Wed, 19 Nov 2008, 13:44
Real Name: Malcolm Reeson
Location: Perth

Lead Wing's BMW E30

Post by leadwings » Fri, 14 Jan 2011, 00:24

ImageImageImageImage

User avatar
a4x4kiwi
Senior Member
Posts: 772
Joined: Thu, 03 Jan 2008, 19:04
Real Name: Malcolm Faed
Location: Australia
Contact:

Lead Wing's BMW E30

Post by a4x4kiwi » Fri, 14 Jan 2011, 05:29

Well done. Excellent job!.

Very good schematics also.
Silicon is just sand with attitude.

Blog: http://malfunction.faed.name

User avatar
leadwings
Groupie
Posts: 34
Joined: Wed, 19 Nov 2008, 13:44
Real Name: Malcolm Reeson
Location: Perth

Lead Wing's BMW E30

Post by leadwings » Fri, 14 Jan 2011, 18:58

Thanks for the kind words. Figure the schematics may be of use to others. Did them in excel, if anyone wants a native copy PM me.

User avatar
a4x4kiwi
Senior Member
Posts: 772
Joined: Thu, 03 Jan 2008, 19:04
Real Name: Malcolm Faed
Location: Australia
Contact:

Lead Wing's BMW E30

Post by a4x4kiwi » Fri, 14 Jan 2011, 21:34

I would like to do an E30 next if I can find the perfect motor. Still looking and it may take a while.
Silicon is just sand with attitude.

Blog: http://malfunction.faed.name

algea07
Noobie
Posts: 1
Joined: Wed, 08 Dec 2010, 00:16

Lead Wing's BMW E30

Post by algea07 » Wed, 26 Jan 2011, 21:15

this is a very nice car, very clean.

did you have much trouble building the motor mounts? i was thinking of doing a direct drive with a kostov dual 9" with a soliton in either a BMW 3 serias or a Merc. i was thinking that i would just have to strip the car myself then take the car and the motor to a mechanic and say put them together. How mush did it cost to install yours?

Did you have much troble regestering the EV, i'm from victoria so i guess they will be simelarish standerds. I would hate to build it then not be able to drive it.

User avatar
leadwings
Groupie
Posts: 34
Joined: Wed, 19 Nov 2008, 13:44
Real Name: Malcolm Reeson
Location: Perth

Lead Wing's BMW E30

Post by leadwings » Thu, 27 Jan 2011, 17:48

a4x4kiwi wrote: I would like to do an E30 next if I can find the perfect motor. Still looking and it may take a while.


Motor I am using (Advanced DC FB-4001) works really well and matches the vehicle weight etc. Gives good performance (better acceleration than the petrol motor) even in direct drive.

User avatar
leadwings
Groupie
Posts: 34
Joined: Wed, 19 Nov 2008, 13:44
Real Name: Malcolm Reeson
Location: Perth

Lead Wing's BMW E30

Post by leadwings » Thu, 27 Jan 2011, 17:59

algea07 wrote: this is a very nice car, very clean.

did you have much trouble building the motor mounts? i was thinking of doing a direct drive with a kostov dual 9" with a soliton in either a BMW 3 serias or a Merc. i was thinking that i would just have to strip the car myself then take the car and the motor to a mechanic and say put them together. How mush did it cost to install yours?

Did you have much troble regestering the EV, i'm from victoria so i guess they will be simelarish standerds. I would hate to build it then not be able to drive it.


I was lucky and EV Works allowed me to use their workshop (and hoist) to strip the car myself, then I left it with them to mount the motor and build the battery boxes.

I toyed with the idea of buying a welder and doing it myself, but the alignment of the motor is critical, and it has to restrain a lot of torque, so recommend you get it done properly.

Also they were then able to sign off on the battery boxes being good for the 20g impact requirements etc.

