LiPo Batteries Are Not Something to Guess At
LiPo batteries are light, powerful, and a big reason electric airplanes perform as well as they do. They are also one part of the hobby where “close enough” is not a good setup method.
You need to know the battery’s cell count, capacity, connector, recommended charge rate, and the limits of the airplane. If one of those terms is new, that is okay. Take the time to learn it before charging.
Cell Count and Voltage
A LiPo cell is about 3.7 volts nominal. A 2S pack has two cells, a 3S has three, and so on. The charger must be set for the correct chemistry and cell count. The airplane must also be designed for that voltage.
Capacity is listed in milliamp-hours, or mAh. More capacity can mean more flight time, but it also means more weight. A larger pack is not automatically an upgrade if it changes the center of gravity or overloads the power system.
Balance Charging
Balance charging lets the charger monitor the individual cells and bring them to the proper voltage together. Many chargers require both the main power lead and the balance connector. Follow the instructions for that charger instead of copying somebody else’s hookup.
A common charge rate is 1C, but only use that when the battery manufacturer allows it. Set the charger from the label on the pack, verify the cell count before starting, and stay close enough to notice heat, swelling, odor, or an error.
After the Flight
Do not keep flying until the power falls away. Use a conservative timer, then check how much capacity goes back into the battery. Let the pack cool before charging it again.
If the battery will sit, use the charger’s storage program and follow the battery manufacturer’s guidance. Many LiPo systems settle around 3.8 to 3.85 volts per cell for storage, but the charger instructions should be your guide.
When a Battery Is Damaged
Stop using a pack that is swollen, punctured, crushed, has damaged wiring, becomes unusually hot, or behaves differently from normal. Do not poke it, flatten it, freeze it, or soak it in salt water.
Unwanted lithium batteries do not belong in household trash or curbside recycling. Use an appropriate battery recycler or household hazardous-waste program. If the pack is damaged, call the facility or manufacturer before transporting it because special handling may be required.
Next Up
Lesson 7 moves to the transmitter and the control-direction check I want you to make before every flight.