The MAX17043/MAX17044 are ultra-compact, low-cost, host-side fuel-gauge systems for lithium-ion (Li+) batteries in handheld and portable equipment. The MAX17043 is configured to operate with a single lithium cell and the MAX17044 is configured for a dual-cell 2S pack. The MAX17043/MAX17044 use a sophisticated Li+ battery-modeling scheme, called ModelGaugeTM to track the battery's relative state-of-charge (SOC) continuously over a widely varying charge/discharge profile. Unlike traditional fuel gauges, the ModelGauge algorithm eliminates the need for battery relearn cycles and an external current-sense resistor. Temperature compensation is possible in the application with minimal interaction between a C and the device.