jonescg's eCRX build thread

Post by **jonescg** » Mon, 30 Jul 2012, 04:53

Hi Everyone,

Although it is well known that I have little interest in cars (two wheels good I say) my wife said she would still like to have one. We rarely need to move other people around, and rarely need to drive anywhere at all. So the concept seemed silly to me. I did however tell Katherine that I would buy a car provided it was small, lightweight, a two-seater and would eventually be turned into an electric. She agreed, so I spotted a perfect candidate in Adelaide. AEVA member Tim (celectric here on the forum) collected the car and stowed it until I was able to collect it.

So after visiting my family in SE Queensland, my wife and I flew to Adelaide and became acquainted with the 23 year old Honda CRX. That day we drove up to Cudlee Creek in the Adelaide hills for lunch with some biker friends. Chain of Ponds and Gorge road are two very nice roads to test a little sports coupe out

I know the road well on two wheels. That night we had dinner with Tim and talked EV crap for ages. Katherine was a bit bored, no doubt

Early the next morning we set off up Main North road in the dark, dreary weather. After about an hour of driving there was a break in the weather and we got to watch the sun rise... In front of us. That's not right...

I had failed to take the Port Wakefield road, and had been driving north-east along the Sturt Highway

It took about another hour to find our way back through the Clare valley and onto the main road north. In doing so, a passing 4WD kicked up a stone which smashed the RHS headlight

Lights still worked at least.

We stopped at Kimba where a giant galah landed on the car:

I continued to drive the lonely Eyre highway... Katherine couldn't share the driving - she never learned how to drive a manual

Lots of straight roads and desert views for the best part of three days:

And one very straight road:

But we made it home. After our little detour of the road to Renmark, we decided to call it Sturt in honour of the highway and explorer. Sturt is also an anagram of trust. Which kind of sums up everything about this car - trust in the seller, trust in Tim to handle my cash and pick it up, and of course, trust it would make it home OK. And trusty it sure is. After 216,000 km the ICE won't give up.

There is a lot of room behind the seats for batteries, as well as a bit up the front in the engine bay. The fuel tank on these cars were tiny - barely 40 litres. And it doesn't really earn you much extra space once you pull it out. It will take some thought, but for now I need to get it over the pits in WA so I can put a tow bar on it for hauling motorcycles

This car will be powered by the same motor going into the new race bike - An Evo AFM140, driven by a RMS inverter. Tips on battery placement would be much appreciated, as I don't want to lose too much boot or spare tyre space.

Don't expect many updates for a long time, but I will get to it eventually.

Cheers,
Chris

Post by **jonescg** » Fri, 17 Aug 2012, 06:20

So I am almost ready to take the oil burner across the pits. It's currently unregistered and I figure since it will take a long time to save enough cash get it converted, it will be handy as a weekend runabout.

But I got to thinking about weight distribution.

This is a front wheel drive car, and the lins share of weight was onver the front wheels (575 kg and 350 kg rear). The engine bay doesn't leave a lot of room for extra batteries, but it might be possible. Otherwise, it will be super convenient to have a single, 37 kWh battery pack behind the seats. It won't take up bootspace but it will move the weight away from the front resulting in some pretty serious understeer and wheelspin. I plan on using the existing gearbox and clutch to keep things simple, but it would be nice to have a drive right to the diff.

I doubt I can fit more than 6 kWh up front if at all, and really, keeping the cells warm in winter is a nice option. These EiG cells are good from 0 to 50'C but like all lithium cells they drop off in the cold. So keeping them out of a chilly engine bay seems logical.

Any other thoughts?

Post by **antiscab** » Fri, 17 Aug 2012, 14:40

Those EiG cells are Lithium Manganese right?

if so, keeping them cool in summer will be necessary.

50 deg C is a hard upper limit, and operating temp is best around 25 deg C

aging tends to double for every 10 deg C

Matt

Post by **Johny** » Fri, 17 Aug 2012, 15:10

jonescg wrote:These EiG cells are good from 0 to 50'C but like all lithium cells they drop off in the cold. So keeping them out of a chilly engine bay seems logical.

I wouldn't be that concerned about the engine bay being cold. Arrange to insulate the hood so you keep frost away, then close in as much as possible to prevent too much airflow.
I had the same issue in that I needed to get as much weight up front as possible and by the time I'd crowded everything in I wanted there's not much room for air anyway.
Better weight distribution should be the aim I think.

