This is how to use your power tool batteries as a power bank. You will only need a few inexpensive parts.
I made one of these years ago but I got a second hand torch so I thought I'd make another to show the world.
Step 1: How to Go About It.
-A power tool you wont mind voiding the warranty on ( I have found the Dewalt 18v torch works well )
-A car charger for your phone, needs to have an input voltage range 12-24v ($1.99 online)
-Rocker switch ($0.75 online)
-A couple of scraps of wire and some adhesive or hot glue
-Sorry about the video not being well zoomed in but you should be able to work it out.
Thanks for taking a look!