After months of watching my little robot vacuum friends slowly fade away due to their battery packs getting weak I finally had enough. I ripped apart three "dead" laptop batteries and both of my iRobot battery packs (dirt dog and roomba). Within a hour I have what I feel to be a elegant solution. A irobot which will run for over one hour on free batteries. Not only does the vacuum now pickup more dirt and pet hair than I ever recall it doing. It also weighs a lot less. Since I have changed from the Ni-MH chemistry these devices come with to lithium-ion I need to use my own charger on the batteries. I'm excited to go collect more "dead" laptop" batteries from thrift stores and convert some of my power tools to lithium-ion.

This is a portable USB plug. You can take ANY voltage between 2.5v and 16v (and 30v with some better caps) and power anything that needs a USB cord . Charge you cell phone, run an IPOD! This project was surprisingly easy, and I must've spent only 3 or 4 hours on it. a 7.2V RC car NiMH battery will run an IPOD for a LONG time. The USB standard says up to 500mA but this can actually go far past that to around 1.2 amps. It does get a little warm up there though.