Battery Series/Parallel Calculator
Configure your battery bank voltage and capacity in series and parallel
How to Use This Calculator
- Set the voltage of a single battery (12V, 24V, 48V, or 51.2V LiFePO4).
- Enter the capacity in amp-hours (Ah) of one battery.
- Enter how many batteries you'll wire in series (adds voltage, keeps Ah the same).
- Enter how many strings you'll wire in parallel (adds Ah, keeps voltage the same).
- Read your total bank voltage, capacity, total batteries, and energy in kWh.
Series vs. Parallel Rules
Series: Voltage adds, capacity (Ah) stays the same. Vbank = V × (batteries in series).
Parallel: Capacity (Ah) adds, voltage stays the same. Ahbank = Ah × (batteries in parallel).
Bank Energy (kWh) = Bank Voltage × Bank Ah ÷ 1000
| Config | Single Battery | Bank Voltage | Bank Ah | Bank kWh |
|---|---|---|---|---|
| 4S1P | 12V / 100Ah | 48V | 100 Ah | 4.8 kWh |
| 4S2P | 12V / 100Ah | 48V | 200 Ah | 9.6 kWh |
| 1S4P | 51.2V / 100Ah | 51.2V | 400 Ah | 20.5 kWh |
| 2S4P | 24V / 200Ah | 48V | 800 Ah | 38.4 kWh |
Batteries & Accessories
Frequently Asked Questions
Series or parallel — which is better?
Higher voltage (series) means lower current, so you can use thinner wire and smaller breakers. For systems over 1.5 kW, build a 48V bank. Use parallel only to add capacity once you've reached your target voltage.
Can I mix different batteries?
No. Mixing voltages, capacities, or chemistries causes imbalance, rapid wear, and safety risks. Always use identical batteries and add a BMS per string.
How many batteries can I put in parallel?
Most manufacturers allow up to 4–8 parallel strings. Beyond that, current sharing becomes uneven. For very large banks, use fewer, higher-capacity batteries instead of many parallel small ones.