GB887855A - A battery charging and discharging circuit - Google Patents

Abstract

887,855. Charging and discharging batteries. ULMER, L. June 18, 1959, No. 20981/59. Class 38 (4). In an arrangement whereby a battery is divided into two or more parts, B1, B2, each in series with a resistor R1, R2, which parts are charged in parallel and discharged in series, the arrangement allowing the use of a charging generator voltage approximately equal to that of a load, the resistors absorbing the voltage difference between the battery and generator and battery and the load, respectively, thermistors or semi-conductors having negative temperature-resistance coefficients are substituted for the ohmic resistances previously used. A load U may be fed from a series circuit of the batteries B1, B2 and thermistors R1, R2 on closing a switch I, which energizes relays Da, Db. When the generator G is also connected to the load through a relay E, a relay Ca is energized, which releases relays Da, Db, thus connecting the battery in parallel. An overload on the generator will operate a relay Cb deenergizing Ca and re-energizing relays Da, Db, thus reconnecting the batteries in parallel. Carbon resistors may be connected in series with the thermistors. The arrangement is particularly applicable to batteries of the silver zinc type which may be used in aircraft for an emergency supply. The resistance of the thermistors, alone or in combination with a carbon resistor, should be preferable equal to the internal resistance of a battery when charged or half the internal resistance when discharged.