Battery Charge Time Calculator

Our intuitive battery charge time calculator will help you calculate battery charge time using the battery's capacity, and charging current. It provides accurate battery charging time calculation for various scenarios, including car battery charging time estimation. We'll also answer questions like how long does it take to charge a car battery and explain what is a battery charge in practical terms.

Understanding what a battery charge is and how to calculate charging time is key to keeping your devices, from smartphones to car batteries, running smoothly. The battery may be either fully or partially discharged, as determined by the state of charge (SoC) percentage. Let's calculate the available capacity, which is the capacity we need to fill to fully charge the battery:

Available capacity = Capacity × (1 - (SoC / 100))

Now, you'll need the charging current to find the battery charging time. Its value depends on the battery type and materials used in them. Each of them has a different efficiency, which determines the level of energy losses during the charging and discharging and impacts overall battery life:

Charging current = Input current × Efficiency

We'll combine these equations into one simple formula to estimate how long it will take to charge your battery:

Charge time = Available capacity / Charging current

And that’s all! With this method, you can easily calculate how long it’ll take to juice up your battery.

Let's use the formula above to estimate the car battery charging time. For one variant of the Tesla Model S, the battery capacity is 200 Ah (you can convert amp-hours to watt-hours with our battery capacity calculator). We start charging at 40%, meaning that SoC is 40%.

Available Capacity = 200 Ah × (1 - (40% / 100)) = 120 Ah

This means we must fill 120 Ah to fully charge the car battery to 100%.

The Tesla onboard charger uses a current of 48 A for the fastest charging speed. Our electric vehicle uses a lithium-ion battery with an efficiency factor of 95% (0.95). Therefore, the effective charging current is:

Charging Current = 48 A × 0.95 = 45.6 A

Finally, we can calculate the time it takes to fully charge a Tesla:

Charge Time = 120 Ah / 45.6 A = 2.63 hours = 158 minutes

Calculating the battery charging time with this calculator is straightforward and efficient; just follow the steps:

1. Input the battery capacity in Ah, or mAh. If capacity is in Wh or kWh, use watt hour calculator to convert watt-hours to amp-hours.

2. Specify the charging current in your chosen unit (A or mA).

3. Determine the state of charge. If the battery is partially charged, enter the current state of charge (SoC) as a percentage.

4. Now the battery charge time calculator will immediately estimate and display the battery charging time in hours. Click on the unit field to switch between time formats and choose the one most convenient for you.

Several factors can affect the time of charging the battery in your electronic device or electric vehicle, in particular:

• Battery capacity — Larger batteries take longer to charge as they store more energy. Check our battery size calculator to determine the appropriate capacity for your device.

• Charging current — A higher charging current reduces charging time.

• State of Charge (SoC) — Batteries charge faster when partially discharged compared to when they are near full capacity.

• Battery chemistry — Different battery types (e.g., lithium-ion, nickel-metal hydride, lead-acid, etc.) have varying efficiency, which affects charging time.

• Temperature — Extreme temperatures (too hot or too cold) can slow down charging or even damage the battery.

• Age and condition of the battery — Older batteries or those with degraded cells may charge more slowly or not fully.