nicla-system: Make the safety timer configuration explicit.

Author: sebromero

libraries/Nicla_System/examples/NiclaSenseME_BatteryChargingSimple/NiclaSenseME_BatteryChargingSimple.ino

@@ -27,12 +27,22 @@ void setup(){
   nicla::leds.begin(); // Start I2C connection to LED driver
   nicla::setBatteryNTCEnabled(true); // Set to false if your battery doesn't have a NTC.
 
+  /*
+  Set the maximum charging time to 9 hours. This helps to prevent overcharging.
+  To get an estimation of charging time, you can use the following formula:
+  Charging time (in hours) = (Battery capacity in mAh) / (0.8 * Charging current in mA)
+  This formula takes into account that the charging process is approximately 80% efficient (hence the 0.8 factor). 
+  This is just a rough estimate, and actual charging time may vary depending on factors like the charger, battery quality, and charging conditions.
+  */
+  nicla::configureChargingSafetyTimer(ChargingSafetyTimerOption::NineHours);
+  
   /* 
   A safe default charging current value that works for most common LiPo batteries is 0.5C, 
   which means charging at a rate equal to half of the battery's capacity.
   For example, a 200mAh battery could be charged at 100mA (0.1A). 
   */
   nicla::enableCharging(100);
+  
   nicla::leds.setColor(blue);
 }
 

libraries/Nicla_System/src/Nicla_System.cpp

@@ -150,8 +150,6 @@ bool nicla::enableCharging(uint16_t mA)
   // Also sets the input current limit to 350mA.
   _pmic.writeByte(BQ25120A_ADDRESS, BQ25120A_ILIM_UVLO_CTRL, 0x3F);
 
-  configureChargingSafetyTimer(ChargingSafetyTimerOption::NineHours);
-  
   return _pmic.getFastChargeControlRegister() == _fastChargeRegisterData;
 }
 

libraries/Nicla_System/src/Nicla_System.h

@@ -101,7 +101,7 @@ class nicla {
    * For example, a 200mAh battery could be charged at 100mA (0.1A).
    * This charging rate is generally safe for most LiPo batteries and provides a good balance between charging speed and battery longevity.
    * @note If your battery doesn't have an NTC thermistor, the charging speed will be limited to ~16mA.
-   * @note There is a saftey timer that will stop the charging after 9 hours by default. 
+   * @note There is a saftey timer that will stop the charging after 3 hours by default. 
    * This can be configured by calling configureChargingSafetyTimer().
    * @return true If the fast charging is enabled successfully. False, otherwise.   
    * @see disableCharging()