go to bed vs recharge one's batteries

go to bed

verb
  • Of a newspaper: to finish being prepared for printing. 

  • To lie down to sleep, put oneself in one's bed. 

recharge one's batteries

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

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