More 12V hackery

I've actually been so busy on the Jeep the last couple of weeks, I've not had time for blogging. The next few posts will make up for that...

First, I did some work on the 12V relay box. I made the cables that will attach the box to the DMOC controller and to the dash instrumentation. The DMOC cables use GM WeatherPack connectors - which are very handy things, well-sealed and robust.

You start by collecting your pin, seal, and crimper:


Push the wire through the seal, and crimp the pin on to the wire and on to the seal:


Push the seals through the connector, close the end, and you're all done. About 1 minute per pin once you get the feel of it. Here is the relay box with its cables attached (the ones at the lower left connect to the DMOC, the ones at the upper right connect to the dash instrumentation).


After looking closely at the wiring diagram, and after deciding to get a 120/240VAC to 12VDC power supply to integrate into the system, I realized two things. First, the glass fuses were pretty much all for the AC power supply and relay. Second, with those fuses gone, there was plenty of room in that box for the heater contactor. So, here is, I believe, the final 12V diagram:


And here is the assembled box, integrated in (the dash wiring is not complete, nor is the heater wiring, but the box is hooked up to the keyed 12V (yellow wire on the left), ground (black wire), and the DMOC:


The current wiring diagram PDF is, as always, here.

Front Components

I got almost all the front components placed very close to where they will go. I reinstalled the front rack, and permanently mounted the vacuum pump and vacuum canister. I test-placed all the other components that will go in the front compartment - the only two items in this picture not in their final location are the Hall effect sensor and the heater contactor:


Here are labels to make it easier to see what is going on:


I'll try to find a box to put the heater contactor in - the guiding principal of the 312V system is to make it very difficult for fingers to come in contact with it.

One problem has become evident - 4/0 welding cable will not fit through the strain relief fittings on the controller. I have a few options:

• Go with a short run of thinner cable (3/0 might work) - if short enough, should not cause too much of a voltage drop
• Drill bigger holes and use the 1" LiquiTight flexible conduit terminators I've used elsewhere
• Just put a rubber grommet on the 1" holes

I'm leaning toward the "drill bigger holes" option right now. Still thinking about it.

Misc Friday

Ahh, Black Friday. A day when every red-blooded American's thoughts turn to... electric conversions. Today was a day for some miscellaneous things I've been putting off for a while. First, I actually installed the "extra" battery mount (one of the first parts I welded). There are three 3/8-16 RivNuts inserted, and three 3/16" by 2" bolts through the rack into the RivNuts. The rack is held level above the sheet metal by three 1" spacers (this was required due to the slope of the fender right next to the mounting point). I also used RivNuts as the top hold-down attachment point:


Next, I made a top for the "extra" battery from polypropylene. Because this battery does not have a rack-style enclosure, I decided to get a little fancy and create a lip around the top to prevent curious fingers from accidentally contacting 312 volts. Basically, I just cut half-way through the box along the edges, and then liberally applied heat with a heat gun. And then, with sufficient force, the edges were bent down:


Next, I reinstalled the heater blower. First, though, I identified the main wire that is hot when the blower is active - it's the light blue wire here. I then added a pigtail blue wire on this so that I can control a relay which gates the heater contactor - I only want the 2000W heater running when there is air flowing:


With some help from KatC, I installed the blower assembly. Here is the view from the engine compartment. The two gold braided wires on the right are the main wires for the heater core. The purple and black lines are the vacuum lines which provide vacuum for the flapper box (TBD - how to hook them up....) And the blue wire is attached to the pigtail I just made:


Finally, I spent some time actually going over the factory service manual wiring diagrams in some detail. This allowed me to determine that some more of the factory harness can go (and should go - it just clutters things up). On the passenger's side, this harness goes to the EGR solenoid, the fuel pump relay, and the "B+" relay (basically, a relay controlling a time delay shutdown circuit). None of those are needed for ElectroJeep, so this whole harness gets guillotined:


On the driver's side, this whole harness which emerged from the bulkhead was entirely dedicated to controlling the gas motor. So, it got chopped. Here you can see the final electrical tape wrapping - basically, each wire gets folded back on itself about 3/4", individually wrapped with electrical tape, and then the whole mess gets taped together:


Tomorrow - weather permitting - I'll reinstall the front rack, finish its holddowns, and start working on battery interconnects (!).

12V Wiring I

I spent some time this week designing and implementing the front 12V system. First, I drew out most of the engine compartment wiring (you can find a PDF here):


I then prepared the relay box. Here it is from the front. You can see the two main relays on the left and right. They are angled this way so the pins will be facing "down"-ish when the box is mounted - I don't trust this box to be 100% water-tight and this will prevent condensation from seeping into the relays. The relay on the left is a 240VAC DPDT relay to handle duties associated with detecting when the charger is plugged in (this is the lower relay in the circuit diagram). The relay on the right is a 12VDC DPDT relay to handle some keyswitch action (mostly: disable the DC-DC converter when the key is switched off):


Here is a view showing the top. There are two rows of 10-place terminal strips. The one in front is row "A" with terminal #1 on the right and #10 on the left. The one in back is row "B". These numbers correspond directly to A1, B2, etc. on the circuit diagram:


There are provisions for 6 keyswitch-controlled and fuse-protected circuits. I am currently using 4. There are also 4 glass fuses for the various signal wires that go out. My current philosophy: fuse early, fuse often. Much easier to replace a fuse than to put out an electrical fire.

Still to do: the charger interlock is drawn correctly on the diagram, but not implemented correctly (the DMOC wants the charger interlock to close a circuit when plugged in; my implementation currently sends a +12V signal, which is not the same thing). Also, this implementation currently disables the DC-DC converter when the Jeep is plugged in. It seems like a good idea to be able to optionally charge up the 12V aux battery when the key is turned on. Again, the wiring diagram above is correct, but the implementation is not quite right yet.

Next up: still have to remove the rest of the dash so I can get at that heater core... you might be able to tell that I am procrastinating on this less-than-fun chore.