Model cells in series or parallel with confidence. Estimate voltage, runtime, energy, limits, and losses. Build balanced battery packs using practical planning inputs today.
This calculator estimates pack voltage, capacity, energy, current capability, resistance, runtime, weight, and cost for battery arrangements built with series and parallel cells.
Use the responsive calculator grid below. Large screens show three columns, smaller screens show two, and mobile shows one.
This sample shows a realistic 4S3P lithium-ion design for a moderate portable system.
| Chemistry | Cell V | Cell Ah | Series | Parallel | Pack V | Pack Ah | Pack Wh | Usable Wh | Max Current | Runtime at 60W |
|---|---|---|---|---|---|---|---|---|---|---|
| Lithium-Ion | 3.7 | 3.0 | 4 | 3 | 14.8 | 9.0 | 133.2 | 102.5 | 30.0 A | 1.71 h |
Sample assumptions: 20 mΩ internal resistance, 10 A per cell, 90% discharge depth, 95% efficiency, and 10% reserve margin.
The calculator combines series and parallel pack relationships with practical derating for efficiency and reserve planning.
Follow these steps to size a battery pack more confidently and compare different layouts.
Series cells add voltage while amp-hour capacity stays the same as one cell path. This arrangement is useful when a device needs higher operating voltage.
Parallel cells add capacity and current capability while nominal voltage stays the same. This is useful for longer runtime and higher current delivery.
Resistance influences voltage sag and heat generation under load. Lower pack resistance usually improves performance, especially in high-current applications.
Reserve margin protects pack life and helps avoid unexpectedly deep discharge. It also gives a buffer for temperature effects, aging, and real-world load variation.
Usable energy is reduced by depth-of-discharge limits, efficiency losses, and reserve margin. These factors make the estimate more practical than ideal laboratory values.
Yes. Enter the correct voltage, capacity, resistance, and current values for each chemistry. The calculator then compares pack behavior using the same equations.
No. Real runtime depends on temperature, aging, balancing quality, discharge curve shape, wiring losses, and how steady the load remains over time.
Stay within current limits, verify cell matching, include protection circuitry, allow thermal management, and confirm that loaded voltage stays within acceptable equipment limits.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.