The Declining-Balance 1 method and the Declining-Balance 2 method calculate the same total depreciation amount for each year. If, however, you run the Calculate Depreciation batch job more than once a year, the DB 1 method will result in equal depreciation amounts for each depreciation period. The DB 2 method, on the other hand, will result in depreciation amounts that decline for each period.
For an example, see Example - Declining-Balance 2 Depreciation for more information.