Battery Fuel Gauge ICs and Monitoring Modules

Battery fuel gauge ICs: select the actual device, not the word “fuel”

Battery fuel gauges estimate the state of charge (SOC) of a rechargeable cell or pack and expose measurements to a host controller. This collection includes surface-mount battery-gauge ICs and populated I²C monitoring boards, alongside unrelated products whose titles contain “fuel” or “gauge.” A MAX17043 module, a MAX17050 BGA replacement chip, a 0–190 ohm tank sender and an automotive fuel-injection driver do not do the same job. Read the selected variant and the individual listing before ordering. The product-page headline can contain several alternatives; it does not mean the package contains all listed models.

What a battery fuel gauge does and does not do

State of charge is an estimate of remaining usable capacity, usually expressed as a percentage. A gauge can also report cell voltage, alerts or additional battery data depending on its exact architecture and firmware. A displayed percentage is not a direct measurement of stored energy or a guarantee of remaining run time. Voltage-only estimators infer SOC from the cell voltage profile and operating behavior; impedance- and coulomb-counting approaches use different models, sensing arrangements and calibration requirements. Temperature, load transients, aging, battery chemistry and learned capacity influence the result. Compare the exact part's data sheet for supported chemistry, cell count, pack connection and host interface. Neither a gauge IC nor a breakout board should be mistaken for a charger, cell-balancing circuit or stand-alone overcharge, overdischarge and short-circuit protection system.

A cell reading near its open-circuit voltage under a light load can differ materially from its terminal voltage under a large load. The system's cutoff voltage and load profile matter just as much as a number on a display. A gauge that reports 50% does not certify that the pack is safe, healthy or capable of supplying a particular current. Specify independent battery protection and qualified charge management for the actual cell and application. Never substitute a status pin or an I²C alert for the required hardware protection.

Battery-monitoring parts represented here

• MAX17043: multiple listings offer populated LiPo fuel-gauge detection modules, usually described with IIC/I²C, low-voltage alert and an A/D-conversion phrase; others describe an IC-based monitoring board. The visible variants include 1, 2, 3, 5, 10, 20 and 50-piece choices across different listings. Confirm whether the selected page supplies a populated module or a bare IC, and check the board's connector, pin labels and external power/logic requirements. An A/D phrase in a reseller title does not establish the board's exact algorithm or resolution.
• MAX17048: DFN-8 MAX17048G+T10 IC listings offer 2-piece and 5-piece packs, while a separate MAX17048/5580 battery-monitor listing has accessory-like “4397 20cm,” “4209 20cm” and “4401 20cm” variants. Select MAX17048 5580 if that is the required monitoring product; a 20 cm option may instead be a cable or a different assembly. Match the physical IC package and target PCB pads before placing an SMD order.
• MAX17050: listings primarily show MAX17050X BGA chips described as replacement parts for Nintendo Switch-family motherboards, with 1, 2, 5, 10, 20, 30 or 50-piece selections. These are component-level repair parts, not plug-in development modules or a claim that every Switch, Lite, OLED and newer revision uses the same component. Verify the board revision, package markings and soldering process; a console-specific title does not establish OEM origin or universal compatibility.
• BQ27441: SON-12 single-cell gauge listings distinguish BQ27441DRZR-G1A from BQ27441DRZR-G1B in the variant selector and show two-piece lots. The suffix matters for configuration and firmware selection. Confirm host voltage levels, battery profile and whether the chosen part is a bare surface-mount chip. Do not treat G1A and G1B as identical simply because the abbreviated headline says BQ27441.
• BQ27220: a five-piece DSBGA-9 bare-IC listing describes a single-cell CEDV fuel gauge and references BQ27220YZFR/YZFT. Confirm the actual supplied ordering code, package and tape presentation for assembly. CEDV gauging, system configuration and battery parameters require part-specific integration; this is not a preassembled display or cell protector.
• BQ34Z100-G1: a two-piece TSSOP-14 bare-IC listing describes a wide-range battery-monitoring gauge. A broad voltage claim in a title is not permission to connect any pack directly to every pin; follow the specific reference circuit, sensing network, voltage limits and battery configuration. It should not be substituted for a MAX17043 single-cell breakout solely because both are called fuel gauges.
• BQ28Z610: listings offer 5- or 10-piece bare chips labeled BQ28Z610DRZR/DRZT and 1–2-cell gauge/protection functionality. Confirm the exact ordering suffix, pack-cell topology, required external components, configuration and protection functions against authoritative part documentation. The seller's “original” wording is not independently verified by inclusion in this collection.
• LC709203F: one populated module listing refers to STEMMA JST PH and QT/Qwiic-style connection. Those are connection formats, not a guarantee that a battery connector and a host I²C connector are interchangeable. Verify the actual board's printed labels, voltage levels and cable orientation before connecting a cell.

