IPS | Battery Charger

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Battery Charger


A battery charger, or recharger, is a device that provides electricity to convert into stored chemical energy for storage in an electrochemical cell by running an electric current through it.

The charging protocol (how much voltage or current for how long, and what to do when charging is complete) depends on the size and type of the battery being charged. Some battery types have high tolerance for overcharging (i.e., continued charging after the battery has been fully charged) and can be recharged by connection to a constant voltage source or a constant current source, depending on battery type. Simple chargers of this type must be manually disconnected at the end of the charge cycle. Other battery types use a timer to cut off when charging should be complete. Other battery types cannot withstand over-charging, becoming damaged (reduced capacity, reduced lifetime), over heating or even exploding. The charger may have temperature or voltage sensing circuits and a microprocessor controller to safely adjust the charging current and voltage, determine the state of charge, and cut off at the end of charge.

C-rate

Charge and discharge rates are often given as C or C-rate, which is a measure of the rate at which a battery is charged or discharged relative to its capacity. The C-rate is defined as the charge or discharge current divided by the battery’s capacity to store an electrical charge. While rarely stated explicitly, the unit of the C-rate is h−1, equivalent to stating the battery’s capacity to store an electrical charge in unit hour times current in the same unit as the charge or discharge current. The C-rate is never negative, so whether it describes a charging or discharging process depends on the context.

For example, for a battery with a capacity of 500 mAh, a discharge rate of 5000 mA (i.e., 5 A) corresponds to a C-rate of 10C, meaning that such a current can discharge 10 such batteries in one hour. Likewise, for the same battery a charge current of 250 mA corresponds to a C-rate of C/2, meaning that this current will increase the state of charge of this battery by 50% in one hour.

Type of Chargers

  • Simple charger
  • Fast charger
  • Three stage charger
  • Induction-powered charger
  • Smart charger
  • Motion-powered charger
  • Pulse charger
  • Solar charger
  • Timer-based charger
  • Trickle charger
  • Universal battery charger–analyzer
  • USB-based charger
  • Power bank
  • Battery cases

Applications

Since a battery charger is intended to be connected to a battery, it may not have voltage regulation or filtering of the DC voltage output; it is cheaper to make them that way. Battery chargers equipped with both voltage regulation and filtering are sometimes termed battery eliminators.