Also 1 thing to note is the limitation of the circuit in 120v Countries... 2 of these psus will max out 1 (15A) circuit in your home. The 3rd unit will have to be ran not on a separate outlet but a separate circuit. Sometimes you can find a 20A outlet or circuit in certain homes but this can still be somewhat shy of the full current draw of these units. 3 of these units need 22-23A 120vAC to get full power. If you can find a way to get 240v. It cuts the AC current draw by over half.
Best to design the power supply to be twice as powerful as you actually need but yes. Obviously if your taking large amounts of power the power needs to be available in the 1st place.
I hope Vlogger doesn't mind me doing this. Would like to save some time for anyone coming across this video. It seems the problem PS is the PD-18 which has a daughter board that needs the grounding wire disconnected. The PL-18 doesn't have this and these don't have running issues. Someone below, who has put a bunch of these together, verifies this with the statement that the longer rectangular labeled PS's (PL-18) never had issues. Whereas the shorter rectangular labeled PS's (PD-18) had issues, even when mixing and matching. Though, it wasn't mentioned whether the daughter board grounding wire was disconnected by this guy. Someone who had problems with his running erratically, resolved the problem by disconnecting that wire. Also, the master PS does not have to be floating at the DC board, but all others need to be floating. Let me also add that, those floating PS's should have a 5w/15v Zener diode added from negative to PS chassis with flow direction of Zener diode so that negative current, DOES NOT, flow to the chassis. The white circle side of Zener diode should be toward the negative side. This protects each, FLOATING PS, in that if there is a DC circuit problem, it will pop the Zener diode which will flow current to the chassis and fault the PS to shut down.
I think you mean the 1 supply that is on the negative end of the circuit, what is your definition of master supply? Regarding daughter boards to ground will this not show up if you test continuity from DC negative to the chassis after the mod? Telling you weather or not there is any low resistance between negative and the chassis? I'm trying to follow what your saying about zenner protection, so if voltage rises above 15V it will send DC to the chassis of your "master supply" as that one still has a dc connection to the chassis and that voltage on the chassis will cause the supply to go into protection? So. in this case we should connect the chassis of the floating power supplies to each other including "the master supply" otherwise the fault won't show up or it might trip your RCD if earth is still connected to the chassis.
Hi. Am I correct in thinking that the first or last power supply that feeds negative into the actual circuit does not need to be modified? Only the other two or other 3 in my case need to be floating? Just wondering as it might help with noise control in a noise sensitive circuit.
Mads, I ordered three of the HP DPS-750 RB power supplies, They just arrived today, I am following your video. They are EXACTLY identical to the units in your video. I was wondering if the jumper installed has anything to do with the input voltage. I'm using 110v here (don't know if you are on 220v or 110v). So I guess it is OK to install the jumper 1 to 4 pins and plug into 110VAC. I see a pair of soldered terminals on the terminal labeled GND and +12v. Am I correct in assuming these are directly connected to the two long copper strips just past the 6 copper pins? I plan to solder the output to them as in your video. BTW: I was just wondering what you're using to dummy-load the 36v out, and what the white caps are for. THANKS MUCH!!!!!
Wow! So grateful for this great tutorial. You earned a new subscriber. I just ordered a lot of 10 of these power supplies for various projects ($54 shipped), including my 1800W induction heater.
If you need any information on these induction heaters, check out this thread: highvoltageforum.net/index.php?topic=530.0 it is chuck full of good advices and best practises for using these units.
The nylon stand offs are not necessary. The case is connected to the negative terminal via the green wire only. The chassis standoffs are screwed to pads that are not connected to anything, they are totally isolated from the power supply. Just disconnect the green wire or cut it off as it is redundant.
I actually have some other server PSUs on my work bench right now, for another project, and they do have bare copper on the GND PCB trace that goes directly to the case with metal screws. It is a HP HSTNS-PL14.
@@KaizerPowerElectronicsDk My supplies are HSTNS-PD18....Your video was very helpful, I would not have thought to use server supplies in this manner, nor would I have know they were available, and the configuration info, well I would have spent a lot of time figuring that one out. Do the PL14s have the ground wire or is it absent?
