Weber and Coulomb's MX-5

Post up a thread for your EV. Progress pics, description and assorted alliteration
User avatar
coulomb
Site Admin
Posts: 6340
Joined: Thu, 22 Jan 2009, 20:32
Real Name: Mike Van Emmerik
Location: Brisbane
Contact:

Weber and Coulomb's MX-5

Post by coulomb »

Renard wrote: Unless your drive was long or hard, I'm surprised by this, since my controller never goes over about 35.
Neither does ours, as long as we remember to reconnect the coolant pump after testing. Sorry, I should have made that clearer; I'll edit it.
It suggests that the coolant circulation is critical.

Oh yes, the WaveSculptor is not to be run at more than low testing power without water cooling. Fortunately, it protected itself automatically, while still allowing us to drive with it at reduced power. We're just mad at ourselves for triggering that protection.
MG ZS EV 2021 April 2021. Nissan Leaf 2012 with new battery May 2019.
5650 W solar, 2xPIP-4048MS inverters, 16 kWh battery.
Patching PIP-4048/5048 inverter-chargers.
If you appreciate my work, you can buy me a coffee.
User avatar
coulomb
Site Admin
Posts: 6340
Joined: Thu, 22 Jan 2009, 20:32
Real Name: Mike Van Emmerik
Location: Brisbane
Contact:

Weber and Coulomb's MX-5

Post by coulomb »

The need to reset the motor controller repeatedly was traced late last night to a bad crimp on one wire, coupled with some as yet unexplained behaviour.

Believe it or not, the A-pack DCU was turning off the power to the CAN bus for 10 milliseconds every now and then, and these would result in the controller errors. [ Edit: the motor controller gets its logic power from the CAN bus. ] We were able to capture a 10 ms "hole" in the 12 V supply, dipping from 14 V to less than 6 V, on Weber's DSO. I managed to catch a 9.2 ms pulse on the chip that controls the CAN bus power. There is some issue that prevents doing debugging in IAR (the TI sponsored development environment for the MSP430 series, as used in the DCU and also our BMUs) when the CAN bus is running. I the past, I've noticed this, and merely commented out something in the routine that sends CAN packets, but this time we really needed CAN packets to have the error show up.

We started with cave man debugging (oh wait, that uses sophisticated printf statements; we had just a beeper; call it Neanderthal debugging), but we needed more. Things progressed more quickly when I found that compiling without optimisation worked around this can't-debug-with-CAN-running problem. From there it was just a short, painful hour of crouching in the foot well of the car at night to find the bad lead. After the lead was fixed, IAR went into one of its hissy fits, where it would refuse to do any debugging, even after shutting down and restarting Windows. But it didn't matter; the fault seemed to go away. Weber and Geoff had just reinstalled the roll-bar properly, which was a hell of a job with the retractable canopy in the way. I caught Weber's eye and said "Let's go for a drive!"

So it meant that rather late last night, five people (three EVers and two of their partners) were able to enjoy a ride in the MX-5 without the fear of having to reset the controller by netbook. The pack was fully charged, and the power was good (for one half-pack). It's showing good promise now.

[ Edit: added that the motor controller gets its power from the CAN bus; clarity. ]
Last edited by coulomb on Mon, 30 Sep 2013, 11:21, edited 1 time in total.
MG ZS EV 2021 April 2021. Nissan Leaf 2012 with new battery May 2019.
5650 W solar, 2xPIP-4048MS inverters, 16 kWh battery.
Patching PIP-4048/5048 inverter-chargers.
If you appreciate my work, you can buy me a coffee.
User avatar
Johny
Senior Member
Posts: 3749
Joined: Mon, 23 Jun 2008, 16:26
Real Name: John Wright
Location: Melbourne
Contact:

Weber and Coulomb's MX-5

Post by Johny »

Good going guys. Enjoy the debugging phase - it's part of the journey I reckon.
User avatar
coulomb
Site Admin
Posts: 6340
Joined: Thu, 22 Jan 2009, 20:32
Real Name: Mike Van Emmerik
Location: Brisbane
Contact:

Weber and Coulomb's MX-5

Post by coulomb »

Johny wrote: Enjoy the debugging phase - it's part of the journey I reckon.

