This question already has an answer here:

In the country where I live, Victoria, an oppresive dictator, named El Jeffo sold off the state owned power generation distribution and retailing companies to the private sector. We were promised our cake and that we could eat it too. But we all know this isn't possible. Now the situation has deteriorated to the extent that there are power generation companies, power distribution companies and retail companies that are essentially billing systems for the power distribution companies - and these billing companies spend vast amounts of money advertising huge double digit percentage discounts for overpriced electricity. Needless to say, with such huge advertising overheads

A coup took place, and El Jeffo was deposed, but given a role to play football manager. A new regime took over, and it decided that solar was good, and paid huge vast subsidies to people that would install solar systems. Things were good, so long as the sun was shining as you could sell AC power back to the network, not noticing the huge increases in prices that were taking place.

Now, the era of belt tightening has come upon us, and for this reason we are looking at improving efficiency. It is no longer profitable to send the power out via AC. Given that most solar is DC, batteries are DC and cell voltages are in the low single digit volts, and I2R losses would be short for short cable runs, and also that DC to DC converters are every efficient, no need for isolation etc would there be any benefit in efficiency in running TVs, LED lighting, most electronic appliances off some DC (everything apart from huge motors and resistive heatime appliances) and what would be good standard voltages for households for power that is generated and distruted only within the household?


marked as duplicate by The Photon, Leon Heller, JRE, R Drast, Voltage Spike Oct 25 '17 at 20:19

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

  • 1
    \$\begingroup\$ Then you a transporting the inefficiency to the user's side since 99% of the electricity must be transformed into AC form anyway. Also DC-DC converter is only cheap and efficient when scaling down. \$\endgroup\$ – user3528438 Oct 24 '17 at 22:19
  • 1
    \$\begingroup\$ I was thinking about storage and generation being local. I can see 60% of the power being lost due to inverting from 10s of volts up to 230 AC then switching down to 12V 5V 3.3V 1.2V etc. Also some motors run quite well at 72VDC but anything higher I am told is more dangerous that the same voltage AC (something about DC trams from memory). \$\endgroup\$ – user142731 Oct 24 '17 at 22:26
  • 4
    \$\begingroup\$ El Jeffo? A country called Victoria? You're making this up. \$\endgroup\$ – Finbarr Oct 24 '17 at 22:32
  • 1
    \$\begingroup\$ Another even closer duplicate: Neophyte question about AC vs. DC (especially for powering a home) \$\endgroup\$ – The Photon Oct 24 '17 at 22:35
  • 3
    \$\begingroup\$ Is this a worldbuilding question? \$\endgroup\$ – circuitbird Oct 25 '17 at 0:35

Nowadays, we could have 230V DC as the household wiring. Modern mains adapters actually rectify the 230V 50Hz AC to DC, then make 10kHz AC out of it, transform it to e.g. 12V AC and rectify it again.

BUT, there is still one big disadvantage of DC in that system. Maybe your grandmother still knows about the old times, when DC in households was still common: The switches need to be spring-loaded, because DC has no zero-crossing and so, arcs lighting up during switch-off a loaded circuit will not extinguish automatically. Same for plugs and receptables, you don't want to accidentally pull a loaded 230V DC 16A plug.

  • 1
    \$\begingroup\$ I don't think that you would want anything over 100V DC. It would add to the costs of devices. \$\endgroup\$ – user142731 Oct 24 '17 at 22:28

There is a standard of sorts for local DC power distribution, which is 48v.

This is about the highest voltage you'd want lying around for 'safe touch' low voltage.

It's used (or at least was used) extensively in telephone exchanges (where the backup power is 4x12v lead acid batteries) and recording studios (where they want to stay off mains for hum reasons).

Plenty of power available for lighting and audio equipment, reasonable cable drop over a 10m span, but it would make for a very weedy electric kettle.

  • \$\begingroup\$ Yes, there are standards for aircraft too etc. But for consumers, it just seems that you are stuck with high power high voltage only. But some of my stuf is coming from batteries that are charged during the day, and for low power devices - less than 100W - or about 10A at 10V - do able with the same kind of wiring there is nothing on the marked. \$\endgroup\$ – user142731 Oct 25 '17 at 6:27