Series vs. Parallel
When people talk about “4S” or “6S” batteries, the “S” refers to cells wired in series. But batteries can also be wired in parallel (P). Understanding the difference helps you choose the right battery and safely charge multiple packs.
Series (S)
Section titled “Series (S)”Cells wired in series add their voltages together while capacity stays the same.
- 1 cell = 3.7V nominal
- 2S = 2 × 3.7V = 7.4V
- 4S = 4 × 3.7V = 14.8V
- 6S = 6 × 3.7V = 22.2V
Higher voltage = higher top speed for the same motor KV, and more efficient current delivery (same power at lower amps).
This is why the hobby has moved from 4S to 6S — same power with less current, meaning less heat in ESCs and wires.
Parallel (P)
Section titled “Parallel (P)”Cells wired in parallel add their capacities together while voltage stays the same.
- 1 cell of 1300mAh = 1300mAh
- 2P = 2 × 1300mAh = 2600mAh (same voltage)
- 3P = 3 × 1300mAh = 3900mAh
Higher capacity = longer flight time but heavier.
Common Configurations
Section titled “Common Configurations”A battery described as “6S2P” means:
- 6 cells in series (22.2V nominal)
- 2 parallel groups (double the capacity of a single cell)
- Total: 12 individual cells
| Config | Voltage | Capacity Multiplier | Common Use |
|---|---|---|---|
| 1S1P | 3.7V | 1× | Tiny whoop |
| 4S1P | 14.8V | 1× | Standard 4S pack |
| 6S1P | 22.2V | 1× | Standard 6S pack |
| 6S2P | 22.2V | 2× | Long range (high capacity) |
Most FPV batteries are 1P (single parallel group). Multi-P packs are heavier but used for long range where flight time matters more than agility.
Parallel Charging
Section titled “Parallel Charging”Parallel charging connects multiple separate battery packs in parallel for charging. This is different from a parallel cell configuration inside a single pack.
When you connect four 6S 1300mAh packs in parallel:
- The charger sees one effective 6S 5200mAh pack
- You charge at 1C of the total (5.2A)
- All four packs charge simultaneously
Critical rule: All packs must be within 0.1V per cell of each other before connecting in parallel. Connecting packs with different voltages causes a high-current rush between them that can damage cells or cause fires.
→ See Charging for full parallel charging procedures and safety.
Series Charging
Section titled “Series Charging”Some chargers can charge packs in series — connecting them end-to-end to double the voltage. For example, two 6S packs in series = effectively 12S (50.4V fully charged).
This is less common in FPV because:
- Requires a charger that supports the higher voltage
- Any cell imbalance between packs can cause issues
- Parallel charging is simpler and more widely used
Which Matters for You?
Section titled “Which Matters for You?”- Choosing a battery: Cell count (S) determines your voltage and must match your motor KV. More S = higher voltage = more speed. Capacity (mAh) determines flight time.
- Charging: Understanding parallel lets you charge multiple packs efficiently and safely.
- Building: 99% of FPV packs are 1P. You’ll only encounter multi-P packs in specialized long-range builds.