RC Batteries · How-To Guide

How to Charge a LiPo Battery

Equipment required, balance charging steps, storage voltage explained — and the mistakes most likely to shorten your pack's life or create a safety hazard.

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How-To Guide · Updated August 2026 · ~6 min read · RC Batteries
Quick Answer

Connect the balance lead first, then the main discharge lead. Set your charger to Balance Charge, cell count matching the pack's S rating, and charge rate at 1C (equal to capacity in amps). The charger handles the rest and terminates automatically at 4.20V per cell. Never use Charge Only mode. Never leave a LiPo charging unattended.

What You Need Before Charging

A dedicated LiPo balance charger is non-negotiable. Standard car chargers, NiMH chargers, and generic USB chargers cannot manage LiPo cell voltages — they will damage packs or create a fire risk. A quality balance charger monitors every cell individually, detects cell count automatically, and cuts power when the terminal voltage is reached.

You also need a LiPo-rated fireproof charging bag placed on a non-flammable surface for every session. Most packs include a balance lead (small multi-pin connector) alongside the main discharge lead — both are used during balance charging.

Inspect the Pack Before You Connect

Check the pack before every session. Any swelling — puffing of the outer casing — means internal damage; the pack should not be charged or used. Inspect connectors and wiring for heat marks or damaged insulation. If the pack is warm from recent use, let it cool to room temperature first.

A 3S pack at rest should read 11.1–12.6V across the main leads (3.70–4.20V per cell). A pack below 3.0V per cell has been over-discharged and may not recover — some chargers will refuse to start charging at this level, which is correct behavior.

Step-by-Step Charging Procedure

Connect the balance lead to the charger's balance port first, matching the pin count to the pack's S rating (2S, 3S, 4S). Then connect the main discharge lead to the charger's main terminals, observing polarity. Set the charger to LiPo Balance Charge mode.

Configure two settings:

Confirm the settings and start the charge. The charger will display per-cell voltages throughout. A healthy pack will show cells tracking closely together — within 0.05V of each other throughout most of the charge cycle. The charger terminates automatically when all cells reach 4.20V and the charge current drops to the termination threshold.

Do not leave the area during charging. Balance chargers are reliable, but LiPo failures — when they occur — move fast. Attend the pack or set a timer and remain nearby. Always charge inside the fireproof bag.

Looking for a full LiPo reference — cell chemistry, S and C ratings, connector types, and how to read pack specs? The RC Batteries Guide covers all of it.

RC Batteries Guide →

When to Use Storage Mode

If you will not be flying within the next 24–48 hours, do not store a LiPo at full charge (4.20V/cell) or depleted (below 3.5V/cell). Both extremes accelerate degradation. The correct long-term storage target is 3.80–3.85V per cell.

Most balance chargers include a Storage mode that brings cells to this voltage from either direction — charging up if too low, discharging down if too high. Use it any time a pack will sit for more than a day or two.

What to Do When the Charge Completes

When the charger signals completion, disconnect the main leads first, then the balance lead. Verify all cells read 4.20V. A cell consistently lower than the others by more than 0.05V after a full balance charge indicates increasing internal resistance — monitor it across sessions. If divergence grows, the pack is approaching end of life.

For storage after flying, run Storage mode before putting the pack away. Store at room temperature, away from direct sunlight, inside a LiPo safe bag.

What Causes Most Charging Problems

For a full overview of LiPo maintenance — storage voltage, discharge limits, and cycle tracking — see the caring for LiPo batteries guide.


LiPo Charging Essentials

Free: RC Starter Field Guide

10-page PDF covering equipment checklist, pre-flight routine, LiPo handling protocol, and the 5 most common beginner mistakes — formatted for field use.


Common Questions
Always use Balance Charge mode — never Charge Only. Balance charging monitors each cell individually and terminates when every cell reaches exactly 4.20V. Charge Only skips cell monitoring and can produce uneven voltages across the pack, accelerating degradation and increasing risk.
The standard safe rate is 1C — numerically equal to the pack's capacity in amps. A 2200mAh pack charges at 2.2A. Some packs are rated for 2C, but 1C produces the least heat and extends cycle life. When in doubt, 1C is always correct.
Storage voltage is 3.80–3.85V per cell. At full charge (4.20V/cell) or fully discharged (below 3.5V/cell), a LiPo degrades faster in storage. Most modern balance chargers include a Storage mode that brings cells to 3.8V automatically, whether the pack is above or below that level.
Yes, with precautions. Always use a LiPo-rated fireproof charging bag and never leave the pack unattended during charging. Place it on a non-flammable surface away from flammables. A quality balance charger with automatic cell-count detection and over-voltage cutoff significantly reduces risk.
The most visible sign is puffing — any swelling of the pack body indicates gas build-up from internal damage and the pack should not be charged or used again. Other signs include significant voltage drop during light load, cells that diverge more than 0.1V during charging, or a pack that gets hot during a slow charge.

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