Using computer Power Supply
 

Let me start off saying I have built quite a few computer power supply conversions. I always add a 10ohm, 10watt resistors to hold the voltage up. I also always spilt the yellow and black wires to make 2 outputs. My latest was a 14A that I can run two chargers on, both at 5A and no issues. I just upgraded to two 10A chargers and grabbed a 610watt,44A on the 12V rail computer power supply, split the outputs, added the 10ohm 10watt resistor to the 5v rail and fired up both chargers at 10A and within a few minutes one of the chargers dropped an "input volt error" meaning the voltage dropped too low. Unloaded I am getting 12.8v but loaded it dips to around 10.5. This is a decent name in computer supplies, so I was a little surprised. Is there something I have missed?

comp power supplies
 

are you putting the resistors on the 12V ? you need to put them on the 3.3
V line . you want to offset the load that your putting on the 12V .
Good luck I am using mine at 24 Amps out works good.

I always heard to put the resistor on the 5V. Are you sure about the 3.3V rail?

woa, your supposed to put resistors on them? i just took my old antec tripple rail and plugged it right into the charger.. charges at 10 amps np. is there an article about this somewhere?

Not necessary but helps stabilize the 12V rail. Here are a couple of my sources for when I started doing the conversion. It may just be this P/S is too weak to supply the 12V when pulling 20A, I can run both chargers at 8A but when I bump to 10A on both chargers one of them pukes :flaming: Oh well I tried :(

http://www.ultimaterc.com/forums/sho...d.php?t=122733
http://www.rctech.net/forum/radio-el...n-charger.html
http://www.tjinguytech.com/my-projects/convert-pc-ps

interesting. I'm getting back into this hobby after about 8 years. and you just cured my delema of what kind of charger I need. the dc units have awesome features for less $ than the comparable ac/dc units but I'd be forced to buy a power supply. but not anymore.
I have several old computer power supplies laying around.

They are great and cheap to boot, especially when you have a bunch of computer power supplies laying around. Funny thing though, is whether they hold the 12V under load. I have an older P/S that is rated for 14A on the 12V rail This one here and it has ran 2 chargers going at 5A and one charger going at 10A and never even blinked. The newer P/S I am having issues with is actually rated for 34A on the 12V rail and then I try to pull 20A it drops the 12V rail to low and one of the charger cuts off.

well now that I had a look, I forgot I put my old one from my current rig into my moms since it went dead.
I just have some cheap old stuff laying around that says it's rated at 18 amps on the 12v rail. the one I have in my rig is an antec rated at 18A but it has dual 12v rails.

is there a write up for a dual 12v rail system?

How much do you need to run your charger? I would try it. Check and see what the no load readings are on 12V and if 12.3V or more give it a shot. Like I said the little Bestec 14A in the link above is one of the best little conversions I have seen :eek:

yeah I'm going to use one of the old ones. but it's a dell rated at 200w. so I don't expect much. I'm actually thinking of getting the Hitec X4 charger though.

I wouldn't look at anything less than 300watt for that charger. If you figure 50wx4 channels for 200w and build in 30% for lack of efficiency you're at 260w. I would really look at min 350w just to be comfortable.

i just did a conversion on a computer power supply and the fan doesnt work. did yours work after you did it? Im thinking my fan on mine is just broken.

Hmm, are you getting any voltage on the 12 line? Any other indicators it is working? My fans have always worked so I would make sure it is still plugged in. Some of them have the fan wired directly but I have done a few where the fan was just plugged in, so it may have come loose.

well I did end up finding my old power supply from a old computer rig in the basement. it's nothing special but it says it's rated at 15 amps and 400w. the real cool part is it's nickle plated. it looks trick.

and i went to the hobby store today and bought a thunder power TP610C-ACDC charger. but I got it home and it doesn't work.
they took it apart and the fuse is good. so I exchanged it for the X4. the one I actually wanted in the first place. I took the worker's advise about the other one being 80w instead of 50w. but to be honest the x4 is going to be more than enough for me for a while.

what do you think of the numbers of it?


http://farm9.staticflickr.com/8199/8...a2d11250_c.jpg

I cut the positive and negative wires on my fan and hooked them right to the 12v and a ground and it still didnt work, im pretty sure the fan is busted