System and Method of Battery Monitoring

A battery monitoring method, in particular for calculating a voltage decay rate (VDR) of a battery (1) installed in a vehicle, wherein the method comprises the steps of:

• SI1) identifying an engine turned off (key-off));
• SI2) counting and waiting a resting time (TR2) after the engine turned off;
• SI3) measuring a voltage (VR2) at battery terminals;
• SI4) calculating a voltage decay, using a formula:
• Voltage Decay Rate=(VDRi−VDRf)/(TVDRf−TVDRi)
• in which:
• Voltage Decay Rate is a ratio in which a battery voltage drops when an ignition is off (Key-off);
• VDRi is a battery voltage measured after the resting time (TR2);
• VDRf is a battery voltage measured before activating a vehicle network;
• TVDRi is an initial time after finishing the resting period;
• and TVDRf is a final time after finishing the resting period;
• SI5) comparing a battery calculated VDR with a limit value (VDRL);
• and
• SI6) registering and/or sending a warning failure sign if the VDR value is greater than the VDRL limit value.