Patent GB-492229-A (GB)
Title: Improvements in automatic charging means for accumulators
IPC: H02J7/00
Filed: 1937-11-29
Abstract: 492,229. Charging batteries. AKTIEBOLAGET LATEX, THIELERS, E. M., and VIGREN, S. D. Nov. 29, 1937, No. 32938. [Class 38 (iv)] A battery-charging system in which the battery is divided into sections which are connected in succession to a charging source, is provided with automatic controlling means including a control switch responsive to the state of charge of the battery sections and operating to disconnect each section as it attains a predetermined state of charge and connect the next section. The three sections B1, B2, B3, Fig. 2, of a battery are charged in succession through the secondary S1 of transformer P and rectifiers L1. A further secondary S2 and rectifiers L2 supply a trickle charge continuously to all the sections. The two movable arms a, b of the control switch are operated simultaneously, one step at a time, whenever winding V is energized so as to disconnect a charged battery section and connect the next section. When the voltage of the section being charged rises sufficiently, the winding for voltage relay R closes its contacts and thereby energizes the winding of relay V which moves arms a, b one step and disconnects contacts 1 so as to de-energize the winding of relay R. This in turn breaks the circuit through relay V so that contacts 1 close in readiness for actuation when the new battery section is sufficiently charged, An additional contact 3, resistance 4 and condenser 5 may be added to reduce sparking. When the sections are fully charged, the arms may be returned to the non-charging position shown in which only a trickle charge is supplied through rectifier L2. On closure of a consuming switch such as X, the circuit through relay R is closed and charging of section B1 commences. Contacts 2 are closed by the first operation of relay V so that all the sections are charged in succession although switch X is open. In a modification, Fig. 3 (not shown), for large batteries, the selector arms a, b actuate power current relays K1, K2, K3 which switch the battery sections in and. out. In the modification shown in Fig. 4, the voltage relays operate at different and lower charging voltages so that all the sections will be partially charged in succession, and this operation will be repeated until the maximum voltage is reached. This is effected by an additional control arm C operated with arms a, b by relay V so as to switch resistances into the circuit of voltage relay R as the arms move to the right. If the main supply is interrupted, the switching from one section to another may take place more rapidly so that the states of charge of the sections are soon equalized. This may be effected by a winding D1 in the supply lead controlling a switch in the circuits associated with the relay V. In modifications, the voltage relay R may be rendered more sensitive by the provision of an additional winding so that switching takes place more rapidly. This additional winding may consist of an opposed compensating winding Rc, Fig. 5 (not shown), across the whole battery. The relays may respond to hydrometer indications of the density of the electrolyte instead of voltage.