Two types of charger are principally used for the charging of traction batteries: the taper type and the pulse type. After connection to the battery, the taper chargers operate at a high current which tapers off as the voltage rises in each cell. When the charge reaches about 2.35 volts per cell, the gassing period commences and that requires a further current reduction which has to be carefully controlled for a further three hours or so. Charging is usually completed over a total of about 12 hours and at the end of the period the charger is usually shut off by a pre-set timer. (Using a two-rate taper charger the total hours required for charging are reduced to about eight). Pulse chargers measure the cell voltage and monitor it throughout the charging operation. The current is switched on for seven-minute periods with seven second intervals in between when the sample measurements are taken. Comparisons of the measurements are automatically made and continue until the gassing voltage point is reached, when the taper control circuits commence to function, the pulsing continuing until successive measurement shows that the battery voltage has been stabilized. Although the battery may then appear to be fully charged it is likely that the cells are not equal and, if left on the charger, the battery will continue to get pulses of current of between three and four minutes duration until all the cells have been "topped up" . Usually this is about 15 hours after charging commenced if the battery was in a fully discharged state.

  • Corporate Authors:

    Allens (Clerkenwell), Limited

    39 High Street
    Wheathampstead, Herts AL4 8DG,   England 
  • Publication Date: 1977-12

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00183823
  • Record Type: Publication
  • Source Agency: Engineering Index
  • Files: TRIS
  • Created Date: Dec 29 1978 12:00AM