I have been using bq24610 to charge LiCoO2 as well as LiFePO4 cells. I am getting perfect and desired characteristics of charging profile with LiCoO2 pack. But the charger is not behaving as expected with LiFePO4 cells. What could I be doing wrong here?
The above figure is the charging profile with LiCoO2 cells. As expected it is charging initially with constant current and then at a later stage the charger switches on to almost constant voltage (with decreasing current). It cuts off at a taper current set at 300mA.
The above figure is the charging profile with LiFePO4 cells. The same charger circuit was used in this case also. The constant current region looks fine, however there is no constant voltage region. At a later stage, instead of maintaining a constant voltage, the charger voltage (Vpack) is also rising. During this region, the battery voltage is rising at a faster rate thereby reducing the current and finally it cuts off.
My question is, eventhough the charger circuit is the same, why is it not able to maintain a constant voltage, as in the case of LiCoO2 pack ?