Post by **PlanB** » Fri, 17 Aug 2012, 15:59

Where you sourcing the EiGs from Chris? I tried emailing them but not getting any replies.

Post by **jonescg** » Fri, 17 Aug 2012, 18:09

I am sourcing them from the supplier: http://www.eigbattery.com/eng/product/C020.pdf

Matt, they are actually an improvement on LiMn, in that the cathode is Li(NiMnCo)O2. The Ni and Mn stabilise the cathode so you don't get CoO2 being reduced, generating reactive oxygen species.

Minimum order of 1000 cells, so something close to $77,000

However I think with a big group purchase we can make this numerator appear less scary. Life cycle is less important to me than energy density. That said they appear to be good for at least 2000 cycle under normal use.

Post by **jonescg** » Sat, 18 Aug 2012, 07:36

So for the electrification of the CRX, I plan on using the EiG Li(NiMnCo)O2 20 Ah cells.

Turns out they really only want to sell me the cells, not the packaging which is weird because I would have thought that's what they want. Anyway, I have devised my own termination system.

I now know why their termination system uses diagonal bits of copper with all of the cells lined up in parallel. The tabs are so far off-set to one side, they practically touch the table they are lying on. So if you were to alternate the polarity (that is, flip the next cell to make a series connection) the positive and negative tabs of the two cells would be damn near touching.

So a diagonal termination system it is then. In a way this actually makes it much easier, as I don't need to work with odd-numbered rows of cells to make the next row line up.

So how does this look?

This is a 12s, 3p arrangement. This gives a 60 Ah cell, and I will need 172 of them in series. Enough to run the PM150 DZ inverter and Evo motor. 37 kWh on board 8) I should have more range than a Nissan Leaf!

The holes are drawn as 4 mm holes, but obviously the brass blocks would be drilled at 3.5 mm and tapped to M4.

Post by **BigMouse** » Sat, 18 Aug 2012, 23:22

jonescg wrote:Minimum order of 1000 cells, so something close to $77,000

$77 for a 20ah cell is pretty pricey, especially when you still have to come up with packaging and connection yourself.

I'm curious why you're more concerned with energy density than life cycle. To the point where you're willing to pay more for a cell with a relatively short life (1000 cycles to 80% retention) in order to get that energy density. Planning long trips in it?

I assume this is necessary to fit 37kwh worth of battery in to such a small car. 212kg is very impressive for a pack of that capacity after all!

Post by **jonescg** » Sun, 19 Aug 2012, 03:09

That price is landed, GST and customs included. It could be less (I fecking hope it's less!)

Life cycle is less important to me because I drive so infrequently. If we use a car, it's usually to travel a substantial distance (like up to 200 km). Any further, we're usually on the Blackbird (1100 cc sport tourer). I'd rather have the juice to get where I need, and have a bit of fun doing it, than have a less impressive pack which lasts for 10 years. After all, come 2017 the next best chemistry will be out and these cells will be throw-away cheap.

Yep, it will be all in the name of range. I have accepted a 100 kg overshoot, so ~220 kg worth of cells just scrapes in. If weight (or money) wasn't an issue I could easily fit >50 kWh...

Post by **jonescg** » Wed, 10 Oct 2012, 23:49

A brief update on the eCRX. It is still a petrol CRX, but now it's a LEGAL petrol CRX

The inspiration to convert it stepped up a notch when I fuelled up the other day. We'd done 225 km and it cost me $40! Had this been electric it would have cost about $8.50.

I am more convinced than ever that I want to put all of the batteries in one place which is easily inspected and easily removed. A 37 kWh pack. (including packaging) will occupy a space of 610 mm deep and 810 mm wide, and roughly 240 mm high.

This will be directly behind the seats, and just in front of the rear wheels. It can sink down a fair bit too, as the petrol tank can come out. Best of all, the whole lot can be unbolted and lifted out with an engine hoist.

I can mount the chargers on top of this box for pre-heating the cabin on cold mornings

however, there will be plenty of room under the bonnet, and it would probably look neater too. Given the recent heat issues with this chemistry, some king of active air cooling of the pack might pay off.

Anyway, I only have $4000 left to pay on the AFM140 and I can begin to get the race bike together for next year, pending continued employment.

