EXHIBIT 21 SUBSIDIARIES OF CHARTER POWER SYSTEMS, INC. C&D Charter Power Systems, Inc., incorporated in the state of Delaware Charter Power of California, incorporated in the state of California, DBA - CalPacific Power Systems, Inc., CalPacific and CalPacific Power Systems Ratelco Electronics, Inc., incorporated in the state of Delaware C&D Charter Holdings, Inc., incorporated in the state of Delaware Cactus Holdings, Inc., incorporated in the state of Delaware International Power Systems, Inc., incorporated in the state of Arizona Charter Power F. S. Ltd., incorporated in the Islands of Bermuda LH Research, Inc., incorporated in the state of Delaware Power Convertibles Corporation, incorporated in the state of Arizona Power Convertibles Ireland Ltd., organized under the laws of Ireland PCC de Mexico, S. A. de C. V., organized under the laws of Sonora, Mexico