I built the first one you suggested Larry and mounted it to a CPU heat
sink from an old junk computer I had. I hadn't checked back here to see
the larger units that you fine folks suggested at the time. It got
plenty warm. Not too hot to touch, but still plenty warm, so I took the
12V fan that was mounted to the CPU heat sink and mounted it too. Put
the set-up in an old small unamplified computer speaker enclosure with
the grill from the other speaker mounted along a cutout I made on the
backside for flow-thru ventilation. I even went for some bells and
whistles. I mounted a 140° thermal switch with a light bulb to the
heat sink.
Everything works great! The air flowing out of the regulator enclosure
is not noticeably warm at all. Cooler than the air flowing out of the
inverter when I was using it for the same MP3 player. So I'd say I'm
ahead efficiency wise.
Even starting out with the MP3s battery fully charged it still must draw
quite a bit of current. It's a old 20 gig player that has an actual
hard drive as opposed to flash memory.
I'm going to check the current draw the next time I use it just out of
curiosity. The 140° indicator light hasn't came on yet.
I kept notes on the sites you all posted for the larger regulators in
case this one ever smokes. Thanks again for your help everyone.

There in lies the problem with the 7805. 60% or more of the power goes up
in heat. Considering that plus the time and effort to rig it up a simple
$15 DC/DC buck converter is cheap.

--
Glenn Ashmore

I'm building a 45' cutter in strip/composite. Watch my progress (or lack
there of) at: http://www.rutuonline.com
Shameless Commercial Division: http://www.spade-anchor-us.com

"Floating Mind" wrote in message
...
I built the first one you suggested Larry and mounted it to a CPU heat
sink from an old junk computer I had. I hadn't checked back here to see
the larger units that you fine folks suggested at the time. It got
plenty warm. Not too hot to touch, but still plenty warm, so I took the
12V fan that was mounted to the CPU heat sink and mounted it too. Put
the set-up in an old small unamplified computer speaker enclosure with
the grill from the other speaker mounted along a cutout I made on the
backside for flow-thru ventilation. I even went for some bells and
whistles. I mounted a 140° thermal switch with a light bulb to the
heat sink.
Everything works great! The air flowing out of the regulator enclosure
is not noticeably warm at all. Cooler than the air flowing out of the
inverter when I was using it for the same MP3 player. So I'd say I'm
ahead efficiency wise.
Even starting out with the MP3s battery fully charged it still must draw
quite a bit of current. It's a old 20 gig player that has an actual
hard drive as opposed to flash memory.
I'm going to check the current draw the next time I use it just out of
curiosity. The 140° indicator light hasn't came on yet.
I kept notes on the sites you all posted for the larger regulators in
case this one ever smokes. Thanks again for your help everyone.

(Floating Mind) wrote in news:12432-449C0826-371
@storefull-3111.bay.webtv.net:

It got
plenty warm. Not too hot to touch, but still plenty warm,

Cool....the idea and story, not so much the heat sink...(c;

People who hate switchers just don't understand them. They're waiting
for their series pass transistors to short putting the 40VDC primary
power unregulated to the electronics...(c;

If you can touch the heat sink, the fan is overkill. Hell, I'm typing on
a Gateway notebook with an AMD Turion 64-bit processor. Its fan comes on
about the time the air coming out of the heatsink feels like a heat gun
used for shrink tubing! Amazing what electronics (except electronics in
American cars) can take.

Glad you liked it. I have a rock solid 115VAC to 14V switcher I built
years ago that runs the ham radio station, here. My 650W RF power amp is
a Tentec Hercules II that was modified to take out the push-on connectors
and other cheapness. At full power it only draws about 126 amps at 14VDC
for its four parallel, push pull power amplifiers. The switcher was
built for it because I didn't like the crap power supply Tentec offered
that wouldn't run it anyway after the modifications. Using remote
sensing for the switcher regulator right up inside the amp to the power
distribution point inside the amp, output at that point only varies .2vdc
from no load to 126 amps on a good antenna. Instead of weighing the same
as a Humvee armored jeep, it weighs about 8 pounds and is quite small.
Efficiency is around 95% so it only gets warm on data modes like old RTTY
where it's keydown for many minutes at a time.

Next thing you know you'll be dumping WebTV for a Athalon 64 on
Broadband!....(c;

Is this what you need?

http://www.amtrade.com/pc_power/250d...owersupply.htm


|G|

Look at :
http://www.logicsupply.com/product_i...roducts_id/504


Hanz

Spammy Spamson wrote:

Is this what you need?

http://www.amtrade.com/pc_power/250d...owersupply.htm


|G|

Hanz wrote in :

http://www.logicsupply.com/product_i...roducts_id/504


Oh, I like the specs on that one....6V to 24V input.

I use it on my computer on the boat. It handles the spikes from the alt..

I have a Via SP13000 in a Venus 668 cases..

Hanz


Larry wrote:
Hanz wrote in :


http://www.logicsupply.com/product_i...roducts_id/504



Oh, I like the specs on that one....6V to 24V input.

Yep, that's a keeper... thanks


|G|


On Sat, 24 Jun 2006 06:59:15 -0400, Hanz
wrote:

Look at :
http://www.logicsupply.com/product_i...roducts_id/504


Hanz

Spammy Spamson wrote:

Is this what you need?

http://www.amtrade.com/pc_power/250d...owersupply.htm


|G|

Hanz wrote in
:

It handles the spikes from the alt..


If you have spikes from the alternator, your battery has an open cell.
Across a good battery there are no spikes as the chemistry absorbs a lot.

Spikes: when the batteries goes from 11.75 up to 14.5 volts during
normal charging. Maybe 'spikes' is a bad word. But the "buck/boost
circuit" of the converter handle it.

Hanz

Larry wrote:
Hanz wrote in
:


It handles the spikes from the alt..



If you have spikes from the alternator, your battery has an open cell.
Across a good battery there are no spikes as the chemistry absorbs a lot.