Lugs: Crimping vs. Soldering

This in not a how-to, it's a how-I-do. If you are planning to do an EV, you should decide which method is right for you. Since this subject has been discussed quite a bit in EV forums, I am going to show how I decided to do my 2/0 cable lugs. I was planning to solder them. There is a great tutorial for that method located here.


But there are some who caution against soldering larger lugs such as this page from the book 'Convert it' by Michael Brown. I have read that crimping is best on welding cable like I am using because it has so many fine strands. In the end, I decided that the best chance I had for consistently good terminations was to crimp.





I started by investing in a good pair of cable shears and a neat little insulation stripping tool.




















This gives a good, clean stripped cable without harming even one strand of copper.













I then fill the lug about half full of Noalox, an anti-corrosion compound.












Before slipping the lug on, I slide a small length of shrink tube onto the cable












Then I crimp.

I weigh 175 pounds so I have to strain muscles I don't even have to accomplish this task.









By trial an error I found that supporting the crimping tool on the lip of a bucket while pulling the other handle down with all of my weight works the best. When the bucket or the handle slips, I bruise places that weren't meant to be bruised.











Here is a successfully crimped cable.












Lastly, I use a heat gun to shrink the tube around the lug and cable.

Wiring

I'm making progress on the control wiring - just taking my time to get it right the first time. I got my first taste of making 2/0 cables today. I thought that with the large crimping tool I bought, it would be a little easier. But no, it's a workout crimping those lugs on the cable. I only have about 50 more to do. I think I'll work on the low voltage stuff for a while.

................................................................Oh, now you tell me.

Control Equipment Layout

The battery restraints have now all been completed, coated, and installed. Today I began to lay out all of the control equipment and system wiring. Almost everything is being installed and pre-wired on a removable plywood panel. This will allow for an organized and contained wiring area. I also placed the battery charger in the trunk where it will likely be mounted.

Rear Battery Restraints

I've made a little progress since my last post. I have now fabricated the battery restraint system for the trunk batteries and media blasted them.


Today I have to drill a few strategic holes to install them, then coat them with paint or undercoating. I now have a diagram as to how I want to wire the 26 traction batteries. This will necessitate turning a few of the batteries around 180°. After I do that, I can install both the front and rear restraints. Then, it's on to wiring up the controls.

She Carries Her Extra Weight Well

I took a break from working on the car this morning to shoot some photos for a magazine article that will be coming out soon in New Zealand. While I was at it, I took a shot similar to one I had from before I started this conversion.
The top photo is with the old 360 engine in it. The bottom photo is after the conversion and is approximately 900 pounds heavier than with the 360 engine. As I said in another post, I prefer the way it sits now.

No-Fly Zone

After a couple fun days of cutting, welding and drilling I have finished the underhood battery restraints. These guys won't be flying anywhere now. Before I bolt the brackets down to the angle iron battery racks, I'm going to clean them up with the die grinder, media blast and paint them.

Tachometer

Here is how (for next to nothing) you can supply a proper square wave pulse to a tachometer that will then read the RPM of your electric motor.

It's still a bit chilly outside this morning so I thought I would play with this issue until it warms up enough to go out and work on the car. I have a digital tach in my existing dash and I have intended from the start of this project to use it for the electric motor. It is advantageous to know the RPM of the motor because there is a certain range (around 4000 for mine) that it is most efficient. Knowing what the RPM is at any given speed will allow me to be in the most appropriate gear to get the best performance from my motor and longest life out of my batteries.

These common motors and controllers like I am using have no output for a tach. For months I have been researching on-line about how to make a tach work. I have read about some ingenious and complicated ways that other people have done it - most of which I didn't really understand or was not capable of doing. I have not found one straight forward description that was easy, inexpensive, and sure to work for my setup. So, here is what I did. This should work for any remotely similar setup using a stock automotive tachometer. Maybe this information will fill a void and help someone else.

I had an old 70's type distributor with electronic ignition which I disassembled.

I salvaged what amounts to a 'magnetic gear tooth sensor'. The collar with the ridges on it rotates with the distributor. Every time a ridge passes the sensor magnet, a small pulse of electricity is generated.

