Electric Pickup Truck Re-wire

A couple years ago, a class of undergraduate students at my college converted a 1997 Ford Ranger pickup truck to electric power. This vehicle originally sported a 4-cylinder gasoline engine with 5-speed manual transmission. It now has an electric motor and control system bought from Electric Vehicles of America. This company sells parts for conversion of cars, trucks, motorcycles, and even boats to electric power. You can find them at the following link:
http://www.evamerica.com

A bank of 20 six-volt golf cart batteries supply 120 volts DC to run the motor. A separate 12 volt battery supplies power for lights, turn signals, and the control system that handles the motor. As it sits today, this truck has a range of 40 - 50 miles on a charge, and can reach 65 miles per hour. Granted, the range is limited. But it works fine for local driving and short commutes.

This vehicle was originally conceived as a test bed for experimenting with fuel cells and, possibly later on, hybrid power systems.

Having driven it myself I can attest to its quiet operation. At highway speed the motor emits a low hum - mostly what you hear is road noise off the tires.

Under The Hood:
In this photo you can see the view under the hood. All the wiring and controls were mounted on a sheet of plywood, per Electric Vehicles of America's recommendations. While wood may seem a bit "crude", it is rigid and is a good insulator. This setup minimizes the risk of a short of the high voltage to the vehicle's chassis. Appropriately, the plywood is painted an "electric blue" color.

The large, oblong black box in the center of the photo is an electronic controller that provides pulse-width modulated high voltage to the motor. To the left and front of that is a smaller, square black box which serves to convert the 120 volts DC motor supply power to 12 volts to keep the 12 volt control battery charged. When the truck is plugged in to charge, the 12 volt system is thus recharged as well. Two large contactors electrically disconnect the high voltage supply when the truck is parked. One serves as an interlock that is operated when the "ignition" switch is turned to "on". The other contactor is actuated by a microswitch in the throttle control when the accelerator pedal is pressed slightly. A potentiometer in the throttle control works with the motor controller to regulate the speed of the motor. The throttle control box can be seen in the right-hand side of the picture. The high voltage wiring is the large diameter orange cables seen in the pictures. A small electrically operated vacuum pump supplies the power brake booster, since there is no longer a gas engine to supply this.

Sixteen of the batteries, along with the charger, are stored in the rear bed of the truck; the remaining four are secured just behind the front radiator grille. The "shore power" connector for recharging the truck is installed where the gasoline filler used to be. This can be seen in the pictures at the bottom of the post.

Conceptually, a "plug-in" electric vehicle of this type is very simple.

Wiring Issues
The original control wiring was done with cheap, insulated slide on connectors bought at a local auto parts store. Over time these connections worked loose and became intermittent. Last Fall, the professor in charge of the electric vehicle project asked me to do whatever repairs were needed to make the vehicle reliable. I made several suggestions on what needed to be done and gave the professor a parts list. Upon his approval I proceeded.

I ended up replacing most of the control wiring, along with the cheap 1/4" crimp-on slide connectors. The original wiring was #18 gauge; I replaced it with #14. The new connectors, bought from McMaster Carr, were the non-insulated crimp type. I crimped each connector to the wire, then soldered it, then used adhesive-lined heat-shrink tube to insulate the connection. I labeled each connector with a P-touch label, then covered that with clear heat-shrink tubing for protection and to keep the labels from falling off. Doing wiring this way is time consuming, but it vastly improves reliability and makes tracing the wiring for repair a snap. For years I have done this on my own vehicles, too. [On my older truck, when it came time to replace the vacuum lines, I used P-touch labels and clear heat-shrink tube on all of the new hoses as I installed them. Now, at a glance, I know which hoses go where without having to consult the manual.]

You can see pictures of the electric truck wiring, batteries, throttle control, and of the motor below.

It Snapped Clean Away - Replacing the Front Shocks On My Truck

Yesterday I decided to install new front shock absorbers on my rather elderly Ford truck. I've had the parts for a couple months, but decided I'd better get to it before Winter sets in.

Knowing the parts would be rusted, I sprayed them with WD-40 several times in the past week or two. This, in hopes some would penetrate and help the retaining nuts come loose when I removed them.