A while back I bought a bunch of servers for 10$ each and sold most of them for 50 but I kept two, each one has two 700watt psu and I'm going turn it into a 48v+ 57amp 2,400 watt charger for my custom electric scooter
@@Ferraday nah I'm going to use a DC to DC converter with cc and CV, the battery is a 16s12p and it will have a cheap bms for charging only and a active balancer to help it balance more while charging and riding. Only way I can blow up or more likely just ruin the battery is by over discharging it since there is no automatic over discharge cutoff, but I will have a few cheap rc battery buzzers that I'll alarm when voltage goes below a certain point.
great video! Thanks for sharing this. Question about the ground wire. Wouldn't it be safer to ground the cases? Since the DC rail is floating, it's possible, no?
@@KaizerPowerElectronicsDk thank you for the quick reply: well, I will isolate them I think. just in case. one more question (it may have been answered in other comments, sorry): I would like to put two of them in series. I need to disconnect base-case only from the first (that one that is giving plus at the end), right?
@@reserveschirm yes, you can leave the PSU sitting at the negative out, as original. Its only the ones going in series towards the positive side that needs to be isolated.
I also did this and witnessed some strange weirdness going on. I got two of them connected in series. And everything works as expected. I connected the third one and voltages are also alright, but the fan of the third power supply is going fast as hell from the point, I connect a wire to the pole. And if I am touching this supply at the case or poles, I can slow the fan down. Something might be broken there. The fan slows also down, if I remove one of the first 2 Supplies. Running all three sepreatly, the thrid one is also much louder than the other two.
Hi, I have a server source model ASTEC DS850-3. I can't turn it on. The green light is blinking. In the technical documentation it is written that when the green LED flashes `` Main output is OFF``. Do I need to make an internal connection? There is no voltage of 12 V or 3.3 V at the output. Thank you!
You are lucky that there is a datasheet on this power supply. Read page 2 for description of how it works and page 4 for pinout: datasheetspdf.com/pdf-file/655404/Emerson/DS850-3/1
Some power supplies need a certain resistance to turn on. But for the most, a simple jumper will do just fine. Using a resistor will limit the short circuit current, if you place it wrong, so nothing gets damaged. A wrongly placed jumper can damage the power supply.
Do all 3 have the inner grounding removed? Shoud be not only 2 need this done? 🤔 Ther is than no effective grounding for the all cases if a short happening? 🤔
I think personally that 3 in series for 36V is as high as its reliably can go. At 48V with 4 in series, you are so close to the component ratings that the stresses will eventually make one of the power supplies fail. So 60V is out of the question from my experience.
I thought these could not be put in series, that they fail. How long have you had them running for? Lipoconnectionsolutions said he was not able to get these to run in series without failure but he only isolated one of them. Your response would be greatly appreciated since I have 2 I want in series.
Im Chris at lipoconnectionsolutions. They work for a short period of time and then they randomly fail. The same has occurred with others... not my customers .... Ive had others asking me how I get them to work because theirs kept failing. The only way I was able to get them to quit failing is using the sister model with the long rectangular label. Ive tried a combination of long and short label units. Isolated all of the units. Even not doing the isolation and just insulating the cases from each other.. they all had 1 unit fail at least in my 24v model. Dont know what the failure is. I can stack as many as I want with the long label rectangular label and get long life. The short square labels fail.
I guess they got around 20 minute in total runtime so far, being used and thrown out units from a server that went beyond "lifetime" could also mean a lot! @Christofer Parham Is it also original voltage units that fail? If so I would guess the output capacitance of a unit is lower than the others and the capacitive voltage sharing goes ape shit and we get overvoltage on some of the units.
@@KaizerPowerElectronicsDk I think how the power supplies are powered up is very important. If you have two power supplies connected in series to a load, and you power up one but not the other, wouldn't the one that is not powered up see a negative voltage across its output electrolytic capacitors?
Hi, I am new at this , I only need to use one for 12 volts , if the chasis is ground, were do I pick up the positive , ( dps-750ab-3a ) is the two copper strips on pc board have a positive? I am going to power a transmitter on low power. Do I still have to isolate pc board if only using one ?