Post by **jonescg** » Sun, 14 Oct 2012, 05:04

Today I went and bought a hydraulic jack and decided to change the oil in the car. Holy sh*t, was this a gong-show. The CRX was already pretty low to the ground, and the previous owner had it lowered further still. So I had to jack it up in several stages before I could put the supports under and proceed to do the dirty deeds. Well the catch tray leaked, the filter was stuck on firmly so I had to bush-mechanic it off (drive a screw-driver through it and twist) which covered me in more oil... But I finally did the oil change.

All of this has re-affirmed my desire to electrify the CRX. Oil changes are a pain in the arse, the fuel economy is so bad that an F250 looks good in comparison, and the weird vibes at 2100 rpm are off-putting.

So I decided to do some measurements.

A 37 kWh pack of EIG cells is 168s3p. I can make this as 6 blocks of 28s, which once isolated, is in the realm of ELV segments. 6 rows of 84 cells measures in at 605 mm deep and 780 mm wide. I will be separating them with 5 dividers, so lets call it 822 mm wide all up. The height of the cells will average about 240 mm, but will be higher at the back to accommodate the contactors and fuses etc.

(the dimensions here are deceiving - the depth of the pack is going to extend past the speaker wall, while the whole thing will be sunken into the chassis a fair way since the fuel tank will be removed)

This is ideal, as the weight is still in front of the rear wheels. It's pretty substantial (230 kg) so I will be cutting into the chassis and reinforcing with plenty of steel brackets. It also leaves the front pretty light - just a 40 kg motor, 11 kg controller, a small radiator or two for the motor and controller and a couple of 350 V chargers. Just as well as I plan on getting rid of the power steering. I'll keep the heater box as it runs off the 12 V system, and hopefully won't get used that much.

Assuming an average economy of 150 Wh/km, which is probably pretty good going, I can get 250 km on a charge. Not much less than what I can get on a tank of petrol!! I heard that an iMiEV can get 140-160 Wh/km, which is impressive for a car shaped like a brick. Imagine what a CdA of 5.2 will get!

I have to keep reminding myself I have to build a race bike first...

Post by **BigMouse** » Sun, 14 Oct 2012, 15:29

I love that location for batteries. It's part of the reason I bought a coupe. Though with the size battery pack I'm planning on installing, all I'd have under the bonnet is a motor and controller, and the boot would be empty. Then I think I should be converting a smaller car

Looking forward to seeing this conversion underway! One of the nicest EV conversion I've seen was a CRX in Portland, Oregon.

Post by **jonescg** » Sun, 14 Oct 2012, 22:56

Link no good - wouldn't happen to be this one?
http://www.metricmind.com/ac_honda/main2.htm

It's a nice conversion, and he certainly spent a lot of time with the seats out. Since the cells I'm using will offer some impressive space savings, I can do away with the need to remove the spare tyre. That said, a space-saving spare tyre would be nice. I could even fit that up the front too.

I see he also used a clutch. It looks like a lot of trouble and additional weight, but clutchless shifting on a CRX is nearly impossible. Pulling over to change gears isn't attractive, although it does go from third to fourth more easily than back again. Second gear is 1.944 while third gear is 1.346 and fourth gear is 1.033. Fifth is 0.878, but I can't see me using this gear much. Final reduction is a helical 3.888.

Currently the ICE engine sits on 2200 rpm in fourth gear at 60 km/h, so it would be fine for 80 km/h zones. Third might be better suited to the sub 60 km/h zones.

Much to ponder...

Edit - just worked out my speeds at certain rpm.

at 1000 rpm in third gear, I should be going 20.0 km/h
at 3000 rpm in third gear, I should be going 58.5 km/h
at 3000 rpm in fourth gear, I should be going 76.3 km/h
at 4000 rpm in fourth gear, I should be going 106 km/h
at 4000 rpm in fifth gear, I should be going 125 km/h.

The motor's mechanical limit is 5000 rpm, so the fastest I could ever go is 5000 rpm in fifth gear, which is 156 km/h. This is a pretty substantial overdrive, so let's not go here. Max rpm in fourth is more like 133 km/h. However the torque available at the shaft is more than the ICE could ever put out, so maybe making full use of the gears is a good thing?

Post by **BigMouse** » Mon, 15 Oct 2012, 00:21

Yeah, that's the one. The photo I have of it shows the green antifreeze coolant in those clear hoses. Makes for a very cool engine bay.

Post by **Coulomb Racing** » Tue, 16 Oct 2012, 00:11

Hi Chris, looking good so far. Impressed you got it over the pits without too much hassle. If you want a spare pair of hands in future drop me a PM. I'm hoping to buy a MIG welder in December as I'm getting lessons at the moment.

