Instructions

Instructions, cautions and warnings.

  • The battery packs produced by the CMIUTA Electric Company have no any electronic built-in circuitry (PCB BMS). For charging process requires an smart charger with overcharge protection, and cell balancing functions.
  • The battery packs should be connected to the electric engines and to the electronic components of UAVs through a suitable power distribution board (PDB).
  • The battery pack should be kept away from heat generating electronic parts in order to avoid deterioration of cells performance.
  • For safety reason and in order not to shorten the cycle life, max charging voltage should be under 4.20V/cell including tolerance.
  • At cell level, the standard charge condition is CC/CV with a current between 1670mA (NCR18650GA), 2000mA (NCR20700B) to 2200mA/cell (NCR20700A). The charging process should be automatic halted by charging device when either time, battery voltage, or current reach certain values. Read battery pack specs to see the maximum charging current. It differs from one configuration to another, depending on the number of cells in parallel!
  • The discharge end voltage should be more than 2.7V/cell,  including tolerance.
  • The charging temperature should be confined to the range 5°C to +45°C.
  • The discharge temperature should be between -20°C to +60°C.

Storage temperature and humidity.

  • When long duration storage the battery packs should be stored in a stable environment characterized by low-humidity (less than 70%RH), free of corrosive gasses, and an ambient temperature between -20℃ and +20℃.
  • Avoid conditions that can create condensation such as rapid fluctuations in the ambient.

Prohibited actions.

  • DO NOT short circuit
  • DO NOT force a reverse-charge or a reverse-connection
  • DO NOT overcharge
  • DO NOT modify, disassemble, puncture, cut, crush, or incinerate
  • DO NOT expose to liquids
  • DO NOT use or place the battery a high temperatures
  • DO NOT connect the battery directly with AC plug (outlet) or electric car plugs.

Recycling.

When disposing of the battery, recycle it according to local rules and regulations.

Other battery safety requirements.

These batteries packs it is stringent engineered compliance to UAVs/UAS requirements. In order to ensure the safety of the battery pack, please contact CMEC to discuss design of the application from a mechanical and electrical perspective. Also, if there are special usage conditions (for example: a large (DC) current load, a quick charge method, or a special usage pattern), please consult CMEC before finalizing the product specification.

Warranty exemptions.

  • CMEC will not be liable for any damages that are caused by violations of the precautions in this specification.
  • CMEC will not be liable for any problems caused by design defects of battery pack charger or other power electronics (also if you use improper settings of the charger/balancer or PDB/ESC/VESC, do it at your own risk and the warranty are canceled)
  • CMEC will not accept return of any abnormal battery pack that were damaged due to an incorrect cycle process or because was used in other applications.

What shortens lithium battery life.

  1. High temperatures.cmec-batt
  2. Overcharging or high voltage.
  3. Deep discharges or low voltage.
  4. High discharges or charge current.

How can you prolong the lithium-ion battery lifespan.

  • A partial discharge reduces stress and prolongs battery life, so does a partial charge.
  • Batteries charging to 85% have a longer lifespan than enabling full charge. Although longer lasting, a less than full cycle does not fully utilize a battery.
  • 100% DoD is a full cycle; 10% is very brief. Cycling in mid-state-of-charge would have best longevity. 
  • Every 0.10V drop below 4.20V/cell doubles the cycle but holds less capacity.
  • Every 75mV drop in charge voltage lowers the usable capacity by about 10%.

Referring to cycle, using a setup “window” (through BMS) between 3.10V – 4.10V/cell (including tolerance) is right way to prolong the NCR battery pack life, of course, if you have this goal! For example, EVs use 85–25% SoC to prolong battery life.


Abbreviations list:

DoD = Depth of Discharge
SoC = State of Charge
BMS = Battery Management System
ESC = Electronic Speed Controller
PDB = Power Distribution Board
PCB = Printed Circuit Board
EVs = Electric Vehicles
AC = Alternating Current
DC = Direct Current
UAVs = Unmanned Aerial Vehicles
UAS = Unnmaned Aerial System