Today was supposed to be the Silent E's maiden voyage. It took a lot of effort and a last-minute drive to the local surplus shop, but we got the wheels to spin. Unfortunately, they spun backwards.
Oh, but there was plenty of blood. Read on.
So I come home early from work to take care of Melissa's school stuff: meeting teachers and so forth. Then I get to work on the EV.
Nathan's already there, with his girlfriend Amy and her sister's kids, who want to watch the historic event. They've been playing inside, while he's been working outside, in the sweltering heat. But he's replaced the inertia switch with a Ford fuel cutoff switch. This is one of the safety feature I insist on. In the event of a crash (and maybe for really big bumps, too) the switch will disconnect electrical power to the motor. This one is nicer than the inertia switch because (a) it works, and (b) it has a reset button.
We figure we've got everything hooked up. Everyone gathers. I press the accelerator, and...
Nathan tries a few things quickly, with no result. We send everyone back inside and start troubleshooting.
At this point, I must say that the Silent E is easier to troubleshoot than any other car I've ever owned. It must be the inherent simplicity: there are very few things to go wrong, and you can use a voltmeter, a wrench, and your hands to test most of them.
- Batteries connected? Check.
- High voltage to the contactor? Check.
- High voltage through the contactor? Check.
- Wires tight to the controller? Check.
- Wires tight to the motor? Check.
- Throttle potentiometer functioning? Uh-oh.
We measured no resistance change from the potentiometer, or "pot", as it's called. It must be busted. So we head down to the local surplus shop, SkyCraft, affectionately known as "SkyJunk" to the local college students. Nathan isn't convinced this is so "local", since it's 30 minutes away.
While they don't have an exact replica of our throttlepot, they do have 0-5K potentiometers. We take our pot apart and discover that it's just a plain pot on the inside. We measure and discover that the pot is working as expected. Hmmm... must have been the bit that "gripped" the pot's knob. We buy an extra pot, just in case, along with some assorted hardware, and head back home.
While Nathan hooks up the vacuum pump for the power brakes, I put the throttlepot back together. We hook it all up and measure the resistance: 0 - 2400 ohms. What? It's supposed to go to 5K! When we disconnect it from the controller, it measures correctly. Conclusion: the controller has circuitry that messes up the volmeter's calculations.
We gather the masses again. I press the accelerator, and...
THE WHEELS SPIN! With a horrible, loud whistling noise! That's gotta be the Curtis 1231C "whine". I press the accelerator for a few more amps, to make the Curtis switch to heavy-duty mode, the whine goes away, and the wheels spin like crazy.
IT'S ALIVE! (Cue lightning, creepy music) BWAAAAAHHAHAHAHA!
Sorry, everybody does that. Something about "my creation" and electricity.
I let the kids jump in and try it themselves a couple of times. That's when we notice the wheels are spinning backwards.
So much for the maiden voyage tonight. Nathan hadn't believed we'd recover from the throttlepot problem for a week; it's already bedtime for some of the kids. We decide we're done and go inside.
That lasts all of five minutes. I verify that reversing the motor is as simple a switching two connections, and Nathan and I are back in the garage doing the dirty work. One of the cables isn't long enough for its new position. We've got extra cables, with the correct connectors. They're long enough, but the connectors have undersized holes. Nathan starts drilling, holding the wire in one hand and the drill in the other.
I promised you blood, and it's coming. Nathan's thinking, "Any second, it's going to bite, and I'll let go. Any second. Any second...". I'm thinking, "I'd better get him a piece of wood to drill into so he can stand on that." The drill and the car are apparently in cahoots, thinking, "Now we've got them." And sure enough, the drill bites, and Nathan doesn't let go.
He struggles for a moment. I watch helplessly, thinking "LET GO!" over and over. Finally he does, but he lets go of the cable. It's already twisted, so it wraps around his finger. Then the drill tries to rip it off. Finally Nathan lets the drill go, too, but it's too late; his finger is bleeding profusely.
He sits down immediately, because apparently this kind of thing has happened before. He relates the story of his previous injury to me as I put my first aid training to use. He's got a 3/4" cut in the top of his left index finger, a 1/2" cut on the side, and a couple of smaller cuts towards the bottom. They're all pretty deep. The top one goes through the nail bed. I cut off some soon-to-be dead skin and we head off for the urgent care center.
He has no insurance, so the bill comes out close to $300. I'm adding it to the cost of the car. They make him wash his own finger, fix him up with super glue, and give him some extra latex gloves so he can work on the car without getting junk in the wound.
His only regret? (Besides working while tired.) That he didn't defy the car with a hearty, "YOU WANT SOME OF THIS?!?" and shake blood on it.