Every once in a while, I need a 12 v. DC power source to trouble shoot
something. I have been using a battery charger, 12 v. around 6 amp.

Is that okay, or is there a dedicated power source for this purpose? Maybe
one of those power rescue jumper battery pack thinguses? Kinda spendy, but
sure I could score one at a yard sale. How do they last? Very
rechargeable?

Something with variable connectors for the times when you need a clamp, or
just a probe to put the juice at the right place.

Steve

On Tue, 14 Aug 2012 20:20:09 -0700, "Steve B"
wrote:

Every once in a while, I need a 12 v. DC power source to trouble shoot
something. I have been using a battery charger, 12 v. around 6 amp.

Is that okay, or is there a dedicated power source for this purpose? Maybe
one of those power rescue jumper battery pack thinguses? Kinda spendy, but
sure I could score one at a yard sale. How do they last? Very
rechargeable?

Something with variable connectors for the times when you need a clamp, or
just a probe to put the juice at the right place.

Steve


I have a 30 amp-hr or so agm battery in a small Pelican Storm case
with a cigarette lighter receptacle mounted in the side of the case.
Stiff foam is jammed around the battery. It makes a compact and
portable (if heavy) power source for the goto telescope, for fishing
lights, and for the gps-sonar on the little jon boat. I charge it
with a little Deltran 800 mA waterproof battery tender.

You could go with a 7 amp-hr or so for a lighter weight setup.

Pete Keillor

In article ,
Pete Keillor wrote:

On Tue, 14 Aug 2012 20:20:09 -0700, "Steve B"
wrote:

Every once in a while, I need a 12 v. DC power source to trouble shoot
something. I have been using a battery charger, 12 v. around 6 amp.

Is that okay, or is there a dedicated power source for this purpose? Maybe
one of those power rescue jumper battery pack thinguses? Kinda spendy, but
sure I could score one at a yard sale. How do they last? Very
rechargeable?

Something with variable connectors for the times when you need a clamp, or
just a probe to put the juice at the right place.

Steve


I have a 30 amp-hr or so agm battery in a small Pelican Storm case
with a cigarette lighter receptacle mounted in the side of the case.
Stiff foam is jammed around the battery. It makes a compact and
portable (if heavy) power source for the goto telescope, for fishing
lights, and for the gps-sonar on the little jon boat. I charge it
with a little Deltran 800 mA waterproof battery tender.

You could go with a 7 amp-hr or so for a lighter weight setup.

Pete Keillor


Run a Google search on '12V Power supply' (sans quotes), you'll get a
ton of hits.

Even Radio Shack used to carry them, and might still for all I know.

Erik

"Erik" wrote in message
...
In article ,
Pete Keillor wrote:

On Tue, 14 Aug 2012 20:20:09 -0700, "Steve B"
wrote:

Every once in a while, I need a 12 v. DC power source to trouble shoot
something. I have been using a battery charger, 12 v. around 6 amp.

Is that okay, or is there a dedicated power source for this purpose?
Maybe
one of those power rescue jumper battery pack thinguses? Kinda spendy,
but
sure I could score one at a yard sale. How do they last? Very
rechargeable?

Something with variable connectors for the times when you need a clamp,
or
just a probe to put the juice at the right place.

Steve


I have a 30 amp-hr or so agm battery in a small Pelican Storm case
with a cigarette lighter receptacle mounted in the side of the case.
Stiff foam is jammed around the battery. It makes a compact and
portable (if heavy) power source for the goto telescope, for fishing
lights, and for the gps-sonar on the little jon boat. I charge it
with a little Deltran 800 mA waterproof battery tender.

You could go with a 7 amp-hr or so for a lighter weight setup.

Pete Keillor


Run a Google search on '12V Power supply' (sans quotes), you'll get a
ton of hits.

Even Radio Shack used to carry them, and might still for all I know.

