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Complete Battery charging using BQ25504EVM

kartheek RP
Prodigy 180 points
Other Parts Discussed in Thread: BQ25504

I have read that charging Li ion battery has some particular algorithm:

1)Charge at constant current (0.2 C to 0.7 C depending on manufacturer) until the battery reaches 4.2 Vpc (volts per cell),(70% cell is charged)

 2)Hold the voltage at 4.2 volts until the charge current has dropped to 10% of the initial charge rate. The termination condition is the drop in charge current to 10%.

But this type of charging cant be followed with BQ25504EVM,

So is that I wont be able to charge a battery completely to 100% SOC(state of charge)? 

Li ion charging algorithm:

 

  • 0
    TI__Guru**** 166916 points
    The bq25504 only charges using constant voltage, i.e. it will charge until the battery votlage is 4.2V. Since its expected power source is high impedance and typically will not be able to provide a constant current, the energy is delivered in pulses of current. If the power source's impedance drops low enough, then it is possible that the charger could provide a constant charge current up to ICHRG=eff*VMPP*100mA/4.2V where eff can be estimated from the datasheet.
  • 0 in reply to Jeff F
    Prodigy 180 points
    So do u mean battery cant be charged completely to 100% SOC by this BQ25504EVM?
  • 0 in reply to kartheek RP
    TI__Guru**** 166916 points
    The charger will charge the battery until the voltage at VSTOR reaches the VBAT_OV threshold. Since the IC performs no measurement of charge current and no other gauging functionality to report SOC, it cannot guarantee 100% SOC.