< p>Small battery level indicator board for a 3.7V–4.2V lithium battery (1S), suitable for DIY projects, power banks, portable devices, and electronic projects.< /p> < p>Features an integrated IC with 4 high-precision comparators and feedback circuitry, providing reliable charge and discharge indication with an accuracy of just ±1%.< /p> < p>The battery status is displayed through three colored LEDs: < ul> < li>< strong>Green: strong> high level< /li> < li>< strong: Yellow: strong> medium level< /li> < li>< strong>Red: strong> low level< /li> < /ul> < p>Thanks to the internal hysteresis of the comparator, the indicator remains stable without flickering during charging or discharging.< /p> < p>< strong>Features: strong> < ul> < li>Voltage indication levels: 25%: 3.40 – 3.55V, 50%: 3.55 – 3.70V, 75%: 3.70 – 3.87V, 100%: 3.87 – 4.20V< /li> < li>Operating voltage: 3.7–4.2V< /li> < li>High detection accuracy ±1%< /li> < li>Weight: 0.010 kg< /li> < /ul>