Computer PSU converted to DC PSU
 

I had an old 300W 19A computer power supply laying around so I decided today to convert it to a DC power supply for my RC stuff. I got everything done and when I'm using my Volt-Ohm Meter I have 12.8V coming out, but when I try to read Amps I'm only showing 2 Amps.

I'm trying to remember from my high school days in electronics if this is normal because there's no draw on it...For some reason I remember it not pushing max amps unless something is drawing from it to save power. Anyways if anyone is an electronic guru and could help me out I'd appreciate it!

Also, what size female banana connectors do I need so a DC charger will plug in?

Most use 4mm plugs.....

Are you measuring amps on the input or output?

But yes, to measure the amp draw, something has to be drawing the amps. So if you are just trying to measure amps, you do need to have a load on the PS. And then, if you are measuring the output side, you will be measuring the the amp draw of the load, not really the amps of the PS. The other thing to mention, is that as you get close to max load, you may see the voltage drop.

Hope I explained this well enough.:rolleyes:

I was measuring the output. Perfect explanation, I thought it had to be loaded to read the output amps, but wanted to be sure.

Since I posted this I actually hooked it up to my charger and was able to charge a pack at 6A (charger max) without any problems so I think I'm good.

I eventually want to hook like 3 5A chargers to it or one of those 4-pack chargers like the Hitec.

Cool.

i need to find a few of these to make a couple back-up PS for me and a buddy.

Glad it all worked out for ya.

Well reading that makes me nervous lol...it mentions hooking up a resistor to the 5v rail and something about sense wires.

Basically all I did was soldered 3 yellow (12V rail) wires together, 3 black (ground) wires together and soldered the green (switch) and a black wire together and put it back together.

Without the the resistors, I dont think you will be able to get max power out of it. And if I remeber correctly from the first couple I did, without them they get very hot, and last a very short time.

I don't really understand the resistor thing...I can see if it's a power supply without a fan, but if it's one that has a full time running fan that should keep a small load on the 5V rail.

Oddly enough I have 12.8V coming off my 12V rail right now with no resistors. Either way, I'll keep an eye on it and see how it does and add them if it starts to get hot.

It depends on how old of a PS you used, the newer same less than 7-8 years old, need a load on the 5v source, before they will make max 12v output. If you would ask me 13 years ago, I could have explained it in more detail, but it been about that long since I've done any switching PS work or repairs. And to be honest, I didn't need to know it or use it I think I forgot most of it.:lol: