While training with Bee, Naruto was warned about the dangers of the Tailed beast chakra mode. Bee mentioned multiple times that Naruto should be careful in how long he maintains the Chakra Mode because while he was using the Nine tails chakra, The Kyuubi was also absorbing his chakra at an equal rate. However, Naruto maintained the tailed beast chakra mode for quite a long time before he fought madara.
I'm really interested in the exact timeline when the Kyuubi stopped using up Naruto's chakra (So i can better understand just how large Naruto's chakra reserves are). Does anyone know exactly when the Kyuubi stopped taking his chakra back from Naruto?