I just happen to have a spare digital tach that I have never used. This is good for a test instrument so I hooked it up to a converter and powered it up with 12 volts.


The green wire on this, and most tachs that I have seen, is the sensor input. I tried various ways to get the tach sensor to recognize the little electrical pulses produced by the sensor but it wouldn't. So I went back out to my giant stash-o-parts and found an old 70s ECU (Electronic Control Unit). This is what the gear-tooth sensor originally plugged into.

I plugged the distributor into the mating plug. I then hooked the 12 volt power (positive) to the wire that originally went to the plus side of the coil. Then I hooked the ground (12v negative) to the metal case of the ECU. Lastly, I connected the wire that originally went to the negative side of the coil to the tachometer sensor input (green) wire. As I passed the metal collar past the magnet, the tach registered pulses.

Just to be sure, I affixed the collar to a cordless drill and rotated it at various speeds next to the magnet. The tach registered various RPMs. I did not take a picture of that because I only have two hands:) You'll just have to take my word for it.

So that's where I am today on solving this problem. The next step will be to modify it a bit to make it work for this application. The metal collar will be mounted to the tail shaft of my motor (the small shaft at the front) and will spin with the shaft.

The collar has 8 ridges on it. This means that the sensor generates 8 pulses for every revolution of the old distributor. A distributor rotates once for every two crankshaft rotations in a 4 stroke engine. So by my advanced math calculations, I figure 4 pulses of the sensor will equal one electric motor shaft revolution. Solution: grind down every other ridge so only four pass the magnetic sensor per revolution.

The last piece of the puzzle will be to mount the magnetic portion of the sensor to a stable surface where it can be adjusted close enough to the gear to sense the passing ridges.

Beautiful in it's simplicity! Best of all, it didn't cost me anything. However, these should be common, inexpensive junkyard parts if needed to be purchased.

I'll post the 'final chapter' to this when I finish the installation in the car sometime soon.

Just A Small Step Backwards

I took care of raising the front battery rack 3/4 inch. Now I have plenty of clearance for the bottom battery terminals. I also cut out a couple of cell access areas on the second rail. If I haven't mentioned it before, all bare steel on the battery racks is coated with a spray-on rubberized undercoating. All of the batteries can go back in tomorrow so I can fabricate the hold-downs for them. We wouldn't want all of those batteries to go flying now would we?

Front Batteries Installed

Fourteen batteries do indeed fit under the hood, with room left over for the motor controller and other equipment.



I still want to make a couple of modifications to the racks. Now that the hood is back on the car, I can see exactly how much clearance the front row of batteries has. I have decided to raise the front battery rack about a half inch to provide a little more space above the terminals on the bottom row. I am also going to cut the angle iron to provide access to the battery cell covers on the bottom batteries, as the water needs to be checked periodically. I will be able to slide the top batteries over enough to gain access to the bottom row for this task.
















The car sits very nicely with all of the batteries installed. You can see in the pictures how it compares to the stock '70 Duster (without an engine) next to it. Before I started this project I measured the height of the car at the top of each wheel well centered on the wheel hub. With the weight of the batteries, the car sits about 2 1/2 lower in the rear and only 1 inch lower in the front. I had always disliked how high it was in the rear. Now I think it sits perfectly.

Do NOT Mess With a Man and His Sawzall

Ok, I was pissed. So I got my sawzall, got into the engine bay and attacked the K-member. Half way through the job, some guy came walking up the driveway behind me. I didn't see him until he got right next to me and he startled me. I popped up with the sawzall still running, sweat pouring off of my face, and a crazed look in my eye. The guy took two steps back as he announced that he was running for County Sheriff and would like to give me a pamphlet. All I can say is, I'm glad he wasn't selling something or he would be missing an arm right now.


Some days you work very hard and make no progress. Some days you work very hard and accomplish a lot but show no progress. Today was that kind of day. Right now, I am back to where I thought I was this morning. The batteries will now fit. It's going to be close at the front of the hood, but the sawzall and I have become good friends.