Guess: 44kWh.
Lithium-Iron-Phosphate has lower energy desnsity compared to Lithium-Cobalt so they end up with less energy stored in the same space. For both the Tesla Roadster and the Dodge Circuit it looks like they have used all available space for batteries. There is probably a similar cost differential (e.g.: a 44kWh Circuit pack might cost as much as a 53kWh Roadster pack).