Zillablog

Much has happen in the many months since my last post. I apologize for taking so long to post a update.

Mostly we’ve been cranking out new Zilla production at a good pace and slowly catching up on the backorders. At last check we were backordered 4 months and reeling in orders. Orders have been increasing some due to the current high demand for EV conversions, but our production is also gaining capacity and things are running smoother than ever.

The most significant recent change has been bringing on some more help. In June Mandi joined Carrie and Jack in production to manage the daily needs of the business. She has been very helpful in keeping everything running smoothly and planning ahead so we don’t end up short on parts. This has freed up more of my time to work on development which I prefer. Now when you email orders into the office, Mandi is the one who takes care of those as well as planning, purchasing and dealing with the myriad of daily issues that arise in any small business.

The most recent addition to the team is Arthur who joined us in October. Arthur is a engineer with whom I worked ten years ago and I feel fortunate for managing to coax him away from Tesla Motors to come work on fun design projects up here at Cafe Electric. His first project is the Automated Test Equipment (ATE) unit that will automate the testing of Zillas and their subassemblies. Once again, the goal is to free up more of my time (and now his, since I’m making him do the testing) for new design projects.

So, you may ask, what am I doing with all this free design time?
First off, I’ve moved development to my living room at home. The former living room has been outfitted with the requisite huge workbench, proper test gear, monster computers (mostly Mac of course) and a good entertainment system. The production shop never had a real prototype area and I find it hard to do development in any production shop. They just don’t coexist well. Plus, there’s no food near the production shop and I need to snack constantly when being creative.
Secondly, I continued the testing of the latest rev of the Zilla control board, and it was just about ready when the crisis of the “Quiet Zilla” hit.

The “Quiet Zilla Problem”. We’re having a bit of a problem with a few Zillas suddenly refusing to communicate with the Hairball and throwing a 1132 error. This tends to happen on units running near the high voltage limit and often cars that had either ground leaks or serious motor fireball incidents. I have seen about six of these, and in each case the integrated DC-DC converters which isolate power to the gate drivers had blown their input stage and shorted the main regulated supply bus in the controller. Fortunately the repair is a relatively easy fix of replacing the DC-DC converters. Still I was very concerned that I didn’t know why the units were failing in the first place. I tested all sorts of parameters and found that we were within the supposed design limits for the parts. Fortunately a recent post by Lee Hart on the EVTech list suggested that this style of DC-DC could likely suffer from design issues which keep it from meeting the data sheet specification for isolation. To make a long story short, that turned out to be our problem (Thanks Lee!) and I’ve spent the last week designing my own DC-DC module to replace it. I expect to test the first one with our own transformer design (with reliable isolation this time!) later this week. If it works well we’ll get some production units built. Due to this problem I’ve put a hold on shipping all Z2K’s and EHV Z1K’s until I can implement the fix. In the best case that will still take a few weeks, but I do hope to be able to ship them before the end of the year. At this time is seems the failure mode is benign, but I still need to check if this was a factor in the one catastrophic failure we had of a new power section at the PIR races (edit: It wasn’t). If the DC-DC failure was involved in that then I may need to instigate a partial recall to avoid major silicon carnage, but so far it looks like the “just in case” protection zeners in the design are doing their job to protect the main power section.

For those of you looking for a update on the Tri-Zilla, nothing is happening. I drive it every now and then and wish I had time to dedicate to it, but for now it’s production first, then enabling lithium battery use, and then maybe the Tri-Zilla. Don’t hold your breath. Besides, we still need a good affordable motor to make it practical, so no hurry there.

That’s it for tonight, I hope you all have a great Holiday season!
-Otmar