Abstract: The system described is for controlling the "rapid" charging of electric batteries whose voltage-time profile exhibits a peak at or about the point when it is fully charged, and is arranged to curtail the charging when this peak is detected. The system may be time-multiplexed to control the charging of a plurality of batteries simultaneously. The peak may be detected by comparing each successive sample of the battery voltage with the preceding sample. The system may include means for adding to each sampled voltage, before it is compared with a previously stored sampled voltage, a predetermined reference increment, whereby to avoid errors due to jitter of the sampled voltage. In such a case, means are preferably also provided for inhibiting up-dating of the stored sampled voltage when the comparing means detects that the next following sampled voltage increased by the said increment has fallen to the same value as the stored sampled voltage.