tailieunhanh - Chapter 12: Charging Methods and Techniques: General Requirements and Selection of Chargers

Charging of batteries must be conducted with direct current. Alternative current or rotary current have to be transformed. Mostly semiconductor rectifiers are employed for this task. Methods for battery charging vary with demand and the charging time is of great importance. The charging devices can be divided into those that charge above gassing voltage and those that do not. Chargers that exceed gassing voltage during charging are employed for charging one battery at a time, while the ones that do not exceed gassing voltage can be used for parallel charging of several batteries. . | 12 Charging Methods and Techniques General Requirements and Selection of Chargers E. WEHRLE THE BATTERY S REQUIREMENTS FOR THE CHARGER Charging of batteries must be conducted with direct current. Alternative current or rotary current have to be transformed. Mostly semiconductor rectifiers are employed for this task. Methods for battery charging vary with demand and the charging time is of great importance. The charging devices can be divided into those that charge above gassing voltage and those that do not. Chargers that exceed gassing voltage during charging are employed for charging one battery at a time while the ones that do not exceed gassing voltage can be used for parallel charging of several batteries. The chargers that exceed gassing voltage attain short times for recharge whereas with chargers that do not charge above gassing voltage very long charging times must be expected. TECHNICAL DATA AND TERMS Technical data on the charging process for lead-acid and NiCd accumulators are summed up in Table . The following illustrates the most common technical terms applied in connection with charging techniques 1 . Copyright 2003 by Expert Verlag. All Rights Reserved. Copyright 2003 by Expert Verlag. All Rights Reserved. Table Technical data for charging of lead-acid accumulators. Line Traction batteries Stationary batteries Automotive batteries GiS PzS Gro GroE OPzS 1 Rated capacity Cn C5 C5 C10 C10 C10 C20 2 Charging coefficient 3 Energy efficiency after Cn has been drawn standard values 4 Maximum permitted charging currents per 100 Ah nominal capacity A a current constant upon reaching 5 5 5 10 gassing voltage I characteristic b decreasing current W characteristic allowed at cell 8 12 12 7 12 at cell 4 6 6 6 c nominal current of the charger for b 16 24 18 14 24 at cell DIN 41774 5 Maximum for the final charging phase 2 3 3 2 2 allowable for days max. . for