James

Post by **jonescg** » Mon, 07 Jan 2013, 23:20

The 37 kWh battery would fit comfortably inside the 620 x 800 rectangle, and would be sunken into the chassis about 200 mm. Best of all, the whole lot could be hoisted out with an engine crane. I wish I had the funds to get started on this project, but alas I have a race bike to build first

Post by **jonescg** » Wed, 09 Jan 2013, 05:51

Hi All, I have a question.

This question spans several threads concerning split pack battery charging, EVSEs and charge point standards. So listen carefully

With the CRX, I have the option of splitting the 168 series pack into 6 convenient ELV segments of about 116 V each at the top of charge. If I was to charge the pack in halves, a pair of chargers will require a sizeable power supply, invariably split from three phase. But loading two of the three phases is not good.

Unlike the race bike, I can split the pack into three isolated segments for charging, and I can run them from the three phases of a standard 5 pin three phase plug. Brilliant!

I would wire them up as above. I could plausibly charge this car using the full 24 kVA of a 32A, 3 phase plug. Probably a bit of overkill, but the option for fast charging is there. Even if I used three 6 kW chargers, that's a full charge from flat in about 2.5 hours.

Now the question. What if I can't find a 32 A, 5 pin three phase plug? What if I can only find a 15 A GPO? I can't run my three big chargers off the one single phase circuit. So is it possible to get a device which limits the current draw from the supply to 12 A or so?

Also, does the Mennekes plug cover the 5 pin three phase supply? Are it's designs any different to that of the J1772?

Thanks in advance

Chris

Edit - yes the Mennekes plug looks the goods!

Post by **Nevilleh** » Wed, 09 Jan 2013, 12:21

You need a Protech BFS 180 charger. Rated at 5400 watts and can be powered by 3-phase for the max output, programmed to do whatever lesser output you want and powered by single-phase 230 V if that's your preference. Mine is set to 162 V and 2200 watts and it delivers a CC of 15 A up to the CV phase. I don't have 3-phase here else it would be doing more.

Post by **coulomb** » Wed, 09 Jan 2013, 14:00

jonescg wrote: So is it possible to get a device which limits the current draw from the supply to 12 A or so?

You can't limit the power at the AC end, but you can get the chargers to limit what they draw. Simply cut back the charge current. Assume an efficiency of say 0.95, and you want 4 A max per charger (so 12 A total, to be comfortably inside 15 A). So that's 240 x 4 = 960 W into each charger, so you don't want to draw more than 960 x 0.95 = 912 W on the DC side.

If each charger is charging 168/3 = 56 cells or 204 V @ 3.65 VPC, so limiting the charge current to 912 / 204 = 4.5 A would do it.

Most of the charging will be at about 3.4 VPC, so you could get your current limiting circuit to take the pack voltage into account, increasing the charge current by a factor of 3.65/3.4 = 1.073, bringing the charge current up to 4.8 A, but the extra complexity doesn't seem justified for 7% faster charging.

Elcon/TC Chargers, with or without CAN bus, can have their current limited, either with suitable limits in the CAN packets, or by putting a control voltage onto one of the pins of the 7-pin connector. Other chargers can usually be current limited by other means (e.g. a knob for Manzanita Micro chargers, I believe).

Post by **jonescg** » Sat, 12 Jan 2013, 03:01

I was chatting with a sparky today and I asked him "how much power can I draw from a 3 phase outlet"? He said I couldn't load up the phase to neutral three times, like I'd planned.

I was under the impression you could get 23 kVA from a 32 A, 5 pin socket. Whether I draw power at 415 V (415 * 32 * 1.732 = 23 kVA) or from three chargers each wired phase to neutral (240 * 32 * 3 = 23 kVA) you get the same answer.

I'm not sure what is more common; 32 A or 20 A 5 pin sockets, but if I choose three 4 kW chargers, each drawing 16 amps from the supply) I can use either socket. 12 kW would still give a rather fast charge - about 3 hours. What I couldn't do is utilise a 15 A GPO unless I dial back the charger output current.

Which leads me to this question:

coulomb wrote: Elcon/TC Chargers, with or without CAN bus, can have their current limited, either with suitable limits in the CAN packets, or by putting a control voltage onto one of the pins of the 7-pin connector. Other chargers can usually be current limited by other means (e.g. a knob for Manzanita Micro chargers, I believe).

