ATX Power Supply Conversion

[Non Action Man]

Ohh and would you say that the AC supply from a laptopstyle charger has the same efficiency or do they lack in power?

I'd say they'd be pretty on par for a cheap ATX PSU, but a good one should out do it easily, looking at PSUs rated gold 80+

Most laptop power supplies I've seen lately are around the 19v mark, with propitiatory plugs on them.

NAM

 

[colorex]

Most laptop power supplies I've seen lately are around the 19v mark, with propitiatory plugs on them.
NAM

Propitiatory? I'm sure you meant proprietary! LOL

 

[ananas1301]

I'd say they'd be pretty on par for a cheap ATX PSU, but a good one should out do it easily, looking at PSUs rated gold 80+

Most laptop power supplies I've seen lately are around the 19v mark, with propitiatory plugs on them.

NAM

Ohh alright Thanks!

 

[bicyclemonkey]

Does the ATX PSU charge the battery faster or something?

 

[jetpackninja]

Does the ATX PSU charge the battery faster or something?

Theoretically? Possibly- depending on your setup.
The two different chargers that I use, one can do 5a the other one can do 6a.
The two laptop power adapters that I have are limited to 4.5a so my chargers will only do 4.5 amps (they can't put out more than they take in).
If I hook up to the ATX PSU, I think it's rated for twenty amps.
So each charger should work closer to it's maximum output (the charger uses some of that to run itself).

Would it charge any faster? Depends what mah batteries and what C rating you are charging at.
If I am charging for example a 1300mah at 1C (1.3a) it's not going to charge any quicker, same for a 2200mah (at 2.2a)

At home I just use the laptop power supplies and never run anymore than 4.5 amps even when parallel charging.
My chargers get warm if I go any higher than that...

 

[ananas1301]

Theoretically? Possibly- depending on your setup.
The two different chargers that I use, one can do 5a the other one can do 6a.
The two laptop power adapters that I have are limited to 4.5a so my chargers will only do 4.5 amps (they can't put out more than they take in).
If I hook up to the ATX PSU, I think it's rated for twenty amps.
So each charger should work closer to it's maximum output (the charger uses some of that to run itself).

Would it charge any faster? Depends what mah batteries and what C rating you are charging at.
If I am charging for example a 1300mah at 1C (1.3a) it's not going to charge any quicker, same for a 2200mah (at 2.2a)

At home I just use the laptop power supplies and never run anymore than 4.5 amps even when parallel charging.
My chargers get warm if I go any higher than that...

Thanks for that! I often charge with 2C which is sometime 4,4 A or even 6,0 A. Of course only if the Lipo is stated to be able 2C charging. But I wouldn´t have kept that in mind unless you wrote this

So thanks. Now I know that there are limits to it, even it is practically for free.

 

[Non Action Man]

Just a note to clarify something about LEDs, you *may* come across one that the "gate" method of distinguishing the polarity may not work. Not a big deal, it just won't light up. Reverse it and you should be good to go. They are a diode, so power will only flow one way.

Also, when I said ground in this application, its actually -ve, as it goes through the resistor before getting to ground.

Just some feedback from friends higher up the electronics food chain than I!

NAM

 

[UndCon]

I am using an old 300W PSU for my hot wire cutter(guitar string "e", made of steel). I drilled a hole in the center of a desk and mounted the tip of a fishing rod to the side the table. The fishing rod is flexxy and removes slack when wire gets hot. Beneath the table I routed the wire so I can move a crocodile clamp along the wire to add or remove heat (shorter wire=more heat) and I have a Voltmeter and an Ampere meter to show the current used.

//UndCon

 

[jetpackninja]

Nice! How do you vary the current?

I am using an old 300W PSU for my hot wire cutter(guitar string "e", made of steel). I drilled a hole in the center of a desk and mounted the tip of a fishing rod to the side the table. The fishing rod is flexxy and removes slack when wire gets hot. Beneath the table I routed the wire so I can move a crocodile clamp along the wire to add or remove heat (shorter wire=more heat) and I have a Voltmeter and an Ampere meter to show the current used.

//UndCon

 

[Non Action Man]

Nice! How do you vary the current?

