Battery Pack Calculator
| Notation: | |
| Total capacity: | |
| Total Watt hours: | |
| Pack voltage: | |
| Number of cells: |
Reference for standard pack voltages
| Battery type | Series | Min | Max | Nominal | Typical use |
|---|---|---|---|---|---|
| Li ion | 1 | 2.5 | 4.2 | 3.7 | Toys, small speakers, cameras, headphones, game controllers |
| Li ion | 2 | 5 | 8.4 | 7.4 | Digital cameras |
| Li ion | 3 | 7.5 | 12.6 | 11.1 | Compact power tools, speakers |
| Li ion | 5 | 12.5 | 21 | 18.5 | Power tools (sometimes marketed as 20v), vacuum cleaners |
| Li ion | 6 | 15 | 25.2 | 22.2 | Vacuum cleaners |
| Li ion | 7 | 17.5 | 29.4 | 25.9 | Older Panasonic ebikes |
| Li ion | 10 | 25 | 42 | 37 | 36v ebikes (almost all European), lawn movers, expensive power tools |
| Li ion | 13 | 32.5 | 54.6 | 48.1 | 48v ebikes |
| LiFePo4 | 1 | 2.5 | 3.65 | 3.2 | - |
| LiFePo4 | 2 | 5 | 7.3 | 6.4 | - |
| LiFePo4 | 3 | 7.5 | 11 | 9.6 | - |
| LiFePo4 | 5 | 12.5 | 18.3 | 16 | - |
| LiFePo4 | 6 | 15 | 21.9 | 19.2 | - |
| LiFePo4 | 7 | 17.5 | 25.6 | 22.4 | - |
| LiFePo4 | 10 | 25 | 36.5 | 32 | - |
| LiFePo4 | 13 | 32.5 | 47.5 | 41.6 | - |
Warnings and notes
The minimum voltages listed are a rough estimate of the absolute minimum voltage you should ever discharge your cells to. Be sure to always check the cell's datasheet before fiddling.
All consumer battery packs will have a BMS that has a cutoff somewhere above 2.5v. Due to the non-linear discharge curves you get very little energy going from 3.0v -> 2.5v, most BMSs will have a cutoff somewhere between 2.8v and 3v. This of course varies between chemistry types.
LiPo cells come in a HV variant that goes up to 4.35 max.
Cells that are below 2.5v may experience physical changes to their chemistry and should be discarded according to local laws.