Enter the battery capacity and the charge current into the calculator to estimate the charging time. Note: real-world charge time (especially to 100%) is often longer due to charging profiles (such as CC/CV taper) and losses.
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Battery Charge Formula
The following equation is used to estimate battery charge time under an ideal constant-current charge (actual time to reach 100% is often longer due to tapering and inefficiencies).
T = C/R
- Where T is the total time (hours)
- C is the battery capacity (charge) in mAh (or Ah)
- R is the charge current in mA (or A)
To estimate charge time, divide the capacity by the charge current (use consistent units, such as mAh with mA or Ah with A). This gives an idealized value; many batteries and chargers take longer to reach 100% due to charge termination behavior (for example, lithium CC/CV taper near the top of charge).
Battery Charge Time Definition
Battery charge time (charging time) is the amount of time it takes a battery to reach a target state of charge (for example, from 0% to 100%) under a given charger and conditions. The time depends on charge current, battery chemistry, temperature, and the charger’s charging profile (for example, tapering near full charge).
Battery Charge Time Example
How to calculate battery charge time?
- First, determine the total capacity.
Calculate the total capacity of the battery.
- Next, determine the charge rate.
Calculate the average rate of charge.
- Finally, calculate the time.
Calculate the charge time using the equation above.
FAQ
The time it takes to charge a battery depends on the current being used to charge and the total size of the battery.
Battery capacity is the amount of electric charge a battery can deliver under specified conditions, commonly expressed in Ah or mAh. (Energy depends on voltage: Wh = Ah × V.)
