Cells, voltage, capacity, C ratings and safe handling—the essentials every electric R/C owner should understand.
Why lithium-polymer became so common
LiPo packs offer high energy and power in a relatively compact package. That makes them useful for electric cars, boats, aircraft and multirotors. The trade-off is that they require a compatible charger, careful physical handling and attention to temperature and voltage. Never treat them as disposable consumer batteries.
Cells and voltage
A typical LiPo cell has a nominal voltage of about 3.7 V. A 2S pack is approximately 7.4 V nominal, 3S is 11.1 V, and 4S is 14.8 V. A fully charged conventional LiPo cell is 4.2 V. Check the entire model—speed controller, motor, receiver power arrangement and manufacturer instructions—before increasing cell count.
Capacity and discharge rating
Capacity is usually expressed in milliamp-hours (mAh), with 5,000 mAh equivalent to 5 Ah. More capacity can increase runtime but also mass and size. The advertised C rating describes an intended discharge multiple of capacity; manufacturer ratings are not always directly comparable. Focus first on verified fit, connector compatibility, appropriate chemistry, and a reputable supplier.
Charging and storage
Use a charger intended for the exact pack chemistry and cell count, connect the balance lead when required, and never leave charging packs unattended. Choose a nonflammable location away from combustibles and keep a suitable response plan. Use the maker’s recommended storage-voltage mode when a pack will not be used for a while; a common target for conventional LiPo is around 3.8 V per cell. Do not charge swollen, punctured, overheated or damaged packs.
After every session
Allow hot packs to cool before charging. Inspect the casing and wiring, check cell balance where the equipment permits, and avoid deep discharging. Store packs protected from impact, extremes of heat and short circuits. Follow manufacturer and local hazardous-waste disposal guidance for batteries that are no longer serviceable.
Know the limits of general advice
High-voltage lithium packs and specialist chemistries can use different limits. Do not apply conventional LiPo voltage numbers blindly to LiHV, LiFe or other batteries. Your exact battery and charger manuals take precedence over a generic guide.
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