When inserted it will put out a steady 14.2 Vdc charge and must be removed when quick charging is not needed as it will cook/dry out batteries if left continuously connected to shore power.
As mentioned above the better option is to purchase the IQ4 module for around $30 that plugs into the same port. It unleashes a 4 phase charging algorithm that bulk charges at a much quicker 14.8 Vdc with absorption voltage set at 14.2 Vdc and a 13.6 Vdc float. The fourth phase entails periodic equalization routines.
Our TH came with an Iota and dual jack, once we installed IQ4 module charging characteristics vastly improved, particularly when charging our battery bank via generator when camping without hookups.