Thanks, Johny, I think that's good advice. We certainly can't avoid it, and it's all part of the journey as you say, so why not enjoy it?

Before the above problem was found with the bad crimp (it was one of those very thin wires that has to be doubled up to make barely enough thickness to crimp to), we thought it might have been the long suffering auxiliary battery. Weber pointed out that it was in fact only 2.3 years old, based on this post when we replaced the original.

Yesterday, Weber took out the old auxiliary battery, took off the cover plate with the snorkel tubes, and cleaned it up. I dropped by Supercheap Auto for a NS40ZLS battery on the way to the lab. I had to check that this was right - this was the most ordinary looking, all-black 40 Ah battery, but I guess the colour varies with time. The dimensions were right, the low profile filler caps fitted, and the transplant went smoothly.

Alas, with every load on (headlights, blower on 4, cooling pump, vacuum pump, power steering pump, and others I've forgotten, the load was some 25 A with the DC/DC fuses out (as measured by the DC clamp guess-o-meter), and the new battery sagged to about 11.9 V. This is not much better than the one it replaced. Well, it needed doing, the old one had had a lot of deep discharges, so its capacity would be badly reduced.
MG ZS EV 2021 April 2021. Nissan Leaf 2012 with new battery May 2019.
5650 W solar, 2xPIP-4048MS inverters, 16 kWh battery.
Patching PIP-4048/5048 inverter-chargers.
If you appreciate my work, you can buy me a coffee.
User avatar
weber
Site Admin
Posts: 2934
Joined: Fri, 23 Jan 2009, 17:27
Real Name: Dave Keenan
Location: Brisbane
Contact:

Weber and Coulomb's MX-5

Post by weber »

The MX-ϟ is back up on stands and all is in readiness for David Blythe (DoT approved engineer) to inspect and test at 10 am tomorrow. All boxes are ticked on the NCOP 14 checklist.

One last-minute bit of engineering design was required when I noticed that the handbrake cables were rubbing on some cell clamps. The photo, looking up from underneath, shows the solution adopted. Some black powder-coated folded steel angle, cut to be a neat fit and siliconed in place. The silicone is only needed to stop it rattling, and seal it from rusting at the cut ends. The handbrake cable itself holds the angle in place. Not pretty, with all those keyholes, but it will do the job. On the right [Edit: in the same photo] you can see exactly the sort of clamps that it's protecting the handbrake cable from.

Image

I'm so excited, I feel like a kid on Christmas Eve. Enormous thanks to all those who've helped get us to this point.
Last edited by weber on Tue, 01 Oct 2013, 05:16, edited 1 time in total.
One of the fathers of MeXy the electric MX-5, along with Coulomb and Newton (Jeff Owen).
User avatar
woody
Senior Member
Posts: 1716
Joined: Sat, 21 Jun 2008, 02:03
Real Name: Anthony Wood
Location: Mt Colah

Weber and Coulomb's MX-5

Post by woody »

All the best for your Engineering Inspection!
Planned EV: '63 Cortina using AC and LiFePO4 Battery Pack
Renard
Groupie
Posts: 219
Joined: Sun, 29 Aug 2010, 18:55
Real Name: Robert Fox
Location: Cobargo NSW

Weber and Coulomb's MX-5

Post by Renard »

The suspense is killing us!
Renard
User avatar
coulomb
Site Admin
Posts: 6340
Joined: Thu, 22 Jan 2009, 20:32
Real Name: Mike Van Emmerik
Location: Brisbane
Contact:

Weber and Coulomb's MX-5

Post by coulomb »

Renard wrote: The suspense is killing us!
Sorry, we've been busy.

Today was the day of the registration test, and our result was: an F!

All was good with the electricals, though we will be using some stainless steel zip ties on the conduits down the transmission tunnel. These zip ties are available from the electrical section of Bunnings. If the plastic cable ties let go and cables were to wrap around the tail shaft, well, this could be bad. He also suggested that we put more polycarbonate in the battery boxes, especially around the wheel well area. Stones end up everywhere, and do amazing amounts of damage.

