Built my own portable DC power supply based on the one Tom Sachs sent to AvE, which in turn is based on a DML186/LXLM01. I wanted to make mine a bit neater,
Makita DML186 18V Li-Ion LED Flashlight
Makita DML186 18V Li-Ion LXT LED Flashligth - Batteries and Charger Not Included Green : Amazon.co.uk: DIY & Tools