The wire has a certain amount of resistance per unit of length. So by varying the placement of the clip, he's changing the length of the circuit, and hence the resistance. At a set voltage, if you vary the resistance, you alter the current.

A hot wire cutter is an awesome use for an old ATX PSU!

Technically, you can alter the PSU to make it vary it's output voltage, but you need to do a bit more work, have a basic understanding of SMPS and really helps to have a wiring diagram! you can even make them go higher in output voltage, but then you have to disable the over volt protection, and replace the output capacitors to make them handle the highr voltages.
NAM

 

[jetpackninja]

Ahhhh- thanks. I failed to read his post carefully enough

 

[colorex]

I am using an old 300W PSU for my hot wire cutter(guitar string "e", made of steel). I drilled a hole in the center of a desk and mounted the tip of a fishing rod to the side the table. The fishing rod is flexxy and removes slack when wire gets hot. Beneath the table I routed the wire so I can move a crocodile clamp along the wire to add or remove heat (shorter wire=more heat) and I have a Voltmeter and an Ampere meter to show the current used.

//UndCon

Can you make a tutorial thread about this? I'd like to try this myself!

 

[UndCon]

HI!

Non Action Man is correct!
(I control current by relocating the clip beneath the desk)

I will try to make a summary of the hot wire cutter and take pictures. My problem is it is on a desk located in my very small shed/workshop and in order to use it I have to move the desk outside in my carport - otherwise I cannot cut full sheets of Depron.

//UndCon

 

[ananas1301]

The idea of a hot wire cutter is pretty darn awesome!

It makes so many cuts easier then having to do it with a blade (which take time and alot of energy as you have to keep pushing down the blade to get good cuts)

I would love to see the pictures!
I have an old pc lying around and I could take that out and have some king of variable table, which I only need to connect the two wires to the power output and I would immediatley have a nice surface for cutting!

 

[ananas1301]

A few hours ago I went down into the basement and looked for a reasonable good ATX Power Supply

Found something quite good I think 25 A are more than enough

Anyway here some pics:





Anyway, I realised that I would need a resistor for this but I don´t have one. So I opened up a couple of things that had electronic components hoping the resistor I need is somewhere there as well.
What I did is opening up a Parkzone charger and take all the guts out of it (which I regret massively right now because I could have had a second charger for my batteries with this power supply)
I found a lot. But the only stuff I can name are the capacitors and the resistors. All the other stuff looks kinda cool but I don´t have a clue about what they actually are. Does anyone fancy telling me? Thanks for that.











Tomorrow my search for the resistor will go on

By the way! I have a built in switch for this ATX on the back of it. Do I still need to build a switch like this guide says or can I just leave it out because I have one? And do I only need this resistor for the LED? Couldn´t I just use it without the LED and therefore I would need to change anything inside it. The only thing I would need to do is get a ground and the cable with the right power output (the red one I think) out there so I can use it for whatever I want to use it for.

 

[Non Action Man]

Nice find! You don't need the LED if you don't want it and the switch you're talking about, is that a mains switch?

You'll be looking for the yellow wires for the output, they are the 12v.

You will, however need the power resistor, rated for at least 10 watts. None of the ones pictured ther are right. The resistor(s) for the 5v (red wire) load are cheap, it's best to buy them, that way you'll get what you want.

On a side note, I made up a lead to plug into my Rx so I can power it from the PSU. Great for checking I have the channel allocation right and trim setup while charging the batteries.

Let me know if you need any help,

NAM

 

[ananas1301]

Hey non action man!

So I think what I´ll do is get the yellow with a ground and a red one with a ground out of the ATX.

So I can, if I get another charger with a plane from HH I could use it on those 12V ouput and for the receiver or any other that needs 5V I can use the red one.

Do you know what the voltage is for most of those LED´s like the 4 I got out there?
Do you think getting the orange one out as well for LED´s would be good or not?

 

[Non Action Man]

For those LEDs, just assume a low voltage, so if you use a red or the grey wire, use a 240 ohm resistor. If you hook it up to one of the orange wires, then you can use a 150 ohm resistor.

NAM

 

[jetpackninja]

You can use a dual filament automotive light bulb in place of a resistor. Wire it so that both filaments are used.
makes a nice glow from inside the PSU too

 

[Non Action Man]

good point. as long as your using about 1 amp, all should be good