I'd love to know how to do this, and in such a way that all three chargers were putting out a fairly even current. Do you know how to wire up the charge enable pins such that it can limit charge current?

Post by **antiscab** » Sat, 12 Jan 2013, 06:01

jonescg wrote: I was chatting with a sparky today and I asked him "how much power can I draw from a 3 phase outlet"? He said I couldn't load up the phase to neutral three times, like I'd planned.

That's only a problem if your loads have harmonics, and aren't actively PF corrected, as the neutral current gets pretty big.

Your chargers are PFC, so yes you can.
The resulting neutral current is pretty close to 0

jonescg wrote: I was under the impression you could get 23 kVA from a 32 A, 5 pin socket. Whether I draw power at 415 V (415 * 32 * 1.732 = 23 kVA) or from three chargers each wired phase to neutral (240 * 32 * 3 = 23 kVA) you get the same answer.

sort of. the first part is - 45 * 32 * .732 = 23 kVA

but for the next part, you are limited to the neutral current being 32A.

jonescg wrote:
coulomb wrote: Elcon/TC Chargers, with or without CAN bus, can have their current limited, either with suitable limits in the CAN packets, or by putting a control voltage onto one of the pins of the 7-pin connector. Other chargers can usually be current limited by other means (e.g. a knob for Manzanita Micro chargers, I believe).

I'd love to know how to do this, and in such a way that all three chargers were putting out a fairly even current. Do you know how to wire up the charge enable pins such that it can limit charge current?

With TC Chargers:

enable line pulled to ground = full power
enable line at 5V (or floating) = off

*but* it is linear in between those two, so you can either put a resistor between ground and the enable line to set a current limit, or you can use a power supply to vary the voltage between 0 and 5v.

Matt

Post by **jonescg** » Sat, 12 Jan 2013, 17:59

OK so three 2 kW chargers wired phase to Neutral would be the only way I could make use of a 5 pin plug? This way maximum current down the Neutral is 3 * 11 A. Damn. There goes my fast charge idea

It's a shame TC don't make them run off 415 eh? But then I couldn't use a single phase outlet...

Nancy just sent me a manual so I will look into a power adjuster circuit to suit a 10-15 A outlet.

Post by **antiscab** » Sat, 12 Jan 2013, 20:45

jonescg wrote: OK so three 2 kW chargers wired phase to Neutral would be the only way I could make use of a 5 pin plug? This way maximum current down the Neutral is 3 * 11 A. Damn. There goes my fast charge idea

no no - they are active PFC, ie PF is 0.99

put one on each phase - neutral and the resulting neutral current will be close to 0 (it will actually be only ~1% of the line current).

so you can draw 32A on each phase.

The only problem is if the PF was like 0.5 while the displacement PF was 1. Then the neutral current would be big.

Matt

Post by **jonescg** » Mon, 14 Jan 2013, 05:51

antiscab wrote:
With TC Chargers:

enable line pulled to ground = full power
enable line at 5V (or floating) = off

*but* it is linear in between those two, so you can either put a resistor between ground and the enable line to set a current limit, or you can use a power supply to vary the voltage between 0 and 5v.

Matt

OK, I have read through the pdf that Nancy sent me, and I think I have the gist of it. The charger will limit the DC output current according to the voltage at ENABLE. The charger's own 12 V supply can be used to generate the 0-5 V signal. So a voltage divider providing 3 V to ENABLE can fix the output to say, 33%.

This is good to know. I can now devise some more relay logic to allow either full charge power, one third power, or off (the usual position).

EDIT - fixed

Now, there are a few limitations to this idea, namely, I plan on using three 4 kW chargers from a 5 pin, three phase supply. So I would need to ensure that the way they are wired up could allow for both single phase and three phase charging. This will be hard! I might just have to settle for 6.6 kW charging from a 32 amp socket, three phase or otherwise.

Post by **antiscab** » Mon, 14 Jan 2013, 13:03

jonescg wrote: I plan on using three 4 kW chargers from a 5 pin, three phase supply. So I would need to ensure that the way they are wired up could allow for both single phase and three phase charging. This will be hard! I might just have to settle for 6.6 kW charging from a 32 amp socket, three phase or otherwise.

hard wire a 5-pin male plug to the bike.

for single phase charging, make an adapter that makes all 3 phases common.

maybe put a 15 CB in there aswell, just in case you forget to back the power off and you end up drawing 60A.

Matt