One addendum - since they are accumulators, however powerful, they should lose their charge over time, perhaps quickly, perhaps slowly. Basically, use the charge within a month or lose it.
That prevents dreadnoughts from loading up with a bunch of charged accumulators and doing a series of fuelless jumps straight to a capital.
However, it does not prevent Battle Riders from sporting Jump-6 drives and one accumulator, good for one jump. Or maybe two accumulators. You get the idea: these suckers have to be beyond the military's eager grasp.
That prevents dreadnoughts from loading up with a bunch of charged accumulators and doing a series of fuelless jumps straight to a capital.
However, it does not prevent Battle Riders from sporting Jump-6 drives and one accumulator, good for one jump. Or maybe two accumulators. You get the idea: these suckers have to be beyond the military's eager grasp.