Hi Paul. You do not need to isolate the chassis, when only using one. It is ONLY needed when putting them in series for 24V or higher. The negative 0V and positive 12V outputs are side by side. You can easily find the negative rail with a multimeter and test connectivity to the chassis. The other big one is positive. My PSU has both sides of PCB connected to either negative or positive, as you can see i soldered the large wire on both sides.
Now that you have soldered the jumper wire does this mean that whenever I plug the pc in the psu has power but then I press the PC case button it activates the pico that is being powered by the PSU?
Thanks for this video. I like to use these powersupplies for powering ledstrips in the house (a lot of them 1000 w +) for transporting the power i want to use 36 V and than bring it down to 12 using a buck converters. Is it possible to take 12 volts if you have 3 in series by using the + and - from the fist one? (used to power some local stuff) or you reccomment an different powersupply for this?
I have the same power supply and isolated the ground of one of them. (going to make a 24v charger power supply) after I floated the ground I'm measuring 6v between the case and ground. There is no continuity to the case or to mains ground. Is this normal?
@KaizerPowerElectronicsDk thanks for the quick reply. With some load it drops to zero. While going over it I've noticed one of the diodes om the controle board marked AE (there's a bunch of them near the AC side) is blown but everything works so I'm gonna push my luck and see how it holds up with a full load lol. I'm guessing it's a Transient Suppression diode that's not too essential
Since I'm pushing around 60A to charge large 12S lipo cells that's the least of my concern ;). I've found out the dioide is only linked to the fan controle so one of the 2 psu's skips over one of the intermediate fan speeds wich for me is no problem at all. Even after 5 years still a great video!
Technical issue question. Are only certain HP power supply can be put in series? I tried to put HP power supply HSTNS-PL18 750w in series , 3 of them, but the power cord(s) began to burn up. Pls advise. Thx.
@@KaizerPowerElectronicsDk I figured out what was burning. The ground wire(s) of the mains that were powering the power supplies were burning. I have 6, 750W power supplies connected in series, and found out that only one unit/power supply can have ground wiring. I didn't go with disconnecting the ground wires inside the power supplies because I didn't want loose wires or floating wires. For any person that is looking to build a DIY power supply, make sure you have only one ground wiring for the series connection unit. And thank you Kaizer for putting up this instructional video that expanded my knowledge about series power supply DIY. Best. P.S. Also, I have 3D printed my series power supply housing. Each power supply with custom cooling fan with lid (the top lid removed) and spacing.
Hi, I bought two of these to use in series, but both of them have nylon standoffs. Can I still use them as 24v psu? I thought of insulating the cases to make it safe but I do not know that much about electeonics
@@KaizerPowerElectronicsDk by 0V you mean the middle pad here th-cam.com/video/xRAlXCzsY3Q/w-d-xo.html , right ? I'm still learning and don't want to mess anything up. If so, it shows no continuity.
They are still alive, check out the latest videos where I use them: th-cam.com/video/Q3JOZFh0z_Y/w-d-xo.html and th-cam.com/video/VCfnuYSuDhc/w-d-xo.html and th-cam.com/video/8Xo6V50JdDw/w-d-xo.html
Thanks. I have the same supplies. Did you remove anything on the other side of the PSU? The other standoff screw, the mains earth ground wire that is green/yellow, or the black wire on the daughter board on the side of the supply? I’m asking because my negative is isolated when I check continuity, but when running, I can measure 6v dc between the case and dc negative.
@@BATTERY73 mains earth wire and standoff grounding point are left in place, since that is for protection of humans. The black wire to daughter board is removed.
Kaizer Power Electronics Just to confirm, there are two wires on that daughter board. Green and Black, both removed? I don’t have stable voltage if the cases touch. The black wire doesn’t have continuity to the DC side? I thought it was AC related.
HI, I have connect four up power supplies (same model as yours) and isolated the dc ground on all four (exactly same as you've done) however only 3 supplies power up and the fourth does not. Note I have swapped the power supplies around and used spare ones, but the issue still happens....note always the first server in series (it's positive connected to next supply and it's negative to load)....any ideas please?
Could be some overvoltage condition or avalanche on a diode. Maybe the control circuit is not completely isolated at a higher voltage and you have more leakage or something. Never tried 4 in series.
