dokuwiki

Lk280f eve

Gobelpower

Question: One of the cells is from October? Something to be concerned about?

Answer:

• Yes, Cell #12 has a production date of 31 Oct 2024, while the others are from late December 2024.
• Difference in age: about 2 months.
• Difference in voltage:
  1. October cell: 3.2522 V
  2. Average of others: ~3.2437 V
  3. Difference: 0.0085 V (8.5 mV)

• Conclusion:
  1. Not a concern. This voltage difference is very small.
  2. Cell resistance and voltage are similar to the rest.
  3. If stored properly, a 2-month difference is negligible.
  4. → Safe to include in the battery pack.

Question: What is the difference between the lowest and highest cell?

Answer:

• Cell voltages:

[3.2450, 3.2437, 3.2431, 3.2441, 3.2423, 3.2437, 3.2430, 3.2431,

   3.2419, 3.2434, 3.2425, 3.2522, 3.2423, 3.2437, 3.2435, 3.2437]

• Highest voltage = 3.2522 V (Cell #12)
• Lowest voltage = 3.2419 V (Cell #9)

• Voltage difference = 3.2522 V - 3.2419 V = 0.0103 V (10.3 mV)

• This is an excellent result. Most BMS tolerate up to 30–50 mV difference before balancing is needed.
• → No balancing required at this point.