Wiring Things Up and Testing

Much of my time was spent wiring up the controller, charger and integrator box from the Belktronix kit.


I had to unbolt the charger in order to get access to the fast-on connectors on the side of the main motor controller.


The Belktronix instructions come with a checklist of things to do before powering up the system. I had my handy Fluke meter out to find any problems.


Here's a top-down look at the vehicle integrator module all wired up. I've just turned on the ignition key and all the proper LEDs have lit in the integrator module.


Another sign of success is that the fan on the controller (near top of picture) is now spinning.


I wired the DC-DC converter right into the alternator input connection, again leveraging the existing main fuse in the under-hood fuse box. The voltage is about 13.8, which shows that the DC-DC working. Note that the potbox sitting on the headlight, still not routed into the passenger compartment.

At this point I felt that EV urge to try spinning the motor.


Yay! The hub spins and the controller didn't blow up. This means I actually got several things right. Okay, time to clean up this spaghetti wiring.


Here is the cable for the potbox routed through one of the rubber plugs in the firewall on the passenger side.


The cable from the potbox wasn't long enough to extend all the way into the engine compartment, so I found some shielded 4-wire cable and made an extension cord by using red male and female fast-on connectors. This is a picture of the passenger footwell. The potbox is to the left in the driver footwell and the cable goes forward, through the rubber plug in the prior picture to the driver components.


Her is some of the wiring after a bit of cleanup. I drilled several 1/8" holes in the front edge of the plastic mounting board and used these for tie-wrap holes to bundle the cables together.


Here is a closeup of the bundled cables nearer to the integrator module. It's not pretty, but I think it'll work. Note the BatMon board below, connected to the IsoBatMon circuit with its 7.5A blade fuse. In the lower-left of the photo, you can see the blue male/female fast-on connectors I used to connect the charger to the orange cable going to the charging socket on the outside of the car.

Routing the Cables Underneath

Not surprisingly, we need to connect the batteries in back with the batteries in front and also include the main circuit breaker under the parking brake. These lines are typically routed under the car in the trough left by the exhaust system.

Many people use pool tubing to protect the battery cables from road dirt. After looking at the tubing selection at the local hardware store, I opted to use reinforced radiator hose tubes (outside diameter 1", inside diameter 3/4"). These hoses were cheaper than pool tubing and were more built for the harsh automotive environment. The were also more flexible so I could bend them around corners to properly route the cables.


I'll have to add more pictures later of this, but here's a good shot from under the car of the cables inside the radiator hose. I used hose mounting brackets bolted into the existing studs that held up the exhaust shields. Note the break in the cable near the center of the picture to attach to the high-current circuit-breaker. I tie-wrapped battery terminal covers over the breaker connections to protect them as well.

In the background is my trusty 914 EV charging up (power cord on the right side) for the next run to the hardware store.

While not pictured, the battery cable enclosed in radiator hose snakes back to the two holes on either side of the trunk just behind the rear seat. These holes previously had plastic plugs in them, but they now have grommets for the battery cable. The last picture in this post shows where the cables come up through.


This is one of the neighborhood students named Joseph. He drops by to watch whenever he sees me working on the car. Our interactions are noteworthy because he only speaks French and I only speak English. He helps out when he can despite our language barrier.

Wiring up the Vacuum Pump

One of my goals for this kit was to utilize as much of the existing infrastructure of the car as possible in terms of fuses, relays and wires. To properly wire up the Gast vacuum pump, I wanted a fuse for safety and ideally a relay to protect the pressure switch from arcing too much.

Fortunately, the Civic had the features readily available for this in the form of the radiator fan circuit. The under-hood fuse box had a fuse and relay for this. The whole circuit was powered when the driver turns on the key, so the pump won't run with the car is parked.


This is the radiator fan connector. The black wire is ground and the black/red-stripe wire comes from the relay that powers it. I was able to cut off this connector and strip away the plastic protective sheath to use these wires.


