I followed this how-to with an iGo car adapter. I glued the trim pot in the case and used the solder iron to melt a whole in the case so I can adjust the putput with a small screwdriver. It works GREAT. I can set it for ANY voltage from 12 down to zero. Just make sure you measure the device while the car is RUNNING as different alternators put out different post voltages (all the way up to 14.2 V in my experience) A little time with a volt meter and VOILA; run your projects while mobile. I can run my Arduino or whatever while in the car...