#342 12V/60A power supply (PSU) for 20 dollars? Unbelievable, but true. And high quality.

we want TC power for neopixels for example or for battery charging or for radio stations our power supply has to be strong and stable strong means in this case more than 60 amp ere's at 12 volts or so and these days it has also to be good for the environment but it should cost less than 20 dollars including shipping unbelievable that's what I thought too ritzy youtubers here is the guy with a Swiss accent with a new episode and fresh ideas around sensors and microcontrollers remember if you subscribe you will always sit in the first row recently I bought a very stable frequency standard for cheap and discovered that they used a second hand oscillator from a mobile tower to build it I thought this is cool give a professional gear a second life and save some money good for us and good for the environment then I discovered that a similar concept exists with used server power supplies short PS use because computer chips become obsolete faster than power supplies it seems that thousands of those parts can be bought on eBay in this video we will have a look at a secondhand HP power supply make it usable as a 12 volts and 62 point 5 ampair power supply because this is ideal for LED lighting we want to be able to switch it with mqtt I will not show how you can increase its voltage to thirteen point eight volts because it's too dangerous but I'm sure you find a how-to if you really want this is the power supply I bought of eBay for less than twenty dollars including shipping and in some countries you get them even cheaper different versions from different suppliers exist and all have in common that they are high quality and extremely strong mine was not dirty insight because data centers are air cond patient and remove dust from the air and they all have very similar dimensions and also a similar pinout of course they are not good-looking because they were made to be plucked into a server rack they also have no on/off switch which is the first problem we have to solve but first let's have a look inside oh thank you HP for this nice touch glad you like the channel - because I show you the internals you do not need to open yours and if you do so be warned capacitors keep their voltage long after the PSU is unplugged I strongly suggest you film you endeavour after you are buried your wife then can make a little money by posting the video to youtube under the motto he wanted to be like made he from electro boom this PSU is very densely packed and has lots of inductors and one sizable electrolytic capacitor for the power rating it is astonishingly small and lightweight this is usually possible by using high switching frequencies with this probe I can measure switching noise and here around the transformer we find a signal with peaks at 2 microseconds which is 500 kilohertz the main electronics are on this port where you also find a trimmer to change the output voltage unfortunately only in a minimal range more about that later let's now focus on the connections on the right we have large areas of copper on the top as well as on the bottom side and here we have pins numbered from 27 up to 38 we could buy edge connectors like those to connect cables to these pins most of the makers just solder the wires on the pins which is very easy because the contacts are of high quality speaking of quality you can imagine that nobody wants to have a few killed processors and memory chips only because of a bad power supply so we can assume that these power supplies are of high quality they also are very efficient this one for example 90% 240 Watts input at 220 watts output do you know why because the last 20 watts are converted into heat and because temperature must be constant in data centers the air conditioning system has to remove this seat so the operator has to pay about three times for the lost energy this is why the fan usually does not run if you do not maltreat it too much I assume they also choose a high quality fan back to the connector this copper area is ground and this one is 12 volts the same thing on the bottom unfortunately there is no voltage if we connect it to mains we have to connect pin 33 and 36 with a wire or a resistor depending on the model mind works with a wire pin 37 is essential it provides 12 volts even if the rest of the supply is off because it is rated at 2 point 5 ampair we easily can use it to power an MCU or even a Raspberry Pi in my case I will add 8 3.3 volt switching regulator to power an esp8266 pin 34 can be used to measure the current it gives a nearly linear voltage of around 1 volt per 20 ampere so you can save the 60 amp ere shunt resistor if you do not need a precise reading pin 30 is also current and pin 31 and 32 RI square C signals for the pmbus pin 35 is a 3.3 volt status signal it is high when the PSU is on by the way on pin 36 we see a smart concept this pin is a little shorter than the others so it for sure connects later than the other contacts and disconnects earlier you find this concept also in USB plugs where they want a stable power before connecting the data lines brilliant if you want just a manual switch you connect it between pin 33 and 36 I said before for some models you have to add a resistor in series but where do you find this information just enter the model number and the word hack or so and you find the information for many PS use you search for this info before you buy one then you are sure you can use it by the way if you hear snoring in the background it comes from my lab cat dishka I did not want to wake her up just for my recording back to the project I decided to use a 5 volts relay instead of a switch or a wire to connect the two pins like that I can switch the whole beast with a tiny ESP or one this relay consumes around 70 milliampere and therefore I need an n-channel FET to switch it and because I used the 12 volt standby voltage I insert a resistor which drops the voltage from 12 to 5 volts at the 70 million pair used by the relay then I connect the gate via a protection resistor to GPIO 2 for convenience I added an LED to the same pin and I said before I added a switching regulator for 3.3 volts I would not want to use a linear regulator because it probably would become quite warm of course it would be much nicer to create a PCB with these parts and an edge connector to attach it to the PSU maybe somebody creates one I could have used toss mota for the esp8266 but i decided to write a small sketch based on our OTA template from video number 3 3 2 and the pops-up mqtt library I stopped using async mqtt because I only had trouble with it and I had to replace the flash memory as shown in video number 34 because the old 512 kilobyte was too small for OTA the newer ESP o ones have 1 megabyte flash which is ok if you want it simpler you are one of those 4 12 volts and tasmat eyes the ESP oh one I leave you a German link on how to do it now I can switch the power supply from node read for example and you can add it also to home assistance etc and does it work of course I connected to my 300 watt electronic load so I cannot test the full power with it but in HP We Trust I'm pretty sure it will meet its specs and if we check the stability it is quite good twelve point three two volts at idle and only 0.1 volts less at 27 amperes for sure sufficient for a large LED installation I suggest consulting video number 246 if you intend to build a extensive neopixel project dealing with such high currents needs some precautions if you want to become happy you can use it also for the charging of a car battery or a radio transmitter the only problem here we need more voltage 13.8 volts would be suitable for most radios and also a late acid battery would be pretty charged at that voltage and now it gets dangerous this is why I will not show the how-to on this channel anyway every model needs slightly different massaging but if you want you find the information in the interwebs this was all for today when I first saw this opportunity I wanted to share it with you of course I hope that the supply will be sufficient for all of you and that prices will not increase after this video summarized we discovered an opportunity to get a powerful quality PSU for nearly no money because it is secondhand also environmentalists should love it you saw how easy it is to create a proper 12 volts 62 point 5 ampair power supply with a manual switch everybody can use a mechanical switch on this channel we always want a little bit more this is why we added an ESP or one to create a connected power supply you even could connect pin 34 to a zero of an esp8266 and return the current consumption via MQTT this concept is particularly interesting in home automation scenarios because we can integrate it into our preferred system if we need it and do not fear death we can increase its voltage to thirteen point eight volts just Google for your particular model as always you find the relevant links in the description I hope this video was useful or at least interesting for you if true please consider supporting the channel to secure its future existence thank you bye

Channel: Andreas Spiess

Views: 246,793

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Id: 0IX3euYOb5E

Length: 12min 6sec (726 seconds)

Published: Sun Jun 28 2020