The brake deceleration test was acceptable. Our engineer used a fancy machine that records pedal pressure and deceleration.
Image   Image
Considering the tyres that were allowed to harden for over 4.5 years without use, and the new brake pads not being bedded in, the okay deceleration of 0.65 g was really quite good. The car was loaded with 2 x 20 kg bags of chook feed and a ten litre container of water behind the back seat, to achieve close to worst case weight.

He also didn't like our tyres. While they are just within their rated loading of 475 kg, he considers that commercial tyres like that aren't really meant to be run close to their ratings. Weber has found some tyres that fit the existing wheels and give an extra 220 kg of load rating. The existing tyres are 185/60R14; the ones he found are 195/60R14. He strongly recommends a wheel and tyre upgrade, but will pass the car without this.

Where we failed was with the brake vacuum system. After only two brake pulses, the brake assistance is noticeably less on the third press. So we need a vacuum reservoir. We have some 65 mm poly pipe and assorted bits of plumbing (pipe and end caps from Bunnings; fuel/vacuum cable from Clark Rubber; barbed joiners and T pieces from Supercheap Auto). We're about half way through the install. Our engineer will return tomorrow afternoon for a retest, and hopefully we'll get a pretty blue compliance plate. He has the machine to make the plate on the spot.

It looks like after that, we'll need a roadworthy certificate, download a registration form off the web, fill it in, and bring it to the Department Of Transport office for actual registration.

[ Edit: 110 kg -> 220 kg; 110 kg was for the rear axle, which is the axle of most concern. Department of Transport, not Traffic, duh. 190 -> 195 tyre size. ]
Last edited by coulomb on Tue, 01 Oct 2013, 15:46, edited 1 time in total.
MG ZS EV 2021 April 2021. Nissan Leaf 2012 with new battery May 2019.
5650 W solar, 2xPIP-4048MS inverters, 16 kWh battery.
Patching PIP-4048/5048 inverter-chargers.
If you appreciate my work, you can buy me a coffee.
User avatar
coulomb
Site Admin
Posts: 6340
Joined: Thu, 22 Jan 2009, 20:32
Real Name: Mike Van Emmerik
Location: Brisbane
Contact:

Weber and Coulomb's MX-5

Post by coulomb »

I forgot a mildly amusing anecdote. We were ready for the brake test on the road, when I realised that things were too quiet. Oops! Forgot the coolant pump (again!) and the power steering pump. We had turned these off earlier to be able to hear the vacuum pump coming on and off. I asked the engineer if he was comfortable and would like a drink, while Weber jumped under the bonnet to turn up the power steering voltage (we have a knob for that), and reconnect the bullet connectors for the coolant pump. Oops!

Image   Image

When I pulled out the bullet connectors earlier, and had inadvertently pulled out the wire from the crimp connector. Oh well, it must have been a bad crimp in the first place. We quickly replaced it, and found that the other wire had pulled out as well! Oh, no wonder, we had used the blue connectors; these wires were thin enough to need the red connectors. So we used a red connector, and found that the red bullets are a different diameter to the blue connector, so it wouldn't fit! Meanwhile, time is ticking away on the engineer's meter... We made it fit for the test. It's another thing we need to fix properly as soon as the vacuum system is updated.
MG ZS EV 2021 April 2021. Nissan Leaf 2012 with new battery May 2019.
5650 W solar, 2xPIP-4048MS inverters, 16 kWh battery.
Patching PIP-4048/5048 inverter-chargers.
If you appreciate my work, you can buy me a coffee.
User avatar
coulomb
Site Admin
Posts: 6340
Joined: Thu, 22 Jan 2009, 20:32
Real Name: Mike Van Emmerik
Location: Brisbane
Contact:

Weber and Coulomb's MX-5

Post by coulomb »

Two pony tails off for a registration brake test!

Image

Edit: Thanks to Jeff Owen for these photos.
Last edited by coulomb on Tue, 01 Oct 2013, 17:10, edited 1 time in total.
MG ZS EV 2021 April 2021. Nissan Leaf 2012 with new battery May 2019.
5650 W solar, 2xPIP-4048MS inverters, 16 kWh battery.
Patching PIP-4048/5048 inverter-chargers.
If you appreciate my work, you can buy me a coffee.
Renard
Groupie
Posts: 219
Joined: Sun, 29 Aug 2010, 18:55
Real Name: Robert Fox
Location: Cobargo NSW

Weber and Coulomb's MX-5

Post by Renard »

At least the failed item was not fundamental.

