The 5.2V is safe for all 5V-powered electronics like Arduino, Raspberry Pi, or Beagle Bone
Boost converter chip has really nice extras: synchronous conversion, excellent efficiency, and 700KHz high-frequency operation
2A internal switch (~2.5A peak limiting) means you can get 500mA+ from a 3.7V LiPoly/LiIon battery.
Low battery indicator LED lights up red when the voltage dips below 3.2V, optimized for LiPo/LiIon battery usage
PowerBoost 500C is the perfect power supply for your portable project! With a built-in battery charger circuit, you'll be able to keep your project running even while recharging the battery! This DC/DC boost converter module can be powered by any 3.7V LiIon/LiPoly battery, and convert the battery output to 5.2V DC for your 5V projects.
The output was tweaked to be 5.2V instead of a straight-up 5.0V to give little bit of 'headroom' for long cables, high draw or the addition of a diode on the output. The 5.2V is safe for all 5V-powered electronics while preventing brown-outs during high current draw because of USB cable resistance.
The PowerBoost 500C has a TPS61090 boost converter from TI. This boost converter chip has some really nice extras. Disconnect the output completely by connecting the Enable pin to ground with synchronous operation. This completely turns off the output Onboard 500mA charge-rate 'iOS' data resistors. Solder in the USB connector and you can plug in any iPhone or iPod (no iPads) for 500mA charge rate. Full breakout for battery in, control pins and power out. 90%+ operating efficiency in most cases, and low quiescent current: 5mA when enabled and power LED is on, 20uA when disabled (power and low batt LED are off)
Item Specifics Dimensions: 22mm x 37mm x 2mm / 0.9" x 1.5" x 0.08" Height w/ JST: 7mm / 0.3" Weight: 4g