Monday, August 10, 2009

Flurries in August?

Big flurry of activity over the last week. The guys at VisionSteel have been busy with their day jobs, but put together the rest of the "bracketry" and the front battery box.

The picture on the left is the big picture. There are four batteries up front. My contribution to manufacturing so far has been to cut the plywood for the control board. It will reside over the motor. Clearance for contactors, fuses, and the controller should be a lot easier in this rear position. For the first pass, I'm using plywood. once the layout is proven out, I'll probably go with a plastic board, similar to a chopping block.

It's tricky to get the batteries in here, but we came up with a combo layout:

  • two upright on the bottom, tall & narrow

  • two sideways on top, flat and wide.

This picture shows how the front box fits in, just behind the AC evaporator. There's still good clearance between the batteries and the ODE shaft where the belt driving the AC Compressor will spin.

Here's where we put the aux pumps. The 12V vacuum pump (replacing manifold vacuum) for the brakes is on the left toward the rear. The Power Steering pump, also 12V, on the right, just over the steering box. It was salvaged off a 2002ish Toyota MR2 and has the reservoir built right onto the pump unit. Additionally, this unit has a speed input so that the boost varies inversely to the speed.

I've finally ordered the cabling/lugs & connectors. I did pick up some 3/4" flex conduit to run from the rear battery box to the front. That was interesting. I stopped by the electrical section of the local Lowe's, priced the fancy purpose built UL conduit, and went on thinking that I'd wind up with normal clear vinyl tubing. On to the plumbing section to price the normal household tubing, and it was twice as much! So, I'll have the robust, UL listed stuff like I wanted. Schweet.

It's been great working with James, Dave, (and now William) at VisionSteel. They've really tried to make sure that the structural parts are robust, but haven't lost sight of the craftsmanship. Go back to the May 10th post, and check out the picture of the rear battery box. Even though these batteries aren't wet, I still wanted to minimize the chance of battery stuff coming forward in the event of a rear-ender. After all, that's where the cuties ride. We'd discussed putting a plate across the front of the box, just behind the rear seatbacks. Check out the picture below of the flashy cover they came up with to address the issue:

So, Progress Continues, if slowly.


Tuesday, May 12, 2009


Big progress today. The driveline is back in the car. James whipped up the "beam" to attach the motor clamp to the motor mounts. Badda bing badda boom and it's back in.

Now we can find homes for all the other pumps (vacuum, power steering), get the AC compressor back on a belt off the ODE and locate a couple more batteries. There's a lot of room left over up here since we crammed 8 batteries in the back, and will put two more under the rear seat. We only need to squeeze two under the "bonnet". Since they're AGMs, I can mount them sideways or on end. I suspect that the control board will now wind up above the motor. This will make for a layout curiously similar to EVAmerica's S10 examples. It will also make "Show and Tell" easier. We'll put the control board on a hinge so that it can swing up to show the motor while the batteries stay put between the AC Condenser and the motor.

Here you can see the two arches bridging between the clamp around the motor and sleeves around the existing motor mount bolts. The next shot shows the mount...mounting.

Now I'll have to remember how the Google SketchUp works so that I can adjust my 3D model.
Before too long, I'll have to get serious about my wiring diagrams. I'll also have to clean out the third bay of the garage again so that I can set up my electric shop.

Very exciting!

Sunday, May 10, 2009

Fab Fab Work

Making headway on the fabrication of adapter, mounts etc. I spent some time down at the shop yesterday and took some pics of the progress. James has finished the adapter and has the motor & trans hooked up. We'll get it back into the car in the next few days and figure out what the motor mounts need to look like.

James has also fixed up the rear battery box. Here's a picture of it, loaded with four of the odysseys and a dummy Trojan AGM we were using before the odysseys arrived. My battery supplier loaned that Trojan case to us. The guys at the shop have had tons of fun tossing it back and forth in front of visitors...pretty impressive to be playing catch with something that looks like it ought to weigh 80lbs.

The real laugh comes when they toss it to the guest. Anyway, the battery box looks great. He got four down low, then four more right on top of the axle at trunk level. We were poking around yesterday, and there will be enough room under the rear seat, where the gas tank lobes were, for two more, so we'll have two in the front, with lots of leftover room for pumps and switchgear.
While I was at the shop, we...well, James, whipped up the clamp for the motor. I actually got to try my hand at MIG welding. Of course, I could only do a couple of lines on the bottom of the clamp; he didn't want my dribbly bead left visible after the whole thing's assembled.

