If you want to run 24V with bursts of 72V, surely it's as simple as using a remote switch to bring the other two packs in series with the circuit?

I understand you want bigger and badder, it's the DC - AC conversions and Inductor packs I don't see the point of. It's quite probably in my ignorance, but is there a benefit to using inductance and ac-dc conversion to achieve the step up in voltage?