Re: Modding a PC Power Supply into a 12 Volt Supply for your DC charger
 

Hey Kurt,

You could hunt for a PSU that has 0V minimum ratings for the power rails.

Then you should not need the resistor, or have any problems.

I just did a conversion myself and did not require the resistor.
Everything seems to be working fine so far.

I also got a big daddy PSU, 40A on the 12V rail.

I'll post up the details later this weekend.

Cheers,
Mike.

Re: Modding a PC Power Supply into a 12 Volt Supply for your DC charger
 

I just made one today, added a standby green LED to show it's plugged in and a red LED to indicate it's switched on, it's a handy tool for checking servo's, motors and as a charger power supply.


Standby..
http://i478.photobucket.com/albums/r...f/DSCN8539.jpg

Powered up..

http://i478.photobucket.com/albums/r...f/DSCN8540.jpg

Labels to avoid problems..

http://i478.photobucket.com/albums/r...f/DSCN8541.jpg

Re: Modding a PC Power Supply into a 12 Volt Supply for your DC charger
 

Im wanting to do this and add a 12v car outlet and a usb plug, anybody have any tips for doing this?

Re: Modding a PC Power Supply into a 12 Volt Supply for your DC charger
 

Both of those items should be very easy to add.

Just run the 12V car outlet from one of the Yellow 12V wires, with a black ground wire also.

For the USB, depends on your power supply. If it has the +5V Stand By, then use those, otherwise just use a red +5V wire.

You wire the +5V feed to pin1 on the usb plug, and the ground to pin4. As you will ONLY be using this to charge USB devices you also join pin2 & pin3 together in the plug.

Cheers,
Mike.

Re: Modding a PC Power Supply into a 12 Volt Supply for your DC charger
 

finished mine tonight

basic, only 12v leads as it's all I'll ever use, but with a fancy switch "thumbsup" tomorrow I plan on taking it all back apart and hitting it with some paint

don't hate on the overpriced Venom charger :roll:



http://i113.photobucket.com/albums/n...U/IMAG0579.jpg

http://i113.photobucket.com/albums/n...U/IMAG0582.jpg

http://i113.photobucket.com/albums/n...U/IMAG0585.jpg

Re: Modding a PC Power Supply into a 12 Volt Supply for your DC charger
 

painted it today :mrgreen:

http://i113.photobucket.com/albums/n...U/IMAG0587.jpg

http://i113.photobucket.com/albums/n...U/IMAG0593.jpg



even stuck on some little rubber feet 8)

http://i113.photobucket.com/albums/n...U/IMAG0594.jpg

Re: Modding a PC Power Supply into a 12 Volt Supply for your DC charger
 

Hi everyone,

Took my time, but here is my build up:

As you know, this topic is not a new one, and I found this thread on RCC to be most useful. I read it from the start and took notes along the way, with a bit of added research elsewhere >HERE<

I thought I would documenting my recent mod.

First of all, why do this?

Well, recently a friend (Splat) and I both purchased a new battery charger which can do 4 batteries at once. It's a Hitec X4 AC Plus - details >HERE<

This unit has built in AC power, but only for 110V (USA). So we needed to power it from a 12V DC source as here in Australia we run 240V AC.
We could have gone out and purchased a purpose built 12VDC power supply, but they are pretty darn expensive (around the $200 mark for a good unit).

A computer power supply (PSU) is very cheap and provides a very stable and efficient power feed that suited our needs perfectly.

Anyways, on to the mod.

WARNING: PSU's can hold a charge for a short period of time. This charge can KILL or INJURE. Please ensure you understand these risks and know how to mitigate them before beginning any work.

First, get a PSU. I had an old unit sitting around home that I modded up for Splat. This was my first mod and worked a treat.

Once I had "practiced" on Splat, I wanted to make sure my own unit was a top notch job.

I splashed out on a new PSU which had a high Amp capacity on the 12V rail.
Attachment 186287

I picked this unit up locally in Australia from ARC Computers for $79 >LINK<

The reason I chose this unit:
Attachment 186288
40A on the +12V rail!

