Free calculator
RC Battery Run Time Calculator
Work out how many minutes your RC model's battery lasts from its capacity in mAh and its average current draw.
How to use the calculator
- Capacity (mAh): the figure printed on the battery.
- Average current draw (A): the hardest number to know. Use the reading from your ESC or measure it as explained in the FAQ.
- Usable capacity: leave it at 80% for a LiPo. That margin keeps you from over-discharging it.
Example
With a 5,000 mAh battery, an average draw of 20 A and 80% usable capacity, you have 4,000 mAh to work with: 4 Ah ÷ 20 A = 0.2 hours, or 12 minutes.
How to get more run time
- More capacity: a battery with more mAh lasts longer, but it also weighs more. Check that it fits in the battery tray.
- Smoother driving: full-throttle punches send current draw through the roof.
- Shorter gearing: a smaller pinion lowers current draw and temperature. You can estimate the effect with the RC car speed calculator.
- Bearings and drivetrain in good shape: friction drains the battery too. See how to clean and maintain an RC car.
- A second battery: the simplest way to double your run time.
To find out how long it will take to recharge, use the LiPo charge time calculator. And to learn what affects run time, read how long an RC car battery lasts.
Frequently asked questions
How many minutes does an RC car battery last?
It depends on the capacity and the current draw. A 5,000 mAh battery with an average draw of 20 A, using 80% of its capacity, gives about 12 minutes. With smoother driving or a less powerful motor, it lasts longer.
Why not use 100% of the battery?
Because discharging a LiPo below about 3.0–3.2 V per cell damages it. Keeping a 20% margin protects the battery and extends its life.
How do I find the average current draw of my RC car?
Some ESCs log current draw, and you can also measure it with a watt meter. Another way is to charge the battery after a run and see how many mAh the charger puts back: if it put back 4,000 mAh after 12 minutes of driving, the average draw was about 20 A.
Related guides
Free tool
RC Car Speed Calculator
Enter the motor kV, battery cells, pinion, spur gear and tire size to see your RC car's theoretical top speed.
Free calculator
Free tool
LiPo Charge Time Calculator
How long your LiPo battery takes to charge, based on its capacity, the charger current and the charge left in it.
Free calculator
Free tool
LiPo Voltage Calculator by Cell Count
Nominal, maximum, storage and minimum voltage of your LiPo by cell count, and what state it's in based on the voltage you measure.
Free calculator
RC cars
How Long Does an RC Car Battery Last?
Find out how long you can enjoy your RC car before you need to recharge the battery, so the fun doesn't stop early.
4 min read
RC cars
RC LiPo Batteries: How to Choose, Charge and Care for Them
What the cell count (S), mAh and C rating on a LiPo battery mean, how to choose one for your RC car, plane or boat, and how to charge it, store it and tell when it's damaged.
4 min read