I discovered a Bosch 18v reciprocating saw sitting on top of someones trash can. It didn't have a battery, but that didn't deter me. I have several DeWalt 18v batteries for my drills and I knew there had to be a way to use them. So I brought it into my workshop and began playing.
I disassembled the saw and traced the wiring to figure out which terminal was positive and which was negative. Once I determined which was which, I ran some wire from the DeWalt battery to the saw terminals to make sure that it operated. It did. Now to make it usable.
Step 1: Materials
Bosch 18v reciprocating saw, drill, or other tool
DeWalt 18v Battery
4 - female disconnect crimp-on connectors (16 AWG)
1 - 5 inch length electrical wire (16 AWG)
1 - zip-tie