[Doc Wu]

Although I understand that reasoning, does not the DC-DC converter do the same thing? When the input voltage drops, at what point does it's 5v output shut down at? Since it converts to 5v, even if it doesn't operate as a boost-buck module, it ought to be good to 6v in.

In addition, the D-link routers internal regulators work just fine at 12v and do their own internal conversion to 5v or whatever they use internally. We run them routinely on an old robot that was wired for the old Linksys bridge. (Discovered by accident, when a student didn't realize they weren't direct plug-in replacement)

It seems like all these voltage conversions are inefficient and redundant.

If your battery is dropping below 6v then you're probably only seconds away from it dropping below 4.5v anyway. Continuing to run like that only damages batteries.

Note that this is just a theoretical discussion. If your robot is not wired to the current rule, I'll still call you out on it in inspection!