I'm a bit surprised you didn't have a reservoir, but I suppose you have been very limited with cubic capacity under the bonnet. I have the same pump as you and my reservoir is about 3/4 litre. Also I oblige the pump to run for several seconds after it reaches its pressure switch cut-off point so as to get extra vacuum storage.
Renard
User avatar
coulomb
Site Admin
Posts: 6340
Joined: Thu, 22 Jan 2009, 20:32
Real Name: Mike Van Emmerik
Location: Brisbane
Contact:

Weber and Coulomb's MX-5

Post by coulomb »

This is something I wanted to show a photo of earlier, but it was still being "glued" by silicone, and so held on temporarily with hideous tape. Now that the silicone is set, the tape is gone.

Image   Image

This is the CAN-ethernet adapter that is so useful for connecting to a laptop or netbook, so it can view telemetry from the motor controller. Now that the DCUs are hidden underneath the passenger seat foot well, we had to find a place for this adapter, preferably somewhere within reach of the expensive purple CAN cable that we already had. The space between the air conditioning evaporator and its blower fan was the perfect place. As you can see in the second photo, it lives behind the glove box, and the ethernet cable can be plugged in from under the glove box. When not in use, the adapter is completely out of sight.

Yes, that bar that the bottom of the glove box screws into is quite rusty. One day...
Last edited by coulomb on Tue, 01 Oct 2013, 20:26, edited 1 time in total.
MG ZS EV 2021 April 2021. Nissan Leaf 2012 with new battery May 2019.
5650 W solar, 2xPIP-4048MS inverters, 16 kWh battery.
Patching PIP-4048/5048 inverter-chargers.
If you appreciate my work, you can buy me a coffee.
User avatar
weber
Site Admin
Posts: 2934
Joined: Fri, 23 Jan 2009, 17:27
Real Name: Dave Keenan
Location: Brisbane
Contact:

Weber and Coulomb's MX-5

Post by weber »

I emailed the engineer some weeks ago saying, "We're not sure if we need a vacuum reservoir. How many repeated brakings are required and in how short a time?" In reply he referred to the fade test in the abridged ADR31/01 brake tests, and included a copy. This required 15 successive brakings, but allowed up to 45 seconds between them. This was easily met without a reservoir.

But in driving tests today he asked for repeated brakings in rapid succession, about 0.5 to 1 second apart. And in that case there was a noticeable decrease in vacuum assist on the third braking and the low vacuum warning light came on with the 5th braking.

We've now added two reservoirs totalling 2.9 litres (2 of 460 mm x nominally 65 mm dia PVC pipe). Is yours really only 0.75 L, Renard?

Jeff Owen may not believe this, given my aversion to non-SI units, or he may be surprised that I'm admitting it Image but I already owned a 1/8" BSP taper tap with which Coulomb and I tapped the holes to put the brass fittings into the PVC. Not that they wouldn't have made their own threads.

Now, at a rate of two brakings per second, the low warning light doesn't come on until the 13th braking, so presumably there will not be a noticeable decrease in vacuum assist until about the 7th such rapid application. I hope this is sufficient.

Image    Image

Image    Image

Image

Engineer is returning at around 12:30 pm today (Wed).

Later we'll have to take the reservoirs out and paint them black (or red?) and tidy up that wonky vacuum line. But right now we just want to ensure we get her registered before we take her to Canberra for the AGM and festival.
Last edited by weber on Wed, 02 Oct 2013, 19:29, edited 1 time in total.
One of the fathers of MeXy the electric MX-5, along with Coulomb and Newton (Jeff Owen).
Renard
Groupie
Posts: 219
Joined: Sun, 29 Aug 2010, 18:55
Real Name: Robert Fox
Location: Cobargo NSW

Weber and Coulomb's MX-5

Post by Renard »

weber wrote:

We've now added two reservoirs totalling 3 litres (2 of 460 mm x 65 mm dia PVC pipe). Is yours really only 0.75 L, Renard?

