[FoRK] Mac Mini makes me ask: When does 12vdc become powerstandard?

Lucas Gonze lgonze at panix.com
Mon Jan 17 21:02:13 PST 2005


But how many generations will it be until wall warts don't take up 2.25 
slots in a power strip?

On Mon, 17 Jan 2005, Stephen D. Williams wrote:

> Miniature, high power dc-dc and ac-dc converters are now cheap, tiny, and 
> efficient.  Another generation or so and we'll have Star Trek like power 
> units that will intelligently convert whatever you give them into something 
> useful while telling you exactly how much power is left, etc.
>
> I assume the modern power supplies still work by voltage pumps, switchers, 
> and capacitance.  There must have been some major improvements in capacitance 
> capacity to produce smooth power with all of that switching and pumping. 
> These new network appliance ac-dc supplies (D-Link, et al) weigh a couple 
> ounces and put out 2.5A @ 12v.  20 years ago it took about 5-10 lbs. to do 
> that.
>
> sdw
>
> Russell Turpin wrote:
>
>> Ken Meltsner:
>> 
>>> Car manufacturers are looking at a new, higher voltage standard given the 
>>> popularity of electronic devices.  It was somewhere around 30-40 volts, 
>>> but I can't find a good reference.
>> 
>> 
>> The advantage to higher volts is that then devices
>> draw less amps. IIRC, that means smaller wires for
>> the same power draw. In any case, it has to do
>> with saving money on wiring, not the total
>> amount of power consumed. All the devices in a
>> car combined draw less power than a windlass.
>> Some boats operate on 24vdc, for the same
>> reason. But...
>> 
>>> Don't assume that 12 vdc is here to stay.
>> 
>> 
>> Don't buy a boat that operates on 24 vdc. It
>> complicates things. It's not just that you have to
>> put your batteries in serial. That's something you
>> might do anyway, if you use 6v golf cart batteries
>> from Walmart. (Good amp-hours for the buck!)
>> The larger problem is that boats with 24vdc
>> circuits ALSO have 12vdc circuits. That has been
>> the standard for so long that virtually every radio,
>> radar, fish finder, DC hair dryer, beam, GPS, fridge,
>> air conditioner, DC stereo, bow thruster, windlass,
>> refridgerator, transponder, and splicemaker work
>> from it. So you end up with a system that is
>> fowl and fish.
>> 
>> Until hybrids become ubiquitous, most cars will
>> run off a one battery bank. I've never seen a
>> 24v single battery. I'll bet you a C note that the
>> 12vdc standard survives longer than the Republican
>> Party. ;-)
>> 
>> 
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