Notes, cautions, and warnings.
- The battery packs produced by the CMIUTA Electric Company have no any (BMS) electronic built-in circuitry. For charging process requires a 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 the heat generating electronic parts in order to avoid deterioration of cell performance.
- For safety reason and in order not to shorten the cycle life, max charging voltage should be under 4.20V/cell including tolerance (we recommend 4.10V/cell, to achieve more cycles – read below in page more info about NCA cell lifespan).
- At cell-level, the standard charge condition is CC/CV with following rates:
– NCR18650GA = 1670mA/cell
– NCR20700B = 2000mA/cell
– NCR20700A 2200mA/cell
The charging process should be automatically halted by charging the 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 2.70V/cell, including tolerance (we recommend high than 3.10V/cell, to achieve more cycles – read below in page more info about NCA cell lifespan)
- 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.
- The current interrupt device (CID) may activate if the battery is charged continuously after it has reached a fully-charged state (maximum 4.20V/cell) or if the battery is charged at a high temperature.
NCR18650GA has a lifespan up to 1000 cycles, and NCR20700B up to 2000 cycles, but these numbers strongly depend on discharge rate, SoC and DoD values, or cell temperature.
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.
- 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 at high temperatures
- DO NOT connect the battery directly to AC plug (outlet) or electric car plugs.
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 with UAVs/UAS requirements. In order to ensure the safety of the battery pack, please contact CMEC to discuss the 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.
- The CMEC will not be liable for any damages that are caused by violations of the precautions in this specification.
- The 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)
- The CMEC will not accept a return of any abnormal battery pack that was damaged due to an incorrect cycle process, or because was used in other applications.
What shortens lithium battery life.
- High temperatures.
- Overcharging or high voltage (battery SoC).
- Deep discharges or low voltage (battery DoD).
- High discharges or charge current.
How can you prolong the lithium-ion NCA 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 a full cycle does not fully utilize a battery.
- 100% DoD is a full cycle; 10% are very brief. Cycling in mid-state-of-charge would have better 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 a right way to prolong the NCA battery pack life, of course, if you have this goal! For example, a high-end EV use 25-85% SoC to prolong battery life.
DoD = Depth of Discharge
SoC = State of Charge
BMS = Battery Management System
ESC = Electronic Speed Controller
PDB = Power Distribution Board
PCB = Printed Circuit Board
EV = Electric Vehicle
AC = Alternating Current
DC = Direct Current
UAVs = Unmanned Aerial Vehicles
UAS = Unmanned Aerial System