Right, agree. But then there is the tradeoff of the popularity and availability of 12VDC devices due to RV/Boating. But strictly from a technical point of view you are spot on.
> But then there is the tradeoff of the popularity and availability of 12VDC devices due to RV/Boating.
Which is exactly why we need to get away from those 12V old garbages asap. 12V is so bloody wasteful, in terms of both wasted power and wasted conductor material.
The only reason why its still around is people got used to it and don't wanna change.
Assuming this means highest voltage that's still mostly safe and does not require a whole bunch of insulation, we might be looking at something from 80 to 100 VDC? No idea where I read it from but apparently it takes about that much DC voltage for people to "feel something" when touching conductors with dry skin.
The EU safety regs have a cutoff of 50VAC and 75VDC. (Those are only ~5% different in peak voltage.)
Below those levels, you have only general product safety regs to comply with. At/above those and up through all “reasonably household” voltages, you (probably) have to comply with the EU low voltage directive. “Probably” because the LVD itself isn’t law but member states have generally implemented it in their laws.
You break skin at about 50VDC. We could keep ~120V for distribution. There are problems tuning control loops of buck converters dropping more than about 30V (though you can just have multiple buck converters in a row).
Correcting the power factor from 120VAC gives you a boost circuit that gives you 360-400VDC. Some motor control and battery technology standardizes around this voltage. Cars are a big one, but also PFC direct to inverter motor control, which is becoming popular in white goods.
What does breaking skin mean in this context? My understanding was that humans largely act like a resistor with some parasitic capacitance and inductance. Wouldn't more voltage equal more current in a mostly linear relation?
A lot of industry like datacenters and vehicles are moving to 48V. 48V is right on the limit of what is considered low-voltage and therefor doesn't have special safety requirements. And because it's a multiple of 12V, it can work well with old equipment by putting exiting supplies or batteries in series, and using very efficient constant-ratio down-converters.
There are a few people that use 24 - 48V DC batteries/solar charge controllers in RVs and then step down for the motors, lights, etc.. for the rest of the rig. Pretty simple conversion for an RV.
Which is exactly why we need to get away from those 12V old garbages asap. 12V is so bloody wasteful, in terms of both wasted power and wasted conductor material. The only reason why its still around is people got used to it and don't wanna change.