Wednesday, October 20, 2010


Well the car has finally been registered. After a 12 week delay comprising 7 weeks to receive the approval letter from Qld Transport and 5 weeks waiting for an inspection, it is done.

Of course Murphy's law came into play when I took it for the final inspection at the QT depot at Zillmere. When they checked the brake lights it turned out that one of the bulbs had blown while driving it to the inspection and when I tried to blow the horn it also didn't work. That turned out to be a loose connector. Luckily the inspector was a human being and allowed the vehicle to pass.

I have been doing some testing of the acceleration of the car and have been tweaking the motor controller settings to improve the acceleration. Unfortunately I improved the acceleration to the point where the front transmission mount broke. I have ordered a new mount and will put it in next Saturday.

While waiting for the part I am manually balancing the battery pack. I have made a single cell charger from a PC power supply that is capable of puting 40 amps into a cell. I am also using a high power resistor 0.22 ohms 150 watt to bring higher voltage cells down to a lower value. Unfortunately with these cells the voltage tends to bounce after charging and discharging. ie the voltage may rise to 3.4 volts when charging but when you remove the charger it goes back down to 3.38 volts after a few minutes. So there is a lot of waiting involved. Once I get it roughly balanced I will let the BMS do an automatic balance at top of charge.

I have also put a small DC pump onto the high pressure port of the auto transmission to try to keep the clutches engaged when the motor is not spinning. This partially works but I am drawing atf from the cooler loop which creates a vacuum in this loop to the point where the pump stalls. I will have to draw the fluid from the transmission sump, so it needs another outlet brazed into the sump to connect to.

Ian Bartie is also making an ATC (Automatic Transmission Controller) to replace the vacuum modulator in the transmission. It will control the pressures and gear change points in the transmission electrically from the motor controller. The device comprises a model airplane servo which drives a pin into the box via a cam mounted on the servo shaft. When the motor current is high the controller will drive the servo so that the pin moves into the transmission and out again under low current. This should simulate exactly the effect of engine vacuum on the vacuum modulator. Testing on the existing vacuum modulator showed that moving the pin only 1mm gave a change point from 2nd to 3rd gear speed variation, from 40 km/hr to 80 km/hr.

Saturday, July 10, 2010

Ready for Rego

Well it's finished. Last Monday the certification engineer did the final inspection of the car and it passed!!!.

He now has to write a report to Qld Transport and include the NCOP14 check sheet. It will then take 3-6 weeks for them to approve the vehicle and forward the approval docs. A roadworthy certificate will also probably be required. I can hardly wait.

I have a few shows lined up to display the EV. The Alternative Technology Association are having an EV open day at Albion. I won't be registered by then but I will be borrowing Graeme's (Suzi Springwood) trade plates to get it there (~1Km). I have also been asked to display it at the Green House at the Woodford Folk Festival at Christmas.

I have still got a fair bit of fine tuning to finish the car. The auto box still lurches if you accelerate quickly from stopped. I will have to include the electric pressure pump to keep the clutches engaged and this will stop the lurching. The gear change points are set about the right speed now but it still changes gear a bit hard. I have to come up with a simple way to drive the vacuum modulator push rod so that it goes in by 4mm under full throttle and pulls back out when idle. I am thinking maybe a model servo connected to the pushrod through adjustable linkages. The servo input can be modified to take a variable DC voltage instead of the normal pulse train by removing the integrator circuit in it's front end. It can the be driven from the throttle pot.

There is also some noise problems with the BMS causing random alarms and also fine tune the State of Charge calculation.

Wednesday, June 23, 2010

Yet another long weekend spent working on the car. My wife will be very happy when I finish this project.

The new handbrake cable was fitted and adjusted. Wired the motor speed sensor to the controller and fit a cover to the controller bus bar connections.

The heater is controlled by a solid state relay which I operate from an illuminated switch mounted on a blank plate where the ash tray used to be. It produces a decent amount of heat and I think you could use it to heat the vehicle as well as demist, although it uses a lot of power.

I got to use my new MIG welder to make the battery hold down bracket. MIG really makes welding simple.

I had a final read of the NCOP14 regs to see if I missed anything and it turns out I did. I forgot about the requirement to disable the vehicle while its plugged into a power point. I haven't run any cables from the fuel flap for a switch. However the charger does output 12vdc onto 2 of its control terminals while its powered up. I will use this to operate a relay which will isolate the 12v feed to the contactors. The relay will also drive an input into the BMS master to start the charge cycle.

