Keeping it cool
An irony of the eTrixie project is that VW Beetles are air cooled, but eTrixie’s new motor controller needs water cooling! In part nine we look at ancillary systems such as water cooling the motor controller and the 12v system.
12v battery
The 120v system powering eTrixie is electrically isolated from the car. eTrixie’s old 12v system still exists. Because 12v starting current is no longer needed, I’ve replaced the old lead acid battery with a smaller LiFePo4 motorbike battery. This is connected to a 400W DC/DC converter which takes the main battery voltage and converts it to 12v. The main job of the 12v system is running the ignition relays and powering the lights (brake, tail indicator and headlights).
DC/DC converter (left — above charge port), water cooler (right)
A new job for the 12v system is the water cooler — the motor controller is mounted on a water fed chiller plate which is connected to a high-end PC water cooler.
Water cooler
There is also a need for a couple of new dash board indicator lights — one to show when the ignition is turned on and another to show the handbrake is engaged. The solution for this is to repurpose the green oil pressure light to be the ignition ‘on’ indicator and the red generator light to be the handbrake indicator. This is a great approach as it keeps the dashboard unchanged.
Repurposed dash lights
That’s about it for ancillary systems — because ’65 Beetles don’t have power brakes, power steering or air-conditioning there is nothing required here. I’m still thinking about heating — I’m researching options for this — still a few months to go until winter!
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