Could also use a variac+ fw rectifer+caps -- 0-120V dc.
--
EA



Erik

On 2012-08-15, Existential Angst wrote:

[ ... ]

On Tue, 14 Aug 2012 20:20:09 -0700, "Steve B"
wrote:

Every once in a while, I need a 12 v. DC power source to trouble shoot
something. I have been using a battery charger, 12 v. around 6 amp.

[ ... ]

Could also use a variac+ fw rectifer+caps -- 0-120V dc.

Beware of this -- it does not float free of ground, and
depending on the wiring of the power cord, might have the whole circuit
running about 120 VAC above ground. Having a transformer in there to
isolate things is beneficial. (Granted, you might not recognize a high
frequency transformer in a switching power supply -- they look kind of
strange compared to the 60 Hz power transformers.

Enjoy,
DoN.

--
Remove oil spill source from e-mail
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

"Erik" wrote in message
...
In article ,
Pete Keillor wrote:

On Tue, 14 Aug 2012 20:20:09 -0700, "Steve B"
wrote:

Every once in a while, I need a 12 v. DC power source to trouble shoot
something. I have been using a battery charger, 12 v. around 6 amp.

Is that okay, or is there a dedicated power source for this purpose?
Maybe
one of those power rescue jumper battery pack thinguses? Kinda spendy,
but
sure I could score one at a yard sale. How do they last? Very
rechargeable?

Something with variable connectors for the times when you need a clamp,
or
just a probe to put the juice at the right place.

Steve


I have a 30 amp-hr or so agm battery in a small Pelican Storm case
with a cigarette lighter receptacle mounted in the side of the case.
Stiff foam is jammed around the battery. It makes a compact and
portable (if heavy) power source for the goto telescope, for fishing
lights, and for the gps-sonar on the little jon boat. I charge it
with a little Deltran 800 mA waterproof battery tender.

You could go with a 7 amp-hr or so for a lighter weight setup.

Pete Keillor


Run a Google search on '12V Power supply' (sans quotes), you'll get a
ton of hits.


He is too lazy and stupid to use Google and so he just comes here instead...

I'm surprised he can even take a **** without consulting the group...then
again , he's so full of it I coulda missed...

On Tue, 14 Aug 2012 20:20:09 -0700, "Steve B"
wrote:

Every once in a while, I need a 12 v. DC power source to trouble shoot
something. I have been using a battery charger, 12 v. around 6 amp.

Is that okay, or is there a dedicated power source for this purpose? Maybe
one of those power rescue jumper battery pack thinguses? Kinda spendy, but
sure I could score one at a yard sale. How do they last? Very
rechargeable?

Something with variable connectors for the times when you need a clamp, or
just a probe to put the juice at the right place.

Steve

Why not use an old computer power supply? They have decent clean
power and are a couple bucks at the swap meet if you dont have old
computers around.

http://www.playtool.com/pages/psucon...onnectors.html

Lots of old AT style power spplies kicking around.

Remember..its Yellow (+`12) and any black

Gunner

One bleeding-heart type asked me in a recent interview if I did not
agree that "violence begets violence." I told him that it is my
earnest endeavor to see that it does. I would like very much to ensure
- and in some cases I have - that any man who offers violence to his
fellow citizen begets a whole lot more in return than he can enjoy.

- Jeff Cooper

Gunner Gunner Asch writes:


Lots of old AT style power spplies kicking around.

Remember..its Yellow (+`12) and any black


I can't recommend that. PC supplies are highly optimized
for one task - being as cheap as possible.

Most of them will not function without minimum loads on one
or more of their outputs. (They regulate all the outputs
based on one output voltage.)

That said, it won't cost you much to try one.


--
A host is a host from coast to
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

On Wed, 15 Aug 2012 07:00:54 +0000 (UTC), David Lesher
wrote:

Gunner Gunner Asch writes:


Lots of old AT style power spplies kicking around.

Remember..its Yellow (+`12) and any black


I can't recommend that. PC supplies are highly optimized
for one task - being as cheap as possible.

