Sources: Power Tool Batteries for Portable or Emergency Operation

• DC-DC Converter:
  • DIANN
  • CLLENA

• Schottky Diodes:
  • BOJACK
  • AKOAK
  • Tnisesm

• Battery Adapters:
  • Milwaukee
  • DeWalt
  • Makita
  • Ryobi

• Anderson Powerpoles, Wire:
  • Powerwerx

Schematic Diagram:

            + ----red------>|----|
Tool Battery              Diode  |  
            - ---black-|         |
                       |         |
                       |         |
            + ----red------>|----*--red---- + ------ yellow ------- +
Tool Battery           |  Diode        DC-DC Converter               Radio
            - ---black-*-----------black--- - ------ black -------- -

The tool battery connector has red/black wires. The DC-DC converter has red/black and yellow/black pairs. The diode has a stripe on one end; make sure that the diode is in the red wire with the stripe on the side away from the tool battery, towards the DC-DC converter (like the cross-bar on the diode symbol). If you use multiple batteries, each battery gets its own diode, and all the diodes are connected on the stripe end; all the black battery wires are connected together.

Combiner for Multiple Batteries and/or Solar Panels using Schottky Diodes:

Note:

James Ogann, KC0AA, reports that over-discharging a lithium tool battery can damage the battery.