Jeff Owen may not believe this, given my aversion to non-SI units, or he may be surprised that I'm admitting it Image but I already owned a 1/8" BSP taper tap with which Coulomb and I tapped the holes to put the brass fittings into the PVC. Not that they wouldn't have made their own threads.


Actually, my reservoir may be more like 1 litre, but it's in a hard-to-measure position.

The 45 second gap between brakings is reasonable in reproducing city driving with traffic lights etc. The other scenario of rapid brakings would correspond with a steep descent -- but then surely one should be in a lower gear and regenerating too.

It's a delicate balance with these engineers: they may be asking for something not legally necessary or in some way unreasonable, but I think it can sometimes be prudent to humour them rather than to insist on the letter of the law which may be on one's own side.

As you say, those brass fittings make their own threads, but with plumbing still being BSP you are forgiven.
(Disclaimer: I still own a few UNC and Whitworth taps.)
Renard
User avatar
woody
Senior Member
Posts: 1716
Joined: Sat, 21 Jun 2008, 02:03
Real Name: Anthony Wood
Location: Mt Colah

Weber and Coulomb's MX-5

Post by woody »

Renard wrote: It's a delicate balance with these engineers: they may be asking for something not legally necessary or in some way unreasonable, but I think it can sometimes be prudent to humour them rather than to insist on the letter of the law which may be on one's own side.
A case of "You don't have to agree with me, but it's easier if you do"...
Planned EV: '63 Cortina using AC and LiFePO4 Battery Pack
User avatar
coulomb
Site Admin
Posts: 6340
Joined: Thu, 22 Jan 2009, 20:32
Real Name: Mike Van Emmerik
Location: Brisbane
Contact:

Weber and Coulomb's MX-5

Post by coulomb »

Today was the day of our registration retest.

The result was: PASS!

The ~ 2.9 litres of vacuum reservoir seems to have impressed the engineer.

Here he is "printing" the plate with his genuine birchwood hammer:

Image   Image

Here it is on the MX-5, in the area where the windscreen wiper linkages operate.

Image   Image

Next: safety certificate (formerly known as the roadworthy certificate), and hopefully registration. Woot!
MG ZS EV 2021 April 2021. Nissan Leaf 2012 with new battery May 2019.
5650 W solar, 2xPIP-4048MS inverters, 16 kWh battery.
Patching PIP-4048/5048 inverter-chargers.
If you appreciate my work, you can buy me a coffee.
User avatar
Johny
Senior Member
Posts: 3749
Joined: Mon, 23 Jun 2008, 16:26
Real Name: John Wright
Location: Melbourne
Contact:

Weber and Coulomb's MX-5

Post by Johny »

Congratulations guys - well done!

Edit: Also nice that you got a solid plate - mine was a foil stick-on and he wrinkled it!
Last edited by Johny on Wed, 02 Oct 2013, 11:57, edited 1 time in total.
Renard
Groupie
Posts: 219
Joined: Sun, 29 Aug 2010, 18:55
Real Name: Robert Fox
Location: Cobargo NSW

Weber and Coulomb's MX-5

Post by Renard »

Great news!

I suspect that an engineer needs to get you to do something to feel that he's doing his job.

Just as a matter of interest, what date did you start?

Edit: In NSW we don't get a plate, just a paper certificate.
Last edited by Renard on Wed, 02 Oct 2013, 12:26, edited 1 time in total.
Renard
User avatar
PlanB
Senior Member
Posts: 471
Joined: Sat, 16 Jan 2010, 15:24
Real Name: Kris McLean
Location: Freemans reach
Contact:

Weber and Coulomb's MX-5

Post by PlanB »

Nice milestone for Spring guys. Just want to say I'm onto you. I've kept a spreadsheet of everything you've put into that vehicle & the total exceeds the cars volume. Conclusion, the machine is a tardis!
User avatar
weber
Site Admin
Posts: 2934
Joined: Fri, 23 Jan 2009, 17:27
Real Name: Dave Keenan
Location: Brisbane
Contact:

Weber and Coulomb's MX-5

Post by weber »

The amazing Andrew Burrows of Chandler's Corner Auto was able to fit in a Safety Certificate inspection for us straight after the Engineer approval. He has taken a keen interest in the project all the way through its 4.75 year history. Started Jan 2009. He knew about Ron Penfold's EV from something like 16 years ago, and knew that it was powered by a starter motor from a Sabre fighter jet.

