High Currents
In this part we’ll talk about high voltage and current cabling, switches and fuses.
So far I’ve got conduits running down the tunnel from under the back seat to the front of the car. These will carry cables from the battery in the front to the back. I also have the front and rear battery boxes in place. So the next challenge is to hook the two batteries up and connect them to the motor.
The copper cables to do this job are double insulated with a bright orange outer layer. The wire is stranded copper so it remains fairly flexible and has a cross-sectional area of 70mm². Often called welding cable, this cable is designed to carry high voltages (120v in this case) and high currents (peaks of 100s of amps).
70mm² (AWG 2/0) Cable for eTrixie
The cables need to be protected from fault currents; in this case with 600 amp fuses. Also I need a “master switch” — a manual switch I can throw to disconnect the battery. To meet the standards of the LVVTA both poles (positive and negative) of both battery banks need to be fused and switched as close as practical to the battery. So eTrixie needs to have two big dual pole switches and four 600 amp fuses. This is a pretty sensible precaution!
Fuses and Dual Pole Switches
The hook-up of the batteries, fuses, switches, contactors, shunt and motor required 24 terminations. I was pretty nervous each time I had to cut the cable (mistakes would be expensive!) but I grew in confidence — a clean cut is essential so the stranded cable does not fray, but instead slides freely into the copper lug. Also a hydraulic crimper ensures a great termination. And then finished off with a heavy adhesive lined heatshrink!
Crimpers and cutter
Terminated cable (sorry the heatshrink is a bit rough on this one)
Read more about the conversion:
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Electric certification in part one
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Power and brakes in part two
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Removal of petrol components in part three
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Flywheel and clutch upgrades in part four
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The AC induction motor in part five
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New Fuel in part six
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High Currents in part seven
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The Loom in part eight
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Keeping it cool in part nine
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Putting it all together in part 10 (including a video of the first drive!)
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Bottom balancing and battery management systems in part 11
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Getting the certification examination in part 12
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eTrixie the Movie! Video walk through
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A DIY EV in the real world in the final part
