The Isotope Decay-At-Rest (IsoDAR) experiment is a short baseline neutrino experiment designed to measure neutrino oscillations by placing a high flux electron anti-neutrino source near a kiloton scale scintillator detector. A high current proton beam will be used to produce the large number of electron anti-neutrinos needed. Reaching the design goal of 10 mA of 60 MeV protons on target requires advancements in accelerator technology. This can be achieved using a high intensity H$_2^+$ ion source followed by a radio-frequency quadrupole and spiral-inflector to axially inject ions into a compact cyclotron. Presented here are the results of our latest studies of this injection system.