v2.3.0.11
Document and Entity Information (USD $)
12 Months Ended
Mar. 31, 2011
May 27, 2011
Oct. 03, 2010
Document and Entity Information      
Document Type 10-K    
Amendment Flag false    
Document Period End Date Mar. 31, 2011
Document Fiscal Year Focus 2011    
Document Fiscal Period Focus FY    
Trading Symbol ENS    
Entity Registrant Name EnerSys    
Entity Central Index Key 0001289308    
Current Fiscal Year End Date --03-31    
Entity Filer Category Large Accelerated Filer    
Entity Common Stock, Shares Outstanding   49,046,585  
Entity Current Reporting Status Yes    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Public Float     $ 1,149,080,278