RPi Easy SD Card Setup - eLinux.org

Mobile battery power supply options
A Battery Elminator Circuit (BEC) should be able provide a solid 5V output at upto 3A
which will be plenty to handle the load on a normal RPi
Something like http://www.hobbyking.com/hobbyking/
store/__15212__HobbyKing_Micro_UBEC_3A_5v.html Connect this BEC to a 3S LiPo
5000mAh batter and you should get 15 hours of run time off one full charge. You could
also connect it directly to a 12v car battery for even longer run time.
Over-voltage protection
Here is a nice upgrade for your PSU - a over-voltage protection circuit (see original post
(http://blog.3b2.sk/igi/post/Tipy-a-triky-011-Prepatova-ochrana-Voltage-protect-Tipstricks.aspx)
in Slovak language). It can protect your device (RPi) from unwanted damage
by high voltage from a faulty/malfunctioning PSU. In such case, it will short-circuit and
burn its fuse immediately.
Steps:
▪ choose appropriate fuse (according to expected load): 1-1.5A (fast type)
▪ first don't put the fuse in its holder - you have to initially adjust the circuit, so use a
piece of wire (or you can use a lower-current fuse too if you don't mind spending/
burning it during the adjustment process)
▪ set the 2k2 pot (trimmer) to its max. value
▪ connect protection circuit to a power supply (if available a stabilized lab-PSU is
preferred), set to 5.25V output (max. for USB; or exact 5V if you want) and 1-1.5A
current limit