Wednesday, April 8, 2009


I was down at the shop today, and they mentioned that the coupling was cut and ready for a test fit on the motor shaft. Later, I received these pictures of the coupling and flywheel mounted. Every day, in every way, I'm getting closer and closer.

Tuesday, April 7, 2009

Battery Selection

I finally made a decision on batteries. I'm going to go with 12 Enersys Odyssey AGM 12V, 100Ah batteries for a pack voltage of 144VDC.

Most people recommend Flooded Lead Acid as the best balance of initial cost, capacity, and cycle life (charge/discharge). However, I didn't want to get involved in the water maintenance and ventilation issues. I guess the biggest thing was that I didn't want buckets of acid in the trunk, just behind my kids' seats.

Absorbed Glass Mat (or Valve Regulated Lead Acid) are maintenance free, sealed, more or less dry, don't give off hydrogen during charging, and don't have to be mounted upright. They also have good characteristics around current draw, so acceleration is reportedly pretty snappy with AGMs. The downside is that charging a series pack of AGMs requires a more intelligent charger ($) to avoid damaging the batteries, and they tend to wear out more rapidly than FLAs if you draw them down too much too often. These are guaranteed for 400 cycles if typically drawn down to 80%Depth-of-Discharge and 800 cycles if only drawn to 40%DoD.

If you figure that a charge/drive cycle is going to happen 4 times a week, that's about two years if I drive it until it gets slow each time. However, I don't expect to drive it until it creeps each time, so hopefully this set will last for three or four years. By the time they're done, the price for LithiumIon batteries should be more palatable.

For more info on battery type selection considerations, look here . Or here. Or here.

Yabba Dabba Do

As if ripping the engine out of a functioning vehicle and selling off pieces wasn't committment enough, now I've really gone past the point of no return. Up until now, it still would've been plausible to salvage a V6 from some other bimmer, and pretend like the whole goal of the project had been to upgrade from the stock 4cyl to a hot-rod V6.

Not anymore. Now we're into ripping sheetmetal! At this point, we're ready to head off to the drive-in for a rack of dinosaur ribs Flintstone style!

We cut the floor out of the trunk so we can lower the rear batteries. This is the beginning of planning the structure of the battery box. We'll start on the front layout and battery box(es) once we have the motor installed.

Ungunking the seats

With the car out of the garage, I was able to spread out the seats and other upholstry pieces for some steam cleaning. Check out the color of the water that came back out through the vacuum.

Off to the Car-Spa for some rehab

I've got to be one of very few people in the world that is actually excited to see his car get hauled away on a flatbed. One night in early March, we hauled the prime-mover-less 318ti down to a buddy's machine/fab shop for the mechanical work.

They're going to design & build the motor/transmssion adapter plate and coupling, motor mounts, and battery boxes.

It felt pretty silly moving it out of the garage into the driveway. I had to crouch inside the car and steer while James pushed. With electric windows stuck up (no battery, no wiring harness, therefore no rolling up or down), and a narrow garage door to navigate, we couldn't have the door open to walk & steer. Additionally, all the seats are out, so there's nothing to sit on. The good news was that with no engine, trans and a whole bunch of other stuff, the car moves pretty easily with just a nudge.

Sunday, January 25, 2009


Things are moving forward slowly. I sold the engine and a few other parts to a local independent BMW service shop. We had a 60 degree day this week, so I took the transmission and clutch parts to the carwash to clean the gunk off.
I heard this morning that my electric motor has arrived at my buddy's fab shop, so I'll take the transmission over tomorrow so they can start scheming on the coupling and adapter plates.

I've been noodling with a 3D modeling environment, Google's SketchUp. It's pretty easy to pick up for simple shapes and designs. There's also a big library of models that other people have put together. I found a 3D model of a mid-90s BMW 325 sedan. The rear is not the same as my hatchback, but the front is the same. I was able to delete the ICE components from the model and add simple blocks that show the layout of major components in the converted car. The batteries, motor, and controller blocks are all dimensionally correct, although I don't really know if the original model of the 3 series is truly the correct size, so i don't put much stock in the appearance of lots of extra room. Anyway, it's fun to go spinning around in space, looking at the pieces.

