| For a while now, I've been meaning to try using
an old computer power supply as a 12 volt DC power supply for a battery
charger. Well, I finally had enough of the slow "wall-wart" chargers and
bought a Triton. It's DC only, so I thought I would give the PC power supply a try. |
This is completed unit. It was rated at 250 watts and
came out of an old Intel 486 PC (pre. ATX spec.). According to the label,
it delivers +12 volts DC at
up to 10 amps. (which is more than enough). These old units work nicely because
they turn on (with a real switch) without having a motherboard connected. On
the newer ATX spec. units, you have to fake them out to make them turn on
(with a $10 Power Supply Tester or by connecting the right wires).
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| Remember to use a voltmeter to verify everything. There
are a few similar 4 pin (usually white) plugs that normally go to the
computer drives. Basically, you just need to connect one of the yellow
wires and one of the black wires to the battery charger input. I ended up
doing 2 sets. If you are going to charge at more than 3 amps (so you don't melt the wires)
use 3 or 4 sets of the yellow and black wires. I attached a little plastic panel to the side of the PS to
hold the parts. Any sturdy, non-conductive material should work. If you are
comfortable going inside the power supply (as long as you fully insulate
everything from the metal case, and there is extra room inside) you can
drill holes in the metal case (don't let shavings fall inside) and install
the components in the case itself. |
| Pin |
Color |
Voltage |
| 1 |
Yellow |
+ 12 volts |
| 2 |
Black |
Ground |
| 3 |
Black |
Ground |
| 4 |
Red |
+ 5 volts |
|
In addition to the switch, I had some other parts in my junk
box. I ran the yellow and black wires to binding posts/banana plug sockets. They work
normally or you can use them like "battery terminals" if your battery
charger only has alligator clips on the inputs. I also
installed a 12volt automotive power status light to the +5 volt DC output.
Yes, the +5 red wire and a black one for ground. On most of these power supplies, they
expect (and work better) with a slight load on the
+5 volts line. If you have a need for +5 volts DC also, go ahead and tap
into it as well. There
might be another separate set of wires that go to the old external A/C power switch. You
can solder the proper wire pairs together to bypass this switch, or do as I did
... use the wires to install an on/off switch (same setup as when it was installed
in the PC). In case you were wondering, inside the power supply (at
least on this one) all the black wires are connected together or
tapped-off the same point. Same with the yellow, etc. However, each 18
gauge wire can only supply a couple of amps without getting hot or
melting. That's why you connect the multiple wires in parallel when you
need higher amps. |
| Triton Battery Charger
I use the 12 volt DC power supply to power this Triton charger. It
will charge just about any battery. The wires on the left side of the
unit (with medium sized alligator-clips attached) input 12 volts from
the power supply or other 12 volt DC source (like a car or field
battery). The right side is the charger output. It has banana plugs so
you can attach what ever cable and connector you need to charge the
battery in question.
Manufacturer's Link
Buy One at Tower Hobbies
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| Related Links: |
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Converting PC P.S. for R/C use |
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PC P.S.
with all voltages tapped for use |
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All about PC Power Supplies |
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