@@KaizerPowerElectronicsDk HI, many thanks.....I have one idea, and will let you know if works....meanwhile curious....I have floated all my power supplies yet some forums say you only need to float those you connect to a master I.e. One grounded connected to my other 3 which would be floated.......what do you think plz....could this be the cause of my original issue?
@@lukebrown6913 It can only be the one sitting as the last in the negative end that can be grounded, as it is at the grounded end. I did not try that either, I floated all mine.
@@KaizerPowerElectronicsDk sorry, plz can I ask one final question please....each power supply is 750w, but putting four in series won't increase the wattage i.e. 2500w....series only increases the voltage ..is this right?
@@lukebrown6913 Power in Watt is P = U * I. Current in a string is the same all way through. Voltage is divided by each link in the series connection. So you have 62.5A from a single power supply, that current rating will be the same with more in series, but the voltage goes up. So from 1 power supply 12V * 62.5A = 750VA, but 3 power supplies 36V * 62.5A = 2250VA.
I got my 10 units and have been experimenting with them in series. I had some success, but could not get more than 3 in series working at a time. Even with the three, I have some interesting behavior. Without a load, as soon as I connect the 3rd one to the series, one of the fans slows way down. Similar behavior if I change order and swap entire units in and out. Adding a load, same behavior. Remove the third unit and the fans spin up due to the load. The output voltage and current is fine, but the fan just never spins up, even as the PS heats up. When I was trying 4 in series, I initially had success, but then started getting smoke out of the last unit (no load applied!). I tried swapping units in and out to get the 4 in series working, but either got a chip next to the fan overheating, or a supply shutting itself down right away. One power supply now has it's fan minimum speed permanently increased to about 30%. My thermal camera has been critical for these experiments! I feel like I need to make a whole video analysis of these power supplies.
Keeping in mind that these are built for 12V output, the power electronics part in the inverter is not rated for much. It could perhabs be 40 or 60V parts, if even that high. So if voltage sharing or grounding of the chained power supplies is not removed, you are pushing the parts above their limit or creating ground paths that makes them work against eachother. I assume you did remove all grounds of negative rail except on the last in the chain at the negative rail?
@@KaizerPowerElectronicsDk Thanks for the info. I'm fairly new to hooking up power supplies in series, so it's been a challenge understanding all of these oddities. I removed all grounding on the secondary side in my first attempt. Then I tried grounding one secondary in the chain, and moved the grounded unit to all different places in the chain (1st, 2nd, 3rd, then last). I actually overheated and blew up a tiny diode connected to ground (there are 4 diodes connected to the earth wire near the fan). Using my FlIR One, I saw that the diode area heats up FAST when when the 4 are chained, and not at all when there are 3 or less. I made a video showing all the things I tried and the results. I'll try and post it tonight.
UPDATE: I disconnected the ground on the rear of the daughter board, and my 4 in series worked! It was a brief, unloaded test, so cannot confirm if there are any side effects. I was thinking of connecting that rear ground wire to the cut ground wire in the front since they are essentially connected in stock units via earth ground. If I was an electrical engineer, I'd know why this appears to have worked and the problems it could cause.
Hey men. How are you? I have some problems here. I did the modification, and when turm on, they don't gave me the 12volts. I read like 5 volts, 3 volts, 6 volts. The 3 power supplys the same thing. If i reconnect the green terminal to the chassis then 12 volts. Do you know what can be wrong??
Did you check that each power supply work on its own before modifying them? Sounds like one or more are broken and its continuously starting up/shutting down from under/over-current or -voltage.
Hey I am having problems as well. Hope you figure something out. HSTNS-PD18 some are not isolating with the standoffs and green wire removed idk why...
@@KaizerPowerElectronicsDk yes I check each psu before modifying, and all works grate. I think maybe here in Venezuela, uses 110volt outlets with only two terminals, I think that I need the ground of the 3rd terminal. Tomorrow I will try in my office. Thank you very much for your reply. Very good videos. Best wishes for you.
I tried with 4 to get 48V but the last one sparked in the fan area. I think its broken now, but the other three still work in series (36V). Is 48V just too much for the internal parts?