Most of them will not function without minimum loads on one
or more of their outputs. (They regulate all the outputs
based on one output voltage.)

That said, it won't cost you much to try one.
Only the +12 needs a load - and that's the one he'll be loading.
I've used them for years.Clean, accurately regulated power - and I'm
always scrapping computers, so there are always several around. I used
to just plug an old hard drive on one Molex plug if I wanted to use
the 5 volt output, or needed 12 volts for a low current application.

"Steve B" wrote in message
...
Every once in a while, I need a 12 v. DC power source to trouble shoot
something. I have been using a battery charger, 12 v. around 6 amp.

Is that okay, or is there a dedicated power source for this purpose?
Maybe one of those power rescue jumper battery pack thinguses? Kinda
spendy, but sure I could score one at a yard sale. How do they last?
Very rechargeable?

Something with variable connectors for the times when you need a clamp, or
just a probe to put the juice at the right place.

Battery chargers are usually charging at about 14 V, iirc. And proly have
considerable ripple.
How bout an ole car/motorcycle battery, kept on a trickle charger when not
using it as a power supply?
--
EA



Steve

"Existential Angst" fired this volley in
:

Battery chargers are usually charging at about 14 V, iirc. And proly
have considerable ripple.

No! Really?

Do you mean by that that they have NO filtering, and only supply un-
regulated full-wave rectified power?

Do you mean by that that they might regulate so poorly as to put out 18-
20 V to a small load? Do you mean that the "ripple" might be "all there
is", and there is no continuous DC being supplied?

Do you mean that typical lead-acid battery chargers are completely
unsuitable as power supplies for electronics?

If that's what you meant... you're right!


Lloyd

On 2012-08-15, Steve B wrote:
Every once in a while, I need a 12 v. DC power source to trouble shoot
something. I have been using a battery charger, 12 v. around 6 amp.

Hmm ... most battery chargers don't have any filtering -- they
just feed rectified AC to the battery to charge it. Fine, for a
battery. Terrible to power electronics circuits -- unless you add some
serious capacitors across the 12V out of the charger.

How much capacitance you need is a function of what kind of
current load you have. I would pick say 10,000 uF for a typical load on
a battery charger -- and perhaps up to say 80,000 uF for higher loads.

Of course -- if you have a *good* battery connected across the
charger, that will do just as well as a capacitor -- and actually be
closer to what automotive electronics are expecting anyway.

Is that okay, or is there a dedicated power source for this purpose? Maybe
one of those power rescue jumper battery pack thinguses?

For a short time only with the likely load from the brakes.
While they are heavy, they are a tiny subset of what the car's battery
normally provides. Mine suggests that you wait six minutes after a
failed start attempt -- to keep the battery from overheating -- before
the next try.

Kinda spendy, but
sure I could score one at a yard sale. How do they last? Very
rechargeable?

Depends on the quality of the things. The one I have has a
regulated trickler charger built in -- running from a wall wart -- and
it is designed to be connected full time so the battery is at optimum
charge when you need it. (Mine even has a cigarette lighter socket in
it, which I expect to use to recharge my cell phone and my Nook e-reader
until power comes back. It was gone four days (minus a few hours)
earlier this year -- the longest which we have had, though other areas
have had longer outages. (And this is in various areas outside the
Beltway -- you would expect them to have better power around the center
of the government. :-)

Something with variable connectors for the times when you need a clamp, or
just a probe to put the juice at the right place.

Well ... as I said, my jump start box has both the battery
cables and the cigarette lighter socket. Anything else and you need to
make your own adaptors. :-)

Enjoy,
DoN.

--
Remove oil spill source from e-mail
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---

"Steve B" wrote in message
...
Every once in a while, I need a 12 v. DC power source to trouble
shoot something. I have been using a battery charger, 12 v. around
6 amp.

