The 21-year-old progressed through the Addicks' youth system but did not make a first-team appearance.
He spent last season on loan at National League side Woking after a four-month stint with the Cards during the 2015-16 campaign.
"Terell has become available and is one the recruitment department have been looking at," said boss Paul Cook.
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League One side Wigan Athletic have signed Charlton Athletic defender Terell Thomas on a one-year deal.