Monday, January 12, 2009

The Fleet

Someone asked me if I was going to sell the Yukon once I had the EMW finished. I pointed out that I still needed something to tow the EMW home when it runs out of juice in town!

Sunday, January 11, 2009

The Pull Continues

This weekend, work continued on pulling parts. Saturday 1/10 I got the transmission separated from the engine. Now I need to get it to the car-wash to get it cleaned up.

Today I finally got the gas tank off. On this car, the tank is a single molded plastic tank with two "lobes" that sit like saddlebags on either side of the driveshaft under the rear seat bench. The thing that makes taking this thing down tricky is the fact that the e-brake cables run underneath it and the driveshaft runs underneath it. This means that you can't take it out in one piece unless you take those three parts off first.

After going through two or three 16mm sockets trying to get the brake caliper bolts off so I could get the calipers off so I could get the rotors off the rear wheels so I could get the e-brake cable end off the e-brake shoes (inside the disk...) so I could pull the cable off the back so i could pull it out from underneath the gas tank...whew...I decided to cut the gas tank in two and pull it out on either side of the shaft and cables.

It took a couple of hours to get the tank cut down the middle. Of course I was trying to be very careful to avoid making sparks whilst hacking through this thing. Now that it's done, I'm trying very hard to not think about potential ways this little task could've gone wrong.

The Big Pull

On Saturday the 3rd of January, we got serious. My buddy James came over to help me pull the engine and transmission out. Actually, it was much more like James was pulling the engine and I was handing him tools as he asked for them, and keeping his coffee warm.

It went real well. He all the necessary gear to make it smooth. I had disconnected most of the hoses and wires in advance. There were a few that were too hard to get to. I had been trying to keep everything together so that the engine might be installable in someone else's car with little or no rework. However, there was one bundle of fuel injector sensor and controller wires that was too hard to reach. So, we got the wire cutters out and snipped a big bundle of stuff. That bundle and the heater hoses were the only real casualties of the removal.

First Steps

The weekend before Thanksgiving, I got started on the teardown. The hood came off, and the battery came out. I don't know how detailed I'll be on each step of the way, but this was fairly simple.

The weekend after Thanksgiving, I got the exhaust system down and out of the way. While down there, I took off miscellaneous heat shields and stuff that won't be necessary in a setup without the exhaust pipe running the length of the car.

The beginnings of an Electric Vehicle conversion project

I'm sure someone's going to give me grief about whether or not a kilowatt-hour is analagous to a gallon of gas, but the blog URL was available and that works for me.

For years, I've thought about doing a project like this. In summer '08, it occurred to me that if I was ever going to convert my own car from gas to electric, I should probably get on with it. Sooner or later, the major manufacturers will get on with making EVs available, then it wouldn't make a lot of sense to go through all of this one your own.

Michele and I started talking about it, and she agreed that I needed some sort of project or hobby to keep from just working all the time. The final straw was an "icebreaker" activity at a men's retreat I attended. We were supposed to identify something interesting about ourselves, and include that in our introduction. It occurred to me that I didn't have anything really interesting since my time living in Germany in the early 90's.

The research and hunt for a donor car began in September. Skipping ahead a little bit, in mid-October, I found a nice little 1997 BMW 318ti with bunches and bunches of miles. 207k of them in fact. It ran fine, and probably would've been a lot of fun to zip around town in as it was. But that wasn't the plan.

So here's a summary of design goals for my EV Conversion Project

  • Target Range: 40 miles
  • Max Speed: 60 mph
  • Typical Top speed: 45-50mph
  • Typical Avg speed: 30-40mph
  • Typical Route: Home -> School -> Church -> Grocery -> Home ~11mi
  • Capacity: 2 Adults & 2 kids + light groceries or school backpacks
  • Total Budget: $15,000
  • Completion Goal: 3/31/09

That's how the whole thing got started. I'll add more entries with pics of the teardown of the "ti". We're still looking for appropriate nicknames for the ride once it's done, so the terms I use to refer to the vehicle may change now and then. I think it'll be related to the number of knuckles that are skinned up.