I burned a few of mine this way too. The power going to the fan passes through a set of TINY diodes (on the board near the fan). Those diodes get hot fast and quickly burn. The neg side of the fan is connected directly to ground (small wire with screw terminal on the board near the fan). I'm no expert, but it seems to me like that area is seeing the high series voltage due to that ground. To try and solve it, I connected the ground wire we removed from the front to this ground wire near the fan to make the fan use our isolated "ground". It improved strange fan behaviors I saw with 3 in series, but I have not yet been brave enough to try 4 again. I bought a cheap astec 42v 6000 watt power supply around that time (35$ shipped), so no longer needed the 4 HPs in series.
I just realized I posted about this "fix" in these comments 9 months ago, but I had no clue why it worked at the time. I must have gotten a little smarter in 9 months. According to my 9 month old comment, I DID get 4 working in series with no magic smoke. Nice!
@@aromaticpillow Was wondering if you could possibly answer a few questions on those Cisco Astec power supplies. Is the C13 computer plug proper for these? Do you have to do anything special to get them to start up? I see the connectors in back, are they labeled?..IE, 3.3v and 12v...If you can, much appreciated.
Did you try to connect them in parallel? I have a plan to connect a couple of 19V laptop chargers in parallel to run some cordless tools. I know that I should protect each charger by diode, could anyone advice what kind of diode should I use? Could this parallel connection actualy work? Thanks.
That was the right question for the right guy! I made a 2kW series/parallel power supply from 12 old laptop power charges, abused it as power supply for a induction heater and it regulated very well: th-cam.com/video/5iMFYdDMfXo/w-d-xo.html
@@KaizerPowerElectronicsDk Thank you. I have already watched your videos. It seems it works without diodes but I would prefer to use them. Could you please explain the purpose of capacitors in your setup? How to connect them and what capacity to use? Maximum output current of my project will be 50A at 19,5V
@@martinrob7230 The idea of adding capacitors was to have some surge current supply from changing loads in the induction heater, to give the power supplies more time to regulate to load.
Hello thanks fo the video my hp1500w power supply heats up quite a bit at 40% load I wanted to know if this is normal? I have other hp1200w power supplies which are much cooler. What is the normal temperature of the power metal cases? Thanks in advance :)
@@KaizerPowerElectronicsDk thank you for the answer I check by touch and it is possible to touch it between 5 and 10 seconds maximum so is it normally good?
@@mehdi660 server psu are designed from 5 to 50 degree inlet temperature, above 44 degrees you will start feeling pain www.jm.com/en/blog/2015/february/too-hot-to-handle/
The best I can give you, but I have not tried myself. www.rcgroups.com/forums/showpost.php?p=25149870&postcount=2238 and th-cam.com/video/4P1-lpzYV1Y/w-d-xo.html
@@KaizerPowerElectronicsDk You can increase the voltage using several methods ... they work a short period of time... and guess what they randomly fail. Ive been selling these Psus way to long and just when i think i figured it out and got something solid.. I go to put it on the market and I have to warranty returns because they dont fail on my bench or load station after hours of testing they fail randomly with the end user. Most of the time when users are requesting 13.8 they really dont have a good reason to other than it would be nice but the wattage gains arent worth it vs having the units run at their native voltage of 12.3... they can go to 12.6 without issue via a trim pot thats built into certain models but when you got for those higher voltages where you have to defeat the OVP and resistor trickery... Its always ended up being a fail in the real world for my users.
Look for a "Cisco WS-CAC-6000W". There are versions of 3000 / 6000 or even 9000 Watt! You can get them very cheap of off ebay and are quite easy to modifiy from 38...52 V output at over 100 Amps! You can read about modifications in the MFK-forum over here: forum.mosfetkiller.de/viewtopic.php?f=2&t=63559&p=284968#p284968
Just ordered one for 30$ incl shipping. It has a 42v output stock! My 3 HP supplies run OK in series for 36v, but they exhibit some strange fan behavior that i am not 100% comfortable with.
I got a few HP 723600-201 power supplies but can't seem to find a video on jumping the power on traces. It has ten thin traces on top and ten on the bottom. Anyone worked with this style of pin outs. It might be the one where you jump pins 1 to 4 with a 220ohm resister or the other method is jumping pin 30 and 31 which are on the top and bottom. The problem is that one PSU has 6 pins and the other has 8 . Mine has 10 so there should be a way to do it. The far right pin on top (near the long negative pin) is labeled S20
It may have to do with that being a hot plug power supply. I read a thread about removing something on a hot plug power supply, so I made sure I didn't get a hot plug supply. Did you figure it out?
