Learn Something

Monday my Zilla controller arrived. Yowza! One less excuse for not getting the car running.

I spent much of the day happily rearranging the parts I plan to put in a water-resistant box in the rear of the Ghia. I think I have the correct layout now. It will minimize wiring and coolant hose runs and fit all the bits I want to keep dry — the Zilla and Hairball, the potbox, the DC/DC, and the contactors.

There’s a problem — or opportunity — though. The Zilla controller comes in two pieces: the power stage, the one that does all the heavy lifting of feeding battery power to the motor, and the Hairball, which is much smaller and covered with places to connect little wires to. The Hairball makes all the decisions and tells the Zilla power stage what to do. There are several versions of the Hairball, with different capabilities.

You’re way ahead of me, aren’t you? Yep, they sent me the wrong Hairball. I ordered the base version, which senses the throttle position by reading the resistance from something called a potbox, which is essentially a volume knob (potentiometer) with an arm on it that the throttle cable pulls on. What they sent me expects something called a Hall Effect Pedal Assembly, which is a replacement for the entire accelerator pedal that contains Hall effect sensors and wires directly to the Hairball. The Hairball they sent me won’t work with a potbox, so to use it I need to buy a HEPA.

The advantage of the HEPA is no potentiometers. They wear out, get dirty and crackly like the volume knob in your stereo, and stick. On your stereo that’s not a huge deal, but the Zilla equivalent to crackly music is a car that lurches or stumbles. The Hall effect sensors should last pretty much forever with no degradation, plus there’s no throttle cable or throttle springs or separate pot box to deal with.

The problem is that I’ve already spent the money on the potbox etc.

So now I’m faced with trading in the the better Hairball for the crappy one and hating myself in a few years when the potbox dies, or keeping the better Hairball paying more money for the HEPA and feeling smug about it for as long as I own the car.

Hmmm. Looking at my choice of words there, it looks like I may have made my decision.

The wire attached to my Bare Bonz fuse panel was too short to reach my battery way in the back of the Ghia, so they sent me some more cable and a nice power junction box.

Sadly, there’s no good place to put the junction box along the route. There’s an OK place (under the driver’s side back seat) but I couldn’t find any good mounting points.

So I bought another junction box and will put one in the back and one in the front, just exactly the right distance apart for a single run of cable. This will be handy later, as the junction boxes have screw terminals for the attachment of power wires for high-current add-ons like power windows or air conditioners or 120vac inverters. There’s one junction near the rear electronics and one near the front electronics.

Tonight I installed the rear junction box, along with a 60amp fuse holder (no fusible links in THIS vehicle) and also a ground terminal strip. I’m running a separate ground system, and I’m going to replicate the +12v run with a terminal strip at each end.

Why a separate ground? I don’t want to have to troubleshoot any wacky grounding problems. Besides, electronics projects don’t use the project box for distributing power, and this is just a great big electronics project.

Well, one more.

I’m about done with my internship at Spaceport America (I built them some fancy Excel spreadsheets) and there’s about a month between now and the start of school. Let’s see how far I can get on the electric car in one month.

The remaining excuse is that I’m still missing the Zilla motor controller. Kind of like missing your carburetor on a regular car — it’s the component that controls the flow of energy to the motor.

I’ve begun rebuilding the 12V wiring in the car, which was such a mess that I pulled most of it out. I bought a new harness and fuse panel kit called the Bare Bonz from Ron Francis Wiring. I like it a lot. So far the fuse panel is mounted. I have all the parts needed to extend heavy-gauge wire from the rear (where the battery is located) and the front (where the fuse panel lives). I’m also going to put in a separate grounding system. This car will be complicated enough without having to troubleshoot wacky ground problems. I’m going to wire it like an electronics project — which, in fact, it is.

I’ve been ordering lots of goodies from Ryan at EV Source. I’ve got contactors (giant relays), tools of all descriptions, a small radiator to keep the controller cool, a PakTrakr battery monitoring system, etc. I still need to acquire a DC/DC converter, which will take the place of a gas car’s alternator and keep the 12V battery charged.

I’m kicking around ideas for the electronics box in the rear of the car. It will be a water resistant enclosure for the expensive electronics in engine compartment. Being a VW, the comparment is open to the rain from above and road splash from below. I want a see-through panel on the front so I can show off the bits that make it go.

So anyway I wanted to tell all my readers what I’m up to, so I have some accountability

Wish me luck and egg me on!