PowerBoost 1000 Charger - Rechargeable 5V Lipo USB Boost @ 1A - 1000C

This little 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 running your 5V projects.

The 5.2V is safe for all 5V-powered electronics like Arduino, Raspberry Pi, or Beagle Bone while preventing icky brown-outs during high current draw because of USB cable resistance.

The PowerBoost 1000C has at the heart a TPS61090 boost converter from TI. This boost converter chip has some really nice extras such as low battery detection, 2A internal switch, synchronous conversion, excellent efficiency, and 700KHz high-frequency operation. Check out these specs!

• Synchronous operation means you can disconnect the output completely by connecting the ENable pin to ground. This will completely turn off the output
• 2A internal switch (~2.5A peak limiting) means you can get 1000mA+ from a 3.7V LiPoly/LiIon battery. Just make sure your battery can handle it!
• Low battery indicator LED lights up red when the voltage dips below 3.2V, optimized for LiPo/LiIon battery usage
• Onboard 1000mA charge-rate 'iOS' data resistors. Solder in the USB connector and you can plug in any iPad, iPhone or iPod for 1000mA charge rate.
• Full breakout for battery in, control pins and power out
• 90%+ operating efficiency in most cases (see datasheet for efficiency graphs), and low quiescent current: 5mA when enabled and power LED is on, 20uA when disabled (power and low batt LED are off)

To make this even more useful, we stuck a smart load-sharing Lipoly charger on the other side. The charger circuitry is powered from a microUSB jack, and will recharge any 3.7V/4.2V LiIon or LiPoly battery at 1000mA max rate. There's two LEDs for monitoring the charge rate, a yellow one tells you its working, a green one lights up when its done.

Since the built-in battery charger has load-sharing, it will automatically switch over to the USB power when available, instead of continuously charging/draining the battery. This is more efficient, and lets you charge-and-boost at the same time without any interruption on the output so its fine for use as a "UPS" (un-interruptable power supply).

Just be aware that the charge rate is 1000mA max, and there's some inefficiency during the boosting stage, so make super sure that the USB adapter you're using to charge with is high quality, can supply 2A and has thick power wires. This one from Adafruit is ideal and has been tested, lower quality ones will not act well due to the voltage drop on the wires or droop on the power supply. This is especially true if you're actually drawing 1000mA out of the PowerBoost 1000C, the MCP73871 maxes out at 1.8A.