Ben Nelson's Electro-Metro Build thread

[bennelson]

Originally Posted by MetroMPG

OK, so Ben: you've ben driving around on 48v with a 300A limit, correct?

Have you been going in 2nd gear or 1st? (You said you don't have the shifter hooked up.) Any point in asking what you think of the performance?

The shift linkage isn't hooked up yet. I just climbed down under the car and manually shoved it into gear.

My very first safety-check test was in first gear. I quickly found that it wasn't nearly fast enough. Speed topped out at around 15 mpg.

Right after that, I put it into second. I think 30 mpg is the fastest it has gone so far in second. I haven't tried third yet, but I don't think I want to pull away from a dead stop in third, and I can't shift yet to start in second and go to third.

Some guys are coming over tomorrow to have a "work on the car" day. I am planning on discussing a whole lot of these various issues at that time.

The controller is a 48-72V 400 amp peak. I started off with 4 batts in the back, but since then have added two in front in the the radiator position, so it's at 72V right now.

I just went for a ride with my sister (who was over for dinner tonight) in the passenger seat. She has a Focus and a Metro. She said performance was about the same as her Metro.

Of course, my max speed is fairly limited right now, but we just went down the street where it's 25 and then 15 MPG speed limits.

I still have some mechanical issues. I don't think the motor is lined up perfectly. Makes a bit of a mechanical noise.

[bennelson]

Yesterday, a couple of new EV friends came over.

Swee came by, but could only stick around for a little while.

Tom and Royce also came over. Tom is a Master Scrounger who is building his own 300+ volt AC Dodge Neon. Royce is big into robot design.

I gave the all the tour of what I had doing so far on the car.

I expressed my concern about how the motor was mounted in there, not quite right. The motor/tranny isn't quite level, and I can't make the gear shifter reach because of the little bit of twist.

I also have no amp-measuring device on the car, so I have no idea how much energy it is pulling.

Tom and Royce rigged up Tom's home-designed battery monitoring circuitboard device and we went for a ride. First with Tom in the passenger seat (engineering position) and then second, with Royce as engineer.

Something wasn't rigged up right on Tom's ride. We hooked it up right and rode out with Royce. He used his cell phone as a voice recorder and read the readings on the fly while I said if I was accelerating, cruising, or letting off the go pedal.

Both of them said the car sounded pretty good, other then the motor going CLUNK any time I pulled away from a dead stop because of my cheap-o home-brew motor-mount, which needs to be re-done.

We believe the car was pulling around 150 amps while cruising.

We decide the next step is that I really do need to make the motor fit better, so I can level it out. That means somehow shortening the whole thing. I most likely have to shorten the spacers where the motor attaches to the transmission. I may also have to trim a bit off the tail end of the motor housing. This means cutting CAST-IRON!!!!! Supposedly, this can be done with a machinist's mill.

Of course this all means yanking out the motor and transmission again. On the upside, I will keep getting better at it!

[Clev]

Originally Posted by bennelson

That means somehow shortening the whole thing. I most likely have to shorten the spacers where the motor attaches to the transmission. I may also have to trim a bit off the tail end of the motor housing. This means cutting CAST-IRON!!!!! Supposedly, this can be done with a machinist's mill.

The ADC tailshaft can be cut by putting 12V on the motor and holding a hacksaw blade against the spinning shaft until it cuts through. I have no idea whether that'll work on cast iron.

[Johnny Mullet]

Can't you simply lower the motor and get a 5 LB sledge hammer to "form" the unibody to fit the assembly so it's level? Sounds kinda "redneck" but it sure beats doing all that work. You could always add some support to the unibody if you are concerned with strength.

[bennelson]

I had talked with a couple guys about the best way to fit the motor in. It really has to move over a little farther than in looks. A sledgehammer would not be good enough.

The iron that needs to be cut is the shell of the motor, not the tailshaft itself. Also, when I was trying to cut the tailshaft before, I first tried it on a bandsaw. Didn't even put a dent in it. The tailshaft is hardened - a special cut-off wheel had to be used.

Looks like the best thing to do is trim down the coupler and spacers.

[MazdaMatt]

Hm, so your brakes, through the boostless booster, are working "okay"? That means you can definately just find an MC of a slightly smaller size and replace it. This actualy would have similar results as the folcrum adjustment. There's no hocus pocus in the brake system, it is all simply about "mechanical advantage". In the end, you get the same ratio of piston-to-pedal motion as your piston-to-pedal force. So if the folcrum adjust makes the pedal move too much with not quite enough brake force, then go to a smaller MC and you're set.

You will find that having a booster makes for some "dead movement" in the top of the pedal motion. This is due to the rubber or springy parts in the booster compressing, and the pin moving a little before it hits the pin on the MC. That can be eliminated by bolting up the Honda MC directly. If you get "okay" braking, then you are very close to a successful un-boosted system. No boost = no power loss when braking

btw: Congrats on your first in-town trip. Musta felt great

[bennelson]

Originally Posted by MazdaMatt

btw: Congrats on your first in-town trip. Musta felt great

Thanks, it was fun!

Tom, who was over here the other day said that he has several aluminum vacuum tanks just sitting around, and would be happy to give one to me. (I told you he is a Master Scrounger!)

I am sort of leaning towards some sort of vacuum pump system right now, because it keeps the car closest to the original setup. Also, I am only running with 6 batteries. If I decide to go to 12, it doubles the weight of the battery pack. If I already have the power brake setup, the car would be ready with that extra stopping power. If converted to manual brakes, I might still have to change them later anyways.

[Daox]

Great progress Ben! I got your email Tuesday morning (still not internet at the new house). Too bad, I would have loved to come out and see stuff and talk with some other EVers. But, I don't think I would have had time anyways.

[bennelson]

I took the motor off.

Looking at the lovejoy coupler and spider - there was definate wear going on in there. Which in one was is actually incouraging; it means that I should be pulling the motor and get all these mechanical lengths and distances worked out better.

I am going to give the machinist a call tonight and see if I can stop by and have him take a look at the motor again. See if he has any more ideas on making the whole thing shorter.

Once I had the motor off, I was able to twist the transmission into a position where I would be able to get the shifter hooked up again.

I also got a note from the mailman saying they have a package for me which requires a signature. So rather than them leaving it, I have to make a special trip to the post office. I think it is the ammeter and voltmeter I ordered through E-Bay. (Yep, straight from China!)

I also e-mailed a guy on the EVDL and am going to be buying a used 72V charger from him. Still not dirt-cheap, but a better price than I could find on anything new.

So, suddenly I feel in EV limbo again, waiting for other people with superior skill to lend me a hand with this project.

[johnmyster]

Ben,

Are there other couplers on the market that could be used? Are other EV modders all using lovejoys? By design, yours will be wearing (sliding) to deal with any mialignment.

In industrial conveyor drive systems, we'll use these couplers that look almost like a spring. It's just a metal cylinder with a spiral cut in it, or a series of cross cuts. Maybe they don't make any high-torque enough for your application, but if they did, it'd be a non-wearing solution to the problem. They just bend.

Also, most inboard/outboard (stern-drive) boats use a system that could be interesting. It's an internal spline, mounted in a bowl full of rubber that bolts onto the flywheel. IT accounts for any misalignment of the crankshaft and the gimbal bearing.

I know you're under space constraints here, but you've got a bellhousing, and perhaps some other EV modder out there could use something a bit different.