Could I instead putting a jumper between the starting pins, a switch on the not modefied power supply, to start that way all power supplys together ? 🤔 Would be nice If someone would make a video how that could be done. 😊
As long as the capacitance variance is no larger than each capacitor in the string would see below its rated voltage. You do know about capacitive voltage divider?
@@KaizerPowerElectronicsDk Ok so sounds like it's ok, I saw another video mention it so wasn't sure. & No I don't know anything, but I am reading about it now
@@gg-gn3re I wrote a small article about it, for large electrolytic and other DC bus capacitors in series or parallel: kaizerpowerelectronics.dk/tesla-coils/drsstc-design-guide/dc-bus-capacitor/
You can put them in parallel without problems. You do not need to remove the negative side grounding for that. You could add diodes on each positive lead to avoid one power supply pushing power into the other, which can give funny regulation results.
@@KaizerPowerElectronicsDk I have a breakout board for hst pl11 with 8 16awg wires connecting to a distribution bolt. so I could add another one and connect it to the same bolt to get more capacity for my car audio amplifiers
Your best bet would be the rcforums, but I did check there and google. Best approach would be to find a picture of one with similar pad layout and then try to make the short circuit with a 1K5 resistor to limit the current if you hit something wrong.
@@JawadAhmadsahibzada Sure that's all good, please, tell us all where to get one for $24. As 1200w, 12v, 100A power supplies can be had today for that price on ebay.
150W induction heater: th-cam.com/video/A8FWSzfHgGc/w-d-xo.html
1800W induction heater: th-cam.com/video/jmAZhjl8Ybk/w-d-xo.html
36V 2200W server power supply: th-cam.com/video/xRAlXCzsY3Q/w-d-xo.html
40V 2000W laptop power supply: th-cam.com/video/5iMFYdDMfXo/w-d-xo.html
1800W IH 10 minute stress test: th-cam.com/video/v-TsBLFp8yo/w-d-xo.html
This is bloody brilliant, thanks very much. Like the rest of your stuff: straight to the point, clear, no b/s, just excellent info. Great.
Thank you Steve!
Also 1 thing to note is the limitation of the circuit in 120v Countries... 2 of these psus will max out 1 (15A) circuit in your home. The 3rd unit will have to be ran not on a separate outlet but a separate circuit. Sometimes you can find a 20A outlet or circuit in certain homes but this can still be somewhat shy of the full current draw of these units. 3 of these units need 22-23A 120vAC to get full power. If you can find a way to get 240v. It cuts the AC current draw by over half.
That is a advantage in most of Europe. 230V 10-13A on single outlets
Best to design the power supply to be twice as powerful as you actually need but yes. Obviously if your taking large amounts of power the power needs to be available in the 1st place.
I hope Vlogger doesn't mind me doing this. Would like to save some time for anyone coming across this video. It seems the problem PS is the PD-18 which has a daughter board that needs the grounding wire disconnected. The PL-18 doesn't have this and these don't have running issues. Someone below, who has put a bunch of these together, verifies this with the statement that the longer rectangular labeled PS's (PL-18) never had issues. Whereas the shorter rectangular labeled PS's (PD-18) had issues, even when mixing and matching. Though, it wasn't mentioned whether the daughter board grounding wire was disconnected by this guy. Someone who had problems with his running erratically, resolved the problem by disconnecting that wire. Also, the master PS does not have to be floating at the DC board, but all others need to be floating. Let me also add that, those floating PS's should have a 5w/15v Zener diode added from negative to PS chassis with flow direction of Zener diode so that negative current, DOES NOT, flow to the chassis. The white circle side of Zener diode should be toward the negative side. This protects each, FLOATING PS, in that if there is a DC circuit problem, it will pop the Zener diode which will flow current to the chassis and fault the PS to shut down.
