How to Charge a LiPo RC Battery (with Voltage Chart)
Charge an RC LiPo on a balance charger set to LiPo, the correct cell count and 1C (the pack’s capacity in amps, so 5 A for a 5000 mAh pack), with both the main lead and the balance lead connected, on a fireproof surface and never unattended. A standard LiPo cell is full at 4.20 V, should be stored at about 3.80–3.85 V and must not be run below about 3.0 V. The voltage chart below shows those values for 1S to 6S packs.
By Kyle HilsonUpdated: November 20266 min read
This article is part of the RC Basics guide. It applies to the soft-case and hard-case LiPo packs used in RC cars, boats, planes and helicopters. If your charger or pack manual gives different limits, follow the manual.
How do you charge a LiPo battery, step by step?
- Let the pack cool. After a run, wait until it is at room temperature before charging.
- Inspect it. No puffing, dents, cut wires or a damaged balance plug. A swollen pack does not get charged; see swollen LiPo batteries.
- Place it safely. Inside a LiPo bag or a metal box, on a non-flammable surface, away from anything that burns.
- Set the charger: chemistry LiPo (or LiHV if the label says so), the cell count printed on the pack (3S = 3 cells), and the charge current (1C unless the label allows more).
- Connect the main lead first, then the balance lead. The balance lead lets the charger see and equalise every cell.
- Start in balance mode. Check that the charger detects the right number of cells before you walk away from the menu.
- Stay nearby. If the pack gets hot, swells or smells, stop the charge and move it outside with the LiPo bag closed.
- Disconnect when done: balance lead first, then main lead.
Using a Traxxas iD charger with another brand’s pack needs an adapter and the right settings; see charging non-Traxxas batteries on a Traxxas charger.
LiPo voltage chart: full, storage, nominal and empty
Values for standard LiPo cells (not LiHV). Pack voltages are the per-cell value multiplied by the number of cells.
| Pack | Full (4.20 V/cell) | Storage (3.85 V/cell) | Nominal (3.70 V/cell) | Stop running (≈3.5 V/cell at rest) | Minimum (3.0 V/cell) |
|---|---|---|---|---|---|
| 1S | 4.20 V | 3.85 V | 3.70 V | 3.50 V | 3.00 V |
| 2S | 8.40 V | 7.70 V | 7.40 V | 7.00 V | 6.00 V |
| 3S | 12.60 V | 11.55 V | 11.10 V | 10.50 V | 9.00 V |
| 4S | 16.80 V | 15.40 V | 14.80 V | 14.00 V | 12.00 V |
| 6S | 25.20 V | 23.10 V | 22.20 V | 21.00 V | 18.00 V |
- Full: chargers stop at 4.20 V per cell. Racing bodies check this: NAVIGA’s 2024 boat-racing rules, for example, disqualify a LiPo cell that measures above 4.23 V (see NAVIGA Mini Eco).
- Storage: 3.80–3.85 V per cell for anything longer than a few days. Most chargers have a “Storage” mode that charges or discharges to this level.
- Stop running: a resting voltage around 3.5 V per cell after a run is a sensible point to stop; the ESC’s low-voltage cutoff (often about 3.2–3.4 V per cell under load) is the last line of defence, not the target.
- Minimum: below about 3.0 V per cell the cells are damaged. Many chargers refuse to charge a pack that low.
Which charge rate should you use?
“1C” means a charge current equal to the capacity: 2200 mAh → 2.2 A, 5000 mAh → 5.0 A. 1C is the safe default and takes roughly an hour from empty, a little longer because the charger slows down near the end. Some packs are labelled for faster charging (for example “5C charge”); only use more than 1C if the label says so and the charger and power supply can deliver it. Charging slower than 1C is always fine.
| Pack capacity | 1C charge current | Approx. time from empty at 1C |
|---|---|---|
| 1300 mAh | 1.3 A | about 1 hour |
| 2200 mAh | 2.2 A | about 1 hour |
| 5000 mAh | 5.0 A | about 1 hour |
| 5000 mAh on a 2 A charger | 2.0 A (0.4C) | about 2½ hours |
More example times, including NiMH packs, are in how long to charge an RC car battery.
