What this fuel gauge does for a single-cell Li-ion pack
The BQ27421YZFR-G1D is a single-cell Li-ion battery fuel gauge from TI's Impedance Track series, communicating over an I²C interface. It monitors charge and discharge in portable equipment where knowing the remaining capacity matters more than a simple voltage-based estimate.
If your BOM calls for an automotive-grade gauge, this isn't it — but for a consumer or industrial portable, the range is sufficient.
No stock-holding claim — we quote to order.