About ten years ago my father bought me a portable power station for Christmas. It is a plastic box with a pair of cigarette lighter plugs as well as a set of lugs in the back connected to a 7 AH battery in the case. The power station offered a portable 12 V power supply that is effective to charge batteries for scanners and cell phones as well as antenna relays and TNC's. You could operate a low power radio for a bit of time, but with a 7 AH battery, it won't last too long, so I didn't use it for such purposes.
About a year later, a presentation at a local ham club showed a similar box, with the same internal battery, but this one was much more versitile. In addition to two cigarette lighter sockets, and lugs, a 100,000 candle power spotlight as well as a regular flashlight with blinker option and 9, 6 and 3 volt coax sockets are all included.
About a year ago the batteries started to die on me and I finally got around to buying new ones this month. I opened up the cases and replaced the cells. The power box with the light was easy as it was just plugged in with the lugs. The original box had soldered lugs which made life a bit more difficult.
The hardest part was actually getting the cases back together by getting the wires running through the tight spaces so that the cases could close again.
So after less than $20 of new parts, I have two fully-functional portable power supplies and auxillary lighting.