Systm #86: Three Portable USB Battery Packs You Can Build
In today's episode, we're going to help you build three USB battery power supplies so you never run out of power for your favorite gadgets!
We've played around with USB power supplies before: back in Voltage Regulators: Breadboarding a DIY USB Power Supply we built one around a $1.59 7805 from Radio Shack.
How about something even simpler, like hacking a trio of batteries onto a cut off USB Extention cable?
In this episode David Calkins shows you his version of a 7805 power supply, the USB Extention Cable power supply, and walks us through building one of Lady Ada's most excellent MintyBoost battery packs, which features a LT1302 Micropower High Output Current Step-Up Adjustable and Fixed 5V DC/DC Converter
All of 'em deliver USB power... the difference between them?
Lady Ada's MintyBoost offers the most efficient use of the battery, since the 7805 tends to turn a lot of your battery power into heat!
The USB cable hack, while quick and dirty, doesn't offer a regulate supply. That means as the batteries run down, your voltage will dip. Some USB powered devices won't like this. (It won't hurt them... they just won't charge.)