Battery Runtime Calculator — Life Estimator

Understanding Battery Capacity (mAh)

Battery capacity is typically measured in milliampere-hours (mAh). This unit represents the amount of electric charge a battery can hold. For example, a 3,000mAh battery can deliver 3,000 milliamperes of current for exactly one hour. In the world of smartphones, portable power banks, and drones, mAh is the standard metric used to compare battery sizes. However, mAh alone doesn't tell the whole story—voltage and efficiency play a massive role in how much work that charge can actually perform.

The Reality of Battery Efficiency

A common mistake is assuming that a 5,000mAh battery powering a 500mA device will last exactly 10 hours. In the real world, this is never the case. Several factors reduce the available runtime:

• Internal Resistance: As a battery discharges, it generates heat, which is energy lost from the system.
• Voltage Regulation: Most devices require a steady voltage (e.g., 5V). As a battery's voltage drops, regulators must work harder, consuming extra power.
• Temperature: Batteries perform differently in extreme cold or heat, often leading to reduced capacity.
• Depth of Discharge: For many battery chemistries (like Lead Acid), discharging below a certain point can damage the battery, so only a portion of the capacity is used.

mA vs. mAh: Knowing the Difference

It's easy to get confused between mA and mAh. **mA (Milliampere)** is a measure of current, or the *speed* at which electricity is flowing out of the battery. **mAh (Milliampere-hour)** is a measure of capacity, or the *total amount* of fuel in the tank. If you think of a battery like a water tank, mAh is the size of the tank, and mA is how wide you open the faucet. A wider opening (higher mA) means the tank empties faster.

Privacy for Tech Enthusiasts and Engineers

When you are prototyping a new product or calculating the power needs for a proprietary electronic device, you shouldn't have to share your technical specifications with a third-party server. Many online calculators are used as data-gathering tools to see what kinds of batteries and power draws are currently trending in the DIY community. **OrangeTool respects your intellectual property.** Our calculator runs entirely on your local machine. We don't track your mAh inputs, we don't know what you're building, and we never see your calculations. It's a clean, private utility for professional results.