Sunday, November 23, 2008

Video: Motor in Vehicle Test

After we mounted the motor to the transmission, we had to see if it worked.

Well the wheels turn, how about the whole car?


Motor Adaptor Pt. 4

Last week I cut the shape of the motor adaptor, this week I drilled the holes. My first step was to print out another template and lay it over my metal plate.

With a trusty can of WD-40 and a drill I started on the holes. The transmission has -a lot- of mounting holes. The bell housing was sized for both 5/16" and 3/8" bolts, but my measurements (and drilling) weren't perfect, so I overdrilled all the holes to 3/8".

The wooden test piece I made a few weeks earlier came very handy in drilling out the bolt holes. I highly recommend making a test adaptor out of wood before going straight to metal.

And many test fits to make sure I had things lined up right. Holes 1, 2, and 4 of the motor mount came out perfect - I have no idea what happened to #3, but it's ugly.

By the way, I first started drilling the holes with a cheap 3/8" drill bit I had lying around. It didn't last very long - maybe 3 or 4 holes before it made more noise than shavings. Home Depot had this $10 titanium metal drill bit (the most money I've ever spent on a drill bit), and you get what you pay for. I highly recommend spending the extra cash to get the right tool before you start on your adaptor plate.

Periodically test fitted on the transmission as well...

Matt was coming by later that day with the motor coupler, so I went ahead and started charging the batteries just in case things worked out so we could take her for a test spin.

Matt has arrived, and he did a great job on the coupler! The two flanges are connected via shoulder bolts, and the old clutch is held on by some very nicely machined S-shaped brackets.

We mounted the motor onto the adaptor plate.

Then into the car.

Unfortunately it didn't slide in all the way on the first try. The coupler was a little longer than the distance between the transmission and motor. Should be pretty easy to fix - we went up to Home Depot and picked up some washers and longer bolts.

The gap is less than ideal, but it will work for a quick test. The front view with the coupler looks great.

And it fit! We definitely had to take this baby for a test drive.

We jacked up the rear end of the car and connected the motor to see what would happen. Sweet, the wheels turned! Unfortunately I don't have a picture, but I do have a video. You'll see it in the next post. Our first try resulted in the motor turning the wrong way, so I switched around the S1 and S2 connections for the proper rotation. My final connection was - to S2, S1 to A2, A1 to +.

I wired up my better battery to the motor / contactor, and a (mostly) dead battery to the contactor. I then connected the contactor to my Pot Box. It's not a full blown controller, but it will allow me to at least turn the power on and off from the accelerator pedal.

All the wires just about hooked up...

That's my rear end there finishing up the wiring while a patient audience waits...

Once it was all wired up we took her for a test drive. We only went a hundred feet or so, but it was a blast! I'll post the video of the car's first electric test drive next. The car still has a ways to go before it will be hitting the open road, but there was huge progress today.

Sunday, November 16, 2008

Video: Working With Metal

A couple videos of Brian and I cutting the aluminum plate. They're probably a good reference if you've never worked with thick metals before and wanted to know how freaking slow it is to cut them.

Check out how lightning fast Brian blazes through with a circular saw.

The unstoppable jig saw, but beware the man-eating wolf!

Motor Adaptor Pt. 3

My 1/2" aluminum plate arrived early last week, so this past weekend I spent a lot of time on the adaptor. By the way, I ordered my plate from Excellent service and a great price ($77 shipped). They have some standard sizes on their website, but they'll cut to size if you give them a call.

Using my template, I traced the shape of the transmission bell housing onto the aluminum.

I then (tried) to cut it out with my jig saw. Yeah, in half an hour I went half an inch. I was getting nowhere fast. Brian, one of the guys from, lives in town so I gave him a visit. He just bought a Honda Civic to convert but has been spending his time lately on building an electric race car for a SAE competition.

Brian had a circular saw with a metal cutting disc and offered to give me some help.

He obviously couldn't make curves in the plate, but he graciously made many many cuts to trim it down for me.

And more cuts...

Notice the size of the cutting disc shrink?

Thanks Brian! Huge help for me!

The straight cuts will allow me to fit the plate in the car, but it doesn't have the nice shape I was hoping for. Attempt #2 at using my jig saw.

