20 Amp Battery Charger with Computer Power Supply - 220v AC to 1.5v / 3v / 6v / 9v / 12v / 24v DC 

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Purple Wire is “5v Standby” it gives constant 5v/2A while the supply is plugged in (even if it is turned off) Grey Wire is “Power Supply OK” it gives 5v when the power supply is working correctly.

Great work as always. I also have a battery charger for my 260Ah battery. That seems like a PC power supply but inside the power supply case I fixed a specially designed charger circuit which is awesome. That charger have great features like anti spark, reverse polarity protection, charging control, current limitation safety and much more. A regular PC power supply don't offer such features.

One of the few that properly explains his work, I'm the total ignorant on electronics, but these explanations make me understand everything better.

It's worth a mention that the output power of -12V/-5V lines doesn't scale up with max power output of the PSU. They are limited at 6W/2.5W power output (@0.5A max current, as in your case), even if you have a 400W model. And that limitation carries over to any combination you'd use them in, for example the 24V. So "... 24 volt and all this at very high 20 Amperes" is definitely overblown.

NEVER re-charge batteries as described. Use a charging circuit to limit the current, have a proper charging cycle, and shut-off when charged. THE METHOD HERE IS AN EXTREMELY UNWISE.

Well that quite interesting i forgot that you can take the -12 v blue wire and as well the 12v to make up 24 . But the -12 will not give more that 0.7 to 0.9A usually better tap on the transformer or better you can reworked a bit but that mean you have to remove the supervisor ic . Got mine simple one done few year's ago . Great work

Congratulations for this video. I am a follower of your channel for two years ago or perhaps more. I have seen more than 40 videos about computer supplies but no one with this focusse. Very interesting and practical!!. Perfectly explained as always. Thanks and continue . Greetings from Madrid. Spain.

You are lucky that the very old capacitors didn't explodes :-)

Be VERY careful... For example, the -12V (blue wire) is only rated for a VERY small load! As for the two 'unknown' wires: - the grey is a 'Power-Good' output (to tell the computer MoBo that the supplies are all 'stable') - the purple is +5VSB (it's the 5v 'standby' voltage which is present even if the green 'start' wire hasn't been grounded)

It's an intelligent usage of SMPS with its different combinations of power supply. GREAT

I had no idea you could get so many voltages with different combinations of wires. Awesome!

Good information but littered with incorrect information. Charging lead acid batteries in this way is fine in emergency situations, but if you look at the info on the battery itself, they advise not to use a current higher than 2.1 amps. As this set up has no current limitations, a discharged battery will draw a lot of amps, which is detrimental to battery health. And in the case of lithium ion batteries, NEVER use this setup. There are easier ways to burn your house down. Always charge lithium with CC-CV charging protocol and never exceed the C ratings. All in all a good video fudged up by the lack of knowledge regarding what you are talking about.

The purple wire Is 5v too, It always outputs 5v even when the green wire isn't shorted to ground

Don't charge lithium cells with constant voltage! It will probably draw tens of amps. They must be charged with constant current. There are cheap CC buck converters for that purpose.

In computer classes, we were always told, never open your power supply, neither your monitor. At that time, the monitor had the big cathode ray tube. And the power supply had some cooper wiring and capacitors.

Plz see carefully that it is rated only 0.5 A for -5v and -12v. so if you want to use -5v and -12v in combination then you can draw only upto 0.5A. Otherwise you may end up with damaging it 😌.

hey hey, i just discovered your channel today, and so far, really great content, i also love recycling old electronics to experiment and make new stuff with it!! And if you haven't found out yet, i also wanted to tell you about the purple and grey wires because they can be very useful, the grey one is called "power good" and is used for safety, when you turn it on, the psu as a self test fonction that verify that every rail output the right amount of voltage, if everything is ok it will output +5V after a few milliseconds, but if something is wrong it will remain at 0 and a pc won't turn on, in a project like yours, you could use it with an led to make sure everything is ok before using it, i'm sure a more advanced user could even use it with some transistors to prevent part of a circuit from turning on if something is wrong!!!! the purple wire is the 5VSB(stand by) and could be used to make your projects a little more fancy if you ever want to go that way, it's the only wire that will still output 5V even when the psu is turned off(but still plugged), a pc use it for a bunch of things, like keeping the battery charged, powering the mobo's led, sleep and wake up functions, etc.. it could be used for any number of things in a diy projects, from a simple always on led, to a more complex circuit like a clock, or even power a microcontroller... basically, anything fancy you'd want your project to be able to do while it's main part is off, you can, so long as it doesn't require more than 5V!!! XD Anyway, keep up the good work, i love watching electronic videos while i'm working on something too, specially when it's about recycling old stuff into something new and useful, because not only is it fun, it can help to save the planet a little and even save you some money in the process!! XD

🤔 Before cutting the connectors, try to learn of them. This will avoid the problem you encountered with the 2 unknown wires.

