A constant-voltage charge given to dry-charged batteries to get them ready for installation. Most lead-acid batteries are shipped from the manufacturer in a dry-charged state. The battery was charged at the factory, the electrolyte was drained, and the cells were sealed.

When the battery is ready to be put into service, electrolyte having the proper specific gravity is poured into the cells, and the battery is given a constant-voltage freshening charge. The battery is considered ready for service when the specific gravity of the electrolyte does not change in three hours of charging.