Considering a PC power supply with my Cellpro 4s

[ghopper]

Hi,
I'm thinking of using a 400 Watt PC power supply I have laying around. I was wondering is there any reason you can't just connect to one of the free four pin molex connectors from a fully functioning PC? I understand you wouldn't want to be doing other major loads on the machine which might drop the voltage and available amps. Most good PC are running with 28 amp 12 volt lines. I'd appreciate any thoughts on this.

Dan

[R.Lim]

Just wondering what are you trying to tell us? Isn't it cheaper to power your PC with 220/110V straight from the net?

[ghopper]

I would like to power my cellpro 4s charger using a pc power supply. I was just wondering if you could safely do that just by setting up a 12 volt lead from a working PC using a free 4 pin molex connector that the PC has. The only article I have seen using a PC power supply was basically just using that and not the entire working computer. Seems that if it is safe, a whole lot easier than modifing the PC Power Supply as the article does.

[widower]

You will have to do the math. Your 400W supply will have a max current for 12V. It will not be able to supply the 400W just to 12V. The only peripherals that use 12V are hard drives, cdroms, floppies, and anything else that has a motor (fans). You will need to google to find some average numbers for current of each peripheral. Then whatever is left over, you can use for your charger as long as your supply isn't running hot.

[mikelebron]

I would like to power my cellpro 4s charger using a pc power supply. I was just wondering if you could safely do that just by setting up a 12 volt lead from a working PC using a free 4 pin molex connector that the PC has. The only article I have seen using a PC power supply was basically just using that and not the entire working computer. Seems that if it is safe, a whole lot easier than modifing the PC Power Supply as the article does.

Yes you can use your power supply... W/V = A Watts / volts = Amps Idealy you would get 33 amps out of the 12 volt line BUT most power supplies break out and distribute the load accross many rails... Therefore you will most likely only get 18 - 24 amps +-. That is plenty of power you power your charger.

Here is one I built last week.

I have a 12v, 5v and 3.0v leads.. Let me know if you want directions to build.

[wren1702]

I think he wants to power his PC and his charger at the same time. :shock:

[mikelebron]

I think he wants to power his PC and his charger at the same time. :shock:

What!... that nuts..

[wren1702]

I say pick up a new or better yet used PC power supply and convert it! I love mine!

[HeliDan]

For what it's worth, just because a PC [multi-voltage] power supply is capable of 400W, does not mean that all that power can be supplied to one potential. They usually have a rating for each potential. You should verify this prior to attempting this........

-One guys observation-

[Helibelly]

Hi, would it not be easier and safer to purchase a seperate power supply? Hobby city for instance have a 6 amp one for about $16, which is fine for the cellpro 4cell charger.
Eric.

[JaggedEdge]

I'm using an old 4amp 12volt laptop power supply for my DNG2 charger.

[ghopper]

Thanks for the responses all. I just rechecked my spare 450 watt power supply and it has two twelve volt rails one 15 amp and one 17 amp. I don't think I'll be putting a whole computer together. I'll just mod the supply to provide the juice I want to recharge at home.

Dan

[HeliDan]

One other thing that I think I remember reading, the PC supplies don't regulate if they are not loaded. Although I do not know how much load is required, I would bet a 25% to 50% load would be required........

Please let me know if that's wrong........

[mikelebron]

One other thing that I think I remember reading, the PC supplies don't regulate if they are not loaded. Although I do not know how much load is required, I would bet a 25% to 50% load would be required........

Please let me know if that's wrong........

All that is needed is a 10 Ohm 10 Watt Ceramic resister on the 5 volt line.. You will also need to short the PC_ON wire to the ground.. normally if your PS does not have a on off switch you can use this to trigger the power supply on. Some power supplies will need more power drawn to get to 12 volts.. this will depend on the PS...

[wren1702]

Here's what I consider "The Bible" when it comes to converting a PC power supply.

A must read!

http://web2.murraystate.edu/andy.batts/ps/POWERSUPPLY.HTM

Make sure and read the update as well:

http://web2.murraystate.edu/andy.batts/ps/DESIGN_GUIDE.HTM

[mikelebron]

Attached is the summarized version of the above link. I created this based on the PS I posted. Hope this helps.

Mike

[mkoutnik]

This is also good reference material... http://www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-Power-Supply

[mikelebron]

This is also good reference material... http://www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-Power-Supply

That is a good one actually..

[ghopper]

Thanks for the links guys. Looks like one trip to Radio Shack will get me all I need to do this project. I'll keep in mind I can just get a ready made one for $16.00 and shipping thou.

Dan

[mikelebron]

Yea... but doesnt feel good when you complete a project!

[mkoutnik]

I just finished my power supply. It turned out awesome!! :D

All you need at radio shack is...
1) 10 ohm, 10 Watt resistor (qty 1)
Tip: you may want to go with 1 ohm, 10 watt (qty 2 wired in series) this will boost the output voltage. It boosted the output voltage from 11.75 V to 11.95 V. The only downside is the 1 ohm resistors will put out a lot more heat. I also suggest using themal compound to attach the resistors to an internal heat sink.
2) SPST switch (qty 1 optional)
3) LED & LED holder (qty 1 optional)
4) 330 ohm, 1/4 Watt resistor (qty 1 optional)
5) Binding posts (qty 2 or more depending on how many temrinals you need)

This project is very easy and it makes you feel like you accomplished something when you're done. Especially if nothing pops or blows up when you turn it on for the first time...:P

[mikelebron]

Awesome.. post a pic of the beauty!

[mkoutnik]

Here's some pic's to the finished PS. I've also got a blue LED cooling fan on order...so that will add some character. :D (My wife thinks I'm a complete dork...)

[ghopper]

Picked up my parts from Rat Shack yesterday for 12.00 total. Got to spend a little time with it last night. I should finish it up tonight. I intend to just shrink wrap unused wires of the same color together, or would it be preferable to just cut them off at the circuit board and forget about them?

Dan

[mkoutnik]

If you're never going to use the extra wires...just cut them off at the circuit board.