I'm using LTC4015 to charge a 2 cell 7.4V Li-ion battery. When the Input power(12V DC) is connected I am able to read the charge current and is approximately correct, but when I turn on the module with only battery LTC returns the battery current as zero(external multimeter says 13mA). And when there is no battery connected LTC's charger status says battery short fault instead of missing fault. Can you please check the attached schematic for any possible errors(Ignore the AC section).
The voltage divider on your VBAT node may be responsible for the battery short fault. Try using higher-value resistors. This will also lower the constant drain on the battery.
As for the current…
Thanks, It worked. Current error was a firmware error and we corrected it.
Can you check the chem and cell_count registers to make sure they read what you expect?
Try a little higher input voltage, up to 28V.
Are there any status indications that give a hint about…
As for the current error, where are you pulling the current from? Is it passing through the battery sense resistor for measurement by the LTC4015? If you pull more current, does the LTC4015 see it?
Now I'm trying to charge a 7 cell LiFePO4 battery with the same circuit with an Input Voltage of 24V. The VBAT as read from LTC4015's register is 17.5V and the VIN is around 24. The SYSTEM STATUS register gives out 0x02C7 which shows everything is normal, but the CHARGER STATE is always in charger suspended fault. I checked the suspend_charger bit in CONFIG_BITS and it is 0.
What could be the possible reason for this?
The charger_suspended bit is not necessarily a fault. Do you ever manually suspend the charger?
I think the problem may be that the target voltage for a 7-cell LiFePO4 battery is 25.2V (by default anyway) and your VIN voltage is less than that at 24V. You will need a higher input voltage to charge that stack. Do you modify the per-cell voltage digitally?
I manually suspend and release the charger at the start of the program. I didn't modify the per-cell voltage. I noticed that the battery starts charging when battery voltage goes below 17V and stops approximately around 20.3V(2.9V/cell). I increased the input voltage to 26V but still the problem exists.