he SparkFun Battery Babysitter is an all-in-one single-cell Lithium Polymer (LiPo) battery manager. It’s half battery charger, half battery monitor, and all you’ll ever need to keep your battery-powered project running safely and extensively.

The Battery Babysitter features a pair of Texas Instruments LiPo-management ICs: a BQ24075 battery charger and a BQ27441-G1A fuel gauge. The charger supports adjustable charge rates of up to 1.5A, as well as USB-compliant 100mA and 500mA options. It also features power-path management, guaranteeing power to your project even if the battery has died. The self-calibrating, I²C-based BQ27441-G1A measures your battery’s voltage to estimate its charge percentage and remaining capacity. It’s also hooked up to a current-sensing resistor, which allows it to measure current and power! It’s a handy IC to have, if you ever need to keep an extra eye on your project’s power draw.

Features:

• LiPo Charger and LiPo Fuel Gauge combined into one board
• DIP-switch-selectable charge rates of 100mA, 500mA or 1.5A
• MicroUSB port for charging, or external options
• Dynamic power-path managment maintains a reliable output supply
• On/Off switch disconnects the battery for more power saving
• 5V-tolerant I²C interface to fuel gauge
• Fuel gauge measures voltage, percentage, and current

Documents:

• Schematic
• Eagle Files
• Hookup Guide
• Datasheet (BQ24075 Charger)
• Datasheet (BQ27441-G1 Fuel Gauge)
• Arduino Library
• GitHub