Tuesday, June 22, 2010

Odds & Ends Part XIII

Lots to report today, but sadly no pictures. You'll just have to imagine how stunning the work is.

I finished the straps and mounting system that will hold the batteries in the rack that will be mounted over the motor. I still need to figure out how I'm going to get some brackets around the batteries to keep them compressed. I had it all worked out in my mind how I'd do it, but once I started working with the rack, I realized what I had in mind just won't work. Funny how that happens, you tend to not see in your mind's eye how different pieces will interfere with each other until you start assembly. Anyway, it shouldn't be to hard to sort it out, I'll just have to come up with something different.

Once I had all that done, I placed the rack in it's space so I could start figuring out how I was going to place some of the elements that have moved. I need to find new locations for the Link-10's shunt, the emergency disconnect, the bracket to hold the traction pack fuse and the anchor for the throttle cable. You may remember in a previous post I built the mount for the throttle pedal, but I hadn't built anything to hold the assembly that anchors the cable.

The shunt's new home was easy enough. It's going to be roughly in the same location it was, but I had to cut a small piece of angle aluminum to mount it to. Just out of dumb luck one of the new braces used to hold down the batteries was in the perfect spot to anchor the throttle cable. So that's sorted. Last I had to build a small bracket to hold the emergency disconnect switch on the front the new tray. I cut, drilled and had the whole thing mounted, and it looked great. Then I screwed on the big red knob that you slap to break the connection, and realized that I wouldn't be able to slap it down because it ran into the tray. I'm not sure if I'm just working too fast, or why I'm making such silly mistakes. Fortunately, it will be easy to fix that as well.

In addition I reconnected the lines to the reverse switch in the transmission. I really wish I had the proper connector to connect it up. I found the connector online and numerous places that sell it. It's about $4.00 or so, and it's made by Tyco. Would you believe every place that I could find it, it was out of stock, and had a lead time of at least 4 months. Apparently Tyco makes one batch a year and when they're gone, you wait.

I also ran an auxiliary 12 vdc line to the back of the car. This line is switched with the ignition. One of the things I found in the 2 months I was driving the car was that if the car sat idle for 24 hours, the 12 volt system would manage to drain about 1 kWh out of the traction pack. There are only a few things actually drawing power when the car is off, and they are drawing tiny amounts. The one thing that is on, however, are the DC to DC converters. They are providing 13.2 vdc to the car, as well as the SLI battery.

I know that you can leave a trickle charge on a lead acid battery forever, and it will always draw just a bit of power. I don't think they'll draw 1 kWh in 24 hours, but something is. I think it's either the DC to DC converters just using it up because they are inefficient, or the SLI battery is drawing it off. I'm just not sure, so I'm going to run some experiments. I'll disconnect each, one at a time, and watch what happens to the traction pack. When the SLI battery is disconnected, I'll look to see what happens to the traction pack and then I'll disconnect the DC to DC converters and see what happens to the SLI battery. If one of them is the culprit, and there appears to be no adverse affects to disconnecting it when the car is off, I'll use that new 12 vdc line to run a separate contactor that will disconnect the appropriate component when the car isn't running.

Lets see, what else is there to report. Oh, I also cut some plate aluminum to fit over the ends of the batteries in the front tray. This will make it easier to clamp them down and compress them. I still have to build that apparatus though.

Ok, that's it for today. Stay tuned because I'll have lots more to report tomorrow and I'll have some pictures up to show the progress.

1 comment:

Anonymous said...

The connector to the reverse swiitch I believe is the same as a standard Bosch fuel injector clip. Can be bought at most auto parts stores. I'm using one on my 3series.