Lithium Ion Battery Calculator
Calculate voltage, energy, and runtime for standard lithium-ion NMC and NCA batteries. Useful for 18650 cells, 4S packs, 6S packs, and general Li-ion battery planning.
Li-ion Pack Tool
Enter cell capacity, series count, parallel count, and load to estimate nominal voltage, full-charge voltage, total mAh, Wh, and runtime for NMC or NCA battery packs.
Lithium-ion NMC/NCA Estimator
This calculator uses 3.7V nominal and 4.2V full-charge cell voltage, which are common references for standard Li-ion cells such as 18650 and 21700.
Calculation Results
These results show nominal voltage, full-charge voltage, total pack capacity, total energy, and estimated runtime if load power is entered.
Educational Estimates Only: Results use nominal and full-charge reference voltages common for standard Li-ion cells. Real usable energy, cycle life, cutoff voltage, and runtime vary by chemistry, current draw, temperature, protection settings, and manufacturer design. Verify with datasheets for critical use.
Li-ion Basics
Standard lithium-ion NMC and NCA batteries are known for high energy density, common 3.7V nominal cell voltage, and 4.2V full-charge voltage.
Standard lithium-ion batteries such as NMC and NCA are widely used when energy density matters. A typical Li-ion cell is around 3.6V to 3.7V nominal, reaches 4.2V at full charge, and often uses a cutoff around 3.0V per cell depending on the design and protection settings.
Li-ion batteries are popular because they offer high energy density, but they usually trade some cycle life and thermal stability compared with LiFePO4. Many consumer and mobility applications use these cells in 18650, 21700, or custom pack formats with series and parallel groupings.
For example, a 3000mAh 18650 cell at 3.7V stores 11.1Wh, a 4S pack has 14.8V nominal voltage, and a 6S pack has 22.2V nominal voltage.
Li-ion facts
- 3.7V nominal cell.
- 4.2V full charge.
- 500–1000 cycles.
- High energy density.
Examples
- 18650 cell 3000mAh = 11.1Wh.
- 4S pack = 14.8V nominal.
- 6S pack = 22.2V nominal.
Li-ion or LiFePO4?
Li-ion gives higher energy density. LiFePO4 gives longer life and more safety in many stationary and deep-cycle applications.
What is the cutoff voltage?
Around 3.0V per cell is a common cutoff reference for typical Li-ion packs, though exact limits depend on the cell and battery management system.
Frequently Asked Questions
These are common questions about lithium-ion voltage, energy density, cycle life, and pack calculations.
Li-ion or LiFePO4?
Li-ion gives higher energy density. LiFePO4 gives longer life and more safety.
What is the cutoff voltage?
Around 3.0V per cell for typical Li-ion.
What is the nominal voltage of a Li-ion cell?
Typically 3.6V to 3.7V per cell.
What is the full charge voltage?
4.2V per cell is the common full-charge reference for standard lithium-ion cells.
How many cycles do Li-ion batteries last?
Many typical Li-ion cells are often rated around 500 to 1000 cycles, depending on chemistry and usage conditions.
Why are Li-ion batteries popular?
They offer high energy density, which means more energy in a smaller and lighter package.
What is 4S in Li-ion?
4S means four cells in series, which gives about 14.8V nominal and 16.8V full charge.
What is 6S in Li-ion?
6S means six cells in series, which gives about 22.2V nominal and 25.2V full charge.
How do I calculate Wh for a Li-ion cell?
Multiply mAh by voltage and divide by 1000.
Is this useful for 18650 batteries?
Yes. It works well for 18650 and 21700 cells when you know capacity and pack configuration.
Plan Li-ion Packs Better
Use this calculator to estimate lithium-ion pack voltage, energy, and runtime, then compare related tools for chemistry and battery sizing.
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