Battery Charge Time Calculator
Estimate battery charging time, stored energy, grid energy, average input power and cost from capacity, state of charge and charger performance.
Default project preview
2.69 hours
Energy added to battery
7 kWh
Grid energy consumed
8.08 kWh
Conversion and auxiliary loss
1.08 kWh
Effective stored rate
2.6 kW
Calculator
Build the material order
Your order will appear here
Enter the project details and calculate a rounded material estimate.
Input and output guide
What each value means
The labels and units below are part of this calculator’s visible methodology. Replace every default with measurements or product data from the actual project.
Battery usable capacity
Enter this project assumption in kWh. The current imperial default is 10 kWh.
Starting state of charge
Enter this project assumption in %. The current imperial default is 20 %. Minimum: 0. Maximum: 99.
Target state of charge
Enter this project assumption in %. The current imperial default is 90 %. Minimum: 1. Maximum: 100.
Charger input power
Enter this project assumption in kW. The current imperial default is 3 kW.
Charging efficiency
Enter this project assumption in %. The current imperial default is 90 %. Minimum: 1. Maximum: 100.
Auxiliary battery-system load
Enter this project assumption in kW. The current imperial default is 0.1 kW. Minimum: 0.
Electricity price
Enter this project assumption in per kWh. The current imperial default is 0.18 per kWh. Minimum: 0.
How to read the outputs
Energy added to battery
usable stored energy. Default preview: 7 kWh.
Grid energy consumed
charger input × time. Default preview: 8.08 kWh.
Conversion and auxiliary loss
grid energy minus stored. Default preview: 1.08 kWh.
Effective stored rate
after efficiency and auxiliary load. Default preview: 2.6 kW.
Charging cost
entered electricity rate. Default preview: $1.45.
SOC increase
target minus start. Default preview: 70 percentage points.
Methodology
Transparent calculation
BuildMeter converts every input to a consistent internal unit, applies the selected allowance, and rounds products up to whole purchasable units.
Stored energy needed = battery capacity × SOC increase. Effective stored power = charger input × efficiency − auxiliary load. Time = stored energy ÷ effective stored power.
FAQ
Battery Charge Time Calculator questions
Why can charging slow near full capacity?+
Battery management systems often reduce power near high state of charge to protect cells.
Is usable capacity the same as nameplate capacity?+
Not always. Some systems reserve capacity at the top or bottom, so use the usable value available to the owner.
Does the estimate include standby loads?+
Yes, through the editable auxiliary-load input during charging.