Thank you for the information :)
I think you mean the 1 supply that is on the negative end of the circuit, what is your definition of master supply? Regarding daughter boards to ground will this not show up if you test continuity from DC negative to the chassis after the mod? Telling you weather or not there is any low resistance between negative and the chassis? I'm trying to follow what your saying about zenner protection, so if voltage rises above 15V it will send DC to the chassis of your "master supply" as that one still has a dc connection to the chassis and that voltage on the chassis will cause the supply to go into protection? So. in this case we should connect the chassis of the floating power supplies to each other including "the master supply" otherwise the fault won't show up or it might trip your RCD if earth is still connected to the chassis.
Hi. Am I correct in thinking that the first or last power supply that feeds negative into the actual circuit does not need to be modified? Only the other two or other 3 in my case need to be floating? Just wondering as it might help with noise control in a noise sensitive circuit.
You are correct that the bottom negative one can be left unmodified. But only that one.
Mads,
I ordered three of the HP DPS-750 RB power supplies, They just arrived today, I am following your video. They are EXACTLY identical to the units in your video. I was wondering if the jumper installed has anything to do with the input voltage. I'm using 110v here (don't know if you are on 220v or 110v). So I guess it is OK to install the jumper 1 to 4 pins and plug into 110VAC.
I see a pair of soldered terminals on the terminal labeled GND and +12v. Am I correct in assuming these are directly connected to the two long copper strips just past the 6 copper pins? I plan to solder the output to them as in your video.
BTW: I was just wondering what you're using to dummy-load the 36v out, and what the white caps are for.
THANKS MUCH!!!!!
Im in 230VAC country. I used caps for current surge on the load. I just have a lot of power resistors :)
Wow! So grateful for this great tutorial. You earned a new subscriber. I just ordered a lot of 10 of these power supplies for various projects ($54 shipped), including my 1800W induction heater.
If you need any information on these induction heaters, check out this thread: highvoltageforum.net/index.php?topic=530.0 it is chuck full of good advices and best practises for using these units.
what size are the nylon screws i need to float it
The nylon stand offs are not necessary. The case is connected to the negative terminal via the green wire only. The chassis standoffs are screwed to pads that are not connected to anything, they are totally isolated from the power supply. Just disconnect the green wire or cut it off as it is redundant.
I actually have some other server PSUs on my work bench right now, for another project, and they do have bare copper on the GND PCB trace that goes directly to the case with metal screws. It is a HP HSTNS-PL14.
@@KaizerPowerElectronicsDk No doubt.
@@KaizerPowerElectronicsDk My supplies are HSTNS-PD18....Your video was very helpful, I would not have thought to use server supplies in this manner, nor would I have know they were available, and the configuration info, well I would have spent a lot of time figuring that one out.
Do the PL14s have the ground wire or is it absent?
A while back I bought a bunch of servers for 10$ each and sold most of them for 50 but I kept two, each one has two 700watt psu and I'm going turn it into a 48v+ 57amp 2,400 watt charger for my custom electric scooter
mashed potatoes you’re gonna blow up your scooter battery but good luck
@@Ferraday nah I'm going to use a DC to DC converter with cc and CV, the battery is a 16s12p and it will have a cheap bms for charging only and a active balancer to help it balance more while charging and riding. Only way I can blow up or more likely just ruin the battery is by over discharging it since there is no automatic over discharge cutoff, but I will have a few cheap rc battery buzzers that I'll alarm when voltage goes below a certain point.
great video! Thanks for sharing this. Question about the ground wire. Wouldn't it be safer to ground the cases? Since the DC rail is floating, it's possible, no?
The cases are still grounded to mains earth.
Was thinking that perhaps it's a good idea to equalize the output voltages as best you can when connecting them in series, especially 3 of them.
hey there, good video - what did you do with the loosened black wires that used to go to the control board? just hanging around surely not ... ?
Thank you, well, for reasons not investigated, it worked with floating black wire, so its floating :)
@@KaizerPowerElectronicsDk thank you for the quick reply: well, I will isolate them I think. just in case. one more question (it may have been answered in other comments, sorry): I would like to put two of them in series. I need to disconnect base-case only from the first (that one that is giving plus at the end), right?
@@reserveschirm yes, you can leave the PSU sitting at the negative out, as original. Its only the ones going in series towards the positive side that needs to be isolated.
