From a user experience perspective, there are five fundamental principles for battery charging:Charging always occurs when connected to the charger. Charging is managed autonomously by the hardware.
What are the different ways to charge a battery?
There are, broadly speaking, two different ways to charge a battery: quickly or slowly. Fast charging essentially means using a higher charging current for a shorter time, whereas slow charging uses a lower current for longer.
What happens when a battery is fully charged?
At this stage, the battery voltage remains relatively constant, while the charging current continues to decrease. Charging Termination: The charging process is considered complete when the charging current drops to a specific predetermined value, often around 5% of the initial charging current.
How does a programmable battery charger function?
A programmable battery charger functions by changing the charge rate, for the value shown, between 0.1A and 1A. The charger in Figure 3.19 is programmable with a voltage from D-A converters. The charging current is directly proportional to the program voltage. A small sense resistor in the bottom side of the battery senses the battery charging current.
About 65% of the total charge is delivered to the battery during the current limit phase of charging. Assuming a 1c charging current, it follows that this portion of the charge cycle will take a maximum time of about 40 minutes. The constant voltage portion of the charge cycle begins when the battery voltage sensed by the charger reaches 4.20V.
The constant voltage portion of the charge cycle begins when the battery voltage sensed by the charger reaches 4.20V. At this point, the charger reduces the charging current as required to hold the sensed voltage constant at 4.2V, resulting in a current waveform that is shaped like an exponential decay.
How complex is a battery charging system?
The complexity (and cost) of the charging system is primarily dependent on the type of battery and the recharge time. This chapter will present charging methods, end-of-charge-detection techniques, and charger circuits for use with Nickel-Cadmium (Ni-Cd), Nickel Metal-Hydride (Ni-MH), and Lithium-Ion (Li-Ion) batteries.