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Battery Power Level LED Indicator
A lithium ion battery may have a few LED lights to indicate battery power level. It use very simple method to give very rough estimates of battery power level.
Most of BiXPower batteries use inside battery cell voltages to provide a rough estimate of battery power level. This method is simple and only consumes very little battery power. Following curve shows a typical lithium ion cell voltages vs its charge/discharge level:
However, such a voltage-only method can not provide very accurate power level, since no clear correlation exists between voltage and the available charge. Just treat the power level LED lights as a rough estimated. The last LED that indicate full charge may disappear quickly and the first LED may stay very long time when begin charging battery. This is normal and it does not mean battery is defective.
Battery cell voltage also depends on temperature, and dynamic relaxation effects can cause a slow increase in the terminal voltage after a reduction in load current. Thus, purely voltage-based monitoring is unlikely to provide charge-level accuracy better than 25%.
Fuel gauging of chargeable battery cells is a complex task due to the many interdependent parameters that influence cell capacity. Simple methods of measurement, therefore, deliver inaccurate results that are adequate only for non-critical applications.
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