# Power consumption / conditioning



## Owen Bartley (Oct 18, 2006)

I've been reading a little bit lately about green homes, and reducing power consumption, etc., and was wondering how much current most gear draws when it is turned off. I know most things still trickle a small flow, and some even have clocks, status LEDs, etc. Does it make sense to have all your gear on a switchable power bar, and to turn it off when not in use? Are there power conditioners that do anything to regulate the draw when equipment is off? 

Just wondering if anyone else has looked into this, or if anything good has been published. I haven't been able to find anything too reliable online, just lots of varying opinion.


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## lcaillo (May 2, 2006)

You cannot externally regulate the power drawn by a unit in standby. It will draw what it needs. You can turn everything off, but some units will take a while to reboot and to load data.


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## alan monro (May 9, 2006)

lcaillo said:


> You cannot externally regulate the power drawn by a unit in standby. It will draw what it needs. You can turn everything off, but some units will take a while to reboot and to load data.


Owen, 
Most amps cds etc on standby use up to 5 watts. In a rack of equiptment say 5 units that is like having a 25w lamp burning all the time [5x5] . At night i turn everything off. Kind regards Alan.


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## Owen Bartley (Oct 18, 2006)

Thanks guys, maybe what I'll do is put some of the components without a clock or memory that I'd need to use on a switched power strip and turn that one off when not in use.


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## nova (Apr 30, 2006)

A switched power strip will work, but be aware, some of your gear may still need to draw power for a time to cool. For example; many DLP/LCD TV's and projectors have fans that run for 10 - 15 sec or more after they are powered off. If you kill all power to them before they are ready you may damage them.


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## lcaillo (May 2, 2006)

nova said:


> A switched power strip will work, but be aware, some of your gear may still need to draw power for a time to cool. For example; many DLP/LCD TV's and projectors have fans that run for 10 - 15 sec or more after they are powered off. If you kill all power to them before they are ready you may damage them.


While there is little sense in recommending that one not let fans on lamp based projectors and RPTV run their cool down cycle after powering down, this is one of the most overstated fears with regard to lamp life. I have discussed the matter with numerous engineers from lamp and display makers and the consesus is clear that manufacturers are being very conservative with regard to the risk of damage in this matter, and that the primary reason to run a cool down cycle is to allow for restart sooner if the client decides to turn the set back on.

The only mechanism that has been suggested that might be cause for the need for a cool down cycle with fans that might affect lamp life is any thermal lag in the system that might allow temperature to increase for a moment. I have not been able to identify anything of the sort in any RPTV set that I have measured. It MIGHT be an issue in very compact units with very high output lamps. I have not measured any of these, and this was suggested by one of the lamp makers, though they feel the possibility is small. 

The need for power in the cool down cycle has been vastly exaggerated by those who sell lots of UPS devices, and there is certainly nothing wrong with being cautious. We have sold hundreds of lamp based units, however, and rarely sell a UPS. With the relatively high number of outages in this area, one would think that if it was a significant issue we would be changing lots of lamps. In fact, we rarely see lamps that do not exceed the life expectancy of the vendor. The idea that failure to run fans in the cool down period will damage or shorten the life of a lamp is very close to the level of myth. It is a "common wisdom" that is simply mistaken.


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## nova (Apr 30, 2006)

I do not disagree with you. But I think it is worth considering (allowing equipment to cool down as designed) for anyone who wants to use a power strip to turn everything off.


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## lcaillo (May 2, 2006)

Certainly, I would recommend using equipment as designed. I just would not get bent worrying about the occasional absence of a cooldown period. I would not do it as a routine method of shutting down.


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