As for licencing, suggest you get in touch with someone from Victoria who has gone through the process there to see what is required. Really the guys at the pits have no idea - they wanted me to put some spring washers on a couple of bolts, but had no idea on the EV side of things. Make it look neat!!

rmlane
Groupie
Posts: 33
Joined: Sun, 19 Dec 2010, 03:39
Real Name: Richard Lane

Lead Wing's BMW E30

Post by rmlane » Tue, 15 Feb 2011, 01:30

Looks great - what was the mass change after the conversion?

User avatar
leadwings
Groupie
Posts: 34
Joined: Wed, 19 Nov 2008, 13:44
Real Name: Malcolm Reeson
Location: Perth

Lead Wing's BMW E30

Post by leadwings » Tue, 15 Feb 2011, 01:42

rmlane wrote: Looks great - what was the mass change after the conversion?


Car is about 50 kg heavier than it was as a petrol car with a full tank. If I had managed to find a 6 cylinder version to convert, I reckon it would be less than 20 kg.

Thwworm
Noobie
Posts: 1
Joined: Mon, 28 Mar 2011, 01:34

Lead Wing's BMW E30

Post by Thwworm » Mon, 28 Mar 2011, 03:21

Wow i love your work and e30's
I've just stumbled on to this site recently and it seems the e30 is a prety good car to convert to a ev.
Keep up the good work

User avatar
Richo
Senior Member
Posts: 3310
Joined: Mon, 16 Jun 2008, 00:19
Real Name: Richard
Location: Perth, WA

Lead Wing's BMW E30

Post by Richo » Mon, 28 Mar 2011, 05:34

I like the "electrons only" sticker.
It's the small finishing touches that make the difference between a good eV and an excellent eV Image
Help prevent road rage - get outta my way! Blasphemy is a swear word. Magnetic North is a south Pole.

Digger11
Groupie
Posts: 53
Joined: Fri, 12 Mar 2010, 19:55
Real Name: Digger Jones
Location: Melbourne

Lead Wing's BMW E30

Post by Digger11 » Sun, 24 Apr 2011, 16:09

Did you do much of the design work yourself ?

Weber who is building an MX5 for over 2 years seems to get stuck at every little stage with one issue or another.
How did you solve the 100's of problems that Weber has run into ????
Last edited by Digger11 on Sun, 24 Apr 2011, 06:10, edited 1 time in total.

User avatar
leadwings
Groupie
Posts: 34
Joined: Wed, 19 Nov 2008, 13:44
Real Name: Malcolm Reeson
Location: Perth

Lead Wing's BMW E30

Post by leadwings » Fri, 29 Apr 2011, 20:00

Frankly I didn't do much "design" work.

As I say above I had the battery boxes made by EV Works as they have to be 20g rated and have an engineer sign off on them. I am an engineer, but it's been many a year since I did any calculations!

As for the rest, I was copying a pretty common drive train (45 LiPos = 144V nominal, ADC 4001 and Zilla controller). Main traction cable sizing advice came from Ian Hooper (EV works again).

Other than that ran a spreadsheet on cost/weight for all the bits, and spent a whole lot of time looking/thinking about where things were going to go - but agian not what I would call "design".

Does that make sense?

User avatar
gholm
Groupie
Posts: 110
Joined: Fri, 27 Aug 2010, 04:48
Real Name: James Neale
Location: Coogee
Contact:

Lead Wing's BMW E30

Post by gholm » Sun, 01 May 2011, 01:10

Definitely makes sense.
Sometimes you just need to pay the man to do his thing.
DIY doesn't always cut it, especially with family/work/life expectations.

Awesome conversion man, love that vehicle... a real driver's car.
Nice work.



drgrieve
Noobie
Posts: 12
Joined: Thu, 28 Apr 2011, 18:14
Real Name: David grieve
Location: Sydney

Lead Wing's BMW E30

Post by drgrieve » Wed, 09 Nov 2011, 20:32

Can you tell us a bit more about the direct drive. I'm looking at a E30 conversion but I didn't think about the idea of direct drive until I saw this thread.

I have a lot of questions!

