Safe use of Lipo batteries

General information

Lithium batteries have an excellent capacity-to-weight ratio. Thanks to high discharge currents and a suitable shape, Lithium-polymer batteries (Lipo or Li-pol for short) are the most commonly used in RC models. The battery does not suffer from the memory effect. They can be charged from any charge level, there is no need to shape them and self-discharge is minimal. However, Lipo batteries need good care.

The battery cell has a nominal voltage of 3.7V. However, the actual voltage depends on the battery charge level. Lipo batteries consist of individual cells connected in series. When connected in series, the total battery voltage increases – hence the designation 2S (7.2V), 3S (11.1V), 4S (14.8V), etc.

There are usually two connectors on the battery. The main connector that connects the battery to the model and the service balance connector. The main connector is connected to the first and last battery cell and has a total battery voltage. The type of connector is usually selected according to the discharge current of the battery. The service connector has more contacts (number of cells + 1) and is used to monitor the voltage of individual battery cells.

Battery capacity is usually stated in mAh (milliampere hours). Capacity gives us the current that the battery is able to supply for one hour. Capacity is always per cell, so the energy contained in a battery is a multiple of the capacity and voltage of the battery. The stated capacity is nominal. Actual usable capacity may vary depending on current consumption and ambient temperature.

The discharge current is also an important value. The discharge current is given in multiples of C, where C is the capacity of the battery. Multiplying these values gives the maximum discharge current of the battery. Thus, for a 450mAh 60C battery (60 * 0.45 = 27), we can discharge it with a current of up to 27Amp. The charging current is indicated in the same way.

Use and safety

Lipo batteries must be cared for properly. They are safe if the rules of proper handling are followed. Failure to follow safety procedures may result in damage to the battery and, in extreme cases, fire. The seller is not liable for damages caused by incorrect use of batteries.

  • Do not use damaged, inflated or otherwise defective batteries.
  • Follow the principles of correct charging.
  • Discharge the batteries at temperatures of 10–50 ° C. In the colder months, the batteries must be preheated before use.
  • Do not discharge the batteries. The voltage of the discharged cell is 3.2V. However, we usually land with the model at a voltage of 3.3–3.5V per cell. If the cell voltage drops below 2.5V, it may be irreparably damaged.
  • Do not exceed the maximum discharge current of the battery. If the currents are too high, the battery heats up and has a large voltage drop. Over time, such a battery may inflate.
  • Never short-circuit the battery contacts.
  • Do not dispose of batteries in a fire.
  • Store batteries away from flammable objects at temperatures up to 30 ° C. Non-flammable case is suitable for storing and charging batteries.
  • Store batteries (14 days or more) at a storage voltage of 3.8V per cell.
  • Do not immerse the batteries in water.
  • Do not puncture, disassemble or modify batteries – risk of ignition.

Battery charging

The battery must be recharged after each discharge. The following rules must be followed for safe and reliable charging.

  • Always charge Lipo batteries only with a professionally designed charger designed for Lipo batteries.
  • Do not exceed the maximum battery voltage of 4.2V per cell (4.35V for HV batteries).
  • Do not exceed the charging current. The basic charging current is 1C. Better Lipo batteries can be charged with a current of up to 3C, sometimes the manufacturer states a value of up to 5C. Select the charging current according to the specific battery and the manufacturer's re­commendations.
  • Always charge the batteries with the service connector connected. If possible, use the Balance program.
  • DO NOT CHARGE BATTERY WITHOUT SUPERVISION! If possible, continuously check the voltage of the individual cells and the battery temperature.
  • Charge the batteries on a non-flammable surface or in a non-flammable case.

  • Carefully the charging parameters before charging.

Battery disposal

Damaged or defective batteries must be disposed of in an environmentally friendly manner. Lipo batteries are not normal waste. The battery intended for disposal should be discharged. Dispose of the discharged battery at a collection point or place it in a red container for batteries.