How to use the Battery Series & Parallel Calculator
The Formula
Series adds voltage (4 × 3.2 V = 12.8 V). Parallel adds capacity (2 × 100 Ah = 200 Ah). Pack Wh = total V × total Ah.
Practical Example
A 4S2P pack means four cells in series per string and two strings in parallel—common for DIY lithium banks.
About Battery Series & Parallel Calculator
Series vs. parallel
Series adds voltage (4 × 3.2 V = 12.8 V). Parallel adds capacity (2 × 100 Ah = 200 Ah). Pack Wh = total V × total Ah.
Configuration label
A 4S2P pack means four cells in series per string and two strings in parallel—common for DIY lithium banks.
Frequently asked questions
Q: Must all cells match? A: Yes—use matched cells and a BMS rated for your series count. Q: Can I mix old and new? A: No—parallel strings should be balanced and matched.