Using MAX17043 Battery with Arduino Uno

MAX17043 practical reference

A single-cell fuel-gauge IC that reports accurate state-of-charge over I2C, far more reliable than estimating from raw voltage. Rather than just reading the battery's terminal voltage (which sags and recovers unpredictably under varying load), the MAX17043 uses a proprietary ModelGauge algorithm to track the cell's actual state of charge over time, giving a genuinely useful percentage reading for battery-powered projects — wearables, handheld devices, or anything that wants to show a realistic 'battery remaining' indicator rather than a rough voltage-based guess.

Key specifications

• Chipset: Maxim MAX17043 single-cell Li-ion/LiPo fuel gauge
• Operating voltage: 3.0V–4.2V DC (matches a single Li-ion/LiPo cell's voltage range directly)
• Operating current: ~50 µA typical, very low quiescent draw suitable for always-on battery monitoring
• Measurement: State-of-charge percentage (0-100%) via Maxim's ModelGauge algorithm, plus raw cell voltage
• Accuracy: No characterization or calibration required — works out of the box across most standard Li-ion/LiPo chemistries
• Interface: I2C, up to 400 kHz
• I2C address: 0x36 (fixed)
• Additional feature: Configurable low-battery alert via an interrupt output pin

Pinout and connection notes

This chip is specifically designed for single-cell (1S) Li-ion/LiPo batteries only and reads the cell voltage directly through its VDD pin rather than through a separate sense input, so it should be wired directly across the battery terminals (not through a regulator) for accurate readings; the ALRT pin can be used to trigger a low-battery warning or safe shutdown in software.

• VDD: Power, 3.0–4.2V DC (typically wired directly to the same single-cell battery being monitored)
• GND: Ground
• SCL: I2C clock line
• SDA: I2C data line
• ALRT: Low-battery interrupt output, configurable threshold
• QSTRT: Optional quick-start pin to force an immediate state-of-charge recalculation

Integration checklist

1. Confirm the exact part number and breakout-board revision.
2. Verify supply voltage, current demand, logic levels, and signal direction against the datasheet.
3. Check controller pin assignments and bus address or interface mode against the example code.
4. Power up with external loads disconnected, then test signals before full integration.
5. If readings or communication fail, check power and ground first, then pin mapping, interface settings, and library initialization.

Troubleshooting and reproducibility

Record the board used, wiring, library/version, supply arrangement, and measured behavior. Use the selected board-specific wiring example as the source of truth. Never assume visually similar modules share identical voltage tolerance or pin order.