Dual rate battery charger with low rate, a preset percentage of the high rate

Claim 1

A BATTERY CHARGING APPARATUS, COMPRISING IN COMBINATION, CONSTANT CURRENT CHARGING MEANS FOR CONNECTION TO A BATTERY TO BE CHARGED, FOR SUPPLYING A D.-C. CURRENT TO THE BATTERY AT A HIGHER VOLTAGE THAN THE BATTERY TERMINAL VOLTAGE INCLUDING MEANS TO CHARGE SAID BATTERY AT A HIGH RATE AND A LOW RATE; SENSING MEANS LIKEWISE CONNECTED TO THE BATTERY, SENSING THE TERMINAL POTENTIAL OF THE BATTERY; SAID SENSING MEANS INCLUDING OUTPUT MEANS TO PROVIDE AN INDICATION OF A PREDETERMINED CONDITION OF SAID TERMINAL POTENTIAL, RELAY SWITCHING MEANS TO CONTROL THE CHARGE RATE AT WHICH THE CONSTANT CURRENT CHARGING MEANS IS CHARGING THE BATTERY AND TO SWITCH SAID CHARGING MEANS FROM CHARGING AT SAID HIGH RATE TO CHARGING AT SAID LOW RATE IN RESPONSE TO SAID OUTPUT MEANS PROVIDING SAID INDICATION; TIMING MEANS CONTROLLED BY THE RELAY SWITCHING MEANS FOR REGISTERING THE ELAPSED TIME OF HIGH RATE CHARGE APPLLIED TO THE BATTERY, SAID TIMING MEANS INCLUDING MEANS FOR TERMINATING THE CHARGING OF THE BATTERY AT SAID LOW RATE AFTER THE BATTERY HAS BEEN CHARGED AT SAID LOW RATE FOR A PRESETTABLE PERCENTAGE OF THE TIME THAT THE BATTERY WAS CHARGED AT SAID HIGH RATE.