recharge one's batteries vs recharge one's battery

recharge one's batteries

verb
  • To recover mentally by taking a break or engaging in a relaxing activity. 

recharge one's battery

verb
  • Used other than figuratively or idiomatically: see recharge, battery. 

How often have the words recharge one's batteries and recharge one's battery occurred in a corpus of books? (source: Google Ngram Viewer )