Bloomberg News is reporting that Emerson has approached Chloride Group PLC, a British supplier of batteries for sudden blackouts, about a takeover.

Emerson proposed a cash offer on March 18 and the Ferguson-based company said it may make a further announcement if a formal offer is made, according to Bloomberg. It didn’t give any financial details.

Chloride, however, said separately the 255 pence-a-share, 0r $1.3 billion, offer from an unidentified suitor undervalues it.

The purchase would bolster Emerson’s Network Power division, its fastest growing unit. Demand for equipment that protects hospitals, banks and airports from power failures helped boost second-quarter revenue at the unit 28 percent to $1.52 billion. Schneider Electric SA of France took the lead in the power- protection market in 2006 with its $6.1 billion purchase of American Power Conversion Corp.