Occasionally we want to install a device or peripheral in an asset - and the only available voltage source is higher than the maximum input voltage of our device. 

We can use a DC-DC converter to drop the voltage down to a suitable level. All DC-DC converters will have an input voltage range, and then output a new dropped voltage - this is often configurable (usually via a screw) or fixed. 

For flexibility we can use a configurable model, if we know the input voltages we are dealing with (i.e 24V trucks) and always need the same output - a fixed converter may be simpler and cheaper. 

Some examples for reference - all should be tested by the reseller before installation. These are by no means the lowest cost available - Ebay is also a useful resource. 

Australia

• approx $20, 24-12V converter: Jaycar 24V to 12V DC Voltage Converter Module
• approx $25, 6-28V in, 3-15 out configurable: Jaycar DC-DC step down converter