Lithium Calculator

Battery Capacity (mAh):

Voltage (V):

Current Draw (mA):

Efficiency (%):

How to Use the Lithium Calculator

A Lithium Calculator is a digital tool that estimates the runtime, energy capacity, and performance of lithium-ion batteries based on parameters such as battery capacity, voltage, current draw, and efficiency.

This calculator is especially useful for engineers, hobbyists, and anyone working with electronics, portable devices, or renewable energy systems that rely on lithium-based batteries.

Why Use a Lithium Calculator?

Lithium-ion batteries power nearly everything today—from smartphones to drones, electric vehicles, and solar power banks. Knowing how long a battery will last under a specific load helps with:

Designing efficient systems
Avoiding unexpected shutdowns
Optimizing battery usage for longer life
Planning energy requirements for projects

How to Use the Calculator

Enter Battery Capacity (mAh):
This is the milliamp-hour rating of your battery (e.g., 3000 mAh for a smartphone).
Enter Voltage (V):
Most lithium-ion cells are rated at 3.7V nominal, but larger packs may vary (7.4V, 11.1V, etc.).
Enter Current Draw (mA):
The amount of current your device consumes. Example: a sensor may use 200 mA, while a motor could draw 1500 mA.
Enter Efficiency (%):
Since no system is 100% efficient, account for losses in voltage regulators or circuits (typically 85–95%).
Click "Calculate Battery Life":
The calculator will display:
- Estimated Runtime (hours): How long the battery will last before depletion.
- Energy Available (Wh): The usable watt-hours of energy after efficiency losses.
- Battery Capacity: For quick reference.

Example

Suppose you have:

Capacity: 5000 mAh
Voltage: 3.7 V
Current Draw: 1000 mA
Efficiency: 90%

Result:

Runtime = 4.5 hours
Energy = 16.65 Wh

This means your device will run for about 4.5 hours before the battery is fully drained.

Why Efficiency Matters

If you connect a lithium battery to a circuit, some energy is lost as heat in regulators and converters. By factoring efficiency into calculations, you get a real-world estimate, not just a theoretical one.

FAQ: Lithium Calculator

Q1: Can I use this calculator for any battery type?
A: It’s designed for lithium-ion and lithium-polymer batteries. For other chemistries (like NiMH or lead-acid), the calculation may not be accurate.

Q2: What if I don’t know the efficiency of my system?
A: A safe estimate is 85–90% for most electronics. More advanced systems may reach 95% or higher.

Q3: Does this consider battery aging?
A: No. Battery capacity decreases over time with charge cycles, so real-world runtime may be less for older batteries.

Q4: What is Wh (watt-hour) and why is it important?
A: Watt-hours measure total stored energy (Voltage × Amp-hours). It’s useful for comparing batteries of different voltages.

Q5: Can I use this for electric vehicles?
A: Yes, but only for rough estimates. EV batteries are much larger, and factors like temperature, load variations, and regenerative braking should also be considered.

Q6: Is the calculator accurate?
A: It provides theoretical runtime under constant load. Real-world results may differ due to fluctuations in current draw, temperature, and battery health.