Thanks so much! You mention the higher voltages get less current, predictably. Does the watt rating of the ATXPS affect how much current you can get at 24v? I have an 800w PS, I would think it could supply a decent amount of current at 24v?
The ATX power supply only makes a limited amount of current using the 24V configuration. Look at your name plate, and you will see the current that is available from the -12V supply.- it is usually less than 1 A typically 500mA to 700mA To get 24V you connect the +12 and the -12 wires. The current is limited by the -12V current. even though the +12V is capable of a lot more..
AAAAAAHHHHHHHHAAAAAAA!!!!!! (that was said out loud, in my head, and with body language!) removing the ironclad idea that negative/common/0v has to be used, period, makes all the sense in the world. the idea is voltages in reference to each other (not +12v/0v/-12v, but for example: +12v red test probe/jumper lead in reference to -12v which takes the place of black test probe/jumper lead in the comm/0v/negative) yielding 23-24v same idea: +12v red lead/+5v black lead=7v, +5v red/-12v black=17v, etc. wow, that is an aha, duh, i get it now moment. a picture may be worth a 1000 words, disproman, but a youtube video....priceless!!! subscribed, liked and humbly appreciative of your efforts and clear explanation sir. thanks so much. sniff :'-)
Yes, you should be able to get that voltage from the power supply. But I don't know how much current you'll be able to draw . My guess it would be at least 5 Amps for most power supplies. In any event, if you overload that voltage combination the power supply will simply turn itself off . The to restart it , remove the load, and unplug the power supply for 15-20 seconds and plug it back in, and it will start up .
If you look on the nameplate of your power suppy, there is a rating for the minus 12 V supply. Typically it is between 0.4 to 0.6 Amps. That's the limitation even though the plus 12V can supply much more than that. However, I still use the -12 and +12 combination to charge batteries that need more than 12V e.g. a string of four lithium batteries in series needs about 18 to 20 V to charge. It just takes a bit longer to get the batteries charged up.
Hi sir. The triangle combination: electric box Amps circuit breaker + PSU + UPS : can you upload a video about this combination and what is the right way, according to our circuit breaker, choose correct PSU and UPS? For not overloading and not making damages? Thank you!
My video camera has now become obsolete and I can no longer create videos. Perhaps one day when I get rich enough, I'll be able to afford to buy a new camera. In any case, the configuration that you need depends very much on the specific type and model of equipment that you have. I recommend that you find a local electrical technician who should be able to assist you.
@@disproman Sir, thank you for your reply. I had already thought about your suggestion. But, unfortunately, not know any local electrician who would agree to assist me with just advice. Like videos on TH-cam, who video builders just create the videos from big love on IT technologies. Hope one day I find some electrician who will assist me. Thank you.
Your power supply will have a name plate on it somewhere and it will also have a POWER rating , i.e. watts as well as voltage and current ratings. Remember that POWER = VOLTS x AMPS. In your case, the power supply POWER rating will be about 250 watts, or (approx) 12 V x 20 A = 240 W. So you are correct, you are getting the maximum current of 20 A from your power supply at 12V. Note that at a lower voltage e.g. 5 V, you can get more than 20 A of current but still limited to 250W of power. IF you overload the power supply, it will simply stop working. Also there is an internal , hard wired fuse that will destroy itself, if there is a large over load like a dead short. It's there are a last resort to prevent over heating and a possible fire.
@@disproman Thank you for your response. I have a few ATX units and am trying to build a supply with the most power I can get from it. So I should just use a couple of the negatives and 12v positives for optimal results? Would adding a Buck/Boost improve matters?
@@bp9293 Adding a buck/boost would not change the output DC voltage. There are internal regulators that keep the voltages as rated no matter the input AC voltage. You could try the parallel connection of multiple power supplies. Just make sure that they all have the same ground connection. The easiest way to do that is to use a power bar. I have not tried that - dunno , for sure. The limitation , of course, is the fuse or breaker on the AC side. If you overload one of the power supplies and it shuts down, the others might not be able to handle the load, and they will shutdown too. Also, you should connect ALL the yellow wires, not just one or two, and all the black wires - the physical connections from multiple power supplies might get a bit complicated.
