

| Subject: | Re: Making a 12v battery charger from a peecee power supply |
| From: | Steve W |
| Date: | Sat, 6 Dec 2003 09:56:02 -0800 |
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 __________________________________ Do you Yahoo!? New Yahoo! Photos - easier uploading and sharing. http://photos.yahoo.com/
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