Each LiPo cell is 3.7 volts nominal and 4.2 volts full, so a 2S pack is 7.4 V and a 3S pack 11.1 V. Capacity in mAh sets runtime; the C rating describes discharge capability, though labels are often optimistic. Always balance-charge on a LiPo charger, usually at 1C, never leave it charging unattended, store packs at about 3.8 volts per cell, and retire any pack that swells.
LiPo batteries made modern RC fast. They also demand respect. Get the right pack for your vehicle and handle it properly.
Reading a LiPo label
| Label | Meaning |
|---|---|
| 2S, 3S, 4S | Cells in series; voltage = cells × 3.7 V nominal |
| 5000 mAh | Capacity; more means longer runs and more weight |
| 50C | Discharge rating; max current ≈ capacity in Ah × C |
| Hard case | Protective shell, standard for cars and trucks |
| Connector | XT60, XT90, EC5, IC5, Deans-style T-plug |
Cell voltages
| State | Volts per cell |
|---|---|
| Full charge | 4.20 (4.35 for LiHV) |
| Nominal | 3.7 |
| Storage | About 3.8 to 3.85 |
| Do not go below (resting) | About 3.0 to 3.3; set your ESC’s low-voltage cutoff |
Charging safely
- Use a balance charger set to the correct cell count and LiPo chemistry.
- Charge at 1C unless the maker approves more.
- Charge on a non-flammable surface or in a LiPo bag, and never leave it unattended.
- Let packs cool before charging after a run.
- Store at storage voltage in a fireproof container, away from heat.
Picking a pack
Check the vehicle’s manual for supported cell counts; running 3S in a 2S-rated system can destroy the ESC. Match the connector, and make sure the pack fits the tray. Brushless systems draw more current, so they benefit from packs with real discharge headroom; see brushless vs brushed.
Retiring packs
Swollen, punctured or damaged packs should be retired. Follow the maker’s discharge guidance, then take them to a battery recycling drop-off.
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Common questions
What does 2S or 3S mean on a LiPo?
The number of cells in series. Each adds 3.7 volts nominal: 2S is 7.4 V, 3S is 11.1 V, 4S is 14.8 V.
What is LiPo storage voltage?
About 3.8 to 3.85 volts per cell. Most chargers have a storage mode for packs not used within a few days.
How fast can I charge a LiPo?
1C (the capacity in amps, so 5 A for a 5,000 mAh pack) is the safe default unless the maker approves faster charging.
What should I do with a puffed LiPo?
Stop using it. Discharge and recycle it according to the maker's instructions and local battery recycling rules.