As others stated the -12V cannot carry much current. It's a single wire, I can't tell what size those wires are, maybe a 22AWG, that is a 0.6mm2 wire rated around 0.9A for power transmission.

Need to be very careful charging Li-Ion batteries. They do not like continual charge beyond 4.2V. Need to add in a voltage cut off circuit set for the nominal 4.2V.

I made an electrolysys power supply it works good for remove rust

@ 24v it has very few amps. Im surprise it survived being connected to that big motor!

My friend just... THANK YOU!!!🙇‍♂️ I don't spend 100 euros for buying two 12v 5a power supply for my Imax chargers (1s-6s 80w).. I use them for recharge my 5s batteries!! I use 12v 1a power supply from wireless home phone... To charge (balance) a 5s4p battery make 10 hours...😨 with 0.7 amber...!! So I have 4 batteries 5s4p and 2 imax 80w.. Waiting for low voltage and I will charge them with 1.5a... I want to believe, I will charge them all in 10 hours...!! Thanks again for your idea!!!👏🏼👏🏼👌

Damn!, thank you very much. Finally i found a video on you tube explaining how to reuse this power supply. I saw a lot of videos in spanish (my native language) and nobody showed simple examples like you. Greetings from Venezuela. Suscribed.

I think (not 100% sure) the 2 unidentified wires are most probably connected to PGI and PGO pins of an integrated circuit supervising voltages (PGI = "Power Good Input", PGO = "Power Good Output"). That kind of IC monitors voltages (Over Voltage Detection, Under Voltage Detection, etc...), and is often an 8 pins IC in relatively recent PC power supplies, and is located in the secondary part of a power supply

Batteries of all kinds should never be charged without a proper protection or management system. There's a high risk of explosion. Better use this psu unit as a benchtop power supply.

Very good video thank you so much my friend for this information ♥️♥️♥️♥️♥️♥️🆗️👍👍

Wooow superb . I finally found a video about a great power supply . Hats off bruh ❤️❤️❤️❤️❤️

The problem you have there is over current when charging. You could easy cause a fire and buckle the plates in a battery.

06:54 - "So let's do the multimeter check for the exact output voltage and here 12.8 volt DC" [Multimeter reads 12.79v] 07:02 - "Now we have our red wire which is +5v and we have 5v exact" [Multimeter reads 5.095v] LOL You crack me up buddy!

@9:10 what diode being used?

Its not a really great sandwich, its a really great power supply @12:11

Thanks a lot You just saved me 100 $$ by blue and yellow wires.😂😂

What is that diode used for 12v battery charge

The fully charged voltage of a 12v battery is 13.4v. hence you should have at least 13.4v power supply to fully charge the battery. This 12v power supply cannot charge it fully.

for charging a lead acid batteries, you need a boost converter to boost the output from power supply to 13.8V.. and you must notice, to charging a lead acid battery with this method, the charging process is unregulated.. so, you can charge a lead acid battery with this for short period of time, if the battery voltage is nearly 12V, just use the and adaptor 12V because that is regulated charger..

It would have better if you tell us about the Amps on each combination to better use it

No use when u use -12v because -12v have only 0.5 ampere means 500 mili ampere if u use any voltage combination with -12v out put will be only 0.5 ampere means 500 mili ampere

Dose it is same for my model st_300blp

your video is very good but dangerous action and no safety. to understand it i need to play many times and write some notes and drawings. thanks for sharing. i'm computer technician

glove on the left hand. I gash my fingers real good while harvesting parts from sheer sheet metal housings, and now I have scar tissue in enough places that I don't need gloves.

The Purple One is 5v StandBy which means if the Green Wire isnt connected to ground it will still output 5v the Grey one is P.G(Power Good)

فكرتك جيدة ولكنك لو استخدمة بوردة شحن بطاريات الليثيوم بدل الموحد سوف يكون الشحن افضل ومتوافق أكثر كما يمكنك استخدام بوردة مديول الرفع كونفرتر 5 امبير تستطيع التحكم في الخرج وتدريح الفولت من 1.2فولت وحتي 40 فولت وهذا افضل

Man you could fly with the first motor with the fan if you use 24V LOL

Love you bro , finally I am not opening my computer ❤❤❤

Charging a Li Ion battery like that shown is dangerous. You must have a BM circuit to charge Li Ion batteries.

