Charging Methods

Author: E.E. Kimberly

Charging methods must be chosen to fit the type of service. Batteries used for electric vehicle propulsion are discharged during the travel hours of the vehicle and are then recharged in off-service hours. They are sometimes given a "booster" charge during the noon hour, if the vehicle is near the charging station at that time. The booster charge is kept as high as possible without objectionable gassing, in order to store a maximum amount of energy in the short time allowable. A short-time booster charge not only replaces some used-up energy but it also accelerates the circulation of the electrolyte and makes the remaining portion of the original charge more readily available for high discharge rates. When a battery is charged in off-service hours, a moderate rate with the usual tapered "finish charge" is preferable. Equipment designed for charging the batteries of a fleet of vehicles will automatically provide a tapered charge.

Batteries used for central telephone or power station service are usually charged continuously at a low "trickle charge" rate. A constant voltage of appropriate value impressed across the battery terminals is sufficient for proper charging. In no case should the battery temperature be permitted to exceed 110 F.