Choosing IC, module, or repair component

A bare DFN, SON, DSBGA, BGA or TSSOP component requires the correct PCB land pattern, assembly method and supporting circuitry. A populated breakout may add headers, resistors and a battery connector, but its component inventory depends on that particular board; it does not automatically include a battery or charger. Console-board BGA repairs require component identification and skilled rework. When a listing says “battery detection module,” check the product image and selected option to see whether the gauge is populated, how many boards ship, and whether connection leads are included. A nominal piece count in a title may be overridden by 1PCS, 5PCS or another selectable pack quantity.

Different gauge families use different algorithms and registers. An I²C connector and the word “fuel gauge” do not imply pin compatibility, a shared device address or the same firmware library. Determine the specific part number and revision, its communication address, pull-up rail, recommended bus voltage, alert behavior and how the host initializes or configures the gauge. If several devices share a bus, check address conflicts and the total pull-up loading. A battery port is not a generic logic-power connector; compare the board's battery polarity against the mating cable before first power-up. Follow the device manufacturer's design guidance for power sequencing and voltage exposure.

Measurement, configuration and commissioning

Start with the cell chemistry and the number of cells in series, not with a marketing capacity label. A single-cell lithium-polymer application and a multiseries pack require different gauging architectures and voltage sensing. Check the chip's supported battery-profile workflow, any configuration memory or learning cycle, and whether software must write design capacity, termination voltage, taper current or other model parameters. Some devices provide a quick voltage-based estimate without a current-sense resistor; others require current sensing and more extensive pack characterization. Do not assume either topology applies to every item listed here.

Validate readings at a full charge, under representative load, near system shutdown and at the low and high ambient temperatures the product will encounter. Watch for voltage sag, relaxation after load removal, sudden SOC jumps and stale communications. Treat manufacturer accuracy claims, if present on an individual data sheet, as conditional on its specified setup and battery profile, not as a guaranteed end-product tolerance. Logs of raw voltage, reported SOC, temperature, charge/discharge current where available, and elapsed operating time help distinguish wiring faults from model mismatch. Reserve room in firmware for error states when the gauge is missing, uninitialized or reporting an impossible reading.

Search matches that are not battery fuel gauges

Several products here refer to literal liquid fuel. Stainless 0–190 ohm float senders for boats and cars have length variants from roughly 100 mm through 600 mm; a separate oil-gauge listing includes 100/200/300 mm sensor choices and a PAD/gasket-only choice. An electrical resistance sender is a mechanical tank-level component, not an I²C battery IC. Match sender length to tank geometry, resistance direction, gauge input and liquid compatibility; a gasket-only selection is not a sender. The “Fuel Gauge W/Grommet 5022917” item is a mechanical replacement, not a rechargeable-battery monitor. Generic “universal” in a listing does not prove fit on a specific vehicle.

Automotive ECU fuel-injection drive chips also appear: ATIC39-B4, 30344, 30407/30460/30566, 6A930, 30621, 30651, 40017, 40038, 40055, 40184 and STA508A/STA509A selections. These are described as injection or pump drivers, not as battery-capacity gauges. CJ125/CJ125B/30522 and L9780AC choices refer to air/fuel oxygen-sensor circuitry, again a different function. Part markings and automotive board revisions must be independently matched before repair; this collection makes no vehicle-fitment or safety-performance assurance.

Other included matches are unrelated electronic parts: LM339N comparator ICs, TSH-06F IC testers, ACS712 current-sensor variants (5 A/20 A/30 A), CC6201 Hall switches and SCD30/SCD40/SCD41 CO2 sensor boards. The SCD30 menu distinguishes “Sensor base plate” from “SCD30 Sensor”; SCD40/SCD41 options can be chips, purple/red boards or modules. AGS10, SGP30/SGP40, TGS813, TGS2611, ME4-CO-E4, BMP/BME environmental sensors and other gas/pressure devices do not become fuel gauges because they are visible on the same collection page. Do not use a battery-gauge firmware library or battery wiring instructions for any of these products.

Pre-order engineering checklist

1. Identify the measured quantity: battery state of charge, liquid tank level, engine fuel-injection drive, current sensing, gas or air-quality measurement.
2. Read the selected variant for exact part suffix, component versus assembled board, sensor versus empty base plate or gasket, and pack quantity.
3. For a battery IC, verify cell chemistry and series count, host bus, package footprint, supply and logic levels, battery connection and configuration requirements.
4. For a module, verify what is populated and which cable or connector is included; for a repair chip, verify actual board revision and soldering requirements.
5. Plan charging, protection and error handling independently. A fuel-gauge percentage is information for a battery-management design, not a complete safety system.

Use the individual product specification and selected option as the purchase authority. This collection description helps separate overlapping search terms; it does not reclassify or remove any included product.