Battery charging time is the amount of time it takes to fully charge a battery from its current charge level to 100%. This depends on several factors such as the battery’s capacity, the charger’s voltage output, and the battery charge level. The basic formula used in our calculator is: Charging Time = Battery Capacity (Ah) / Charger Current (A)
You can calculate the charging time by entering the battery capacity, charger output current, and battery charge level into the calculator. The result will show the estimated time required to charge your battery fully. What units can I use for battery capacity? Check the battery specifications mentioned on the battery cover.
2000mAh = 2Ah 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
Because the charge C-rate is relatively high, we'll again assume a charging efficiency of 90% and then plug everything into Formula 3. Your phone battery will take about 1.6 hours to charge from 5% to full. None of these battery charge time formulas captures the real-life complexity of battery charging.
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).
To calculate charging time using Formula 2, first you must pick a charge efficiency value for your battery. Lead acid batteries typically have energy efficiencies of around 80-85%. You're charging your battery at 0.1C rate, which isn't that fast, so you assume the efficiency will be around 85%.