To get the voltage of batteries in series you have to sum the voltage of each cell in the serie. To get the current in output of several batteries in parallel you have to sum the current of each
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The voltage of a single 21700 battery cell is typically 3.7 volts. When connected in series, the voltage increases accordingly. It is important to select battery cells and configure the pack to match the voltage and capacity requirements of the intended application.
» Electrical » Cells Per Battery Calculator The Cells Per Battery Calculator is a tool used to calculate the number of cells needed to create a battery pack with a specific voltage and capacity. When designing a battery pack, cells can be connected in two ways: in series to increase voltage, or in parallel to increase capacity.
So, you would need 42 cells in total to create a battery pack with 24V and 20Ah using cells with 3.7V and 3.5Ah. 1. Why do I need to connect cells in series for voltage? Connecting cells in series increases the overall voltage of the battery pack by adding the voltage of each individual cell.
At its core, a single 21700 cell usually holds 4000–5000 mAh with a nominal voltage of 3.6–3.7 V. Fully charged, it hits 4.2 V, and cutoff usually happens around 3.0 V. In practice, I’ve seen these cells hold up better under high current draw compared to 18650. Less heat, less sag, and more usable runtime.
