Wednesday, December 16, 2009

The Controller

After finishing work on the primary 12 volt system last week, I decided this week that I would start getting the controller mounted into the chassis and start connecting all the wires to it that it requires. The Zilla controller will sit in the electrics bay above the platform that holds all the 12 volt relays and other bits. It means that once the controller is in place, I can't easily get to the 12 volt tray below it. That is certainly not ideal, but with the limited space I have, it was unfortunately necessary. The fact is that all of the components mounted on that tray are not the sort of things that should fail. There's certainly no fuses down there.

That's the Zilla controller, with the hairball above it. All the high voltage lines run to the controller, and all the control wires run to the hairball. There's a RJ-45 connector on both the controller and the hairball, and it came with a cable that runs between the two. My guess is that the hairball does all the calculations and feeds the signal to the controller which simply spits out the appropriate amount of current to the motor.

You may notice that I moved the main contactor (that white cylinder toward the top right corner of the frame). It had been located in the lower right frame, but it became clear that running the 2/0 cable to the controller with the contactor in the old position wasn't going to be very easy. I think it will work out much better in this location.

I also spent some time trying to figure out if I will be able to make the stock tachometer work with the Zilla. The Zilla can drive a standard tachometer for a 4 or 6 cylinder car. The problem I face is that the signal that was sent to this tachometer was clearly sent via the CAN bus in a format that I have no way of determining. The tachometer itself has 4 pins that plug into a circuit board right behind the instrument.

On a normal aftermarket tachometer, those four wires would be laid out like this:
1 - to the coil or alternator
2 - 12 volt positive
3 - chassis ground
4 - 12 volt for the instrument's light.

On the stock tach, I was able to measure one pin at 8.5 volts, a second at .56 volts and the other two had no voltage. Nor did they have continuity to ground. Uh huh. Well, it's likely that there was some sort of signal sent down one of those two wires that shows no voltage, but which wire, and what that signal was, I have no idea. It could have been a 12 volt pulse. It could have been a pulse that tied the instrument to ground. No way to tell. I'm likely going to have to replace it with an after market one. But before I do, I'll experiment with it a bit. I might get it to work, I might get it to send off some funny smelling blue smoke. Either way it will be fun.

Oh, and still no word on the batteries. Curses!

Tuesday, December 8, 2009

12 Volt System Tests Done (I Mean it this Time)

I got the replacement relay for the heater switch, dropped it in and it works just like it's supposed to. So here's how it works. The Car must be on for the heater fan to work. The heater fan must be on in order for there to be power delivered to the switch on the dashboard that turns on the heater. If the cars not on, no power to the switch. If the fans not on, no power to the switch. So there should be no way for the heater to be on unless the car is running and the fan is on. I'm trusting that means no exciting fires in my dashboard.

I got a bench power supply the other day. "What's that" you say? I'll explain. If you build any sort of electronic devices, you need some way of providing power to them to test them or operate them or whatever you have planned. Well a bench power supply lets you set the precise voltage and current (amps) you want to deliver to the equipment. "But Tim, you're not bright enough to build any high end circuitry" you say. Well, you're correct. But the great thing about these is that they can function as battery chargers.

You say "Well then, why don't you just buy a battery charger you dimwit?" Whoa, that was kind of harsh. The thing about these batteries that I'm allegedly getting someday is that they are 3.3 volts apiece. Not exactly your standard charger voltage. If one of them needs to be charged by itself for some reason, say it lags behind the others in the pack during a normal charge, then I can catch it up with this. I don't expect that to happen much because I plan to follow a fairly conservative approach to charging. But you never know.

Anyway, with that, I was also able to charge the 12 volt battery I'd installed a few weeks ago and have been running down ever since. With it nice and charged up, I felt it was safe to try that energy hog of a power steering pump. I'm pleased to say that the whole system worked flawlessly. I turned the wheels and the pump comes on right away. It stays on for 10 seconds after the wheels are straight again. If during that 10 seconds I turn the wheel again, the timer restarts. Plus no leaks! I'm very happy about that.

I also started modifying some of the carpet that lined the trunk, so that I can put it back in place. I have to cut out holes to accommodate the new equipment, but so far so good.

And you guessed it, still no word on the batteries.

Friday, December 4, 2009

12 Volt System Tests Done (Almost)

Today I spent some time testing the remaining portions of the 12 volt system and all the components I've hooked up to it. Admittedly I haven't checked all the pre-existing 12 volt powered things on the car, I'm just assuming they'll work because I haven't touched them. They worked after the engine was removed, I think they should work now.

I got the replacement off-delay timer relay today, dropped it in and it worked perfectly. I've got the time set to 10 seconds. I figure that should be adequate to prevent any damage to the power steering pump due to short cycling.

I checked that the kill switch on the charging door works properly.

I tested the DC to DC converter relays to be sure they are working. When the car is running, those relays will have power to them and cause the converters to jump their output to 14.2 volts. That will help to keep the accessory battery up to full charge.

I installed the smaller DC to DC converter that is specifically for the Link 10 meter. It will isolate the 12 volt system from the high voltage pack, which are wired together at the meter.

I made sure the fan for the battery pack has power to it. I haven't installed the temperature switch yet, so that test will have to wait for later.

Last, I started testing all the relays and switches for the heating element. Ultimately I found that the dashboard switch, which should only have power to it when the heater blower is on, was live all the time. It took a couple minutes but I isolated the problem to a relay that I'd bought at Fry's Electronics. The coil seems to be frozen closed. I don't know if it was like that when I got it, or I did something horrendous to it and broke it. It's probably that second thing, but I honestly don't know what I could have done. Fortunately, a replacement is cheap.

Still no word on the batteries. Stupid slow container ships.

Tuesday, December 1, 2009

Not Much Left

It's getting to the point where I'm running out of things to do while waiting for the batteries. Today I ran the wires and installed the XM radio receiver that will plug into the new stereo. I also ran the iPod interface cable to the center console. Of course these don't have anything to do with EV specific tasks, but I needed to get them done. I did start putting parts of the center console back together, and tomorrow I can work on some other parts of the main dashboard. I don't want to do too much there though, in case I need to access some of the wiring back there.

I still need to do a bit more testing with the 12 volt system, but with the testing that I've done so far, I've run the battery down to 11.8 volts. I'd like to charge it before I do anymore, but I don't have a 12 volt charger yet. Ones on the way, so I'll be able to tackle that soon.

I guess the next (and probably last) big thing is to build the under body sheets that will help improve aerodynamics. I'll start that tomorrow.