Monday, October 12, 2009

Relay and Regulator Boxes

This week, it snowed. And stayed cold all week (cold enough to kill my sprinkler system's backflow vacuum breaker valve because I did not think to drain it). Oh, well. I found some things to keep me occupied inside where it is warm.

First, I worked on the relay box for the front compartment. Previously, the front relays / terminals / fuses / etc. were mounted on an exposed board on the front battery box. I never really liked this, especially because it exposes high voltage close to where fingers might pry. So, I found a box that would enclose all of the front relays and contactors and fuses - an 8x8x4 box from my local hardware store. I drilled holes for wires to emerge, installed grommets, and bolted relays / terminals / contactors / fuse holders in, and then wired it up approximately according to the wiring diagram I previously published:

Here is the same photo with labels. The "Heater" contactor controls the heater via the heater swith. The "Horn" relay is to hook up a new louder horn. The "Key +12" relay is a booster for the +12 keyed signal, to run a front compartment fan plus a couple of lights. The "Charge Intlk" relay sends a signal to the controller that the car is plugged in to the wall. It also activates a light on the dashboard. The Crydom solid-state relay in the lower left controls the HV voltmeter as well as the DC-DC converter (which should never draw more than 3 amps or so!). And, finally, I separated the high voltage from the low voltage fuses. And wired it all up:

I then put connectors on the end of the cables and put plastic spiral wrap around most of them (I'll add it to the 10-gauge high-voltage wires later as well). Note also the blue tape - it labels what each wire is, in case I forget:

With that out of the way, it was still cold and snowy outside. So I tackled another problem - how to protect the Mk2 Rudman Regulators from the elements and from prying / curious fingers. I found 18 PVC outlet boxes at my local hardware store. My vague memory of the size of the regulators made me think they would fit without much modification. I was wrong. I ended up having to cut the four internal screw posts out - making a lovely dusty mess with my Dremel. I also cut a rectangular port for the 6-pin telephone-style RegBus to come in / out. And I cut a rectangular port for the wires which connect the regulator to the battery. Here is my first prototype:

Seemed to work well, so I made 17 more (sitting on top of printouts of the templates I made):

I then took nylon screws and standoffs and inserted them appropriately...

and bolted all of them together. Here are all 18 stacked neatly on the stove. My wife is a very understanding soul:

I still need to cut the tops from 1/4" transparent acrylic. I will *not* seal the holes - I need a place for air to get in / out. Eventually I will add little fans to each one to keep them even cooler. But this was enough for now.

Next up - my daughter has a production of The Witch of Blackbird Pond at the local theater, so I'll be doing only sporadic work on the Volt914.

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