So, on to Plan B. The local metal supply store had sheet copper 0.020" thick. This turned out to be perfect - I can cut some of the weird shapes right out of the sheet. Cutting straps 3/4" wide, 7 of them would stack up to form the same cross-sectional area as 2/0 cable (0.105 in^2). After much careful measuring (and a first failed prototype - good thing I tried cutting the paper out and fitting it first!) I created a layout that fit on a 8.5" by 14" legal piece of paper:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEip52MUPRm4acVwP-p-a_tzlBx1xX6ZWzMyS5fymQOSUMUOonrJWBjDz56q7lClYdQFPdqvK0cmGagXYa9qC5PSHG6zA4GxXC6hvkw0fvPa8jvRUhWAN5yKS2EjMOp3XycE8WXV91iKilI/s320/01_StrapLayout.jpg)
You can find the PDF here. I printed out 7 of them, and then cut out around the outside edge and used spray adhesive to stick them to the copper sheet:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi7L6T_ulmCslcrEyDI3cSGR2eat2oAeKAuKKSQfSKRqReYsb9GeEkoo0rimYc92yWb0bbaMGfTFjydk1xD72GPb3_i4HivVupmu6aICfjVMMLEfx9v057krhpBWKEPky6AqPh48B-1wgY/s320/02_OnCopper.jpg)
I cut around each one to make for easier handling:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiynNIX8ku1hYHojbLAKTGPt5M2-MEul4QgeHSKTaB1DZdKoPvfj4wumZQXH9WXfIaateUFMczJ2dlZOaMBMYStdrykKExYSuzhayX2wxF2dbgkF_1HduANf_h8oPSpc9mAqQhLVEp8KoA/s320/03_OneChunk.jpg)
Next up - the holes. This hydraulic punch did not do much with 0.0625" copper, but it sails through 0.020" copper like butter. I call it Mr. Punchy:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhwI-W7L7_pz6yQFeUWWjc1_sidBs4AGjqQWsu1-dLpUq9YDHXY7vw64o5DPJ5jnSAOBp-fZmxPZMd5FG6UBuq0bNBcSQieIwg9kiAjp2bouk8As3vJLNpJBsGh18gHpz1Xg6l3P3bTSLs/s320/04_MrPuncher.jpg)
Here are the holes punched in one section. To reach the interior holes, I cut each piece in half. Mr. Punchy can reach pretty far in, though. It is *much* easier to line up the hole punch than it is to drill through thin sheet:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEijyB6c_8FfoQ3ccji5-YS7JN2fUsVwJgqpmb1ex5gb7pmsg9CwGEqez9zPEQSFRpS6rFPl09jEwdoI3QxuNyEoxOl3pemSuic8amRhwbnpUhKwHEbpDrCtlmp2HKkxWIZNapHaQtMNibs/s320/05_HolesPunched.jpg)
My assistant, Naiche, came by and together we used aircraft shears to cut out all 105 pieces:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiD_2vxtn9b0QIyiaKWQCCff2eZykR9vkjkaB7qtYBfUw2apxnzTy3J7gqxQ44sDAGhiRSzjPfVd_Tnv9OMno4Si6teexcBUPStfwXQgGz-knZOgRB9-o1fIVXL_WqS9-MLJv6jciVrdm4/s320/06_PileOStraps.jpg)
Now for the tricky part. To make sure that the straps don't pry the battery posts out of the batteries, I designed a bend in each one - basically, a 3/8" by 3/8" triangle. I tried just using pliers to bend it, but it was very difficult to get a precise bend. So, time to design a tool. This is the bending jig. It is basically just a piece of plywood with holes drilled to align with each different piece. A 1/8" deep inset is routed into the surface, and a welded metal piece is screwed to the base. This piece has a small angle welded to it, on top of which a welded stamp fits:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgbCcfZHd7_34qgWDm_E9mYKEVxBAZ1TucIfTEMXeubXTPByJZ9tM70xgYxXGN4wHiBqv741XiUW-1z2AJ4aUPOv7ugUxk7m6O6dB1wYJdwQpZ5gppznaOBveW3Pt14riLrXrNL5uX6oVI/s320/07_BendJig2.jpg)
You can find the sketchup file here. I extracted a PDF of the base and rotated it so the holes would fit on 8.5" by 11" paper (did not want to make another trip to the copy shop):
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEggy5jT_gAt78Jhe8c8Yj-l4ma8NVEN_Tf_3dVREqkZYIJBu2IsKAHhiDf3CQQgkEHmp9q8qcaK3HwJqJ91Z6HB8ZWo-h7uj3IWz3Hb-P0MoR2WshZlBWcaLZxyabNfoERY9Rb2HTsL3gw/s320/08_BendJigBase.jpg)
This PDF can be found here. After a pleasant afternoon of metal cutting and welding, plus wood routing and drilling, I had my bend jig:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgcPkZu-QMbDTzPtwlC7FfOHZePbda4Jt871h7p3QXxAX1v7YS9URYsb7RfPXe1iRKJrAkIFprPi_WdSADBQ1KNyCuz1vHBcVJfYvWkkDu1FFI0R7j4SwXL07jSuVfe3e8FtIN2-k8wRYg/s320/09_BendJigBuilt.jpg)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhxUAd1XBDh1YCAAi-b-yrsPfrESTvFnQ8CPvqtyJWWBJFyRrsRkS3bRfjQGsg5RC6Me_aqft_20Lrt-eqCaDprpmJ294YhbwODrbh4bxelNkByPzQhEkoYAfKIJAH-PEfOpbgeJblSvcg/s320/10_Bending.jpg)
Remove it all, and you have a nice bent piece of copper strap:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgz1ORhploFz52UfYBduTBz5J8CF-V9HceKRsMxIVJ-m6sfL2_vDck0y2D4gTslo6lQu5s9N2_zhi7eZ6TUPaPkGiCERJ2IkxYjx9P_NPbAXisBpaRx1Dj5jk_2qtdtSkINc2nzfFWMxWY/s320/11_Bent.jpg)
And, finally, after bending all of the pieces and stacking them up, I put heat-shrink tubing over all of them. All done:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh56qA6VwKGBYnzLT4I_S-2TyBccFlVA_87g-w3I4zXkRnpJhOzj3rBRK-tb6M7zTOLufbLjh8NiD4_p4I0SURIkUEe8S8GfM4Js7QCqItu499q4cwQ0xgN3nR5iDwrhNdsEgHz5sAJaqs/s320/12_AllDone.jpg)
Next up, attaching the straps, hooking up the PakTrakr and the regulator harnesses, and then finishing the wiring. So close I can almost taste it...