He's said it takes 4-5 hours to charge up 60 miles worth of range, not fully charge the car although that's perhaps still a little optimistic - at 3 miles per kWh that's still 20kWh which would take more like 8 or 9 hours at 2.3kW. (If you can get 4 miles per kWh though, then you're looking for 15kWh of charge, so more like 6.5 hours)
Edit - looking back at his posts, he seems to be achieving 5 to 6 miles per kWh in his Ioniq, so 4 to 5 hours makes more sense, he might only need 10kWh of charge to achieve that.