The result keeps the Gunners top of the FA Women’s League Cup group B.
Mead registered a goal and two assists and Danielle Van De Donk bagged two goals.
Centre-back Jennifer Beattie opened the scoring.
Charlton are pointless after two matches.
Midfielder Alice Griffiths said: “Obviously it is not great to lose a game but we have to accept who we are playing against today. They have played in Europe this week and we know where we are in terms of the league table.
“It was a chance for us to test ourselves. It is a great experience, even the venue as well, I am not used to playing on pitches like this, so it is good to challenge ourselves.
“As a group we are still positive and together and we are still believing that we can get out of this together.”
PICTURE BY KEITH GILLARD