Enter your Cell Capacity, Nominal/Max/Min Cell Voltage, Battery Chemistry, and your series (S) and parallel (P) configuration alongside your Load Current to calculate your Total Pack Capacity, Nominal, Max, and Min Pack Voltage, and Total Energy for your lithium-ion battery pack.
Total Pack Capacity
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Pack Voltage (Nominal)
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Max Pack Voltage
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Min Pack Voltage
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Total Energy
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Total Cells
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C-Rate at Load
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Pack Notation
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Total pack capacity equals the individual cell capacity multiplied by the number of parallel groups. For example, if you have 3500mAh cells with 2 parallel groups, your pack capacity is 7000mAh or 7Ah.
Series connections (S) increase voltage by adding cell voltages together, while parallel connections (P) increase capacity by adding cell capacities together. A 3S2P pack has 3 cells in series and 2 parallel groups.
Pack voltage is determined by multiplying the nominal cell voltage by the number of series cells. Common configurations include 1S (3.7V), 2S (7.4V), 3S (11.1V), and 4S (14.8V) for different applications.
C-rate represents the discharge rate relative to battery capacity. A 1C rate means the battery discharges its full capacity in 1 hour. Higher C-rates require cells rated for high discharge currents to avoid overheating and damage.
Li-ion batteries typically have higher energy density (3.7V nominal) but LiFePO4 batteries are safer and have longer cycle life (3.2V nominal). LiFePO4 also has a flatter discharge curve and better thermal stability.
Energy in watt-hours equals capacity (Ah) multiplied by voltage (V). For example, a 7Ah, 11.1V battery pack contains 77.7Wh of energy, which determines runtime for your application.
Always use a Battery Management System (BMS) to protect against overcharge, over-discharge, overcurrent, and cell imbalance. Proper fusing, temperature monitoring, and quality cell selection are essential for safe operation.
The notation describes the configuration: 18650 refers to the cell size, 3S means 3 cells in series, 2P means 2 parallel groups. This creates a pack with 6 total cells arranged in a 3S2P configuration.