Abstract: The present invention provides a method for measuring the charge state of an accumulator and a device for implementing such method.The method consists in measuring the temporary voltage drop at the terminals of the accumulator during delivery of a high current. The device for measuring this maximum voltage drop comprises a first maximum detector (43) supplying a voltmeter (42) and connected to the output terminal of a subtractor (44) whose so-called inverting input is connected to the accumulator through a filter (45) and whose so-called non inverting input is connected to the accumulator through a second maximum detector (46).Application to measuring the charge state of an accumulator.