Basic methods for recharging batteries
Constant voltage battery chargers
A constant voltage battery charger is a DC power supply which basically made up from a step-down transformer from the mains with a rectifier that provides the DC voltage which ultimately charges the battery. These forms of charging can be commonly found in inexpensive vehicle battery chargers. Backup batteries and car batteries, usually use lead-acid cells which requires constant voltage chargers. On the other hand, a constant voltage system is used with lithium-ion batteries. However, lithium-ion constant voltage systems usually consist of added circuitry which acts as a protection layer for the battery and the operator.
Constant current battery chargers
A constant current flow is applied to batteries being recharged with constant current flow chargers. When the battery’s voltage is fully recharged, the constant current charger powers off top prevent overcharging. Constant current chargers are mostly used for nickel-cadmium and nickel-metal hydride cells or batteries.
Taper current battery chargers
Taper current battery chargers offers no controlled charging as specified in constant current battery chargers. Thus, taper current battery chargers offer unregulated charging from a voltage source. The charging current decreases as the voltage of the cells builds up. The battery cells can be easily damaged in the process when the battery is overcharged. To avoid the risk of overcharging the voltage cells, there should be a limit in the time and charging rate. This is only applicable to SLA batteries.
Pulse battery chargers
Pulse battery chargers uses pulses of current to charge a battery. Based on the average current of pulses, the charging rate can be accurately controlled by varying the width of the pulses which is commonly about a second. When the charging process is initiated, there are short rest periods of a few milliseconds between charging pulses, which allow chemical actions in the battery to stabilize. Therefore, allowing chemical reactions inside the battery to keep the correct pace with the charging rate of electrical energy.
Burp battery chargers
Burp battery chargers are also known as reflex battery chargers or negative pulse chargers. Burp battery chargers are used in association with pulse charging methods. Burp battery chargers administer short discharging pulses. This can be two to three times the charging current for five milliseconds. Thus, depolarizing the battery cell during rest periods. Gas bubbles which have built up on the electrodes during fast charging scenarios, are forced out. The release of gas bubbles is known as burping.
IUI charger method
IUI charging is a new method of charging which allow fast charging of standard lead-acid batteries. IUI Charging is specific to only specific lead-acid batteries. The charging method works by charging the battery at a constant rate until the cell voltage achieves a configured value. This is usually a voltage at which gassing takes place. This is the bulk charge stage and is the first stage of the battery charging with the IUI charger method. If the configured voltage has been achieved, the battery charger changes to a constant voltage mode while the current drawn by the battery will decrease until it reaches another preset stage. This is the second stage of the charging of the battery and the normal charging of the battery completes at a slow rate. Lastly, the charger changes to a constant current and the voltage rises to an increased preset limit when the charger is powered off. The last stage is to equalize the charge for cells inside of the battery to increase the battery life.
Trickle battery charger
Trickle battery charging accommodates the self-discharge of the battery. Trickle charge is a continues charging method. It provides a long-term current which is constant for standby use. There is a variation of the charge rate which is according to the frequency of the discharge. This method is suitable only to specific types of batteries and can cause damages due to overcharging to lithium-ion batteries and NiMH batteries. In some scenarios, the charger may change over to trickle charging when the battery is fully charged.
Trickle charging will not keep a battery charged if current is being drawn by a load.
Float battery charger
Float charging is most commonly used for backup and emergency power applications where the discharge of the battery is infrequent. During float charging the charger, battery, and load are connected in parallel. The charger operates off the normal power supply which provides current to the load during operation.
Battery charging information
Using a battery charger is a great solution to ensure that the batteries have sufficient energy when they are required. However, there are some important things to remember when using battery chargers.