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Author Topic: Standby and the hair shirt.  (Read 5625 times)

lyner

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« on: 30/04/2007 09:05:22 »
Where is the origin of the preoccupation with the principle of not having electronic equipment on standby?
There is nothing basically wrong with it; it may be that many pieces of equipment consume too much power on standby but it is not a fundamental problem.
After all, many pieces of equipment have clocks running inside them. Are we to turn these clocks off as well?
Wasting a few Watts per item is not a good thing, of course but it is possible to run a simple 'wake-up' circuit running on a few milliwatts,  or even less. This level of 'energy drain'  would really be trivial and well justified in terms of convenience. 
I heard of a proposal on 'The Lions' Den' TV Prog  for a bolt-on unit which would do just this. But, I believe they were obsessed with having it battery operated; where would the energy come for that, then?
Why haven't manufacturers produced equipment with such circuits in them? There is a huge potential marked for such a green idea.
Perhaps we will be encouraged to chuck out all our inefficient gear and  buy new low energy stuff.  How much energy does a new TV, Fridge, Car, DVD player cost to produce?


 

Offline daveshorts

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« Reply #1 on: 30/04/2007 11:20:25 »
I think it isn't a fundamental problem, you are right you can build a wake up circuit running on a few milliwatts. The problem is that most, especially older power supplies will draw a current from the mains even if the device isn't using any power, essentially they are quite efficient if you are drawing 100W but if you are drawing .1W it looks a lot worse. You could certainly build a power supply that was a lot better and I am sure there are some built as such now. It just requires slightly more thought and is possibly slightly more expensive   so it is taking a while to happen.
 

another_someone

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« Reply #2 on: 30/04/2007 13:43:30 »
I think it isn't a fundamental problem, you are right you can build a wake up circuit running on a few milliwatts. The problem is that most, especially older power supplies will draw a current from the mains even if the device isn't using any power, essentially they are quite efficient if you are drawing 100W but if you are drawing .1W it looks a lot worse. You could certainly build a power supply that was a lot better and I am sure there are some built as such now. It just requires slightly more thought and is possibly slightly more expensive   so it is taking a while to happen.

This is certainly an issue with PC power supplies.

A decade ago you could comfortably run a PC with a power supply rated at 200W or less (and ofcourse, that is peak rating, not what one expects to actually consume), whereas modern PC's are coming spec'ed with a requirement for 500W power supplies as minimum.  With this, there is an increasing emphasis on efficiency (as any inefficiency in the power supply is not only lost energy, it is also a source of unwanted heat), but as you point out, the 80%+ efficiency they now seek still only applies to peak load, although there are ever more stringent requirements for 50% loads, but trying to get the power supply to work with the same efficiency while delivering a mere 10W is still a long way off (let alone into the milliwatt region - which in fact many power supplies cannot do at all, so they need shorting resistors to make sure they actually have sufficient current going through them to satisfy their minimum requirements).  Ofcourse, the real irony is that most of the power drawn for modern PC's is not for doing anything useful, but for supporting the sophisticated graphics cards required by modern PC games, and required for some of the fancy graphics features of Microsoft Vista.
 

Offline daveshorts

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« Reply #3 on: 30/04/2007 13:56:26 »
I guess the obvious thing to do is have a very small power supply that runs the circuitry for the standby, and has enough oomph to switch a big relay to power up the main power supply. But I guess this is relatively expensive to do.
 

paul.fr

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« Reply #4 on: 30/04/2007 15:39:13 »
are we not supposed to turn things off at the wall to save electricity? whilst an appliance is on standby they still use electricity, albeit a small amount. The power consumed on standby is regulated by the EU i think!

for modern computers you can reduce the amount of power consumption whilst on standby by altering your power settings, having the machine go idle, or hard disc drives closing down after a set time period of idleness, etc.

you can also use software/hardware to monitor all of you peripheral units and turn them off after another predefined time period.
 