NOTE: There is also NO minimum load requirements for any of the DC outputs

There were some added benefits to buying this PSU also, one of which was the simplicity of the internal layout and the ample space inside the case:
Attachment 186289
Attachment 186290
One thing I learnt while building up Splats unit was to take a close look at the ATX connector plug on the PSU before cutting any wires off.
You need to identify any doubled up wires and take note of them.
Attachment 186291
Here you can see the double orange wires. The smaller gauge wire is the 3.3V sensing wire for this PSU. On some older models it could be brown - check the full wiring guides from the two links at the top of this post for more information.
I traced this wire to the circuit board and set it aside along with some others:
1. Orange 3.3V sensing wire
2. Blue -12V (Not used in my mod)
3. Purple & Black +5V Stand By
4. Gray Power OK
5. Green Power ON
Attachment 186292
You can now also group together the coloured wires:
1. Orange = 3.3V
2. Red = 5V
3. Yellow = 12V
4. Black = Ground
Next up it was time to start chopping off excess wires.
You need to be very careful that you don't cut off too many wires and leave yourself missing some required wiring for the mods.
Also, make sure that you leave plenty of length in the remaining wires to allow you to position things where you need them.
Attachment 186293
Next we take the 3.3V sensing wire and just join it to an orange 3.3V wire. Basically just simulating the join from the ATX plug as shown earlier:
Attachment 186294
Being Mr Safety conscious I then took the time to insulate all the exposed wiring with some heatshrink:
Attachment 186295
I put a plug onto the +5V SB (Purple and Black) wires to allow me to connect/disconnect it from the USB ports - just for ease of assembly/disassembly of the PSU:
Attachment 186296
I quickly made up a little circuit board with a couple of USB ports on it:
Attachment 186297
Attachment 186298
Attachment 186299
The wiring for the USB is very simple.
Purple is +5V, Black is ground
Purple goes to Pin1
Black goes to Pin4
Then also join Pin2 to Pin3 on the circuit.
Check >HERE< for more details on the USB Wiring.
By wiring up the USB like this you can use the ports to charge most USB devices - mobile phones etc.
Then it was just a matter of drilling all the holes for the terminals, LED and making a mount for the switch:
Attachment 186300
Attachment 186301
Attachment 186305
Attachment 186306
Connect up all the wires:
Attachment 186307
Orange wire to the 3.3V terminal
Red wire to the 5V terminal
Yellow wire to the 12V terminal
Black wires to all the Ground terminals
Gray wire to the LED positive leg
Black wire to a 220 ohm Resistor connected to the LED negative leg
Green wire to the Switch
Black wire to the switch
Purple & Black to the USB ports
NOTE: As this PSU does not have minimum load requirements on any of the outputs I did not need to install the 10ohm 10w resistor as per the instructions from the RCC and other links at the top of this post.
Attachment 186308
NOTE: The arrow shows another plug I used for the LED wires, hidden under the heatshrink is my 220 ohm resistor
Attachment 186309
Attachment 186310
Another added benefit to getting this PSU was that it was VERY easy to wire in some thicker gauge wires for my 12V terminal to handle the high AMP draws.
Here you can see some extra holes for wire:
Attachment 186311
This enabled me to easily connect in some much larger wire:
Attachment 186312

Then tidy it all up and test it out:
Attachment 186313

Re: Modding a PC Power Supply into a 12 Volt Supply for your DC charger
 

so does it work?

:mrgreen:

looks good man, great job!

Hmm new project!

Re: Modding a PC Power Supply into a 12 Volt Supply for your DC charger
 

Thanks.

Yep, works a treat!

At my next use I'll take some pics and post them up as well, just to finish off the post.

Cheres,
Mike.

Re: Modding a PC Power Supply into a 12 Volt Supply for your DC charger
 

Where do you get that 2 pin connector on the PCB?

Re: Modding a PC Power Supply into a 12 Volt Supply for your DC charger
 

I got one that's a bit more simple than what some you are doing and doesn't have all the bells and whistles. Simply remove or purchase a PS3 power supply and ad a fan for cooling. Its simpler to remove one from a DOA unit assuming the power supply is still good which most are. Reason being you can reuse the AC cord plug in the rear of the unit that also has an on off switch. The fan is the most complex part of this because you need to cut a hole for airflow and this is not necessary but makes things easier if you solder the fan power directly to the board. Standard banana connectors plug directly into the PS unit you just need to mark the unit neg or pos so you don't make any mistakes. Specs for the unit are 12v 33amp output. I can charge my 65c lipos at max c ratting of 18amps without the unit barely giving off any heat. Also its designed for a PS3 so it gives a very stable dc output. Pics for the curious or interested.

