LiPo cell count and voltage (2S, 3S, 4S, 6S)
What 2S / 3S / 4S / 6S mean, and the nominal, full-charge and storage voltage for each.
The S number is how many LiPo cells are wired in series. Each cell has the same three reference voltages, and the pack is just the cell voltage times the number of cells.
Per cell: 3.7V nominal · 4.2V fully charged · about 3.8V storage · ~3.0V practical floor under load.
Common packs:
- 2S — 7.4V nominal, 8.4V full
- 3S — 11.1V nominal, 12.6V full
- 4S — 14.8V nominal, 16.8V full
- 6S — 22.2V nominal, 25.2V full
A charger set to '4S' charges to 16.8V total because it balances each of the four cells up to 4.2V. Always match your charger's cell-count setting to the pack, and always charge in balance mode so the cells stay even.
Source: LiPo electrical fundamentals (3.7V nominal / 4.2V full per cell)