Series strings raise voltage; parallel strings raise amp-hours. This battery series and parallel calculator turns cell specs and your S/P layout into total V, Ah, watt-hours, and a configuration tag before you order cells or a BMS.
Benefits
- Pack V = series count × cell voltage.
- Pack Ah = parallel count × cell Ah.
- Wh = total V × total Ah with an S×P configuration label.
How it works
- Enter how many cells are in series per string (S).
- Enter how many identical strings run in parallel (P).
- Add nominal cell voltage and cell Ah—read pack V, Ah, Wh, and nSnP.
FAQ
How does a battery series and parallel calculator work?
Multiply series count by cell voltage for pack voltage. Multiply parallel count by cell amp-hours for pack Ah. Pack Wh = V × Ah. Example: 4S2P with 3.2 V 100 Ah LiFePO4 cells → 12.8 V, 200 Ah, 2,560 Wh, labeled 4S2P.
What does 4S2P mean?
Four cells in series per string (4S) and two strings wired in parallel (2P). Voltage follows the series count; capacity follows the parallel count. The calculator prints this label from your inputs so BOM and BMS orders match the physical layout.
Must all cells match in a series-parallel pack?
Yes—use matched capacity and age within each parallel string, and a BMS rated for your series count. Mixing old and new cells in parallel causes imbalance and early cutoff. Re-run the calculator when you change S or P before buying interconnects.
Technical specifications
- Pack V = S × cell_V.
- Pack Ah = P × cell_Ah.
- Pack Wh = pack_V × pack_Ah.
- Configuration = {S}S{P}P (e.g. 4S2P).
- Related: battery-series-parallel, battery-bank-size, battery-energy, ah-to-wh.