13A / USB socket power drain?

[Dr J R Stockton]

John Rumm, to whom thanks, mailed me a link, from which I wandered to , which shows (mainly) pattress-mounting dual 13A switched sockets such as we are all used to, but including a pair of USB sockets for supplying 5v DC power.

I suppose that the USB sockets are fed from the ordinary ring main via one or two 240 V AC to 5 V DC converters; but they could use a local 5 V DC "ring main"..

I am wondering about the power drain of the converters, especially when not in actual USB use. Are they always on, or on only when the corresponding switch is on, or on only when a particular, or either, switch is on?

I see that the USB outlets are capable of delivering 5 watts, so that the standby drain of the converters can be guessed as being in the range of 100 mW to 1 W. A family home might easily have ten such dual sockets, so taking up to maybe 10 W all of the time, if not switched off; maybe about 80 KWh per year, or £10 per year assuming Economy 7.

It is not, of course, a large sum, even at worst; the capital cost h having one dual-USB dual 13A socket instead of a non-USB one is around £15 -- but one should be able to know what the running cost might be.

[Tim Watts]

Let me simplify that for you:

Don't bother!

The USB power standard evolves every 2-3 years and those are already obsolete 2 years ago.

USB Type C is coming with a top power of 100W.

You can get some very nice 4-in-1 plug type PSUs and 4-6 in 1 on-a-lead power packs - and these a) can be turned off; b) replaced easily when no longer of much use.

[tabbypurr]

It doesn't matter, as they're a poor idea and best avoided. USB power is a fast changing field, and most such sockets are obsolescent even when new.

NT

[Dave Liquorice]

Yep though USB type A seems to have stuck as the universal host connector.

100 W @ 5 V = 20 A, hum that'll be interesting to see. Or they going to have some "smarts" that talk to each other and jack the voltage up if they agree? but even 50 V requires 2 A to deliver 100 W...

[Martin Brown]

There is a local switched mode AC to DC converter inside it almost certainly moderately efficient with losses

The only way to tell would be to measure one. Even the datasheets don't say eg.

Picking a random non integral one with a datasheet suggests as I would have guessed unloaded standby power consumption

[Andy Burns]

There are phones with "quick charge" that want 15W, so yesterday's 2A chargers are old-hat.

I have one device with USB C, it's only a USB2 device not USB3, so it did come with a USB-A to USB-C lead, I expect USB-C to USB-C will slowly become the norm ... The latest MacBooks and ChromeBooks come with USB-C at the host end.

Yes, that's the way it will do it, 5A/20V I think.

[Dave Liquorice]

Which on a per household basis isn't that big a deal, but across the

20+ million households in the UK it's 200 MW plus distribution losses or a medium sized power station...

[John Rumm]

And, at long last, a connector you can insert either way round ;-)

(Rather than the 270 degree rotation required with current ones)

[John Rumm]

The main problem with distributing 5V any distance is voltage drop.

Without taking one apart its hard to tell. Chances are they are "switching" converters, and hence power dissipation on no load will be negligible (much as it is with modern phone chargers)

With a traditional linear supply that could be the case, but its not going to be that bad with a SMPSU.

Personally I would be more worried about the quality of the PSU than its quiescent current draw. Many USB chargers are of fairly low quality, have poor mains to 5V separation, and are not designed to intrinsically fail safe. That's bad enough on something you plug in, and even less desirable on something hard wired in.

There has been some testing done on them:

[Nick Odell]

I thought Apple were going in the right direction with their reversible MagSafe plug - until they started going in the wrong direction by not making newer versions backwardly compatible.

Nick

[Huge]

And now they've dropped it altogether.

:o(

[Tim Watts]

No - they jack the voltage up too - by negotiation.

The idea is to take "USB Power" to the next level and power laptops too.

[Tim Watts]

I like the USB C - much more robust and reversible. Two problems solved. But the Type A has done damn well as a form factor. How long is it? 20 years?

[Tim Watts]

Not a moment too soon! Micro-USB was the ultimate abortion. Talk about bad idea for something that's shoved in and out 1000 times a year.

[Tim Watts]

Apple - backwards compatible? When did that happen?

Like all those things with an Apple iPod dock, all now obsolete and useless.

[dennis]

Its another few percent on a typical bill, people are fitting new bulbs to save that sort of money.

I once did the sums to see what happened if everyone went for an IP phone rather than a proper one and that needed a couple of nukes.

[Bob Eager]

We've done our bit. This house has ten IP phones!

[soup]

Snicker. ;O)

[Hanny Z]

Few would use it as much as that, most wouldn?t use it more than daily.

One big advantage of micro-USB is that its designed to wear out the much easier to replace cable rather than what it plugs into so it's very easy and cheap to replace when it does wear out.

[Dave Liquorice]

270 degree? 180 Shirley?