Written by Justin Goetz -
So recently, a situation came up where I had to bring wifi to the middle of nowhere. By middle of nowhere I mean no power, no nothing. So I decided to bring along my Linksys WRT54G (Running DDWRT). I have a small battery pack that I built, and I figured I would power the router off that. At first I was just going to bring my inverter and plug the power brick of the router into that. But its pointless to me why you should conver the power from DC -> AC -> DC again. So after my friend on IRC mentioned I could power the router directly from the DC power source. I thought for sure I would need some kind of adapter, but it turns out the router can in fact be plugged directly into the DC power source. So heres the steps below, so you don't have to go though the same guessing game I did.
Step 1: Find an older power adapter that fits your router's power port. Make sure its old, and not the power adapter you need for the router. (Once this is done, you can't use the adapter anymore to plug into the wall).
This dosen't apply to just my router, in fact anything that runs of a 12v power supply can be powered directly from a DC power source (Such as the battery). This can come in handy when you have to power something in a car or from a battery, and don't want to use an inverter.
Thanks to HeavyMetal in IRC Chat for the idea!