Was is the diff ratio for your donor?
Top speed?
How long before the low end acceleration kicks in?
Any 0-40,60,80,100 times?
Also the 100kph to 130 kph time? (overtaking on highway)
Amps used from start - does the motor get strained?
How much extra efficiency do you think you've gained by going direct drive - or is it worse due to motor not being in efficient power band?

And anything else you think might be relevant!

User avatar
leadwings
Groupie
Posts: 34
Joined: Wed, 19 Nov 2008, 13:44
Real Name: Malcolm Reeson
Location: Perth

Lead Wing's BMW E30

Post by leadwings » Wed, 09 Nov 2011, 22:56

Suspect I won;t be able to answer a lot of your questions, as I don;t have a gearbax conversion to compare it to. All I can say is it drives great.

Was is the diff ratio for your donor? No idea, but standard 318i diff
Top speed? Ive had it up to 120 km/hr and it was still pulling strongly. Suspect 130?

How long before the low end acceleration kicks in? It doesn't take off with a jerk - from wha i can tell the speed controller needs to protect itself so limits amps. So between 0-20 it pulls but not aggressively, then it accelerates strongly from there. Mate had a 2000A zilla, and that can spin the back wheels

Any 0-40,60,80,100 times? Estimate 0-100 in around 9-10 seconds

Also the 100kph to 130 kph time? (overtaking on highway) Don't know. Don't drive on the freeway much, but when I have it accelerates more that adequately for overtaking

Amps used from start - does the motor get strained? As i say above the speed controller limits the amps.

How much extra efficiency do you think you've gained by going direct drive - or is it worse due to motor not being in efficient power band? No idea, but don't think it would make that much difference. The idea of direct drive was more weight saving and by having the motor where the gearbox is gives more space under the bonnet for batteries.

No doubt the car would accelerate much better with a gearbox/lower ratio diff, but it is more that adequate as it is (I am usually forst off at the lights and keep getting speeding fines).

drgrieve
Noobie
Posts: 12
Joined: Thu, 28 Apr 2011, 18:14
Real Name: David grieve
Location: Sydney

Lead Wing's BMW E30

Post by drgrieve » Thu, 10 Nov 2011, 15:58

Thanks - that gives me quite a bit to think over.

Was is the diff ratio for your donor? No idea, but standard 318i diff.

I think your diff ratio is 4.1 to 1. By using a rpm/gear calculator and assuming your type diameter is standard 14" 195 65 or 14" 175 70 (around 600mm), you would see 2200 rpm at around 60 kph.

Guessing that you're peak power is at 3000 rpm which is 84 kph.

At 100 kph your rpm is 3600 and at 120 kph it is 4300.

If you're using an internal motor fan for cooling then under 60 kph the fan may struggle to cool the motor.

Final question. Do you have any issues with hill starts?

User avatar
leadwings
Groupie
Posts: 34
Joined: Wed, 19 Nov 2008, 13:44
Real Name: Malcolm Reeson
Location: Perth

Lead Wing's BMW E30

Post by leadwings » Thu, 10 Nov 2011, 17:03

Must admit I don't exactly understand how RPM relates to power etc in a DC motor - really it seems to all relate back to the amps you are putting through. Data sheet for my motor here http://www.evmotors.com.au/products/download/fb144.pdf

I drive in Perth in summer (40C) and have had no problems with the motor getting hot.

Hill starts no problem, though it doesn't bolt off - though neither would a petrol car. Again a gearbox would help, but given the other downsides (extra space it needs etc) I would still go direct drive if I did it again as it works fine.

drgrieve
Noobie
Posts: 12
Joined: Thu, 28 Apr 2011, 18:14
Real Name: David grieve
Location: Sydney

Lead Wing's BMW E30

Post by drgrieve » Fri, 11 Nov 2011, 21:21

Do you have your motor RPM hooked up to tacho?

Hopefully I can explain.

The normal e30 five speed gearbox runs the following gear ratios (1st to fifth).

3.72, 2.02, 1.32, 1.00, 0.81.

What this does is trade torque for RPM. In first gear the motor in comparison to wheel rotation is completing 3.72 rotations for 1 wheel rotation. In fourth gear they are the same, and in fifth the engine rotates slower than the wheel.

