What if the ship itself had the battery capacity?
The Battery goes out the window and in comes the Dynamo.

Let's say the Moth has 300 units of power capacity.
The dynamo only affects the charge rate, not the capacity.

This, ofcourse, would not change any InfiniBoost capabilities of any ship, but it would limit the time of sustained fire for smaller ships and give even a Moth with a free dynamo 2 minutes of Plasma Devestator fire.

Doable? Desirable?
I think so!

There's a reason for the fact that capacity and charge are both built into the battery. If the capacity is always the same, and the only changing factor is the charge, then is there any reason at all not to use the battery with the highest charge? There's little enough reason to use varied batteries as it is.
-:sigma.SB

A moth with 2minutes of plasdev fire. 0_o

Maybe some ships need a S dynamo while others need a L?

Maybe the L dynamo ships would accept a S dynamo, but would charge at half the rate?

Maybe the battery and the dynamo would be separate objects?