12 volt pc power supply

In article , kruliczek

| but I need a 12 volt power supply. So I took an old (original ibm | powersupply with 63 watts power) and usin radio stack parts added a | 12volt ciggy lighter receptale in the box, I hooked kit to 12 + there | is only out out put (though 2 wires) in this box . I hooked it through | a lighted power on switch. | | everything works ... too welll I think I have about 5 amps 63watts | and 12 volts | | the output voltage I measure is in the range of + 17 volts !!

Perhaps you used a -5v and +12v line instead of ground and +12v ?

Normally this is pretty easy -- use a yellow and black wire (12 volts) for your output, and run a red and black wire (5 volts) into a resistor or light to make the power supply happy.

| is this ok to use with the triton power charger from gp ? or is the | 17 volt reading bad ?

No, do not use it. 17 volts will fry the Triton and whatever else you hook up that's designed to use 12 volts.

Don't give the Triton (or any other 12v device) any more than 14 volts. You'll risk ruining it.

I used the instructions I found at this link to make my power source for my Triton.

There is a link towards the bottom of the page for instructions. The Triton will accept input voltages between 10 - 15 volts, to achieve it's maximum potential, it also needs about 13 amps. Triton will display an "Input Voltage" error if the voltage is below 10,5 volts or above 15.0 volts, but won't fry, it will just shut off. At least that is what my instruction manual says.

| I used the instructions I found at this link to make my power source for | my Triton.

Yes, I've used them too, and my power supply only puts out about 12.5 volts.

| There is a link towards the bottom of the page for instructions. The | Triton will accept input voltages between 10 - 15 volts, to achieve | it's maximum potential, it also needs about 13 amps.

It's happy with a lot less power. You only need 13 amps if you're charging a 15 cell NiCd pack at 5 amps.

| Triton will display an "Input Voltage" error if the voltage is below | 10,5 volts or above 15.0 volts, but won't fry, it will just shut | off. At least that is what my instruction manual says.

I'm pretty sure the instructions do not say it won't fry :)

Yes, it will give that error. But it may still fry if the voltage is high enough. 17 volts is too high -- don't use that power supply with anything until you get it worked out.

I've got a 12v power supply that's been sitting in my closet for decades. I recall hooking up a cassette deck to test it. It worked for a few seconds, then the magic smoke escaped. Damn! So I tried a car radio ... and it worked for a few seconds, then the magic smoke escaped. WTF? Turns out the power supply was putting out 16.5 volts. (Really, I should either fix it or discard it, just in case somebody accidently uses it again ...)

Dropping by 3v at, say, 5-10 amps, you'd better make sure that's a mighty big (ie. 30W) resistor...

The difference between your tape player and radio versus a modern charger such as the Triton is that the latter is a switchmode device which by design is an extremely tolerant device. It controls its entire operation through current and voltage monitoring, thus an overvoltage condition will either be ignored as it has no effect on the unit's operation, or it will detect the parameter as being out of range and give an error message.

| Doug McLaren wrote: | | > Yes, it will give that error. But it may still fry if the voltage is | > high enough. 17 volts is too high -- don't use that power supply with | > anything until you get it worked out. ... | The difference between your tape player and radio versus a modern charger | such as the Triton is that the latter is a switchmode device which by design | is an extremely tolerant device. It controls its entire operation through | current and voltage monitoring, thus an overvoltage condition will either be | ignored as it has no effect on the unit's operation, or it will detect the | parameter as being out of range and give an error message.

Are you disagreeing with me? If so, I trust that this means you will replace anything the original poster fries or damages with his 17 volt power supply? Or maybe just his Triton? Either way, very generous of you.

Unless you will answer `yes' to this statement, I strongly suggest that he not use it until it's fixed. I don't really care if the Triton will give an error message if the voltage is too high or too low (it will, I know), but that doesn't mean it's a good idea to feed it 17 volts. Maybe it won't fry, but we know it won't actually charge any batteries, so there's no benefit to trying.

Putting a resistor in the circuit as one poster suggested isn't the right answer either. The needed value of the resistor would change depending on the current requirements of the charger (which will vary greatly), and that's just not something that's easily adjusted. Also, the power disappaited by that resistor would be large -- going from

17v to 14v with 4 amps would be 12 watts -- that would generate a lot of heat.

The right answer is to either figure out what went wrong (and fix it) with this power supply, or throw the PC power supply away (save the stuff from Radio Shack) and get another and try again. Given how easy cheap/free AT power supplies are to find, and how he picked a very low power one to begin with, I'd suggest the latter option.

Get a real new ATX power supply 200 watt and up.

Search the web for "st. louis switcher" for what to do to power it up.

Makes a good cheap and stable 12 volt powersupply

NOTE the orig. IBM PC 63 watt powersupply was wimpy and had problems regulating unless the +5 and +12 were properly loaded. As old as it is you probably have bad caps in it.

Not worth the risk.

Hugh

Why don't you just spend the 40 bucks and get the converter that was made for it?

I suspect the unloaded supply rises to 17v - a fairly easy fix is to pick up one of those 12 v 3 pin regulators, and mount it with a couple of diodes in the base leg to raise the regulated voltage to 13.2v or 3 diodes to bring it up to 13.8v.Any local hobbyist should be able to help if you are not sure how to go about it.

David

No!!!! Not a good idea as the voltage will still be around 17v when no load is being drawn from the charger

David

Brad wrote:

hey guys thanks for all the info

my batery tester had a weak battery and jacked up all the voltages that i tested by 50% so it has 12volts !!! :)

LOL!!!!!!!!!!!

Why, I made one out of a computer PS for a few bucks. mk

cheapest one in my neck o the woods is 70$ cdn at radiohack

the pieces to convert a ps $15 -------------

the experience ------ pricelesss ( i get to learn some electronics :::)

Might be better to look elsewhere - I have scavenged a few power supplies from computers I rescued from the local tip. Also, went to one of those travelling computer sales on Sunday - they had stacks of used power supplied for A$15

Also see if there is a computer bits for sale magazine at the newsagent

- they are usually full of ads for cheap stuff

DAvid

kruliczek wrote:

I have the Triton unit, and have mixed reactions. My experience seems to favor using a 12V sealed lead acid, or even an automobile battery for the source. It will provide the proper voltage and, most important, will supply enough current for all practical uses. The worst thing about it is - the manual is poorly written, except for someone who already knows all its tricks. I've complained to their Tech support about this, but only got a simple acknowledgment, no indication of any followup. Just be advised.

Olin McDaniel

hey guys here's a pic of the completed fully operational 63 watt power supply.

it has 12volts ( acka tester with new 9volt) and a 5 volt feed

it has an old hard disk for load ( possibly replaced by a 12volt car light later) and a 30 amp illuminated switch for control.

I'm using it for foam cutting now and may use the triton on it if it has sutable amps...

thanks again