How do you charge a LiPo for the first time?
New packs usually arrive at roughly storage voltage. Before the first run, balance-charge it at 1C or less, then check that all cell voltages ended within a few hundredths of a volt of each other. A new pack with one cell far off the others is worth reporting to the seller before you use it. There is no “break-in” ritual that a normal balance charge doesn’t cover; gentle first runs without hard punches are a sensible start.
Which charger mode do you need?
| Mode | What it does | When to use it |
|---|---|---|
| Balance charge | Charges and equalises each cell to 4.20 V | Every normal charge |
| Charge (no balance) | Charges the pack through the main lead only | Avoid; cells drift apart over time |
| Fast charge | Ends the charge early, skipping the slow final stage | When time matters more than the last few percent |
| Storage | Charges or discharges to about 3.85 V per cell | Packs that won’t be used for a few days or more |
| Discharge | Drains the pack slowly | Before disposal, following local rules |
Parallel charging several packs on one charger through a parallel board is common but only safe with packs of the same cell count and similar voltage. Mistakes there cause large currents between packs, so it is not a beginner technique.
What about LiHV and LiFe packs?
LiHV (high-voltage LiPo) cells are charged to 4.35 V instead of 4.20 V and need the LiHV setting; charging a normal LiPo on the LiHV setting overcharges it. LiFe (LiFePO4) cells use their own setting with a full voltage of about 3.6 V per cell. NiMH packs need the NiMH program with delta-peak detection and no balance lead. Always check the label: the chemistry is printed on the pack.
When should you not charge a LiPo?
Warning: a LiPo fire burns hot and can’t be smothered easily. If a pack swells, smokes or hisses during charging, disconnect it if safe, keep it in the LiPo bag or move it outdoors onto sand or concrete, and keep people away.
- The pack is swollen, dented or punctured.
- The pack is hot from a run, or very cold (below about 0 °C / 32 °F).
- You can’t stay near it for the whole charge.
- It is on a bed, sofa, carpet or car seat.
- The charger shows the wrong cell count.
- A cell is far below 3.0 V after a crash or a long storage.
More on the risks and safe disposal: are LiPo batteries dangerous?
Why won’t my charger charge my LiPo?
- “Cell error” or “connection break”: the balance plug is loose, in the wrong port, or one wire is broken.
- “Low voltage”: the pack is below the charger’s minimum. It may be over-discharged; don’t force it with a NiMH program.
- Wrong cell count detected: check the setting and the balance lead before going further.
- Stops after a few minutes: the capacity or time limit in the charger settings is too low, or the pack is already full.
- Traxxas iD packs not recognised: needs an iD charger or an iD adapter; see how long a Traxxas battery lasts for pack care.
FAQ
What voltage is a fully charged LiPo?
4.20 V per cell: 8.4 V for 2S, 12.6 V for 3S, 16.8 V for 4S and 25.2 V for 6S. LiHV packs charge to 4.35 V per cell.
What is LiPo storage voltage?
About 3.80–3.85 V per cell, for example about 11.5 V for a 3S pack. Use the charger’s storage mode.
How low can a LiPo go?
Stop around 3.5 V per cell at rest; never go below about 3.0 V per cell, where the cells are damaged.
Can I charge a LiPo without a balance charger?
Don’t. Without balancing, cells drift apart and one cell can be overcharged even when the pack voltage looks right.
How long does a LiPo take to charge?
About an hour from empty at 1C; longer with a weaker charger, shorter only with packs rated for faster charging.
Can I leave a LiPo charging overnight?
No. Charge only when you can watch it, and store packs at storage voltage instead of keeping them full.
More on this topic: the complete RC Basics guide covers batteries, motors, ESCs and radios.
About 20 years in RC. Mostly boats in the NAVIGA Mini Eco Expert class, with many self-made parts; also a King Motor Baja 5B, a home-built electric plane, home-built nitro planes he has flown, and an RC helicopter. More about SwellRC