Is that okay, or is there a dedicated power source for this purpose?
Maybe one of those power rescue jumper battery pack thinguses?
Kinda spendy, but sure I could score one at a yard sale. How do
they last? Very rechargeable?

Something with variable connectors for the times when you need a
clamp, or just a probe to put the juice at the right place.

Steve

I use these lab supplies:
http://www.caswellplating.com/electr...rectifier.html
http://www.microdaq.com/lascar/psu130.php
and an old Schauer battery charger to which I added a 3A Variac to set
the voltage and a 24,000uF filter cap. The original 6V/12V switch puts
the cap in the circuit when I need 12VDC and removes it for battery
charging, to avoid a spark and maybe blown fuse when I connect.

You could make an equivalent to the Lascar from an LM317 adjustable
regulator, but might not save much if you buy the meters etc new.

On Tue, 14 Aug 2012 20:20:09 -0700, "Steve B"
wrote:

Every once in a while, I need a 12 v. DC power source to trouble shoot
something. I have been using a battery charger, 12 v. around 6 amp.

Is that okay, or is there a dedicated power source for this purpose? Maybe
one of those power rescue jumper battery pack thinguses? Kinda spendy, but
sure I could score one at a yard sale. How do they last? Very
rechargeable?

Something with variable connectors for the times when you need a clamp, or
just a probe to put the juice at the right place.

Steve


As others have said, it's only marginally more suitable than cutting
off a power cord and plugging it directly into the wall.

Don't you have a left-over 12VDC regulated wall-wart or brick you
could use? Wall wart up to 2 or 3A and 6A should be available easily
in a brick. Chinois ones are quite available, but of dubious pedigree
and safety-agency-approval status.

Just don't use the ones that say "electronic transformer" or are
advertised for LED power supplies.

On Wed, 15 Aug 2012 09:27:23 -0400, Spehro Pefhany
wrote:

On Tue, 14 Aug 2012 20:20:09 -0700, "Steve B"
wrote:

Every once in a while, I need a 12 v. DC power source to trouble shoot
something. I have been using a battery charger, 12 v. around 6 amp.

Is that okay, or is there a dedicated power source for this purpose? Maybe
one of those power rescue jumper battery pack thinguses? Kinda spendy, but
sure I could score one at a yard sale. How do they last? Very
rechargeable?

Something with variable connectors for the times when you need a clamp, or
just a probe to put the juice at the right place.

Steve


As others have said, it's only marginally more suitable than cutting
off a power cord and plugging it directly into the wall.

Don't you have a left-over 12VDC regulated wall-wart or brick you
could use? Wall wart up to 2 or 3A and 6A should be available easily
in a brick. Chinois ones are quite available, but of dubious pedigree
and safety-agency-approval status.

Just don't use the ones that say "electronic transformer" or are
advertised for LED power supplies.

My local thrift store has a shoe box filled with miscellaneous
wallwart power supply's. Big uns, little uns, your choice, $ !.00
each.

wrote in message
...
On Wed, 15 Aug 2012 09:27:23 -0400, Spehro Pefhany
wrote:

On Tue, 14 Aug 2012 20:20:09 -0700, "Steve B"
wrote:

Every once in a while, I need a 12 v. DC power source to trouble shoot
something. I have been using a battery charger, 12 v. around 6 amp.

Is that okay, or is there a dedicated power source for this purpose?
Maybe
one of those power rescue jumper battery pack thinguses? Kinda spendy,
but
sure I could score one at a yard sale. How do they last? Very
rechargeable?

Something with variable connectors for the times when you need a clamp,
or
just a probe to put the juice at the right place.

Steve


As others have said, it's only marginally more suitable than cutting
off a power cord and plugging it directly into the wall.

Don't you have a left-over 12VDC regulated wall-wart or brick you
could use? Wall wart up to 2 or 3A and 6A should be available easily
in a brick. Chinois ones are quite available, but of dubious pedigree
and safety-agency-approval status.

