A DIY adapter lets an 18–20-volt cordless-tool battery power USB devices, guitar pedals, lights and other DC gear drawing under 18 volts. The guide uses a buck converter to lower the battery output to the device’s required voltage, including 5 volts for USB.
The build combines a battery adapter, adjustable DC-to-DC buck converter, plastic project box and output ports such as USB-A, USB-C or a 5.5 x 2.1 mm socket. The instructions call for checking and adjusting the converter’s output with a multimeter before connecting the ports. Adapters are available for DeWalt, Milwaukee, Makita and Ryobi batteries.
Some lights and 12-volt vehicle accessories may need more than USB’s standard 5 volts. The guide advises checking a device’s voltage and amperage requirements; higher-amperage applications may need a more powerful converter.
