Your charged your phone in your office? There, Gotcha! You used "company resources".

Believe it or not, lawyers will put arguments like these and the judge will accept those as valid reasons.

btw, I have a similar setup (I don't work on it during office time inside the office, though) with a minor difference. I vnc/ssh to my aws setup rather than my home. This way my laptop lives longer and wife doesn't bicker about electricity bills.