I started work on the passenger side. The nut on the top stud of the old shock was jammed on and wouldn't budge. Thinking I'd come back to it in a few minutes, I started work on the bottom stud. Within a minute or two,the bottom mounting nut came off all right - with the threaded end of the stud still stuck in it!! The rest of the stud was still attached to the truck and was holding the shock. [See above photo - bottom portion]I knew I was in trouble then - as the stud was a permanently attached part of the lower suspension arm. With the threaded portion broken off, there was no way to retain the bottom end of the new shock. After some proverbial head scratching, I went back in the house and got online to see how other folks handle this sort of problem. I quickly found out I was NOT alone - this problem is quite common. AND there is a reasonably inexpensive fix.

Fortunately, auto parts stores sell generic "Help" kits to replace broken shock mounting studs. Check places such as Autozone, NAPA, ... The new stud in the repair kit consists of a double-ended stud: the shock absorber mounts to the long, mostly smooth end; the short, slightly fatter threaded end goes into a hole in the frame or suspension member and mounts with a washer and nut. The old stud, of course, must be removed before the new one can be installed. Below I'll detail, in words and pictures, what I did.

Items needed:

New shock mounting stud repair kit - probably should get one for BOTH sides of the vehicle
hand-held "angle grinder" - preferably a 4.5" one. The wheel on a larger 5 or 6" one is too big and will be hitting stuff you don't want cut.
"Cut off" wheel and coarse grinding wheel for the grinder
an electric drill - preferably a 1/2" one
a set of drill bits - preferably titanium coated
A drill bit the right size for the new mounting stud in the repair kit you bought
Center punch and hammer

Here, in a nutshell, is what to do:

1) Use the angle grinder with "cut-off" wheel to remove the broken stud, cutting it off flush with the suspension or frame member it's attached to.
2) If necessary, use the angle grinder to cut through the top mounting stud on the shock absorber itself. That top stud is usually made of fairly mild steel, so one can cut partially through it and snap it off by pulling outward on the bottom end of the shock absorber. You may need to rock it back and forth a couple times, but it will break off with some effort. This is what I did, because the radius of the grinding wheel would have cut into stuff I didn't want damaged if I had gone clear through the stud. You will be working in tight quarters, so BE EXTREMELY CAREFUL to NOT cut the vehicle's coil spring or any other parts when using the grinder.

3) Use a center punch to mark dead center where the stud was.
4) Drill a hole where you made the punch mark. Start with a 1/8" drill and work up through your drill sizes to - in my case, a 1/2" hole - to accommodate the mounting stud. When drilling, coat the drill bit liberally with motor oil to help it cut.
5) On my vehicle, there was a 1/4" raised "shoulder" that was part of the old mounting stud - and was still on the lower suspension arm. I had to thin this down by 1/8" with the coarse wheel in the angle grinder so I could get the back mounting nut and washer fully threaded onto the new stud. Below is the picture of the hole drilled out and the shoulder ground down.
[Yes, I got the hole off center. Didn't start out that way, but I think the large drill bit "crept" out of the small pilot hole - I had to skip several drill sizes between my largest pilot drill and the final hole size. I also was drilling with a long bit at a really bad angle. At least there's enough shoulder metal remaining it shouldn't hurt anything. The rubber bushing on the new shock still has plenty of shoulder to bear against, so a washer wasn't necessary.]


6) Once the new stud is able to be nutted in place, you are ready to install the new shock. Below is the picture of the new shock installed.


Notes:
I got BOTH the shocks replaced within an hour and a half. The driver's side lower mounting stud did NOT break when I removed the nut, so all I had to do there is cut the top mounting stud on the shock and remove it as described in step 2 above.

Frankly, I expected the worst, given what immediately happened when I started the job. Thus I bought TWO repair kits so if the other one broke I'd have the parts right there.

My local auto supply store only had one lower shock mount repair kit in stock, but they were able to locate one in a neighboring area and get it held for me so I could drive over and get it.

I'm keeping my extra repair kit around in case I need it in the future.

I am eternally grateful to my neighbor for the use of his 4.5" angle grinder and 1/2" electric hand drill, as well as to several good folks on the Internet whose posts helped me deal with the problem at hand.