Here is the black/red power wire connected to the positive side of the vacuum pump.


The radiator fan is triggered by a temperature switch connected to the green wire in the engine wiring harness. I was smart enough to leave many of the leftover harness wires intact and bundled up. The bright yellow wire on the left connects to one side of the vacuum pump switch.


I tied the negative side of the vacuum pump and the other side of the vacuum switch to ground via this existing 6mm bolt. The bolt is bottom center in the picture above with grey and blue wires attached to it with a 1/4" hole ring terminal.

This worked out quite well. When I turn the ignition key to the "on" position, the pump starts right up as the vacuum switch activates the relay. Both the pump and switch are fuse protected by existing fuses in the car.

Installing the Batmon Resistors

In order to shunt current around each fully charged battery, the BatMon boards use an external 3 ohm resistor. Since mounting these resistors involves drilling holes in metal, I wanted to mount them before mounting the BatMon boards to prevent metal shavings from sprinkling into the electronics.



Here are two pictures in the rear trunk showing the drilled holes for the resistor mounting bolts. The BatMon resistors have mounting holes 2" apart that take 10-24 bolts. The Belktronix instructions suggest drilling holes and then tapping them with threads to support the bolts. Since I had a pile of 10-24 rivnuts and rivnut tool from a prior EV project, I decided to use them instead. The top picture shows two holes just over the large red battery post cover. The bottom picture has two holes in the upper left and two holes over the wingnut in the right side of the picture. Each set of two holes will hold two resistors stacked on top of each other.


Here is a view in the engine compartment where the 12V car battery used to be. I drilled four holes here to mount two pairs of resistors.


After drilling the holes, I used the rivnut tool (in the foreground with red handles) to press in four 10-24 threaded rivnuts.


In order to mount the resistors for the two front batteries (just behind the radiator grille), I had to unbolt the large piece of plastic holding up the charger and controller. With this raised, I could squeeze in the drill to produce the two holes on the inside vertical wall just behind the radiator grille. I'll try to note in the open-source instructions that these holes should be drilled BEFORE mounting the plastic and components. I guess hindsight is 20/20...


With the holes drilled and rivnuts installed, I then used 10-24 bolts 1 1/2" long with lock washers to bolt in each pair of resistors.


Here are the mounted pairs of resitors in the trunk. These resistors have fast-on connectors that will attach to each BatMon board.

Since the resistors get quite hot, I've been informed (thanks to Bob K.) to use bare fast-on connectors with heat-shrink tubing around them instead of the fast-on connectors with a plastic covering. The plastic covering tends to melt or burn, causing a mess.

Crimping the Battery Cables

One of the major tasks during construction of an EV is properly crimping all the heavy duty battery cables together. Here's the process that I used.


I measured the distance between the terminals that I needed to connect, subtracted 1/2" and then cut a piece of 2/0 gauge welding cable for that distance. Welding cable is much more flexible than typical 2/0 gauge wire, allowing it to snake around various car parts.

The picture here shows a piece of cable and a special cable stripping tool. In addition to just cutting the cable to proper length, I marked the proper orientation on the cable for the lug at each end with a permanent marker. Once the lugs are crimped on, it's very difficult to twist the cable to get the lugs to fit.


With the tool (you can use a sharp utility knife too), I stripped off 3/4" of insulation.


I then squirted a good dose of Noalox anti-corrosion compound into the 2/0 lug needed for the connection. Make sure to smear the compound with the tip of the bottle all around the inside of the lug to get good protection.


I also smeared a bunch of Noalox on the ends of each cable and worked the compound into the braids. It's a good idea to protect your multi-hundred-dollar investment of cable and lugs with a $7 bottle of Noalox. The Noalox will also make your connections better and last much longer in the harsh automotive environment.

On my previous electric vehicle, I missed putting Noalox on four battery cable connections. After about two months of driving, these connections developed a high resistance and sapped my power during acceleration. After cleaning them up and adding Noalox, the car performed better and it's been fine for several months now.


