Hi,
i've some questions on the setup of a battery with 3s1p Lifepo4 (ANR26650m1b, 2,5Ah) with a discharge of 15A (6C) and charge current of 4A (1,6C) up to 3,6V per cell (COV is 3,8V):
1) What is the general parameter setup for LIFEPO4 Chemistry? What parameters and values do i have to configure concerning lifepo4?
2) The application has to be working between within -30 to +55 degree, that is the operating range of the cells. Does Impedance Track work within this range?
3) I used Chemistry-ID 440 for some tests. Somehow after the learning cycle the RSOC value becomes 0 when cell voltage is around 3V, but the discharge continues down to Termination Voltage 6V (Pack) or 2,05V (Cell)
4) external Balancing stops completely when the first balancing-timer has reached the same level as the next lower one. Unfortunately the device does not start balancing again even after recalculation of the balancing times. The CBR, RSVD_1 (CBM on bq40z50 firmware) and CB bits are set to 1. Update Status is 04
5) The Bq40z50-R1 starts balancing when a charger is applied to the contacts (CB-Bit =1). Refering to SLUA420A (page 3) the voltage drop over the external fets can be to low when the cell voltage is very low (e.g. 2,5V). I suggest, there is no control by the bq40z50-r1 whether the balancing is working at this voltage or not but the balancing-timers will decrease. Is this a firmware-bug?
6) The datasheet of the Lifepo4 states a operation range at -30 but the charging behaviour is very poor. What charging parameters do you recommend? Does it damage the cells if they are charged at -30 degree? Where can i get more information?
Thanks! :-)
Simon