Image    Image

His apprentices had seen MX-5's before but were blown away by what this one contained within its tiny frame. They even had to show the Repco guy who was just delivering parts.
One of the fathers of MeXy the electric MX-5, along with Coulomb and Newton (Jeff Owen).
User avatar
weber
Site Admin
Posts: 2934
Joined: Fri, 23 Jan 2009, 17:27
Real Name: Dave Keenan
Location: Brisbane
Contact:

Weber and Coulomb's MX-5

Post by weber »

We ran out of time to get her registered today, but here are the two mad professors celebrating, and toasting absent friends, in particular Newton (Jeff Owen) who has already spent far too much time here, helping get everything ready in the last several days, given that he has his own urgent project.

Image
One of the fathers of MeXy the electric MX-5, along with Coulomb and Newton (Jeff Owen).
User avatar
BigMouse
Senior Member
Posts: 600
Joined: Thu, 28 Oct 2010, 02:39
Real Name: Vincent Tannahill
Location: Silicon Valley
Contact:

Weber and Coulomb's MX-5

Post by BigMouse »

Great news! Now you've got me tempted to make the trip to Canberra for the AGM. Wollongong is closer than Sydney, so I guess I've got no excuse ;-)

Congrats!
User avatar
weber
Site Admin
Posts: 2934
Joined: Fri, 23 Jan 2009, 17:27
Real Name: Dave Keenan
Location: Brisbane
Contact:

Weber and Coulomb's MX-5

Post by weber »

Thanks guys!

I don't for one minute think that our engineer, David Blythe, was being arbitrary or unreasonable by insisting on significantly more than 5 rapid brake presses before the low vacuum alarm came on. He was happy with the 14 we achieved by adding the reservoirs.

I was only annoyed that he couldn't tell us in advance what that requirement was. But it turns out that's not his fault. There are no regulations about it. It seems that it is assumed in the regs, that vacuum for brake boosting is instantaneous and unlimited, coming as it used to from an intake manifold with the throttle closed.

David Blythe brought his father with him on the last visit. Eric Blythe is also a vehicle compliancing engineer (retired). He complianced an electric vehicle built at the University of Queensland (my alma mater) in the 1980's, a slow lead-acid powered beast.

Not only the hammer but the set of punches has some history behind it since they belonged to father before son. Eric said he got the set cheap because it had no "X". So he just used "I" twice. I don't know why, but I love stuff like that.

And yes PlanB. You got us. I'll bet you were alerted by the fact that "Mazda Miata" (what the MX-5 is called in the US) is in fact an anagram of "Mama Tardis". Well OK, "Mama Taadiz", but you can't blame those Japanese guys for having poor English spelling. Image

Image    Image
Last edited by weber on Wed, 02 Oct 2013, 20:36, edited 1 time in total.
One of the fathers of MeXy the electric MX-5, along with Coulomb and Newton (Jeff Owen).
Renard
Groupie
Posts: 219
Joined: Sun, 29 Aug 2010, 18:55
Real Name: Robert Fox
Location: Cobargo NSW

Weber and Coulomb's MX-5

Post by Renard »

weber wrote: Thanks guys!

I was only annoyed that he couldn't tell us in advance what that requirement was. But it turns out that's not his fault. There are no regulations about it. It seems that it is assumed in the regs, that vacuum for brake boosting is instantaneous and unlimited, coming as it used to from an intake manifold with the throttle closed.


How can it be a requirement if there are no regulations?

I see the the requirement set out in ADR Design Rules 31 Annex 3. Section 1.5.1.1 (http://www.comlaw.gov.au/Details/F2010C00150)

But where does it say that more is required?

But those are happy pictures on the road, and we're all very pleased indeed for you.
Renard
CometBoy
Groupie
Posts: 313
Joined: Fri, 20 Jun 2008, 02:59
Real Name: Bruce

Weber and Coulomb's MX-5

Post by CometBoy »

Congratulations guys.

I have followed your project from start to finish.

The journey along the way was I bit like reading ‘War and Peace’ but in the end you have now created a masterpiece of engineering……

Enjoy!

Cheers
Bruce
Post Reply