BUT there is also the differential gear which is fixed (I think for your car at 4.1). So each number above is in effect multiplied by 4.1. Thus if the gearbox was kept it would be the same as running in fourth gear permanently.

So how do you calculate rpm vs kph? Answer by using one of the many online web tools (as the good ones work out tyre sizes for you) but you can do it manually

It is a function of motor rpm, which is geared down by the diff (divide by 4.1) to give wheel rotations per minute. Then take that number and multiply by wheel circumference (I think yours is 1.9m).

So at 2200 rpm, wheel rotation is ~540 rpm. Which is ~1000 meters in a minute. Which is 60 kph.

drgrieve
Noobie
Posts: 12
Joined: Thu, 28 Apr 2011, 18:14
Real Name: David grieve
Location: Sydney

Lead Wing's BMW E30

Post by drgrieve » Fri, 11 Nov 2011, 21:44

Bah after posting I understand your question. Not rpm to kph but rpm as power and why is it limited.

That is a much more complex question.

This thread explains a bit. Essentially for a series DC motor amps gives you torque, and volts gives you a wider RPM band before torque drops off due to back EMF (which is something I've read but always forget what it is)

http://www.diyelectriccar.com/forums/sh ... 30465.html

But at 144 volts the torque drops off a bit over 3000 rpm. Thus for your car I think you would see that at around 80 - 85 kph. Your acceleration goes from constant to progressively slower as your speed up from there.

Which is great for a round the town car and from what you've said ok for on highway as well.

Thanks!

Nevilleh
Senior Member
Posts: 773
Joined: Thu, 15 Jan 2009, 18:09
Real Name: Neville Harlick
Location: Tauranga NZ

Lead Wing's BMW E30

Post by Nevilleh » Mon, 14 Nov 2011, 12:03

My E30 (diff ratio 4.1)uses two L91 motors in series, both mechanically and electrically, direct drive to the diff. With a 45cell Li battery, that means each motor sees about 72V and the car does 110 kph flat out with a 0-80 kph acceleration of about 10 seconds. If I switch the motors to parallel, acceleration is markedly reduced, but the top speed goes to 130 kph since each motor is now seeing 144V and so can spin faster.
I'm using a nominal 500A controller modified slightly to give me just over 600A.
Originally I used a LogiSystems 1000A controller with the motors in parallel and that gave about the same acceleration as the 500 A one with the motors in series, but a top speed of about 130 kph. That controller blew up and it never did give smooth starts, that's why I went to the Cougar one (built by me).
I find 110 kph is quite OK as there is only a short piece of motorway close by that I use on a regular basis and the speed limit is 100 anyway, but I had thought I could easily add some contactors and switch the motors from series to parallel above 80 kph which would give me the higher top speed. Mind you, the power consumption goes up lots!
Have a look at my posts under "Neville's BMW" and you will see the whole sorry story Image I might stick up a video one of these days.
I used two L91's because I didn't think a 9" motor would fit in the transmission tunnel. From the motor curves, an L91 produces 80 ft.lbs of torque at 500A, so two should do 160 ft.lbs which is more than the 9"motor anyway. That's the starting torque, actually a bit more as I am poking 600A through the things. I find the current at top speed of 110 kph is about 195A and that means the torque is about 24 ft.lbs each, ie total of 48. That corresponds to an rpm of about 3600 (from the motor curves). This gives me a theoretical top speed of 102.3 kph with the 175 x 75 x 14 tyres I have fitted, so I am sneaking a bit more than that!
The motor curves show that each motor is producing about 16 hp for a total of 32 hp at those revs.
The curves are American, so the units are funny, but that's about 23.8 kW which ties in fairly well with my calculated figures from the Cd, weight etc.
By the way, I find the motor temps go to about 60 deg C after driving at 100 kph for an hour, so that's about their limit anyway.
Last edited by Nevilleh on Mon, 14 Nov 2011, 01:31, edited 1 time in total.

Post Reply