“What if you mix the mayonnaise in the can, WITH the tunafish? Or … hold it! Chuck! I got it! Take LIVE tuna fish, and FEED 'em mayonnaise! Oh this is great.”
Those USP devices you buy for your computer usually have a gel-cell battery that lasts for a few years. Less if your power goes out a lot. When you replace them, you pay a bundle, even if it's a standard cell. This short Instructable will demonstrate how to rework an older USP for more capacity with cheaper battery power.
Sounds like a neat idea, but it got me thinking—wouldn't it be better if the USP could power the computer directly with DC? Our Cisco switches can take a direct 12V power supply, and pretty much all computer power supplies convert AC 120V to ±12V and ±5V (or is it ±3.3V these days?—I haven't kept up) and there are any number of devices (like the wireless router, the DSL modem, the VoIP phone) that all have these huge wall worts that are hard to find space to plug in that all work off of 12V as well. I would think it would be a no-brainer to make a USP do the conversion work and feed the devices DC directly, instead of converting 12VDC power into 120VAC power only to have it converted back to 12V/5VDC power.