⚠️ Warning: Incorrect CEDV parameters will cause SOC jump errors. Always validate with a full discharge test.
Schematic notes:
| Command (hex) | Name | Description | |---------------|---------------|---------------------------------| | 0x02 | Temperature | Pack temperature (0.1°K) | | 0x04 | Voltage | Pack voltage (mV) | | 0x06 | Current | Pack current (mA) | | 0x08 | RemainingCapacity | mAh | | 0x0C | RelativeStateOfCharge | 0–100% | | 0x10 | CycleCount | Number of discharge cycles | | 0x16 | CellVoltage1–4 | Per-cell voltages (mV) | | 0x44 | ManufacturerAccess | Access to data flash, control functions |
Because the device measures very small voltages across a sense resistor and cell taps, careful PCB layout is critical: bq40370
is a specialized battery management system (BMS) integrated circuit manufactured by Texas Instruments , primarily used in Dell laptop batteries
. It serves as a "gas gauge," monitoring battery health, cell balancing, and protection. NLBA1 Laptop Battery Analyzer and Repair Tool 🔋 Key Functions & Features Fuel Gauging:
Tracks remaining capacity, state of charge (SOC), and full charge capacity (FCC). Protection: Configure CEDV parameters :
Manages safety features like over-voltage, under-voltage, and thermal protection. Programmability:
It is a programmable unit, allowing manufacturers to define specific charging profiles for different battery chemistries (Li-ion, Li-Polymer). Custom Firmware:
Many versions are customized for specific laptop vendors, making them difficult to reprogram with standard tools. NLBA1 Laptop Battery Analyzer and Repair Tool 🛠 Common Use Cases & Hardware Set cell balancing (internal balancing current ~5–10 mA)
This chip is frequently found in high-end Dell battery models, such as: Dell Latitude 7285 keyboard batteries. Dell PW23Y batteries. Compatible with standard communication protocols used in smart battery systems. NLBA1 Laptop Battery Analyzer and Repair Tool TI E2E support forums
The bq40370 has a safety feature called Permanent Failure. If the chip detects a voltage imbalance greater than 400mV across cells, a shorted FET, or over-temperature, it blows an internal electronic fuse (or drives the CHG/DSG FETs off permanently). You cannot clear a PF flag without proprietary TI software (often requiring an unlock code from the OEM). Result: Recycled battery.