Specs
http://i113.photobucket.com/albums/n...0205121302.jpg

Interior with AAA size comparison.
http://i113.photobucket.com/albums/n...0205121251.jpg

The two outside wires on the 5 wire plug need to be connected or unit wont turn on. Also the 3 remaining are 5v 5v and ground.
http://i113.photobucket.com/albums/n...0205121403.jpg

Can reuse original ac in/on off switch if desired.
http://i113.photobucket.com/albums/n...0205121405.jpg

Fan and feet installed. Feet were necessary because dc out is on the bottom of the unit. Used windshield ribbon to glue them on. Used windshield ribbon because I had a roll I never used and its extremely sticky.
http://i113.photobucket.com/albums/n...0206121758.jpg

Side by side of power and charger.
http://i113.photobucket.com/albums/n...0206121830.jpg

Re: Modding a PC Power Supply into a 12 Volt Supply for your DC charger
 

Got them from JayCar in Australia >LINK<

Pretty sure you could get them from any dedicated electronics shop.

Re: Modding a PC Power Supply into a 12 Volt Supply for your DC charger
 

hi,
i want to build me one of those and already scavenged a PSU.
but when searching to buy a binding post i got confused and i can't seem to find what i need.
- i want it to be insulated (of course).
- can take a 4mm banana jack.
- can hold a bare wire (top screw closed).
- and also i want the top screw to get completely OFF! so i can clip a crocodile directly to the bare metal.

it seems that most are using this kind, but here the top part cannot be screwed off.

can you point me to the part i'm after?

Re: Modding a PC Power Supply into a 12 Volt Supply for your DC charger
 

I've built numerous PC PSU power supplies. Old Junker computers are an awesome source to find abandoned sources of power. Also "dead" power supplies can be used, computer motherboards are very picky on all aspects of the power supplied to it, even if the 5V rail is suffering problems and not feeding the correct voltage, the 12V rail may be fine. Some may take replacing a capacitor or two to get working, and some are not worth fixing.

My next project is to build a box that I can install a PC PSU into and just hook the 24pin, molex, sata, mini molex, 4pin 12V, 6pin 12V, and the 8pin 12V connectors up to pigtails attached to the appropriate banana jacks. Then I wouldn't even have to do any cutting and soldering when the current one dies, just un-hook and plug a new one in. I've already ordered the pig tails and this will be the last setup I will have to solder for myself.

Re: Modding a PC Power Supply into a 12 Volt Supply for your DC charger
 

i just may have to build one....I like the usb ports..great idea

Re: Modding a PC Power Supply into a 12 Volt Supply for your DC charger
 

i built one of these a few years ago and it works perfectly glad someone figured out how to make it work

Re: Modding a PC Power Supply into a 12 Volt Supply for your DC charger
 

I'm trying to use a server power supply, but can't find any documentation on it.

It's a HP/Compaq 3902Q001 400watt PS. It also has a replacement number of 228509-001.
For 32A @ 12VDC it's small (~12" long, 2" x 2").

For a "refurb" they can be had for cheap... HP 228509-001 Redundant Power Supply Proliant DL380 G2 G3 194989-001 PS-3381-1C - Velocity Tech Solutions

Back to trying to find a manual/schematic.

I have 2 used ones, so I don't know if they work or not. I want a PS for a second motor dyno.

Re: Modding a PC Power Supply into a 12 Volt Supply for your DC charger
 

Here's what I found at Mod 12VDC 32Amp Power Supply : Need Help! - RC Groups

I would try to cover everything they talk about but it does a good job explaining.

Re: Modding a PC Power Supply into a 12 Volt Supply for your DC charger
 

Excellent, thanks for linking.8)
I tried my usual "tech places", but not any RC sites for info.

Ahhhhh.....soon to go off & do some soldering."thumbsup""thumbsup"

PS, in my searching, I found them for ~$9 US each, mine were "free" from a site with a huge box getting ready to be recycled. It pays to be nice to site IT guys.8)
:lmao::lmao::lmao::lmao: