The Home Stretch


As you can tell from the last post- I’ve driven the Miata. I worked hard Friday and all weekend to make it come together for Sunday’s drive- while I edit the video from Sunday, I’ll post up my photos of the work I did to get ready- all the final wiring and mounting/integration–

The first big challenge was figuring out how I was going to set up the water-cooling reservoir and pump for the Zilla controller- I had planned to use the OEM coolant overflow tank, adding taps to it using copper tubing and epoxy putty- I tested it and the epoxy putty failed immediately. (duh, it’s not magic… I was hoping it was magic) I realized the OEM reservoir really wasn’t going to be that good anyways, the hose routing was seriously iffy. So instead I thought to use a Nalgene water bottle- it ended up working very well. I hadn’t put anything far forward inside the bumper yet, this fit there without conflicting with anything else. I drilled and tapped (pipe tap) a hole in the bottom of the Nalgene bottle, then screwed in a 1/2 inch barb fitting and put some silicone on it. The bottle and pump are attached to a piece of 1/16″ aluminum (cut-off from the battery regulator base plates) which is riveted a bunch of times to the front bumper steel member. The top of the bottle fits through an already-present hole in the metal at the front of the engine bay, symmetrical to the windshield washer fluid filler hole.






Since then it has sprung a significant leak somewhere, I’ll need to investigate and apply silicone as needed- I’m still pleased at how it turned out. That pump, the Laing D4 is way plenty beefy for the application, it pushes plenty of fluid around, however is very quiet. The system gurgles but only because of the fluid splashing back into the reservoir. It will be nearly silent with a submerged return tube. The pump can not pump pure antifreeze, it is too viscous. I have diluted the antifreeze about 50/50 by my rough approximation, it seems to work fine now.

After avoiding it for weeks, I finally set about mounting and connecting the main power components-




The components are attached to 1/4 inch ABS. It is very easy to work with  and strong, but slightly flexible. Dealing with those very short segments of welding cable is a serious pain… the cable is flexible enough, but when it the ends are crimped it fixes the strands in place and makes the bending behavior less predictable. The lead between the contactor and controller is most visibly distorted. Using solid copper machined bus-bars would definitely be nicer, as would having the various terminals at a more similar height. I ended up changing the position of the contactor mounting points slightly to relieve some stress, I was unable to get it back in place with the cables attached after I unbolted it.

Mounting the Hairball and working on the low-current wiring-



After float charging all the batteries and placing them in the car, doing all this wiring and fixing up the water cooling system I decided to head to bed a bit early Saturday night… Sunday was promising to be a big day, with Beth, Sean and Christian coming up from Santa Clara, a small list of additional things to be done, and the promise of driving the car.


I’m working on the video of the events on Sunday, and processing all the new stuff I now know about where I need to go with the project next- It’s not done yet, but I can say for sure that it is going to be awesome.

Posted on May 18, 2009 at 11:57 pm by Henry · Permalink
In: EV Miata

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