Just don't use the ones that say "electronic transformer" or are
advertised for LED power supplies.

My local thrift store has a shoe box filled with miscellaneous
wallwart power supply's. Big uns, little uns, your choice, $ !.00
each.

I must have a milkcrate full.... it's like an addiction.
Some of the older ones are pretty hefty, as well. You'd have to TAPE them
to a wall outlet... LOL
--
EA

On Wed, 15 Aug 2012 12:05:26 -0400, "Existential Angst"
wrote:

wrote in message
.. .
On Wed, 15 Aug 2012 09:27:23 -0400, Spehro Pefhany
wrote:

On Tue, 14 Aug 2012 20:20:09 -0700, "Steve B"
wrote:

Every once in a while, I need a 12 v. DC power source to trouble shoot
something. I have been using a battery charger, 12 v. around 6 amp.

Is that okay, or is there a dedicated power source for this purpose?
Maybe
one of those power rescue jumper battery pack thinguses? Kinda spendy,
but
sure I could score one at a yard sale. How do they last? Very
rechargeable?

Something with variable connectors for the times when you need a clamp,
or
just a probe to put the juice at the right place.

Steve


As others have said, it's only marginally more suitable than cutting
off a power cord and plugging it directly into the wall.

Don't you have a left-over 12VDC regulated wall-wart or brick you
could use? Wall wart up to 2 or 3A and 6A should be available easily
in a brick. Chinois ones are quite available, but of dubious pedigree
and safety-agency-approval status.

Just don't use the ones that say "electronic transformer" or are
advertised for LED power supplies.

My local thrift store has a shoe box filled with miscellaneous
wallwart power supply's. Big uns, little uns, your choice, $ !.00
each.

I must have a milkcrate full.... it's like an addiction.
Some of the older ones are pretty hefty, as well. You'd have to TAPE them
to a wall outlet... LOL
And MANY of them are also totally unregulated and unfiltered. I've
measured in excess of 18 volts open circuit, with over 4 volts AC
ripple. Some are even only HALF WAVE regulated.

wrote:

And MANY of them are also totally unregulated and unfiltered. I've
measured in excess of 18 volts open circuit, with over 4 volts AC
ripple. Some are even only HALF WAVE regulated.


How do you 'half wave regulate' something?

Steve B wrote:
Every once in a while, I need a 12 v. DC power source to trouble shoot
something. I have been using a battery charger, 12 v. around 6 amp.

Is that okay, or is there a dedicated power source for this purpose? Maybe
one of those power rescue jumper battery pack thinguses? Kinda spendy, but
sure I could score one at a yard sale. How do they last? Very
rechargeable?

Something with variable connectors for the times when you need a clamp, or
just a probe to put the juice at the right place.

Steve



How many amps would you like?

I have units from small 1 amp up to the 50 amp on the bench. Both
adjustable and fixed output.

You can buy them online easily.
B&K, Astron, Pyramid, Tripp Lite,

http://www.astroncorp.com/
http://www.pyramidcaraudio.com/products/Power-Supplies
http://www.tripplite.com/en/products...xtSeriesID=841

--
Steve W.

On Tue, 14 Aug 2012 20:20:09 -0700, "Steve B"
wrote:

Every once in a while, I need a 12 v. DC power source to trouble shoot
something. I have been using a battery charger, 12 v. around 6 amp.

Is that okay, or is there a dedicated power source for this purpose? Maybe
one of those power rescue jumper battery pack thinguses? Kinda spendy, but
sure I could score one at a yard sale. How do they last? Very
rechargeable?

Something with variable connectors for the times when you need a clamp, or
just a probe to put the juice at the right place.

Steve

MOST battery chargers (good ones, anyway) will not put out power into
a "dead" circuit. How much power do you want??? I've used PC power
supplies for years. I also usually have several AGM batteries around
in various states of charge.

The chargers also have very poor regulation if voltage control is an
issue.

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