COAL: 1999 UM Maize Blaze • Everybody Makes Mistakes

Our batteries were made of stainless-encased NiMH cells like this Prius item.

Meanwhile, the teammates—future engineers, all—who’d cocked up cooking the first chassis so the shock mount pushed through and destroyed the entire chassis, necessitating a complete refabrication (oh yeah, that was what set all these monkeyshines into motion), and who’d had such very important top urgent immediate need for this replacement carbon fibre? Turns out they hadn’t finished cocking up: while we were on the road between Ann Arbor and Ann Arbor via Tulsa, they were out watching Star Wars instead of fixing the cracked chassis moulds, so now they still had to do that before they could use them to lay up the composites, which made them miss the curing oven time slot a corporation had donated. They had the nerve to show up seven hours late, whereupon Bizcorp Companyco Amalgamated Industries said something to the effect of “LOLnope”. So now the laid up chassis was room-temperature curing—very, very bad!—and so there was frantic phonecalling to try to find right-now availability of a suitably large curing oven. Ford came through on that one.

I don’t recall when in all of this I reinstalled the van’s radio and took back my Infinity deck, but I did. And guess what else I did: pissed away five figures’ worth of today’s dollars because I wasn’t paying attention. The ’99 race was the first one to allow other than lead-acid batteries; NiMH (nickel metal hydride) batteries were newly permitted. Being the University of Michigan, of course we would be running the newest and best technology. One of the battery companies sponsored (i.e., gave) us our custom-made NiMH batteries. Each was made of a series of cells joined by flat-woven stranded straps like this:

I don’t sturdily remember, but I think the car took six of the custom-made batteries, each with seven cells. Nominal cell voltage of 2v, nominal battery voltage of 14v, and nominal pack voltage of 84v. Each battery cost about $6,000 in 1998. Another company had sponsored (given) us a top-of-the-line battery charging and testing machine, which we built into the cleanroom at our shop space.

During the systems engineering phase of the project, we did an enormous amount of battery testing, which meant charging and discharging at a wide range of rates and temperatures. We built a box into which one of our batteries would very tightly fit. There was a fan at the bottom of the box to draw cooling air down past the cells, and it was all done to very close tolerances because that’s how the batteries would be installed in the car, and we needed to know how much airflow would be needed to keep the batteries below their critical temperature of 50°C (122°F).

So last thing at night, a battery was put into the forced ventillation box in the charging rig in the cleanroom and left to undergo a discharge at whatever rate we were testing, followed by a tapered-rate charge-up. Mostly this was my responsibility. Mostly it went fine, until the night it didn’t. The primary battery ventillator fan had been taken offline and its pilot light on the control panel had been disabled by one of the other engineers during a systems check earlier in the day. He should’ve put them back, but didn’t. I should’ve noticed, but didn’t.

And so in the middle of the night, my phone rang. It was an old bakelite Automatic Electric № 40—very loud and without provisions for any kind of “ringer off” or “do not disturb” mode:

So I woke up in a hurry. There had been an incident in the cleanroom: the battery had exceeded 50°C and begun venting gas violently—it sounded like rifle shots, according to aero/body engineers who were working in the adjacent machine shop. There was frantic drama, and a fire was averted. The expensive-but-free charging rig sustained serious heat damage, as did the stainless steel battery cell casings, and the $6,000 battery was wrecked. There was a hell of a hydroxide mess to clean up, and the university Hazmat team had to be called in with a special cleanup kit. So if you thought I was going to claim to be the only one on the team who didn’t mess up…no.

But we were the University of Michigan, so all we had to do was call money and daddy. The battery company sent us a replacement; the test-and-charge equipment company swooped in and swapped out the rig, and onward we forged. Minimal muss, finite fuss, and no budgetary badness.

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