Offline JimBob

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« Reply #5 on: 01/05/2007 03:04:50 »
In recognition of this problem of wasted energy the computer industry has made almost all of its new motherboards (the exception being for high level server-type computers that are always in use)Power savers as Paul so aptly pointed out. The reason for this is that electrical equipment (I'm generalizing) fails most often at the power-on point as this is the most stress the electrical components receive. Ever had a light bulb go out when it is on? Only twice in ~60 years for me. It is always when it is turned on.

All the computers I have gone through since 1985 have always had a problem show up first at start up, then finally not start at all.
 

lyner

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« Reply #6 on: 09/05/2007 11:19:59 »
The 'power saver' mode is still not very 'power stingy'. They could be using a few microwatts not the 5W, or whatever they take these days.  You would have to, virtually, shut down everything - DRAM would have to be allowed to 'forget' its contents, for example.
Same thing, basically,  goes for TVs etc.
The start-up stress is only a factor because they pare all designs to the bone! They make a  really beefy thyristor which will control a washing machine - heater + motors  (3kW+) and it works every day for years and years; it seems to handle all sorts of fault conditions in other components.
A decent PSU should be able to handle virtually anything - and provide an appropriately 'soft' wake up for all the stuff it is supplying.
Where there's a will, there's a way.
Before long, they will be marketing the idea - and polluting the world with all the extra manufacturing involved.
 

another_someone

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« Reply #7 on: 09/05/2007 13:46:18 »
Some of the modern (expensive) PSU's do have soft wake up (if by that you mean that they send power to different circuits in sequence).

Problem is that most PC's really are a mess in terms of internal wiring, with a lot of the power wiring being daisy chained, so limiting the amount of control the PSU has over them.  There is also some control the motherboard has in starting to spin up disks, and that can have finer control, making sure that only one disk spins up at a time.
 

another_someone

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« Reply #8 on: 16/05/2007 07:53:32 »
are we not supposed to turn things off at the wall to save electricity? whilst an appliance is on standby they still use electricity, albeit a small amount. The power consumed on standby is regulated by the EU i think!

for modern computers you can reduce the amount of power consumption whilst on standby by altering your power settings, having the machine go idle, or hard disc drives closing down after a set time period of idleness, etc.

you can also use software/hardware to monitor all of you peripheral units and turn them off after another predefined time period.

It occurred to me, while you were talking on another thread about your laptop battery; that as people increasingly use laptops, they are never really 'switched off', in the sense that people do not remove the battery, and so they are constantly draining a small amount of juice from the battery (OK, it is only a minute amount; but if the argument is that we should not tolerate any standby power consumption, then that should necessitate the removal of batteries from devices on standby).

In my case, I have all of my computers on UPS, which means that if the power dies, they are running off lead acid batteries which will last about 20 minutes.  The trouble is that lead acid batteries should never be allowed to totally run down, so switching off at the mains would risk damaging the UPS batteries.
« Last Edit: 16/05/2007 07:57:05 by another_someone »
 

paul.fr

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« Reply #9 on: 16/05/2007 09:17:22 »
It occurred to me, while you were talking on another thread about your laptop battery; that as people increasingly use laptops, they are never really 'switched off', in the sense that people do not remove the battery, and so they are constantly draining a small amount of juice from the battery (OK, it is only a minute amount; but if the argument is that we should not tolerate any standby power consumption, then that should necessitate the removal of batteries from devices on standby).

In my case, I have all of my computers on UPS, which means that if the power dies, they are running off lead acid batteries which will last about 20 minutes.  The trouble is that lead acid batteries should never be allowed to totally run down, so switching off at the mains would risk damaging the UPS batteries.

Another thing that most of us are guilty of, wireless mice. How many of us leave the batteries in when the pc is turned off?
 

another_someone

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« Reply #10 on: 16/05/2007 19:35:04 »
Another thing that most of us are guilty of, wireless mice. How many of us leave the batteries in when the pc is turned off?

This is true, but this comes back to the question of removing batteries from remote control units (that was mentioned above).

I think the difference people are concerned about is between a high power unit in quiescent mode, and a low power unit in quiescent mode.  A laptop computer is still a computer, and does not switch from being a high power unit to a low power unit just because it is disconnected from the mains.
 

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« Reply #10 on: 16/05/2007 19:35:04 »

 

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