The current from those combinations is lmited by the current available on the -12V lead - the blue wire usually.In most ATX's, it is about 0.5 A. I have found it to be enough to charge Lithium batteries scavenged from laptop battery packs. .But I am careful to measure the current when I charge them.
You have nicely summarized the voltage. I suggest you to with out -AC power. You just connect the power supply's wire to the battery fan non-stop running mean sucking the battery power. It's mean reverse current not charging but sucking the battery power. How it's resolved.?
There are several ways to resolve this. 1) Simply disconnect the battery when you are not using it 2) A more elegant way is to add a diode in series with one of the battery terminals. You will know which way to connect the diode by seeing if the battery is charging when the power supply is ON. If it is not charging, then simply turn the diode connection around. You might see a slight reduction in charging current, but nothing significant
I suggest that you use the 5 V connection and put a 5 to 7 ohm resistor in series with the battery. This will limit the current to about 500 mA. You can use your DVM to measure the resistance just to make sure that you've got it right, and you can also use the DVM to measure the current if your meter has a scale that goes that high. - most el-cheapo DVMs only measure current up to 200mA. But even if you only have 200 mA - that's still OK to charge your 18650 battery - it will just take a bit longer.If you have access to an electronics surplus place , see if they have a variable resistor ( some folks still call them rheostats) with say, 10 ohms that will let you vary the amount of charging current. But please do NOT leave you battery connected to the 5V power supply when the power supply is off - that will discharge your battery.
I was looking for a way to get around 9v and I think I found it with your video! Thanks!
Thanks so much! You mention the higher voltages get less current, predictably. Does the watt rating of the ATXPS affect how much current you can get at 24v? I have an 800w PS, I would think it could supply a decent amount of current at 24v?
The ATX power supply only makes a limited amount of current using the 24V configuration.
Look at your name plate, and you will see the current that is available from the -12V supply.- it is usually less than 1 A typically 500mA to 700mA
To get 24V you connect the +12 and the -12 wires.
The current is limited by the -12V current. even though the +12V is capable of a lot more..
AAAAAAHHHHHHHHAAAAAAA!!!!!! (that was said out loud, in my head, and with body language!)
removing the ironclad idea that negative/common/0v has to be used, period, makes all the sense in the world.
the idea is voltages in reference to each other (not +12v/0v/-12v, but for example: +12v red test probe/jumper lead in reference to -12v which takes the place of black test probe/jumper lead in the comm/0v/negative) yielding 23-24v
same idea: +12v red lead/+5v black lead=7v, +5v red/-12v black=17v, etc.
wow, that is an aha, duh, i get it now moment.
a picture may be worth a 1000 words, disproman, but a youtube video....priceless!!!
subscribed, liked and humbly appreciative of your efforts and clear explanation sir. thanks so much. sniff :'-)
+patrick holcomb Just came to comment the same thing :D
Can I get 1.67v from the 5v line and 3.33v line?
Yes, you should be able to get that voltage from the power supply. But I don't know how much current you'll be able to draw . My guess it would be at least 5 Amps for most power supplies.
In any event, if you overload that voltage combination the power supply will simply turn itself off .
The to restart it , remove the load, and unplug the power supply for 15-20 seconds and plug it back in, and it will start up .
Thanks! This was very helpful.
How much current can we get from -12and +12 combination?
If you look on the nameplate of your power suppy, there is a rating for the minus 12 V supply. Typically it is between 0.4 to 0.6 Amps. That's the limitation even though the plus 12V can supply much more than that.
However, I still use the -12 and +12 combination to charge batteries that need more than 12V e.g. a string of four lithium batteries in series needs about 18 to 20 V to charge. It just takes a bit longer to get the batteries charged up.
