[LINK] Proposed power supply standard

[Adam Todd]

At 10:00 AM 22/02/2007, jim birch wrote:
>On 22/02/07, Stephen Loosley <stephen at melbpc.org.au> wrote:
>>
>>It appears Australia might well adopt this power supply standard:
>>
>>** High-efficiency power supplies for home computers and servers **
>>     By: Urs Hoelzle and Bill Weihl  for Google Inc., September 2006:
>
>I've often wondered why there isn't a plan for low voltage power around
>homes.  Low voltage gadgets driven by inefficient transformers, left on
>continuously, are rampant around the around the average home; a efficient

Mainly because DC low voltage doesn't travel along LONG wires really well.

Go buy a roll of cable, put a 12 volt battery on one end and a glob on the 
other.  If it glows at all, it won't glow much.  Cut the cable in half, 
better, maybe.

Same for video signals over twisted pair.  Unless you use the correct 
baluns the signal won't make it.  12 volt cameras also need good voltage 
feed, the long the feed cable, the worse the voltage at the other end.

Copper cable is resistive.  With DV low voltage you need to inject your 
power as close to the device as possible.  Multistand cables can help give 
you longer runs, but you still have a cost.

I don't use plug packs if possible.  I have a 24 volt delivery system from 
my solar panels to various points around the house, which are then 
converted to 12 volts to charge batteries.  (As mentioned previously I 
usually see 30+ volts, so normally get 2 x 12 Volt streams.  But in the 
case where volts drop below 24, only one of the chargers/feeders will operate.)

I hate plug packs!  I has 36 of them in my office at one stage and we 
didn't need to heat the room in winter.  An extraction fan in the ceiling 
helped a little in summer :)

The problem really is manufacturers.  Up until only a few years ago, if you 
plugged in a voltage that was too low or too high for the rating of the 
device it took up smoking, and only ever did it once!

Now, manufacturers are using smarter voltage regulation IC's (surface 
mount) that will take, for example a minimum of 9 volts to 48+ volts, to 
drive a device that only runs off 5 Volts or less.)

Personally I prefer everything to sit at 12 volts.  It's very 
convenient.  Running 3,5 and 9 volt devices consumes extra power from a 
battery that results in waste.

Step up converters for Laptop, from 12 volt to 16-24 volt are good PSU's 
too.  But your battery will obviously run flatter faster.

Some of the newest electronic gimos (especially in Sound and Vision) have 
polarity independence.  You can plug in the + or - either way, no more 
shorting and no more smokin'!  Mind you they usually rated at and take 
around 9 (to 24) Volts in, have what amounts to a bridge rectifier in them, 
and then drop the volts to 3 and 5 anyway :)

Now I don't have to worry about which way people hook up the batteries, as 
long as it's not across the terminals!

Volts will drop in the coming years and more and more devices will have a 
polarity and voltage independent input, which is good.

It's way over due and has always been possible, just no one in 
manufacturing bothered to add the 11 cents worth of components to protect 
the device.  With more people buying gizmos and blowing them up, it has 
become a cotton wool strategy to resolve the issue and the cost is too 
insignificant to the value of a happy customer, even if the customer is the 
idiot!