A Battery chargers, or recharger is a device used to put energy into a secondary cell or rechargeable battery by forcing an electric current through it.
The charging protocol (how much voltage or current for how long, and what to do when charging is complete, for instance) 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, and some battery types absolutely require, or may use a timer, to cut off charging current at some fixed time, approximately when charging is complete. Other battery types cannot withstand over-charging, being 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.
Slow battery chargers might take many hours to complete a charge. High-rate chargers might restore most capability abundant quicker, however high rate chargers may be quite some battery varieties will tolerate. Such batteries need active observation of the battery to shield it from overcharging. electrical vehicles ideally would like high-rate chargers. For public access, installation of such chargers and therefore the distribution support for them is a problem within the projected adoption of electrical cars.
The charger has three key functions
- Getting the charge into the battery (Charging)
- Optimising the charging rate (Stabilising)
- Knowing when to stop (Terminating)
Basic Charging Methods
- Constant Voltage A constant voltage charger is basically a DC power offer that in its simplest kind might carries with it a step down electrical device from the mains with a rectifier to produce the DC voltage to charge the battery. Such easy styles ar usually found in low-cost car battery chargers. The lead-acid cells used for cars and backup power systems usually use constant voltage chargers. additionally, lithium-ion cells usually use constant voltage systems, though these sometimes ar a lot of complicated with added circuitry to shield each the batteries and therefore the user safety.
- Constant Current Constant current chargers vary the voltage they apply to the battery to keep up a continuing current flow, switch off once the voltage reaches the amount of a full charge. This style is typically used for nickel-cadmium and nickel-metal hydride cells or batteries.
- Taper Current This is charging from a crude unregulated constant voltage supply. it’s not a controlled charge as in V Taper higher than. the present diminishes because the cell voltage (back emf) builds up. there’s a heavy danger of damaging the cells through overcharging. To avoid this the charging rate and period ought to be restricted. appropriate for SLA batteries only.
- Pulsed charge Pulsed chargers feed the charge current to the battery in pulses. The charging rate (based on the common current) are often exactly controlled by varied the breadth of the pulses, generally regarding one second. throughout the charging method, short rest periods of twenty to thirty milliseconds, between pulses permit the chemical actions within the battery to stabilise by equalising the reaction throughout the majority of the conductor before recommencing the charge. this permits the reaction to stay pace with the speed of inputting the voltage. it’s additionally claimed that this technique will reduce unwanted chemical reactions at the conductor surface like gas formation, crystal growth and passivation. (See additionally pulsed Charger below). If needed, it’s additionally possible to sample the circuit voltage of the battery throughout the remainder amount.
The optimum current profile depends on the cell chemistry and construction.
- Burp chargingAlso referred to as Reflex or Negative Pulse Charging used in conjunction with pulse charging, it applies a very short discharge pulse, generally two to three times the charging current for five milliseconds, throughout the charging suspension to depolarize the cell. These pulses dislodge any gas bubbles that have designed up on the electrodes throughout quick charging, speeding up the stabilisation method and therefore the charging method. the discharge and diffusion of the gas bubbles is thought as “burping”. controversial claims are created for the enhancements in each the charge rate and therefore the battery lifetime furthermore as for the removal of dendrites created attainable by this method. the smallest amount which will be said is that “it doesn’t harm the battery”.
- IUI ChargingThis is a recently developed charging profile used for quick charging commonplace flooded lead acid batteries from particular manufacturers. it’s not appropriate for all lead acid batteries. at first the battery is charged at a relentless (I) rate till the cell voltage reaches a predetermined worth – ordinarily a voltage regarding that at that gassing happens. This initial a part of the charging cycle is understood because the bulk charge part.
- Trickle chargeTrickle charging is meant to complete the self discharge of the battery. Continuous charge. future constant current charging for standby use. The charge rate varies in step with the frequency of discharge. Not appropriate for a few battery chemistries, e.g. NiMH and lithium, that are susceptible to harm from overcharging. In some applications the charger is meant to modify to trickle charging once the battery is totally charged.
- Float charge. The battery and also the load area unit for good connected in parallel across the DC charging supply and command at a continuing voltage below the battery’s higher voltage limit. Used for emergency power make a copy systems. primarily used with lead acid batteries.
Random charging All of the higher than applications involve controlled charge of the battery, but there are several applications wherever the energy to charge the battery is only available, or is delivered, in some random, uncontrolled method. this is applicable to automotive applications wherever the energy depends on the engine speed that is continuously dynamic . the matter is a lot of acute in ev and HEV applications that use regenerative braking since this generates giant power spikes throughout braking that the battery should absorb. a lot of benign applications are in electrical device installations which may only be charged once the sun is shining.
TYPES OF CHARGER:
- Simple Chargers
- Three stage Chargers
- Induction powered Chargers
- Intilligent Chargers
- Motion powered Chargers
- Pulse Chargers
- Solar Chargers
- Time based Chargers
- Triggle Chargers
- Universal battery Chargers
- USB based Chargers
- Power bank
Uses of Batteries :
- Battery charger for vehicles
- Electric vehicle batteries
- Charge stations
- Mobile phone charger
- Stationary battery plants
- Use in experiments