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I took my battery box mockup to Mt Roskill Sheetmetal today. They can't fold over the lip in the complex section I need but so I'll have to spend some time with the anvil.

It would appear that Hyundai will be the first manufacturer to field an electric car in New Zealand. Stuff has a story and Scoop has the press release. I don't suggest looking on Hyundai New Zealand's website because it's inside a flash monstrosity. If you're interested, click "About" at the top, click "News & Events" at the left, and the EV press release is the top one at the moment, click "Read More" for more details.

They're converting Getz in conjunction with Ross Blade at Blade Electric Vehicles in Australia. The first car is to be delivered in November.

Blade appears to be using Thunder Sky cells (like I am) and Azure Dynamics air cooled AC drive systems. The spec sheet for the Australian version looks decent, 120km urban range, 110km/h top speed, 0-60 in 7 seconds, air conditioning and power steering. Hyundai Australia have agreed to honour their guarantee on the rest of the car and Blade offers 5 years labour and the manufacturer's warranty on parts. Is the 0-60 time is in km/h or mph? If the former then it's not very quick.

The New Zealand version is being converted in New Zealand. Does anyone know who's doing it? The 2 door Australian version is priced at AU$35,000+GST. They are planning to build 200 cars per year (will they beat Tesla?) but it's not clear if that is the New Zealand or Australian facility.

I wonder what sort of manufacturer's warranty applies to the Thunder Sky cells? And I also wonder what Hyundai corporate thinks of this, Hyundai New Zealand is a 100% New Zealand owned company and presumably has some autonomy.

Charging single cells was too slow, so I configured my LabJack U3 to measure two cells and doubled my charging speed. I also discovered that my cells are wildly out of balance. This isn't terribly surprising since they were manufactured in March and haven't been charged since.

• Cell 1832 required fewer amp-hours to reach end of charge (defined in this profile as 4.2V at 3A).
• Cell 1833 never got onto the exponential(?) voltage rise near end of charge.
• Cell 1832 took about 4Ah from the beginning of the end of charge voltage rise.
• Cell 1832 had a higher charge voltage throughout the whole charge, it is unknown if this can be used to estimate state of charge (the literature says no).
• Both cells relax quickly after charging is stopped. More than 24 hours later, 1832 is at 3.366V and 1833 is at 3.341V.
• My bench supply isn't well cooled, when run at 3A it overheats, the maximum output current falls somewhat as it heats up but not enough to protect itself. To be fair it's sold as a 2A supply but I'm running it at 3A. You can see the current fall at the beginning of the charge and then rise again after I stick a fan on it.
• Don't power the fan from the charging power supply itself as this messes with your measurements (I'm not sure why).

So we can conclude that cell 1833's state of charge was at least 4Ah less than 1832. We don't know why this is, most likely the cell's self-discharge rate is different, but it could also be differing state of charge when the cells left the factory. Differing self-discharge is easy to measure but you have to wait for the self-discharge to happen. Once a fully featured BMS is installed and regular charging is undertaken, maybe the source will be discovered.

I'm going to have to find some sensible way of storing this data so I can analyse the lifetime behaviour of my cells.

So far, I've fully charged 4 cells and partially charged 5 (>10Ah in without hitting end of charge), my goal of 30 by October 20th is easily achievable.

Stay tuned for White LED - Darlington balancers.

I'm planning to have my car running at the Mini Nationals in Hamilton on the 25th of October. This isn't going to be an easy task as there is a lot to do. F40 Motorsport are working on my motor-gearbox adapter plate. It's not cheap, but they say they can have it done in time. My first cardboard template for the rear battery box didn't work out so well, now I've replenished my cardboard supply I can try again.

I likely won't have time to mount all my cells, but there is a bigger problem, I don't have a BMS. The only safe way to charge without a BMS is in parallel or, better, cell by cell. I need about 30 cells to reach the minimum voltage of my inverter. If the cells are half charged from the factory, then I need about 20*30=600Ah. I've got a 3A bench supply, which will do this in 200 hours, or almost 10 straight days if I connected them all in parallel.

I think I will have to see how well the PFC-30 goes into a 3v cell, they say it's safe into a short circuit so this shouldn't be a problem.

In preparation for this task, I finished the charging part of my battery test bench. You can see below the partial first charge of cell 1939. I wasn't able to make the watchdog timer in my LabJack U3 work, and without that I don't trust it enough to leave unattended. The power supply is limited to 4.2V which is safe in theory, but I would like to watch at least the first charge.

The current jumps around because I fiddled with the voltage limit on the power supply a couple of times. Also, the current appears to be quite strongly dependant on the voltage, but that is because the power supply's voltage regulator is separated from the cell by a quite high resistance shunt. I'll replace this with a much lower resistance shortly -- it made sense when I was trying the system out on AAA cells, but now I'm measuring amps, not milliamps.

I've cut the hole for the lower battery box in the boot. I'm going to have a sheet metal box folded up to fit and I'll spot welded in place (well, I'll spot mig weld it). I used string lines to get the box square, but unfortunately got one corner wrong, so I can't take the cut out part to the sheet metal guy as a template. I'll have to trace it out with cardboard. I plan to fit 28 cells in this box and a bunch more above them.

In other news, I talked to F40 Engineering at the New Zealand Speed Show. I showed them some photos and they are enthusiastic about joining my motor to my gearbox. This is an improvement over my previous engineer who wasn't. I'm going down with the parts on Tuesday.

Recently I've been helping Philip Court with his electric race car. It's going to be at the New Zealand Speed Show on the 20th and 21st of September, that's this weekend!

The GS750V is based on a New Zealand designed Saker SV1GT with a Siemens motor and Evisol controller. Check out the Greenstage website for more information about this car.

"Plug In New Zealand – Switch On To Electric Cars" presented by Dr Mike Duke, Senior Lecturer, Mechanical Engineering, University of Waikato.

6.00pm
Crowne Plaza Hotel
Ballrooms 1 & 2
128 Albert Street
Auckland City