Hi sir. The triangle combination: electric box Amps circuit breaker + PSU + UPS : can you upload a video about this combination and what is the right way, according to our circuit breaker, choose correct PSU and UPS? For not overloading and not making damages? Thank you!
My video camera has now become obsolete and I can no longer create videos. Perhaps one day when I get rich enough, I'll be able to afford to buy a new camera.
In any case, the configuration that you need depends very much on the specific type and model of equipment that you have. I recommend that you find a local electrical technician who should be able to assist you.
@@disproman Sir, thank you for your reply. I had already thought about your suggestion. But, unfortunately, not know any local electrician who would agree to assist me with just advice. Like videos on TH-cam, who video builders just create the videos from big love on IT technologies. Hope one day I find some electrician who will assist me. Thank you.
So if my 12v out is 20amps that is the most I can get out no matter what I do?
Your power supply will have a name plate on it somewhere and it will also have a POWER rating , i.e. watts as well as voltage and current ratings.
Remember that POWER = VOLTS x AMPS.
In your case, the power supply POWER rating will be about 250 watts, or (approx) 12 V x 20 A = 240 W.
So you are correct, you are getting the maximum current of 20 A from your power supply at 12V.
Note that at a lower voltage e.g. 5 V, you can get more than 20 A of current but still limited to 250W of power.
IF you overload the power supply, it will simply stop working.
Also there is an internal , hard wired fuse that will destroy itself, if there is a large over load like a dead short. It's there are a last resort to prevent over heating and a possible fire.
@@disproman Thank you for your response. I have a few ATX units and am trying to build a supply with the most power I can get from it. So I should just use a couple of the negatives and 12v positives for optimal results? Would adding a Buck/Boost improve matters?
@@bp9293 Adding a buck/boost would not change the output DC voltage. There are internal regulators that keep the voltages as rated no matter the input AC voltage.
You could try the parallel connection of multiple power supplies. Just make sure that they all have the same ground connection. The easiest way to do that is to use a power bar. I have not tried that - dunno , for sure.
The limitation , of course, is the fuse or breaker on the AC side.
If you overload one of the power supplies and it shuts down, the others might not be able to handle the load, and they will shutdown too. Also, you should connect ALL the yellow wires, not just one or two, and all the black wires - the physical connections from multiple power supplies might get a bit complicated.
Any idea how much current you get from the 15.3, 17 and 24 volt leads?
The current from those combinations is lmited by the current available
on the -12V lead - the blue wire usually.In most ATX's, it is about 0.5 A.
I have found it to be enough to charge Lithium batteries scavenged from laptop battery packs. .But I am careful to measure the current when I charge them.
You have nicely summarized the voltage. I suggest you to with out -AC power. You just connect the power supply's wire to the battery fan non-stop running mean sucking the battery power. It's mean reverse current not charging but sucking the battery power. How it's resolved.?
There are several ways to resolve this.
1) Simply disconnect the battery when you are not using it
2) A more elegant way is to add a diode in series with one of the battery terminals. You will know which way to connect the diode by seeing if the battery is charging when the power supply is ON. If it is not charging, then simply turn the diode connection around.
You might see a slight reduction in charging current, but nothing significant
how can i get a 4.2v with a 500mA or 1A current? i need that to charge 18650 batteries...
I suggest that you use the 5 V connection and put a 5 to 7 ohm resistor in series with the battery. This will limit the current to about 500 mA.
You can use your DVM to measure the resistance just to make sure that you've got it right, and you can also use the DVM to measure the current if your meter has a scale that goes that high. - most el-cheapo DVMs only measure current up to 200mA.
But even if you only have 200 mA - that's still OK to charge your 18650 battery - it will just take a bit longer.If you have access to an electronics surplus place , see if they have a variable resistor ( some folks still call them rheostats) with say, 10 ohms that will let you vary the amount of charging current.
But please do NOT leave you battery connected to the 5V power supply when the power supply is off - that will discharge your battery.
disproman thanks man..
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Thanks thats realy helpfull
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Plzzz make a video with power supplay with this mated i can understand tha the read is nagitiv just like you sead