So I've been to machine shops before and seen how they cut metal, but I never understood just how important it was -- but wow, you -must- use a lubricant when cutting metal. Without spraying WD-40 on my blade it basically didn't move, with WD-40 it cuts like a champ. A slow champ, but champ nonetheless.

Lots and lots of cutting...

Phew... I took many breaks to allow my jig saw to cool down. November in Phoenix is still 80+ degrees outside, and after a couple inches the saw got hotter than I was comfortable with.

After exhaustive calculations into the precise dimensions of the opening for the shaft, I was able to size and cut the hole.

Who would have thought the hole I needed perfectly matched the top of a Subway cup?

Looks like a pretty nice fit to the test plate I made a few weeks ago.

Well it took 1 circular saw disc, 4 jig saw blades, and 2 cans of WD-40, but I've got an adaptor plate!

Test fit over the transmission...

Looks great! It still needs the mounting holes, but the sun has decided to set. Those will be easy to drill out tomorrow.

Matt has been finishing up a few last items with the coupler. Once I get it back I'll be ready for a low speed test! Wohoo! Stay tuned, I'm shooting to have the first test drive under electric power in the next couple weeks.

Sunday, November 9, 2008

Making It All Fit

I want Lithium Phosphates, but for planning purposes I'm going to size the battery compartment for Trojan J-150s. If I can fit 120V worth of Lead in the car, I can definitely fit 120V of Lithium. I found an old box and cut it to the shape of 4 J-150 batteries. It should be a few inches longer, but that dimension isn't critical for sizing purposes. The cat wasn't happy with me dismantling his playhouse.

It's a very close fit underneath the car, and there is no way one of those Trojan batteries will fit in the car's original 12V spot. Looks like I'll have 4 up front, 6 in back.

I picked up a 24"x18"x1/4" sheet of Plexiglass from Home Depot - it will be my base for all the smaller electrical components: relay, contactor, fuse, shunt, controller, dc-dc converter, etc...

Looks like it will fit nicely over the motor. I'll trim down the top piece to 12" x 24", and then cut a mounting piece that will go along the side.

Rough fit, looks like it may work. By the way, if you ever get the opportunity to cut a sheet of Plexiglass with a Jig Saw, pass. Go too slow, the piece you just cut melts back together. Too fast, you crack it. Not fun.

I finished up the cutting and went to fitting brackets to connect the two pieces.

Plexiglass all cut out and bolted together.

Let's see how it fits in the car.

Looks great! It actually doesn't fit quite right on one of the sides. I assumed the supports for the engine were symmetrical (and visually they look like it), but they're actually off by about 3/4". Oh well, it still looks okay. There are a couple existing mounting holes I'm going to bolt through to the front plexiglass piece. In place, the plate should sit about 1" above the motor. I hope the heat from the motor doesn't start warping and/or melting my plexiglass!

If I were really fancy, I'm sure I could design a complex metal frame that would hold a couple more batteries and all the electrical components tight around the motor. That might be good for space reasons, but I foresee a design, fabrication, and maintainability nightmare. An extra battery in the trunk isn't that big of a deal.

In other news I got my Christmas present!

Two of my tires are good, but the other two are cracked to the point I'm surprised they still hold air. My wife talked to someone on the diyelectriccar discussion board and found some great replacement tires for me. There's nowhere she could hide them for 2 months without me noticing, so I got them early! You gotta love a wife that buys you tires for Christmas!

Sunday, November 2, 2008

Transmission Shaft

The shaft from the transmission has a smaller diameter extension that extends out of the bell housing. Two problems with this... One, it complicates the design on the coupler. Two, it forces us to mount the motor further back and requires a more complex adapter plate.

So what's the best solution? Just cut it off. I had some fun with a borrowed grinder and one sweet cutting wheel.

You can see the piece I removed in the picture below. For anyone else that's planning on trimming the transmission shaft, this was the first time I've ever used a grinder, and it went very fast and very easy. Definitely something you can do at home (with goggles, gloves, and a long sleeve shirt). Sparks were flying!

I didn't have too much other progress on the car this past weekend, but each little bit helps and I'm still one step closer. I'm aiming to buy the Aluminum plate for the adapter in the next couple days, and then I'll have lots of fun.