[Boatanchors] 12 to 24 volts.

[ronw8]

There are simple switching ICs that require a few external components to 
convert and DC voltage to any other DC voltage .

I run my 5 volt DSL modem from my 12 volt battery back up array in my 
shack using one of these as I did not want to waist the energy and heat 
to drop 12 volts to 5 using a 7805 power hog.
It's been running for 8 years!
---
Ron



Stanley Adams wrote:
> Hey Drew, why not just buy a 24 volt switching supply that is on the surplus
> market, there are many many of them that are being junked that come from
> communications equipment.  If you want a simple 12 to 24 volt converter,
> just build a voltage doubler circuit such as is found the ARRL handbook.  A
> few caps, diodes and you got it. The regulation will come from the 12 volt
> unit.  Just a thought to try out.
>
> Stan Adams
> Memphis
> W4SBA
>
>
> Message: 1
> Date: Sun, 11 Oct 2009 09:30:07 -0700 (PDT)
> From: "Drew P." <drewrailleur807 at yahoo.com>
> Subject: Re: [Boatanchors] 12 to 24 volt conversion, the issue of cost
> To: boatanchors at mailman.qth.net
> Message-ID: <347228.86679.qm at web38508.mail.mud.yahoo.com>
> Content-Type: text/plain; charset=us-ascii
>
> On 12V to 24V converters, Michael Tauson wrote:
>
> <snipped for brevity>
>
> "Only a few actually caught on to what I want to do - build (yes,
> build.  You know, individual components and winding transformers and
> soldering and all like that there stuff.) an inexpensive 12-to 24 volt
> converter and learn about toroids at the same time.  How that got to
> buying trucks is way beyond my comprehension but it tells me the
> thread has gotten out of hand.  Go back to my original post to see
> what I'm looking for ... and, as a hint, it has nothing to do with
> adding batteries, adding alternators, or buying vehicles."
>
> I share much the same mindset as you do.  I enjoy designing and tinkering
> with electronics, but I cannot, and probably never will be able to allocate
> funding for construction of big bucks things like high power RF amplifiers.
> In short, I am a product of an era when a career in engineering in the U.S.
> has become all but obsolete; I have little in funding to spare and a big
> desire to experiment.  And besides, I revel in using salvaged components
> obtained for little to no cost - a sort of getting something for nothing.
> This mindset is reflected in my recent post regarding use of motor
> capacitors as DC power supply filters.
>
> How about an intermediate plan?  There is much modifiable computer junk to
> be had for free.  I have had, for example, good luck converting computer
> switch mode power supplies for other uses.  A starting point for magnetics
> in a 12V to 24V converter might be disassembly of the ferrite E-I
> transformer taken from a desktop computer power supply and counting turns
> with an eye to rewinding to your own specs.  The salvaged toroidal energy
> storage inductor could be treated similarly.  These magnetics could be good
> for power levels same as in the original application. If you don't care to
> build the driver circuitry, the PWM control circuit from that salvaged power
> unit could likely be modified to that end.
>
> Another intermediate plan might be modification of a computer UPS unit.
> These usually use a 12V internal gelled electrolyte lead acid battery, and
> the units frequently find their way to the dumpster because no one cared to
> replace the failed battery.  One could yank the battery and install
> connections for providing 12V. The 115V output would then be available
> without further modifications.  Further modification could consist of
> rewinding the unit's transformer for the desired output, or just plug a
> transformer having the correct output voltage into the UPS's 115 V output.
> Then, recify and filter to taste.  Many of these UPS units use a laminated
> iron core transformer operating at 60 Hz, and some others use a high
> frequency ferrite transformer scheme. These would call for a different plan.
>
>
> So, start attending those seemingly otherwise useless computer swap meets,
> cruise the curbsides on trash day, dive those dumpsters and even inquire at
> computer repair shops, proprietors of which often have large amounts of junk
> hanging around.  Or, post a want ad on your local freecycle.org forum -
> you'll likely be overwhelmed with responses.  Then, base your
> plan/scheme/design around that which you will have acquired. 
>
> Detractors of this type of plan might do well to remember that many of us
> are not financially well off, and though our reduced-cost solutions might
> not always be technically optimal, they can represent workable solutions
> when ALL variables - cost included - are considered.
>
> Drew
>
>
>
>       
>
>
>
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