Date:         Sat, 6 Dec 2003 09:56:02 -0800
Reply-To:     Steve W <croatoa@YAHOO.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Steve W <croatoa@YAHOO.COM>
Subject:      Re: Making a 12v battery charger from a peecee power supply
In-Reply-To:  <Pine.GSO.4.21.0312060014290.27899-100000@oola>
Content-Type: text/plain; charset=us-ascii

Hello,
Unless you want to measure the specific gravity
or your electrolyte on a constant basis it is
good to be very carefull in setting up a charger.
 I would suggest buying an automatic charger to
do this.  The ones that are not automatic will
fry your battery by overcharging.  Too much
current or too high a voltage will boil the
electrolyte and release hydrogen gas which is
explosive.  Chargers absolutly have to be
carefully regulated to keep this from happening.
Ever see a battery explode?  You don't want to
believe me.
Steve

--- EMZ <vw4x4@FYI.NET> wrote:
> Man do you guy love to over complaicate things.
>  Power supplies for
> batteries are very easy to build.  All you need
> is a transformer
> bridge rectifier and a capacitor.  Yuo don't
> even need to regulate it.
>
>             Eric                   86-VW4x4
>             vw4x4@fyi.net          86-SS Syncro
>             Pittsburgh, PA USA
> 1936-Chrysler
>                                    92-Jetta GWC
>             www.fyi.net/~vw4x4/vw4x4.htm
>
> On Fri, 5 Dec 2003, Felder wrote:
>
> > I've been talking with another listmemember
> about making a 12v batter
> > charger from a pc supply according to some
> directions my dad found.
> > Thought I'd go ahead and distribute to the
> group. The idea is to
> > install this in my camper so when I'm plugged
> into 120v at a campsite,
> > I'm charging my batteries automatically. My
> dad pointed me to a
> > magazine article that detailed the process.
> Look for a 10 or 15 amp
> > power supply to begin with. I know virtually
> nothing about electricity,
> > but it worked till I fried the board with a
> microtorch. Will be more
> > patient next time.
> >
> > Here's how they did it. It's in September
> 2003 Model Aviation, and if
> > my description doesn't work, email me and
> I'll send you a copy of the
> > article.
> >
> > 1. Make sure it works, if you can. My first
> one did not and I didn't
> > know it until I had done all this (only takes
> 15 minutes or so, not
> > counting the trip to radio shack if
> necessary).
> >
> > 2. Cut ALL the wire off at 6 inches.
> >
> > 3. Remove the "motherboard"
> >
> > 4. Locate the black ground wires and clip all
> but two close to the
> > board.
> >
> > 5. Locate the +12 wires, and clip all but two
> close to the board.
> >
> > 6. Locate the -5 stuff, +5 stuff, -12 stuff
> and anything else and cut
> > it off as close to the board as you can.
> >
> > 7. Take a soldering iron and open a hole in
> one of the cropped +5 wires
> > and another at a ground hole.
> >
> > 8. Now, you should be ready with two black
> grounds, two reds (or
> > orange) +12v, a hole at one ground and a hole
> at one +5v.
> >
> > Everything else should be gone.
> >
> > 9. Now you are going to run a load between
> +5v and ground using the two
> > open holes. The load is what the PS expects
> to see in a device such as
> > a hard drive.
> >
> > 10. The article suggests that you use either
> a 1 ohm, 25w resistor or
> > an automotive light bulb type 1156 or similar
> to provide this load. It
> > says that the light bulb is nice because you
> can read by it and it
> > serves as a pilot light, but he actually
> ended up using a Radio shack
> > 50-ohm, 10W resistor (RS item # 271-133).
> That didn' t work for me, I
> > went with a resistor somewhere close to the 1
> ohm 25w which worked
> > fine. He was worried about the inefficiency
> of the latter, I was not.
> > The author warns that you may need to
> experiement as all the PSs are
> > identical in many ways but subtly different
> in others.
> >
> > 11. Take the two reds and the two blacks and
> double them for the
> > increased current to the battery.
> >
> > 12. Cut a strip of plastic that will span the
> two holes in the metal
> > case of the PS (assuming you removed the
> plastic grommets that secure
> > all the wires through these holes, and you
> bridged the wires properly
> > to obviate the switch). Drill the  plastic in
> the two holes for Radio
> > Shack Multipurpose posts 274-661. Mount the
> posts in the hole in the
> > plastic you mounted behind the metal holes in
> the case, and run the
> > respective wires to each. Now you can have
> screw on and banana-jack
> > connections for 12v at 10 a or greater,
> depending on the power supply
> > you acquire.
> >
> > Everything worked great when I had it clipped
> together, the resistor I
> > chose was showing 13.4 v on my DMM. Then I
> went to solder the
> > connections and melted something down between
> the board layers which
> > hosed the whole deal so it would barely turn
> the fan (used a small
> > torch, should have used an iron). Now I'm out
> of peecee power supplies,
> > but I know what to do and I saw it work. I
> will get a few more when
> > convenient.
> >
> > If this isn't clear, I will either scan and
> email or mail you a copy of
> > the article.
> >
> > Nice fan, too.
> >
> > BTW I took the 4" fan out of the bad unit and
> epoxied a radio shack
> > slide switch to it to make an exhaust fan for
> the kitchen. I will mount
> > it in the upper left corner of the driver's
> side window screen frame,
> > marking and drilling the frame with three
> small holes at the mounting
> > holes of the fan, and leaving the lower right
> hole cantilevered over
> > the screen. I'll wire it into the light
> directly above it, behind the
> > curtain rod so the curtain can slide. Just
> right for a sightly warm
> > night, a day away from the car in the sun, or
> to exhaust the kitchen
> > steam etc.
> >
> >   I don't have one yet, but for a cool light
> see Harbor Freight item
> > 4274-0VGA.
> >
> > Jim
> >
> > On Thursday, December 4, 2003, at 08:09 AM,
> Gnarlodious wrote:
> >
> > > Entity Felder spoke thus:
> > >
> > >> My dad found a copy of a recent model
> airplane magazine that had
> > >> explicit instructions for turning a peecee
> power supply into a 12V
> > >> charger.
> > > Can you send me a copy of that article, or
> turn me on to a webpage
> > > describing the process?
> > >
> > > --Gnarlie
> > >
> > >
> >


=====
Steve
croatoa@yahoo.com

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