Muy buen tutorial, te felicito y a la vez te agradezco por compartir con los que siempre buscamos que aprender algo más de la forma tan sencilla y amena, un fuerte abrazo desde Perú

Thank you so much brother, this has helped me a lot for my project.. Hoping to see 1M soon, you got a sub too now! ;D And for those who are wondering, this is a ATX Power Supply which means that it has a wire which can keep supplying +5V Battery even if its powered off and that is the Purple Wire which does that. The Gray Wire provides +5V if all the other wires function correctly.. I can't go any simpler than this. And big thanks to @sBeDs in the comment section below, he helped me figure this out and I am spreading it forward. I love your videos and I like to recycle old used products and this has helped me create a computer fan powered without a motor but with a power supply. Love your vids, keep doing what you're good at.

Bro amazing what a clean and smothly way to explain every thing ...🙂👌👍🏻👍🏻👍🏻

Pls mention all the possible output voltage for smps

You will fry the batteries if you connect them directly to the supply, this is the wrong way to charge.

Why we can not charge 12 v directly by yellow+ and black- wire??

Some of the fans you can get two speeds, USB 5 volt, or 12volt high speed put in a cooler with ice you have a simple ac unit

Par Excellent Informative Video you have made seems you have digested this particular knowledge & expressing with quite ease! Admirable wisdom a true Teacher must have!

There's no overcharge protection for that?

God gives for your more knowledge

I also have the same power supply

I would not charge lithium ion batteries that way!

I found a corroded AA battery, pack of BC547 transistors, two cans of beer and an old shoe in my old computer.

Can u use that to increase in regulated 13.8volts thank sir..

Excelente tutorial maestro me ha facilitado mucho trabajo muy bien explicado estoy suscrito para sus demás vídeos exelente

person with new cell phone: my charger is 20w me with my moto g5: 300w charger😎😎😎😎

you cannot get full 300 watt by joining all the yellow wire they are all comming from one place lol

Gray wire is power good and purple wire is 5v standby.

very usefull video sir thank you for posting.

Purple +5V StandBy Grey Power Good

You did not have to pull that little power supply board out to find out anything. Diagrams are available online or you can use a multimeter to find out. Either way you won’t be pushing enough power to make much difference!

احسنت ستاذ شكرا الك لي نشر العلم لي ناس نود منك المزيد 🙋‍♂️

Thank you so much Mr, your voice is so good, i like your voice

which daoid are you use in 12v ups battery to controlling DC power?

How many Ampers out of these ??

You need a charging profile to charge with batteries of different chemistry

Thanks for your video. I learned a lot.

The two wires that you didn't understand are probably protection.

Excellent video, I always checked power supply the usual way and never really thought of checking such combination of wires. Blue and orange seems perfect way to charge up 12v battery (and packs), although I wouldn't recommend using it unless you've BMS installed. What is the value of diode you used to drop voltage?

Si ma tension de charge dépasse 14 volts ma batterie sera-t-elle endommagé ?

-12V wire provides lees current, if use it with maximum current and longer duration definitely you destroy your power supply 👍🏻🙄

Very informative video. Shukeria.

hi, please let me know, rating current -12V polarity is < 1 A,, how is it work become 20A if we use it together with 12V polarity

This is a great video. So glad I found it. Best how-to vid out there.

Very very nice 👍❤️🙏 Clear explanation thanks you

At 14:20 you connect the DMM to battery and it reads 11.93V and you say "its completely discharged", am I missing something because no one else has commented on this??? But in my world that battery is near full charge assuming its a 12V battery, full would be 12.5-12.8V. Maybe I am in bizarro inverse realm of the multiverse and just didn't realize it. I have a question and comment about my experience with combining pos & neg voltages from a PSU, but 1st I am curious about that statement.

Amazing workpiece awesome 👏

good work provided detail this will help a lot

without auto cutoff is dangerous !!!

how did you run motors on 24 volts and most PSUs only allow 0.5 to 1 Ampere on -12 volt relay.

Thanks Sir. This ur video is transformative.

An uninformed video! 18650 batteries can be charged with 4.2v, not 3.7v. 12v batteries can be charged with 14.4 volts. In addition, it is necessary to charge by applying 1/10 of the current amperage of the batteries. Bla bla bla bla .....

When I connect a cordless drill motor to the 12v line it just shuts off the PSU like a short protection... why ? The motor is rated for 12v It works on the other lines like 5v, 3.4v

Purple wire is for 5v standby grey is power good when the power is good it has around 5volts

Thanks you for your vidéos.i try to understand like you

Good job 👌👍

very informative.

Jak widać w 11:25 min to nie wszystkie linie są 20A (tylko +5V) i aż dziwne, że się nie spalił jak podłączałeś silnik na 24V bo linia -12 V ma jedynie 0,5A... ;-p

Love from pakistan🇵🇰

U are a genius, great job bro

Can you use this to charge /test lithium batteries ? Would a buck converter and potentiometer do the trick?

My power supply indicates a minus 16v when connected to the blue and red in the multimeter but yours show a positive 16v. How come?

Gracias,muchas gracias, saludos desde Venezuela