Charging Time of Battery = Battery Ah ÷ Charging Current T = Ah ÷ A and Required Charging Current for battery = Battery Ah x 10% A = Ah x 10% Where, T = Time in hrs. Example: Calculate the suitable charging current in Amps and the needed charging time in hrs for a 12V, 120Ah battery. Solution: Battery Charging Current:
Here is the formula of charging time of a lead acid battery. Charging time of battery = Battery Ah / Charging Current T = Ah / A Where, T = Time hrs. Ah = Ampere Hour rating of battery A = Current in Amperes Example Example based on a 120 Ah battery (This information is available on the label of the battery on the top side)
Consider Charge Level: The battery is already at 50%, so only 50% of its capacity needs to be charged: Effective Capacity = 2Ah × (1−0.50) = 1Ah Calculate Charging Time: Now, divide the effective capacity by the charger’s current: Charging Time = 1Ah / 1A = 1 hour In this example, it will take 1 hour to charge the battery from 50% to 100%.
If the capacity is given in amp-hours and current in amps, time will be in hours (charging or discharging). For example, 100 Ah battery delivering 1A, would last 100 hours. Or if delivering 100A, it would last 1 hour. In other words, you can have "any time" as long as when you multiply it by the current, you get 100 (the battery capacity).
As we know that charging current should be 10% of the Ah rating of the 12v battery. This is because a higher rate may cause the battery acid to boil. So charging current for 120Ah Battery = 120 x (10/100) = 12 Amperes Suppose we took 10 Amp for charging purpose, then charging time for 120Ah battery = 120 / 10 = 12Hrs.
Charger Current (A): The charger’s output current is typically measured in Amps (A) or milliamps (mA). To consider the current charge level, we multiply the battery capacity by the uncharged percentage. Effective Capacity (Ah) = Battery Capacity (Ah) × (1−Charge Level/100) Let’s say you have: