Wire Batteries in Series or Parallel
Wiring batteries in series or parallel impacts the voltage, current, and overall capacity of the battery system. Here’s a detailed comparison of the two configurations:
1. Wiring Batteries in Series
- How It Works:
- Connect the positive terminal of one battery to the negative terminal of the next.
- The remaining free positive and negative terminals become the output terminals.
- Effect on Voltage and Current:
- Voltage: Increases (adds up).
- Total Voltage = Sum of all battery voltages.
- Current: Stays the same as a single battery.
- Voltage: Increases (adds up).
- Example:
- Two 12V, 100Ah batteries in series produce:
- Total Voltage = 12V+12V=24V
- Total Capacity = 100Ah (unchanged).
- Two 12V, 100Ah batteries in series produce:
- Applications:
- Used when higher voltage is needed, such as in electric vehicles or solar inverters.
- Helps reduce current for the same power, minimizing wire size requirements.
- Advantages:
- Increases system voltage without requiring larger cables.
- Better for high-power applications.
- Disadvantages:
- If one battery fails, the entire system can be affected.
- Balancing is critical; uneven charging/discharging can damage batteries.
2. Wiring Batteries in Parallel
- How It Works:
- Connect all positive terminals together and all negative terminals together.
- The combined terminals serve as the output.
- Effect on Voltage and Current:
- Voltage: Stays the same as a single battery.
- Current (Capacity): Increases (adds up).
- Total Capacity = Sum of all battery capacities.
- Example:
- Two 12V, 100Ah batteries in parallel produce:
- Total Voltage = 12V (unchanged).
- Total Capacity = 100Ah+100Ah=200Ah
- Two 12V, 100Ah batteries in parallel produce:
- Applications:
- Used when higher capacity is needed for longer runtime.
- Common in off-grid solar systems or low-voltage devices.
- Advantages:
- Increases total capacity, providing more runtime.
- The system remains operational even if one battery fails (to a degree).
- Disadvantages:
- Higher current flow requires thicker wires and robust connections.
- Uneven charge/discharge between batteries if not well-matched.
Comparison Table
| Feature | Series | Parallel |
|---|---|---|
| Voltage | Increases (sums up) | Stays the same |
| Current (Capacity) | Stays the same | Increases (sums up) |
| Use Case | High voltage applications | High capacity applications |
| Wire Requirements | Lower current; thinner wires | Higher current; thicker wires |
| Risk | Single battery failure affects all | Partial operation possible |
| Applications | EVs, inverters, high-voltage needs | Solar storage, long runtime needs |
Can You Combine Series and Parallel?
- Yes, batteries can be wired in a series-parallel configuration to achieve both higher voltage and capacity. For example, combining 4 batteries:
- Two sets in series to get a higher voltage.
- Then connecting these series groups in parallel for increased capacity.
Please seek professional advise on the capability of your batteries