Patent ID: 7345453

Claim:
A battery defect detection method for a battery having a lead acid construction, the method comprising: determining a safe voltage value and a current limit value for the battery; measuring a battery voltage value in real time at the battery terminals; applying an increasing current ramp to the battery over a duration of time t 1 that is non-zero until the current reaches a predetermined current value I peak , wherein I peak is selected from the current value measured when the safe voltage value is attained and the current limit value; recording the time (t 1 ); applying a decreasing current ramp after I peak is reached; recording a time t 2 when the battery voltage value reaches a maximum voltage (V peak ) after I peak is reached; calculating a differential (d)=/(t 1 )−(t 2 )/; comparing the differential (d) to a predetermined delay (D)>0; accepting the battery as good when (d)<(D); and rejecting the battery as bad when (d)≧(D).