Finishing the Potbox

Previously I had mounted the potbox unit inside the weatherproof enclosure and mounted it.  To complete the job, I had to run the potbox signal cable to the controller and the potbox microswitch.  Here you see everything in place, running through a weatherproof cable gland nut to split-loom, and the clear cover on and screwed down tight.  Then you can see the wiring landed on the controller.

Building weatherproof boxes for the electronics

The standard design from EA involves mounting some sensitive electronic parts and terminal blocks out in the open in the engine compartment, subject to to water, dust and other nasty things.  Working for a solar power company, I've learned to protect this kind of equipment as best as possible to give the car the longest possible life without having to worry about electrical failure, rust and ongoing repairs.

I started with the relay board.  EA supplies a thick plastic board, predrilled for mounting the components.  I bought a NEMA4 rated enclosure sized to fit the board inside.  You can see I had to do a bit of machining to make it fit.

I mounted the relays and the terminal blocks to the supplied board.

I then followed the instructions and wired everything up.

Here's how it looks with the clear cover on the box.  I bought the clear cover option so people can see the internal workings of the system and I can keep an eye on things for moisture intrusion, discolored wires, etc.

Next I moved onto the contactor.  The contactor, a small relay and two terminal blocks are supposed to be bolted to the side wall of the engine compartment.  I wasn't comfortable with that, so I proceeded the same way as the relay board above.  Here's the contactor - it's essentially a very large and powerful relay that is wired between the motor controller and the motor.  It needs to handle 600A of current flow.

The boxes I bought did not have internal mounting plates available, so I found these pieces of plastic sheet at Lowes, and machined one to size to fit into the box.

I spent a lot of time figuring out the best position for each part inside the box, making sure there was enough space for wire bends and clearance for inserting and removing wire connectors.  Here's a picture of the final assembly.  You can't see the clear mounting plate with the protective film removed.

Then I moved on to the potbox.  Alert readers will remember that the potbox assembly wouldn't fit into the space defined by EA because the brake proportioning valve was removed before I got the car, so I had to do something.  I decided to disassemble what EA had me build, and stick it into a weatherproof box.

Here's how the potbox fits insde the box.  Just right.

Another change I had to make was to reverse the mounting of the accelerator cable pivot post.  It sticks up too high, so I'll just flip it around.

I figured the plastic sheet wouldn't stand up to the stress of the moving parts, so I made a metal plate that the potbox will mount to, which will then be mounted to some embedded nuts in the box.

I drilled mounting holes in the box and then into the firewall.  I installed rivnuts into the firewall and bolted the box into place.  I sealed around the bolts and washers with silicon sealant.

Here is the potbox in place, with the accelerator cable coming through from the left side and attached to the pivot arm of the potbox.  When I continue the build and figure out where the potbox cable needs to go, I'll drill a hole and install what we at REC Solar call a pongi - a weatherproof fitting that compresses down on a cable as you tighten it down.  I don't want anything coming into the box.

I'll do the same for the relay board and the contactor box when I mount them.  Well I'm off for a 2-week solar monitoring road trip, so the car gets to sit and wait for me to return.

The First Electric Part Installation

So I gathered up my courage and jumped into the first step of the installation instructions. 

I cut out the paper template for the motor controller mount and taped it into place.

I got to install my first rivnut.  It's a decent solution to install a blind nut when you can't get access to the back side of the panel.  Since I'm so paranoid about rust, I decided to paint each hole I drill with rust reformer paint.

I then bolted the standoff bracket into place.

Finally I temporarily bolted the motor controller plate with the current-sensing shunt into place.  I don't have the controller yet so I'll have to remove the plate, bolt on the controller and re-mount when it arrives.

Then I decided to move on to the Potbox mount.  I'm a little concerned about leaving the potbox out in the open, where it can get dirt, mud and water inside it, so I plan to make an alternative mounting scenario, placed in a plastic enclosure.  Lucky I thought of this, because my car doesn't match the instructions for mounting the potbox.  The manual shows quite a large "brake equalizer", but mine just has a simple T-junction for the hydraulic brake lines.  I'll have to do some investigation to find out if mine is a post-factory hack or just a different style than ElectroAuto is expecting.  That's the T-junction, right at the top of the paper mounting template, with the line from the master cylinder coming in from the south-east.  It just ain't gonna fit.

Then I decided to review the steps for installing the transmission and motor, and found about half of the needed hardware was not supplied in my parts pickup.  I left a voice mail for Shari and asked her to let me know what's going on with the rest of my order, because I've had no email or phone contact since my visit to them a couple of weeks ago.  We'll see...