18650 Battery Pack Calculator

This 18650 battery pack calculator is used to determine the optimal configuration of 18650 lithium-ion cells for a specific power requirement.

With a 12V battery pack with 10Ah capacity, the calculator would determine how many 18650 cells to connect in series for voltage and in parallel for capacity.

18650 Battery Pack Calculator

Desired Voltage	Desired Capacity	Cell Capacity	Series Cells	Parallel Strings	Total Cells	Configuration	Actual Voltage	Actual Capacity	Total Power
12V	10Ah	3000mAh	4	4	16	4S4P	14.8V	12Ah	177.6Wh
12V	20Ah	2500mAh	4	8	32	4S8P	14.8V	20Ah	296Wh
24V	15Ah	3500mAh	7	5	35	7S5P	25.9V	17.5Ah	453.25Wh
24V	30Ah	3000mAh	7	10	70	7S10P	25.9V	30Ah	777Wh
36V	8Ah	2500mAh	10	4	40	10S4P	37V	10Ah	370Wh
36V	12Ah	3000mAh	10	5	50	10S5P	37V	15Ah	555Wh
48V	20Ah	3000mAh	13	7	91	13S7P	48.1V	21Ah	*1010.1Wh
48V	40Ah	3500mAh	13	12	156	13S12P	48.1V	42Ah	2016Wh
72V	5Ah	2000mAh	20	3	60	20S3P	74V	6Ah	444Wh
72V	10Ah	2500mAh	20	5	100	20S5P	74V	10Ah	740Wh
60V	15Ah	3000mAh	16	5	80	16S5P	60.8V	15Ah	912Wh
36V	18Ah	3500mAh	10	6	60	10S6P	37V	21Ah	777Wh

18650 Battery Pack Formula

Voltage calculation:

Total Voltage = Number of cells in series × Nominal cell voltage

Capacity calculation:

Total Capacity = Number of parallel strings × Individual cell capacity

Power calculation:

Total Power (Wh) = Total Voltage × Total Capacity

• Voltage: 18650 cells typically have a nominal voltage of 3.7V. To increase voltage, connect cells in series.
• Capacity: A single 18650 cell usually has 2000-3500mAh capacity. To increase capacity, connect cells in parallel.
• Power: Measured in watt-hours (Wh), it’s the product of voltage and capacity.

How do you calculate 18650 battery pack?

To calculate an 18650 battery pack configuration:

• Determine required voltage: Divide target voltage by cell voltage (3.7V) to get cells in series.
• Calculate capacity needs: Divide desired capacity by single cell capacity for parallel strings.
• Compute total cells: Multiply cells in series by parallel strings.

For a 24V, 10Ah pack using 3000mAh cells:

Cells in series: 24V ÷ 3.7V ≈ 6.49 (round up to 7)

Parallel strings: 10Ah ÷ 3Ah ≈ 3.33 (round up to 4)

Total cells: 7 × 4 = 28 cells

Final configuration: 7S4P (7 series, 4 parallel)

How many 18650 batteries to make 1 kWh?

To calculate cells for 1 kWh (1000Wh):

• Choose a voltage (e.g., 48V)
• Calculate capacity: 1000Wh ÷ 48V ≈ 20.83Ah
• Determine series cells: 48V ÷ 3.7V ≈ 13 cells
• Calculate parallel strings (using 3000mAh cells): 20.83Ah ÷ 3Ah ≈ 6.94 (round to 7)

Result: 13S7P configuration, totaling 91 cells (13 × 7)

How many 18650 batteries does it take to make 48V 20Ah?

For a 48V 20Ah pack:

• Series cells: 48V ÷ 3.7V ≈ 13 cells
• Parallel strings (3000mAh cells): 20Ah ÷ 3Ah ≈ 6.67 (round to 7)

Configuration: 13S7P, totaling 91 cells (13 × 7)

How many 18650 batteries would make a 12v 20Ah battery?

For a 12V 20Ah pack:

• Series cells: 12V ÷ 3.7V ≈ 3.24 (round to 4)
• Parallel strings (3000mAh cells): 20Ah ÷ 3Ah ≈ 6.67 (round to 7)

Configuration: 4S7P, totaling 28 cells (4 × 7)

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