Sunday, December 7, 2008

Interconnects, Hold-downs, and Conduit, Oh, My!

Another miscellaneous weekend. First, I tweaked the battery layout - the labels are the PakTrakr sequence that will show up, and gives a handy reference for talking about the batteries. The biggest tweak was battery B5 in the lower rear rack. I rotated it 180 degrees. This lets me use cable to do some of the interconnects. More importantly, it gets rid of the really close interconnect between A5-A4 and A6-A3 that the old design had. There was a potential of 84 volts between those two interconnects, and they were separated by only about an inch. Bad. Now, the biggest potential is 48 volts, found between D3 and D6 and between D2 and E2, in the front compartment. Only half as dangerous... Also, I indicate where the CamLock connectors will go, and have added a key so you can see how I did the bends in the interconnects (you want to add bends to your copper straps so they have a little "give" so they don't pry your battery terminals loose). PDF of the new layout replaced the old one, here.

And then, I got cranking on the interconnects. I tweaked my bending jig - I added a bolt to keep it aligned (and to keep it from falling apart every time I insert a new piece of metal). I also screwed the supporting angle irons into the wood. And, I added a rubber band around the bending irons to gently clamp the copper in place until I am able to place the big clamp. Here is the final bend being made on an interconnect with the adjusted jig:

And here is a large pile of bent interconnects. Only thing left is to drill them and install them. I don't pre-drill them because there are subtle differences in the hole-to-hole spacing.

Next, I finished the hold-downs - as in the lower rear rack, each battery gets a disc of polypropylene above it to firmly hold the battery in place. Most of the discs are bolted through the cover and into the steel hold-down. All bolts are nylon, to avoid any danger of electrical short circuits. Here is the completed upper rear rack:

Here is the front rack, from the bottom. You can see the 8 discs, and the countersunk nylon bolts:

Here's the front rack from the top:

And here are the under-seat batteries:

Finally, I mounted the conduit and the front-back AC cable. The front-back AC cable is needed because the relay that tells the controller "you're plugged in, don't let the idiot behind the wheel drive away" is in the front compartment. This cable is basically heavy-duty 10 gauge outdoor extension cord. I tie-wrapped it to the metal flange underneath the doors:

I also finished mounting the conduit. I used double tie-wraps at several strategic points. The driver's side conduit is a little tricky - there are brake fluid lines and power brake vacuum lines in this area, so I added a loop to the conduit to avoid them all (the tie-wrap that holds the loop in place is attached to a convenient hole in the rear seatbelt reinforcement):

Here is the passenger's side conduit. You can see the double tie-wraps keeping the conduit placed mostly protected behind the frame rail:

And now, bed time...

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