Saturday, August 4, 2007

Day 5, First Week Done!

Friday was a day of mixed frustration and accomplishments. One of my frustrations was that at the very end the batteries in my camera died, and for the first time all week I had forgotten to take the spares out of the recharger and put them in my bag to bring with me. That meant I failed to capture the climactic moments of the week! Grrrrrr ...

But let us start at the beginning. Above you can see the 4 sheets of steel parked by the machine shop doors at 8:30 a.m. Our schedule called for the battery boxes to be fabricated and painted by evening, so they'd set up over the weekend and be ready to install in the van on Monday. Instructor Mike Parker is our in-house precision sheet mechanic, so the idea was he would lecture briefly in the morning, then spend the rest of the day fabricating boxes with Bill Kirkpatrick's assistance and others helping out as necessary. It seemed likely that they might need to work late even so.

After Mike's lecture on ch. 9 of Convert It, "Installing EV Components," Afshin & Larry finished making the spacers for the batteries to obtain final measurements for the boxes. (These spacers account for insulation and the fact that batteries will swell 1/16" over their lifetime.) Remember that salvaged blue inground pool material Mike was cutting laboriously by hand back on Day 3? That process went much faster on the table saw, as Afshin & Larry had predicted.

Next the batteries were lined up with spacers, and measured again. Meanwhile, so work could progress on preparing the connecting cables, the circuit path had to be determined and the terminals oriented so the interconnects were not too long or awkward. This took a while, since the arrangement for the Vanagon is of course different from the charts given in Convert It, which Mike usually uses to convert small commuter cars like VW Rabbits or Cabriolets.
In the picture above you can see a lug connected to the battery posts, and to the right, all the posts in one of the two equal-sized battery packs that will provide motive power for the van. That's a lot of connections! The cables have to be crimped securely to the lugs, or else they will corrode, lose voltage, and heat up, posing a fire hazard. I asked Mike to give Peter and Lynn a lesson on cutting cable and crimping the ends to the lugs.

This is a small cradle-and-punch type of crimping tool. You put the lug in the cradle and hit the top with a hammer. It's the type Mike is most familiar with.

This big vise-grip type made shorter work of the process. Peter and Lynn crimped the cables for both sets of battery packs with it, but the second half failed the vise test. (You place the cable in the vise and pull it as hard as you can to test how securely they're joined.) As it's being used, the crimper will loosen slightly, they learned. Once Bill showed them how to readjust it, the crimps were tight again. The final step of the process is to slide some heat shrink over the lug and center it on the joint, then shrink it into place with a heat gun. You can see some loose heat shrink on the right of the picture, and completed cables on the left.

It's ridiculous that I don't have a shot of Peter and Lynn crimping lugs, since they did it for hours! I was in the machine room watching Barry cut the adapter plate to the appropriate shape for a Vanagon. My last account of the problems we were having with the motor-to-transmission mounting issue was a little garbled, I'm afraid. What the machinist made for us was a jig -- a thick metal cylinder that fit perfectly between the clutch assembly and the adapter plate to hold the motor exactly in the center while the clutch was being mounted. In the picture to the left, the clutch assembly is mounted to the adapter plate, sitting on the jig. We are extremely grateful to Frank, NMTCC's machinist, for devoting several hours to this job while he was supposed to be on vacation!

Making the adapter plate round instead of square was not something we needed to import expertise for, though it did take Barry some concentrated effort (left). "Well, that took longer than we thought," he remarked cheerfully as he took it off the band saw.

That was the slogan of the day. Remember that sheet metal? At 2:30 p.m. it was still sitting on the table in the machine shop, while in the classroom, Mike continued to make drawings and calculate the battery box dimensions.

Afshin had brought in his CAD-equipped computer thinking it might be of assistance in this process, but he was busy working with Paul to locate EV components in the Vanagon. Boy, did they make rapid progress! Paul's philosophy is "Let's get everything up fast so we can test it; we can fine-tune later." By the end of the afternoon he and Afshin had the potbox and controller located and temporarily mounted and the vacuum pump switch installed. (In a gasoline-powered automobile, the engine produces vacuum which boosts braking force -- it is what gives us power brakes. An EV, like a diesel, must use a separate vacuum pump.)

Below on the left they're using the drill press to drill holes in the mounting bracket they welded; on right is the mounted switch.

Meanwhile, Larry and Barry were working away mounting the motor to the adaptor plate and the adaptor plate to the clutch assembly, which required careful measurement of clearances (left) . It's not going to come apart on me because you used Blue Loctite instead of Red, is it?

Machine shop, 3:30 p.m.

Both Dan and Kevin had to be absent today, Lynn and Peter had had to leave at 2:30 so Peter could get to his lifeguard job, and Bill and Mike were in the machine room at ten of four when I proposed that we should break for a debriefing. Larry said, "It would be better if we got these last couple of bolts in, because then the motor-clutch assembly will be complete!" Barry got me to go once round the horn tightening bolts -- giving me a whole new relationship with my transmission -- and the biggest job of the week was done. Hurray! (Cue for camera batteries to expire.)

At 4:00 on the dot Bill hustled into the shop to grab Afshin -- the first piece of steel was about to go into the shear, and he needed help guiding the 100 lb sheet. So Larry, Barry, Paul and I (plus Mike Ewall, who was in observing) debriefed for the day while the first cut was made on the first sheet of the 2 battery boxes & lids that were supposed to be complete by evening. Hmmmm ... the great news was, though, that when we reviewed Monday's work group assignments, we realized that with EV components being installed and the motor-transmission assembly to be mounted, it would have been difficult to mount battery boxes in the van anyway. Our schedule for next week is very tight -- but not destroyed if more time for fabrication is needed.

At 5:30 I left Bill and Afshin sweating at the shear (did I mention that it was really hot on Friday?), and got a text message from Bill today that succinctly reported, "Metal boxes will work." So I guess that means I don't have to grab one of my carpentry-gifted friends to build them for me out of wood on Sunday ... did I mention that I really ought to have had a clear plan for the battery boxes and the needed supplies in hand before the workshop started?

Hope you've enjoyed reading the blog this week! It will be great to reconvene on Monday. Bill looked around the untidy shop at the end of the day and decreed that we will need to start with housekeeping and organizing our tools and parts again -- and then we will get right to working on the van. I'll probably post one more update over the weekend. Thanks for following along.

1 comment:

Matthew said...

Congratulations on getting the battery boxes done!