GB1422826A - Charging circuit for rechargeable batteries - Google Patents

Abstract

1422826 Charging standby batteries IONLITE Ltd 13 May 1974 [5 July 1973] 32120/73 Heading H2H An automatic battery charging apparatus comprises a first timing means for sensing the time during which a battery is being discharged and a second timing means arranged to connect the battery to a charging device when the discharge period ends so that the battery is charged for a time determined by the time the battery was discharging. A battery 10, which may be a battery used for an emergency supply for electric lighting during a mains failure, has its discharge periods timed by a plurality of solid state timing circuits 16, 17, 18, the circuit 16 causing a relay 21 to be de-energised at the end of a first discharge period, the circuits 17, 18 causing de-energisation of relays 22, 23 at the end of a second and a third discharge period respectively. De-energisation of any one of the relays causes a respective time constant circuit 27, 28, 29 to be connected to a timing circuit 31 by contacts 24, 25, 26. At the end of a discharge period the timing circuit 31 causes energisation of a relay 15 so as to connect a high rate charging circuit 13 to the battery 10, the time for which the battery is charged being dependent upon which of the time constant circuits 27, 28, 29 is connected to the timing circuit 31 during the battery discharge period. Solid state devices may replace the relays if desired. A further charging circuit 11 is provided, permanently connected to the battery 10 for trickle charging purposes.