I am reviewing LTC6813-1 datasheet.
Where are find balance current specification in datasheet?
If i use resister size 2012(0.25w), Is it possible to measure blancing?
The EVB uses the balancing resistance 6343 size.
< DATASHEET 71 PAGE = Choosing a Discharge Resistor >
When sizing the balancing resistor, it is important to know the typical battery imbalance and the allowabletime for cell balancing. In most small battery applications, it is reasonable for the balancing circuitry to be able to correct for a 5% SOC (State of Charge) error with 5 hours of balancing. For example a 5AHr battery with a 5% SOC imbalance will have approximately 250mA Hrs of imbalance. Using a 50mA balancing current this could be corrected in 5 hours. With a 100mA balancing current, the error would be corrected in 2.5 hours. In systems with very large batteries, it becomes difficult to use passive balancing to correct large SOC imbalances in short periods of time. The excessive heat created during balancing generally limits the balancing current. In large capacity battery applications, if short balancing times are required, an active balancing solution should be considered. When choosing a balance resistor, the following equations can be used to help determine a resistor value:
Balance Current =
%SOC_Imbalance . Battery Capacity
Number of Hours to Balance
Balance Resistor = Nominal Cell Voltage Balance Current
Best & Regards,
Balance current is user dependent, it can vary from 0mA to (at max) 500mA. As mentioned above, excess heat is generated when cell balancing current is higher. So the wattage of the resistor must also be higher which will allow it to dissipate heat. Ideally cell balancing resistor used in this application will be of 6463mm 1W/1.5W package.
Concerning Balancing, if this function is not used, can S(n) pins of LTC6813-1 be left blank when designing hardware? Without using these pins, would the measurement of LTC6813-1 have any effect?
Nghia Dang Ngoc