Topic: How to build your own power supply? (Read 16377 times)

Don't cheat on PSUs, will cost you more in the long run.

 Speaking as someone that has worked on and with high-power switching DC-output power supplies since the 1980s as a technician - your understanding of modern power supplies is completely wrong.

 You build your own power supply as you state - but you'd end up paying a TON for the needed components, it would be VERY POOR efficiency, and while you might manage to make it be decent reliability it would have a LOT of safety issues.


 Current ATX-type power supplies enjoy a HUGE "economies of scale" factor in their pricing that makes trying to match pretty much impossible for ANY end-user, even someone like me with the experience and training that COULD design and build something comparable (but even with MY experience the result would end up being a lot larger).


 The power densities and efficiency of a modern kilowatt+ ATX power supply is amazing to someone like me that was a line technician working on kilowatt+ supplies intended for use in mainframes at Qualidyne back in the 1980s.

To the OP,

Unless you are board, have some extra money lying around that you don't need and want to experiment with PSU's, it is MUCH simpler, cheaper, and safer to just BUY an inexpensive and professionally designed and manufactured PSU.

Such as these:

For 240: https://centrix-intl.com/details.asp?Parent2ID=1&productid=13323

and for 110/120: https://centrix-intl.com/details.asp?Parent2ID=1&productid=13388

or: https://centrix-intl.com/details.asp?Parent2ID=1&productid=13389

All of which are safer in all categories and pretty much guaranteed to not kill you or burn up/down your miners or your house.

(But, as someone mentioned in a previous post in this thread, "Try not to lick the power supplies or any exposed wire leads while in your bare feet". If you do that with professionally built PSU's like these HP Server PSU's, all bets are off.)

Good luck.

for such an extreme necro-thread I was hoping for pictures of an insane 24-GPU power supply that someone made

I know. Some like to tell people to be careful, because others told them to be careful, and they think it's the way to be. It's not. Well. let me just take that back - it's good to be careful, but it's bad to always give the work to whoever you assume to be best at doing it. About the only thing I wouldn't touch would be certain types of automotive work. as long as you enjoy hard work, all the other stuff is easy. none of it's rocket science. Electrical isn't so bad, if you do it right the first time.

If you dont youtube this you will be commiting a bitcoin mining sin!

And will go to hell and stuff plz plz plz youtube it 

If you think you can design a better PC-type switching power supply, here's how to try.

Download LTspice, which is a circuit simulator optimized for switching power supply design. Take a look at the data sheets for switching power supply control ICs. Read the application notes. Find some switching power supply transformers for which specs are available, and try to design around them. Don't forget protective circuitry. When you have a circuit that works in simulation, post your LTspice file.

If you're really good, you might be able to duplicate the performance of commercial design for 2x to 3x the price in quantity 1. PC power supplies are incredibly cheap for their power output. As a rule of thumb, industrial power supplies cost about a dollar a watt. PC supplies are far cheaper.

I've designed a switching power supply, but it was for a special application for which no off the shelf solution existed.



 

Nou... because i reread it and you are 100% right but the metaphor threw me off

yep, great idea! Youtube revenue from great video of spectacularly blowing up a self made PSU could be higher than any possible savings you hoped to get by replacing decent and expensive PSU's.

Please if you decide to build your own please PLEASE video it when you first power it up.

You should buy the right stuff if you bought your hashing hardware and you care about how long it lasts on you

if you dont:

I used to do (and still do sometimes) dumb stuff like this too. I think the OP just wants to get more power up and running without having to spend a ton. Especially if you have a surplus of crap power-supplies already.

I work for a small custom computer assembly company, and we have shelves full of useless 300w cheap china crap PSU's that come with the cases we end up not using. they are sitting around wasting space. We use them for various personal purposes and testing and consider them disposable. They blow up, chuck it and grab another one.

check this link:
http://www.directron.com/2powersupplies.html

long story short, you can manually power up an ATX powersupply by shorting pins 14 and 15 on the 20 (or 24) pin primary connector.

If you want to rig up two power supplies for your computer, one for each power supply (or more if you are a lunatic) and power them up at the same time it *should* work. Or check the section where it shows you how to build a relay.

I would stick to one crap power supply per juice guzzling video card, 
if the powersupplies are very low quality do not run them at the rated load listed on them, stick to 50-60% (if it says 300w on the sticker and its a single 12v rail dont push it past 150)

I have a few Radeon 5770's and 4870's hashing, and I have had experience with running radeons with insufficent power. If the radeon looses juice from the 6-pin connector under a load, (has happened to me) the motherboard should error out and shut down the primary powersupply attached to the motherboard, some of the older ones also have wonderful beepers on them that will scream like a banshee if they don't have enough power. If you are in the building you will know it.

I take no responsibility for whatever crap you break trying to do this. There is a right way of doing things and the "get it done now for $0" way of doing things.

as for the health risks? Try not to lick the power supplies or any exposed wire leads while in your bare feet.

Good Luck

Power supplies that have a UL approval should deliver their rated output continuously without overheating. UL (which is owned by fire insurance companies) tests that. UL also requires that no single component failure can cause a fire.

Phony UL approval markings are often seen in products from China. But there's a way to check. UL has a database of approvals.  The UL file number on the UL approval sticker must match the manufacturer and the description of the item.

Here's what it takes to test a power supply. Hardware Secrets connects the power supply to a load box, loads it up to its rated output, and runs it for hours at 45C while checking the electrical outputs. See their reviews.

http://www.newegg.com/Product/Product.aspx?Item=N82E16817104054

A little more expensive than an extra PSU, but its a lot cleaner, and allows you to hook it up to your PSU and turn off/on with the PC.

An acceptable solution would be to use multiple cheaper or lower power PSUs, one for the system and one for each video card, all grounded on the same case. Some companies even sell modular supplemental bay PSU models for such a purpose (GPU only supply). The trick is to power on the secondary PSUs when the main PSU gives the "power good" signal.

As someone who has been in the middle of developing motor controls (also DC switchers -- lotsa MOSFETs for the 200A@28VDC we were dealing with as our largest design), I say just buy a friggin' power supply.

There's a reason the higher efficiency ones cost more.  Everything with good efficiency probably has PF correction, and there are some sexy little chips that can basically take care of it for you (adding more switching, of course -- yeah!).  Basically, it's easy to design a power supply.  It's even easy to design one with pretty solid outputs.  Will it be cheaper?  Maybe, but probably not, and it's unlikely that you'll end up with a design that's efficient and if you want to you're going to put in a lot of effort to do what others have already done at pretty low prices.

what about "volts jolt, amps kill"?

BTW, while not actually building a PS, I'm thinking the following server power supply would be a good candidate to power a couple video cards on the cheap:

http://sites.google.com/site/tjinguytech/my-projects/HP47A

Salt water is not good for draining a lipo. A lot of times the the salt water will corrode the tabs, breaking the connection. This makes the pack seem like it has 0 volts when in fact it does not. Best method to dispose of a lipo is to hook it up to a small light bulb and let it drain to zero volts. Then twist the positive and negative leads together and toss in the trash. Of course let it discharge in a fire proof area.

Or the more fun route is to drive a nail through the pack and watch the sparks fly!

My man, don't forget a good surge protector/suppressor, or a backup power unit to go with your PSU.  You gonna think your system as a whole, not just the power supply unit. 

I accidentally shorted out a li-po.... Fortunately, it iddn't explode, because the wire got so hot that it failed! Into salt-water it went...

A waste of ~2BTC!