Rayovac to Sell 80% of Its Equity: The Madison, Wis.-based company said the investment firm of Thomas H. Lee Co. agreed to buy 80% of the nation's third-largest battery maker. Neither closely held Rayovac Corp. nor Thomas H. Lee Co., a Boston-based buyout firm, would disclose the terms of the agreement. Rayovac trails Ralston-Purina Group's Eveready and Duracell International Inc. with about 25% of the battery market. However, it commands about 64% of the rechargeable battery market with its Renewal brand line of alkaline batteries. Rayovac had sales of about $580 million in 1995, according to Information Access Co. It was founded in 1906. The investment firm has a history of buying companies, turning them around and then selling them at a profit.