I had a thunder ac6 but it would NOT charge my batteries as the input from the wall socket was only 50w.
The ac6 (or similar 50w charger - I use 2 of them to charge 2 batteries at the same time) should definitely be capable of charging any 6s lipo. Since it is limited to 50w, it can charge a 6s lipo at around 2Amps. So, if you had a 5000mah 6s lipo, it would take 2.5 hours to fully charge.