What is Float Charging

Float charging is administered when the battery is fully charged, kept fully charged, and hardly ever discharged. 

The load draws electricity from the charger when it is operating normally. The battery takes over when the feed to the charger is cut off. 

A battery is charged at a low voltage level when it is float charged. This lower voltage lessens the chance of overcharging. The battery is kept “floating” by the float charger, which guarantees that it is always charged. The Float charger begins by supplying a charging voltage to the battery. The battery’s charging current steadily decreases as it charges. When the charging current decreases, the float charger lowers the charging voltage. 

If the battery runs out of charge, the float charger will raise the charging voltage once more, and the procedure is repeated. Float chargers can be attached to batteries indefinitely. 

Features of Float Charging

• Only after reaching the proper float voltage is the battery placed in the float charging mode. 
• The battery voltage is kept constant through float charging. To keep the battery’s terminal voltage constant, the charger feeds it the bare minimal current. The battery is charged by the float charger at a rate that is comparable to the battery’s rate of discharge. The battery voltage is thus maintained by the float charger. 
• The boost voltage is significantly greater than the float voltage. 

• To keep the battery’s voltage constant, the float charger steadily charges the battery. 
• Due to the battery’s internal resistance, the float charger handles the battery’s self-discharging. 
• The charging current equals 0 when the voltages of the float charger and battery match. The float charger restarts charging the battery if the voltage drops. The discrepancy between the charger’s output voltage and the voltage at the battery terminals determines the charging current. 
• When the battery voltage drops, the float charger releases current, and it stops when the battery potential reaches the charger voltage. To maintain battery voltage, the float charger trickle charges the battery. 
• Battery overcharging is not a possibility when using the float charging mode. 

• Compared to the boost charger, the float charger features a separate rectifier and transformer with a lower rating.  

What is Boost Charging

Boost charging uses a high current for a small amount of time to charge the battery. Generally, boost charge can be used to quickly recharge batteries that have been severely discharged. 

For example, a drained two volt lead acid battery will receive a boost charge at a charging voltage of roughly 2.35 to 2.4 volts. The charger will, however, transition to the float charge mode with a float voltage of 2.25 volts when the battery voltage increases. 

The majority of battery chargers have features for both boost and float charging. 

Features of Boost Charging

• The charging voltage is higher than the typical float setting voltage during the boost battery charging process. Because of this, boost charging causes the battery to draw greater current. 
• A separate transformer and rectifier unit with a greater current rating are included in the boost charger. 
• The boost charger speeds up the battery charging. This method of charging is appropriate when the battery needs to be charged shortly after a discharge. The voltage at the battery’s terminals decreases as it discharges. Applying boost voltage causes the battery to charge more quickly. 
• After the battery runs out of energy while supplying power to the load when the AC mains fail, the boost charger recharges the battery. 

• Boost voltage boosts the current used to charge batteries. The battery’s internal resistance, however, experiences a voltage decrease as a result of the higher charging current. As a result, after the battery charging current drops, the boost voltage needs to be adjusted. 
• The charger voltage needs to be adjusted to the appropriate float voltage once the battery is fully charged. The battery overcharges and is likely to fail if the boost charging is left on for an extended period of time. 
• In the boost charging mode, there is a danger of overcharging the battery. 
• The battery’s exhaust fans must be running in the room during boost charging since the battery generates more heat and gas while it charges quickly on boost. 
• Once the battery is fully charged, float charging can be used to continue charging the battery.