Lots of photos and little time left before I must sleep, so let's see how quickly I can zip thru the events of Day Three for you -- it really flew by in real life too!
We opened with lecture. Here Bill is discussing some of the tools we will use & standard safety precautions. We also reviewed the assigned reading on controllers and the wiring done yesterday on our controller as well as the other jobs completed on Day Two.
Then it was to work! Here Dave, Dan & Chris are grinding and then cutting the extra supports for the rear battery.
Must include a close-up of Dan in order to show his most excellent t-shirt: "BREAK THE CHAINS - SHOP AT INDEPENDENT STORES" I was glad I'd switched this morning to coffee from my favorite local bakery. I had to resort to Dunkin' Donuts on Monday when my shop is closed & Tuesday when it turned out my shop brews it boxes fresh & I couldn't just waltz in and pick one up. All rectified, I have placed my order with Crossroads Bakeshop for the rest of the workshop! So far I've managed to stay out of any big box stores and picked up all our needed supplies at a local hardware store & electric supply company. This makes me happy because EV's are all about staying local & being independent!
Ralph gets a lesson from Bill on using the grinder to cut thru some angle iron for the front box supports (we couldn't get into the machine shop to use the cut-off saw). St. Bill always sez: we can work around this!
After lunch Dan Monroe of the EEVC joined the class. Yes, here's the guy who sends me all those great EV news round-ups! (There is one waiting sadly in my inbox for me to post right now but I am not gonna get around to it for a while I'm afraid.) Dan's 1997 Saturn build is well underway and his pile of show-and-tell components has diminished accordingly, but as you can see he was still able to load up the table with goodies! He reviewed the selections he made for his conversion with the class -- you can get some of the highlights (plus sources) on his EV Album page.
Judging by the number of questions during & after & everybody's close inspection of the materials this was an extremely valuable experience for our would-be converters -- just like I knew it would be. Thanks a million for generously sharing your time & knowledge with us, Dan.
Things moved very fast during the afternoon work session -- a little too fast, as it turned out. Here Jack is watching Ralph tweak the battery box with power sheet metal shears - he is creating more clearance for the hood latch.
Ben is singing "I'd rather be a hammer than a nail."
EV's may be quiet but building one is not -- especially not when you're banging metal battery boxes into place!
Next Jack & Ralph removed the front battery box to install the angle iron support beneath it.
Meanwhile Julie was removing the wheels (we are taking this opportunity to install new low-rolling resistance tires on the Miata -- the existing set would have failed inspection). Julie and her husband Richard are taking the class together; she is the one with the car expertise & he is interested in the electronics aspect, so they are a complementary team. Although she has done quite a bit of automotive work this was Julie's first introduction to the air impact wrench, which she announced was an amazing tool -- above she is showing Richard how to use it so he can experience the joy of high torque as well.
Dan was cutting foam spacers for the battery boxes
while Bill went over the MIG welding equipment & procedures.
Okay I do have a lot of fun taking pictures of people welding! Ralph was new to MIG welding
and others (like grinning Glenn here!) had prior experience but hadn't done it for a long time.
Once the rear battery boxes were reinstalled with their new supports, everyone was excited to get going on connecting the batteries. A photo of the proper series configuration serves as a guide for location of the terminal interconnects.
The interconnects for all these terminals are anchored by Phillips head screws. That's a lot of screwdriving! We were all a little envious of the much less fiddly large-nut assembly on Dan's batteries (sorry, forgot to take a close-up), especially when it turned out that in moving fast, we had forgotten a crucial step: coating the terminals first with Noalox, an antioxidizing compound that prevents corrosion.
Grant (shown here admiring Dan's Zilla controller with Richard) was the one who thought of the Noalox so he gets extra credit!
Ay yi yi, now some disassembly is on the agenda for tomorrow! "We do it right 'cause we do it twice!" was somewhat the theme of the day ... I felt bad for Chris who had gotten the most screws in (he cheerfully refuses to be on the re-do crew!) but Julie made me feel better when she reassured me that our teaching mistake was certainly instructive! Everybody will remember now that the goop goes on first!
Jack is smoothing out the angle iron for the front battery box support
and here is a shot of him welding.
We regrouped for a brief review and dismissal of the class at 4, but most of the students stayed well past that time chatting with Dan. Bill took some time to meditate on what shape the battery hold-downs in the back might take.
"I really like what Dan has done," he says.
Dan designed his battery containment around these clips (an electrical mount that happens to have a lip that fits neatly over the top of his battery strapping). However this would require a lot of re-engineering of our battery boxes. I bet Bill comes up with a less-work workaround!
Towards the end of the after-class work session we made a significant discovery. Richard is using a voltmeter to demonstrate that our circuit is grounding to the vehicle through the aluminum controller plate and metal-to-metal couplings to the transmission.
More headscratching & brainstorming resulted -- both around the car & up at the whiteboard. There are a number of possible solutions to this problem, but we will be bringing it to the full class tomorrow so we can come up with the fix that involves the least possible amount of doing things twice!
Lots of fun, lots of problems to solve, plenty left to do -- but we are on schedule and feeling very good about things! On Day 4 we will be going in-depth into charging. Our charger was delivered today, so we'll get to open that up & play with it, plus we will host a demo of a professional charging unit utilizing the new J1772 standard.