Okay, with the cable and lug all gooped up, I needed to hold it steady for the crimper. If you have a partner, they can do the job. I didn't at the time, so I used a large plastic clamp and a chair to hold the cable like this. Make sure the orientation of the lug lines up with the marks you put on the cable.


With the cable and lug steady, I can now crimp it into place. Fortunately our local EV group has a crimper, stripper and cable cutter set that we share for people building EVs. These crimpers are often $350 or more, but are well worth it if you can spread the expense around.


Once the lug is crimped on the cable, project the joint with heat-shrink tubing. I use 1 3/4" lengths of tubing for the cables.


Here's the heat-shrink tubing in place, filling in all the gaps to protect the cable from corroding.


Here's a picture of the rear battery compartment with several cables attached. I also added Noalox compound to the battery terminals to keep the connections protected.


Here's where the flexible welding cable really shines. I mounted the contactor just over the motor and near the controller and most-negative terminal of the battery pack. With the flexible cable, I'm able to bend things into place.

Note: I used 2/0 gauge lugs with 3/8" holes for everything except the two lugs on the contactor (closest to the viewer in the picture above). These had smaller (1/4" holes) due to the smaller holes on the contactor. If I had used the larger holed lugs, they would have slid into the contacts and caused a contactor failure.

Installing the Charging Outlet

At some point, I guess we have to charge this thing. Most people like to be clever and put the charging outlet under the gas tank cover. I don't like this because it's near the back of the car, away from most charging station outlets at parking spaces. It also requires more routing of wire to get to the charger.


Instead, I chose to simply cut a hole in the side of the front bumper and use a charging outlet from a boating store. The cable from the outlet to the charger is only 24" long and this is more convenient for plugging into a charging station with the cord dangling lower to the ground.

I purchased the charging outlet from West Marine (my favorite overpriced EV parts store) for $27. It required a 1 7/8" hole. I had a 1 3/4" hole saw, so I used it and then just used a rasp file to enlarge the hole as needed.


Here's a piece of leftover cord from my 914 EV and the Marinco charging outlet (upper left in picture).


You need to make sure you thread the ring nut and sealing cup on the cord BEFORE you slide it through the hole so that it will mount correctly.


With the cord through the hole, I can put the wires into the socket and screw them in tight.


Here's the final installation of the socket with lid. I like the clean look of this.


Back up over the passenger-side headlight, we can see the orange cord dangling over the edge. I cut off most of the charging cord from the Belktronix charger and used female blue crimp connectors to splice in the two tiny black fan wires (coming down from the top left in the picture) into the 120V line. By crimping blue male fast-on connectors to the orange cord, I connected everything together. I'll test this out later.

Mounting the Batmon Boards

The next step involved preparing all the mounting hardware for the BatMon boards that sit on top of each battery. These boards monitor the voltage on each battery and signal back to the charger or the controller if there is an undervoltage (<10.8V) or overvoltage (based on temperature) condition.

The Belktronix kit comes with a bag of tie-wrap mounting pads and instructions to cut the pads in half to hold the BatMon boards to each battery.


Here's one BatMon board and its mounting pieces. The temperature sensor for overvoltage protection is on the end of the wire extending out the top of the picture. The instructions say to cut the tie-wrap mounting pads in half. I found that the remaining plastic tabs on the top of the mounting pads didn't really hold the BatMon boards that well, so I used wire cutters to form-fit the edge of the plastic tabs to the electronics on the board.


Here is the board mounted between the plastic tabs. Notice that the tab on the right just has a diagonal chamfer taken out to accomodate the green LED. The tab on the left needed a bit more work to fit between the red LED and the optoisolator.


Here are all the tie-wrap mounting pads from the kit with form-fit cut tabs, ready for BatMon installation. The smaller mounting pads near the top of the pile hold the temperature sensors onto the battery for proper sensing.