$2 DIY bench power supply for testing emitter and powering a hobby charger.

Issue of the Resistor

Power supplies need a certain minimum load to work properly. The min. load for mine is around 0.8 amps. Thus if you plan on powering LED’s or other such low-power device exclusively, you’ll need a resistor to provide a load. Otherwise you will damage the PSU.

A meaty 10-Ohm, 10 watt resistor from Radio Shack is a good choice. Wire it across 12 volt and ground.

One of those articles also suggested wiring it so that the cooling fan became the load.

-Garry

Excellent idea!

interesting! I wonder if one of these could be used to do home anodising? Most guides I read specify a certain amount of current per surface area, whereas these are voltage controlled instead. It certainly would make it a whole lot cheaper if it would work.

Current for anodising is best at lots of amps. Preferably more than your typical PC PSU can provide. The more amps the better (generally).

That greatly depends on the size of item being anodized. I have read through post that did use a computer power supply for anodizing with small pieces. I use my automotive battery charger to anodize with. It works well with a small host like a cut down mini mag with very good results. I tried a full sized 2D Maglite one time and didn’t turn out so well. The current wasn’t high enough for the amount of surface area in the mag.
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Rit clothes dye from wally world, Sunshine Orange.
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WOW! :open_mouth: :bigsmile:

thanks, I’ll have to go back and read the mtbr thread about it and see how much current I would need…

Also, you can easily get voltages that aren't officially supplied by the PSU. For example using the +12v as positive and +5v as negative will give you the difference between them, in that case 7 volts.

Nice work! I like the enclosure!

If you need a bigger power supply with way more amps you can also convert a server power supply.

How many amps would you need to properly annodize a 2C mag? My power supply can deliver up to 150amps at 13.8v, would that be enough?

Pretty cool, JM !!!

Those supplies should NOT be used with anything expensive and valuable, such as expensive hobby chargers.
See this review of one of them to see why: http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story&reid=324
I’m not going to quote the full review here, but this picture of ripple on 12V rail should be enough:

That’s at 300W btw… Here’s for comparison Corsair AX1200i at 1200W:

Your link and your pics are no good. 404 error.

If they are no good for use with expensive electronics then there are a whole lot of computers (lots of expensive components in there) costing hundreds and thousands of dollars at risk that use them. Someone had better tell Apple, Dell, HP, Compaq, Asus, Gateway, Toshiba, etc...

I completed the wiring over the weekend and fired it up last night. Works a treat! Whisper quiet and puts out voltage in my choice of 24v/12v/7v/5v/3.3v

Fired up the new IMAX B8+ and it works great. Looking forward to going through my cells and running discharge tests to filter out the older bad ones from laptop pulls and to get some good matched sets. :)

Is the 3.3v output close enough for driving a single emitter? Say testing with a single Li-Ion max 4.5v driver. If not, would you use the 5v output with a resistor or something?

-Garry

I think there's enough wiggle room in the specs for a '4.5v' driver to run fine on 5v. I haven't found one yet that isn't happy running even from 2xCR123As.

Considering the forward voltage of an XM-L is around 3.3v I’d say it should be plenty to drive an LED directly. To run through a driver it should still work but not at full potential. An Nanjg powered by it won’t be regulated at full power but will still light up if you just want to make sure it is wired correctly.

You could add a variable output fairly easy. I have a handful of modules, I could mail you one or two and point you in the right direction to modify it. Add a voltage and ammeter, and you could be good to go

Thats danged nice!!! It's guys like you that make the world go around!! Doing projects like that are nothing less than great!!!

Congrats on the thought and the follow through!!! NICE! Dan.

Now I could go for something like that! At least a way to vary voltage with a voltmeter built in!

Also, I'm pretty sure I have one of these power supplies that I bought years ago (+/- 1995) for bench testing 12v car stereos. Maybe only used once or twice.

-Garry