The overload duration could be visually inidcated by the flux bar. The flux bar shrinks by a certain amount during overload, if the part of the flux bar corresponding to that amount was textured differently, the remaining time of the overload could be estimated accurately. If the texture would look like chaotic noise the would communicate the meaning clearly, I believe.
Related to that, it might be interesting to give ion damage the additional property to increase overload duration. In order to not give them the ability to keep enemies in overload indefinitely, they could increase total overload time by an percentage of the time that would be left from the original overload time.
Would make them into even more interesting support weapons.
(There's the rare case were a ship has so much dissipation that it can shed more that 100% of flux during an overload, in such a case the bar indicator would not be precise. That could be fixed by the new texture overruning the flux bar or by resseting it at 0%. But I dont think it's much of an issue to just be vague in these cases.)
