Home : LiPo Safety

LiPo Safety and Management

 

 

LiPo batteries can be extremely dangerous if not handled or cared for correctly. Ensure you familiarize yourself with this entire section before attempting to use your LiPo batteries.  

Charging VS Balancing

  • LiPo batteries require special chargers with a balancer-connector designed to monitor the charge progress. The use of a wrong charger not only shortens the life span, it also can cause the battery to explode.
  • Ensure your battery has cooled before balance charging
  • Always balance your batteries after use.
  • Never keep your battery uncharged as this will shorten the life span drastically or even make them unusable over time.

Storage & Disposal

  • Always balance your LiPo Batteries after use (ONCE COOLED). If you store a LiPo battery uncharged it will be exhaustively discharged
  • If you don’t use your LiPo for a longer time (>2-3 weeks) you should discharge it to approx. 50% of its capacity to store it (cell voltage approx. 3,85 Volt). In this state of charge the chemical decomposition is minimal.
  • If you store your LiPo batteries for longer than 3-6 month you need to cycle charge your batteries.
  • Please refer to your LiPo charger manual for cycle charge.
  • Never discharge LiPo batteries below 3 Volt per cell. This will cause irreparable damages and makes your battery unusable. By default the flight control of the Aerobot MikroKopter is set to warn the user by beeping or flashlights at 3.3V per cell. You should start landing immediately at the time when the charge alert accurse. If you carry on flying and the cell voltage sinks below 3V your MikroKopter certainly will crash.
  • NEVER put LiPos into the household waste! Dispose of LiPo batteries responsibly.
  • Do not store batteries inside an automobile.
  • If you want to keep the connector of the LiPo - NEVER cut the cables simultaneously. First things first. Insulate the cut ends using tape or heat shrink. A short-circuit can cause an explosion!!!.
  • NEVER cut into an expanded LiPo!
  • Keep LiPo battery packs WELL out of reach of children and pets.

Pre/Post flight care

  • When connecting your LiPo to your aerobot, always attempt to connect the negative (black) first.
  • When flying, always listen out for your battery buzzer as continuing to fly after your buzzer sounds, you are at risk of discharging your battery beyond repair, and crashing your aerobot.
  • After each flight, no matter how small, always disconnect the LiPo straight after the flight. Even light power consumption can cause a deep discharge that damages the Battery 

Cautions

All the points above are “common sense”, but…

 

Please take special care of the following points as explosions and injury are easily caused especially for UNAWARE NEWCOMERS and INNOCENT THIRD PARTIES.

 

 

SWELLED LIPOS: Never charge a LiPo pack that has ballooned or swelled due to over / under charging or from a crash.

SWELLING: If you notice your LiPo battery pack is swelling, stop the balancing process immediately, put the battery in a safe container (metal/ceramic) and observe it for 15 minutes with caution.

DAMAGED LIPOS: Never charge a lithium polymer battery pack that has been punctured or damaged in a crash.

OVERCHARGING: NEVER overcharge a LiPo battery.

LIPO CHARGE SPECIFICATIONS: Always follow the battery specification printed on battery pack when setting up the charger. If no specification can be found, contact the manufacturer of the battery before you attempt to charge/balance. A high charge setting can cause the battery to explode, ensure you balance your battery at recommended voltage.

CHARGE SURFACE: Always charge LiPo batteries on surfaces that won’t catch on fire such as cement, steel, ceramic or stone. Wooden tables and carpeted floors are not recommended charging surfaces. Fast charging can cause a battery to reach temperatures of up 70 degree. It is recommended to use chargers with external temperature control.

COOL LIPOS: Allow the LiPo to cool down before charging.

POSITIVE & NEGATIVE WIRES: Never, under ANY circumstances let the positive and negative battery leads touch. It can lead to cell ballooning, cell damage or fire or an explosion.These images show the result of an incorrectly charged LiPo battery          

Balancing LiPo Batteries

Lithium Polymer or LiPo batteries have very specific charging requirements and MUST only be changed by specific chargers designed to charge lithium polymer batteries. A normal battery charger or power supply is not qualified to charge LiPo Batteries. 

Safety and Pre-check

  • When charging LiPo batteries place them in a fire safe environment (Metal or Ceramic Housing) A fast charging progress can cause a battery to reach temperatures of up 70 degree.
  • Batteries that appear to be damage or puffed up should not be charged.
  • Check the wires of the balance connector as well as the main power cables and the Dean Connector for damage.
  • Cool down the LiPo Battery before charging.
  • Double check that the settings for the lithium polymer charger are correct for the pack being charged – this includes the cell count as well as the current settings.
  • Ensure that charging leads are connected correctly. Reverse charging can lead to cell damage or a fire or explosion.

Balance charging

A LiPo Battery Pack is made out of multiple cells connected with each other. When discharging a LiPo pack the cells are not discharge the same amount.

For example a 4S LiPo battery with a voltage of 12.5V can have 3.3V in cell 1, 3.1V in cell 2, 3.05V in cell 3 and 4. (3.3V + 3.1V + 3.05 +3.05 = 12.5V)

A fully recharged LiPo battery should have an equal amount of Voltage in each cell to ensure long life span. To achieve this, a charger with a balance port is necessary. Theses charger can monitor and charge each cell separately.

Charge Voltage

The maximum charge voltage for LiPo batteries is 4.22V per cell. LiPo chargers are normally set to this value and do not need to be adjusted. In any case, NEVER increase the charge voltage above 4.22V.

Charge Amps (A) – Normal Charge vs. Fast Charge

To ensure a long battery life it is recommended to keep the charge below 1C (C-Charge see section 1.1.2.4). 1C for a 2000mAh battery is 2A. 1C for a 6600mAh battery is 6.6A. Is the charge power imprinted on the LiPo higher than 1C the LiPo can be charged with more power to shorten die charge time. Be aware that charging a battery above 1C, even if the imprint allows a higher charge, the life span of the battery will be shortening. Fast charge (charge above 1C) should only be used if absolutely necessary.

Fast charging will raise the temperature of the battery to up to 70 degree (danger of burning). It is also recommended to use an external temperature sensor (place in contact with the battery

and set to 50 degrees) to minimize the chance of damage.