There is also a clause in the regs about having an audible and visual alarm if the brake vacuum is low. I am not sure what other people have done with this, so I might see if I can get away without it for the moment. It's a bit stupid as there is no requirement for this in the original vehicle.

I drove the car down to the AEVA meeting last week and it was well accepted. I found out when I got there that one headlight (connector disconnected) and both tail lights were out (blown fuse). The automatic worked very well and I was able to drive very slowly into the hall under perfect control. The controller has really good low speed control due to its current feedback loop.

I will be ready for the engineers inspection later this week so fingers are crossed. The final thing before registration will be replacing the windscreen as it was cracked when I bought the car.

Monday, June 7, 2010

I got the charger back from repair installed it and charged up the battery. On the weekend I fitted the power socket behind the fuel flap, wired it up, finished tidying up the battery wiring, fitted some plastic sheet into the battery box lid and fitted the lid.

The back seat was then installed and at first it didn't fit. A piece of trim under the seat was fouling the battery box lid mounting bolts. 5 minutes later after the jigsaw had its way with the trim it all fit
with nothing to spare.

The hand brake cable no longer fits so I took it to ATS Cables to get a special cable made. Thanks to Graeme from Suzuki Springwood for the tip. I will pick it up tomorrow and install it tomorrow night.

This will finish the rear section of the car.

What's left?
Wire motor speed sensor
Fit a cover to the controller bus bars
Fit and wire heater switch and test heater
Make and fit a hold down bracket for the aux battery
Fine tune vacuum modulator push rod length
Fit BMS master into dashboard
Fit Asus EEE PC into dash
Fit warning HV stickers to relevent bits

Saturday, May 29, 2010

Getting Close

I haven't been updating the blog lately due to work pressures.

I've taken the car for a couple of laps around the block. It had very good acceleration but the gear box wasn't changing gears properly - too high revs and hard changes. It didn't have any vacuum on the vacuum modulator and this caused the problems. When I connected the vacuum up it changed low and soft. The rod from the modulator into the transmission was changed for one 3mm shorter and it changed OK with no vacuum.

Had a setback when I connected the wrong cable to the battery charger. It blew up the charger and the BMS. I fixed the BMS but the charger had to go back to China for repair. It's due back next week.

Most of the 12vdc wiring is complete. I just need to wire up a switch to turn on the heater solid state relay. The DC DC converter was mounted into the dashboard with anderson connectors as connections and flexible orange conduit for the 144VDC input. Tomorrow the dashboard goes back in.

The battery boxes need a final tidy up and a perspex sheet mounted inside the lids to protect the terminals. I hope to get the car ready for final inspection in 3 weeks.

Sunday, February 21, 2010

Today we had a group effort with 2 other members of Brisbane AEVA helping out with the build. Thanks very much to Greg and Jim for your assistance.

Today we worked out where to mount the charger. As it is a fully sealed unit we decided to mount it under the rear of the car beside the spare wheel well. There is a large recess there where the muffler was previously and it means that the charger will not take up any of the luggage room in the car. A couple of steel brackets and it's now mounted solidly under the car.

We also fitted a number of units to an aluminium plate in front of the batteries. The controller, main contactor and precharge resistor were mounted on top of the plate and a sealed aluminium case was mounted under the plate for mounting terminal strips for connecting to the controller and contactor.

The BMS slave boards were mounted in 2 sealed ABS cases one on the rear battery box for 25 cells and one on the front box for 20 cells. The slave boards are 16 cellls per board and the wiring to the cells will be done in 1 sq mm double insulated cable with a 1 amp 3AG waterproof fuse in each wire. The 4 slave boards are then connected by 2 buses (master and slave) back to the BMS master system which will be mounted under the dash.

Monday, February 15, 2010

Battery Boxes Completed

The battery boxes and motor mount are complete. It took 3 solid days welding and grinding then 2 days painting. Another few hours putting them into the car and I am ready to start wiring. The rear box just fits under the rear seat with about 5mm clearance and the batteries can be maintained by removing the seat (4 bolts) from above. The front box holds 20 batteries and is mounted across the engine bay. The controller contactor and fuse is mounted in front of the batteries on an aluminium plate.

I've mounted some sealed ABS cases for the contactors, fuses and BMS slave boards and run the battery cabling from the rear battery box to the engine compartment in "flexible" orange underground conduit. That stuff is not very flexible and it was a painful experience.

Replaced the bonnet and closed it to see if the battery box fitted. There is only about 2 mm clearance in one spot so I will be doing a small amount of panel beating under the bonnet to give a bit more clearance.

Next weekend more wiring.