I also did this and witnessed some strange weirdness going on. I got two of them connected in series. And everything works as expected. I connected the third one and voltages are also alright, but the fan of the third power supply is going fast as hell from the point, I connect a wire to the pole. And if I am touching this supply at the case or poles, I can slow the fan down. Something might be broken there. The fan slows also down, if I remove one of the first 2 Supplies. Running all three sepreatly, the thrid one is also much louder than the other two.
ever get it figured out?
@@quinnfoster4671 yes, I had to isolate all 3 , from gnd.
@@myduffly Interesting, as you should have only needed to float/isolate 2 of the 3.
Hi, I have a server source model ASTEC DS850-3. I can't turn it on. The green light is blinking. In the technical documentation it is written that when the green LED flashes `` Main output is OFF``. Do I need to make an internal connection? There is no voltage of 12 V or 3.3 V at the output. Thank you!
You are lucky that there is a datasheet on this power supply. Read page 2 for description of how it works and page 4 for pinout: datasheetspdf.com/pdf-file/655404/Emerson/DS850-3/1
@@KaizerPowerElectronicsDk Thank you!
I see some people using a resistor as a start jumper? Whats the difference between a resister and just having a wire?
Some power supplies need a certain resistance to turn on. But for the most, a simple jumper will do just fine. Using a resistor will limit the short circuit current, if you place it wrong, so nothing gets damaged. A wrongly placed jumper can damage the power supply.
Question, can you still earth the casings after isolating ?
Do all 3 have the inner grounding removed? Shoud be not only 2 need this done? 🤔 Ther is than no effective grounding for the all cases if a short happening? 🤔
The enclosure is still mains grounded, so its safe for humans, but the secondary side cant detect a fault to earth, so it will properly burn down :)
@@KaizerPowerElectronicsDk 😂👍
In series does the wattage go up as well or do they have to be in parallel. Looking for a cheap option to get 4000w 60amp 64v
I think personally that 3 in series for 36V is as high as its reliably can go. At 48V with 4 in series, you are so close to the component ratings that the stresses will eventually make one of the power supplies fail. So 60V is out of the question from my experience.
you eliminated all 3 grounds ? did not you left the ground of 1 conected to one of the cases ?
I have tried to both remove all grounds and also leave ground on the last unit at the negative rail, no difference.
@@KaizerPowerElectronicsDk thake you
Would just removing the ground pin (without isolating the chassis) on the AC input work?
THANKS MUCH!!!
This might trip RCD/GFCI from leakage current, when putting more in series.
I thought these could not be put in series, that they fail. How long have you had them running for? Lipoconnectionsolutions said he was not able to get these to run in series without failure but he only isolated one of them. Your response would be greatly appreciated since I have 2 I want in series.
Im Chris at lipoconnectionsolutions. They work for a short period of time and then they randomly fail. The same has occurred with others... not my customers .... Ive had others asking me how I get them to work because theirs kept failing. The only way I was able to get them to quit failing is using the sister model with the long rectangular label. Ive tried a combination of long and short label units. Isolated all of the units. Even not doing the isolation and just insulating the cases from each other.. they all had 1 unit fail at least in my 24v model. Dont know what the failure is. I can stack as many as I want with the long label rectangular label and get long life. The short square labels fail.
@@icecube578 that was me that asked on FB last night
I guess they got around 20 minute in total runtime so far, being used and thrown out units from a server that went beyond "lifetime" could also mean a lot!
@Christofer Parham Is it also original voltage units that fail? If so I would guess the output capacitance of a unit is lower than the others and the capacitive voltage sharing goes ape shit and we get overvoltage on some of the units.
@@KaizerPowerElectronicsDk I think how the power supplies are powered up is very important. If you have two power supplies connected in series to a load, and you power up one but not the other, wouldn't the one that is not powered up see a negative voltage across its output electrolytic capacitors?
@@cruiser97eric1 what if you make a ac cable that combines all the power supplies into one cable
Hi, I am new at this , I only need to use one for 12 volts , if the chasis is ground, were do I pick up the positive , ( dps-750ab-3a ) is the two copper strips on pc board have a positive? I am going to power a transmitter on low power. Do I still have to isolate pc board if only using one ?
Hi Paul. You do not need to isolate the chassis, when only using one. It is ONLY needed when putting them in series for 24V or higher. The negative 0V and positive 12V outputs are side by side. You can easily find the negative rail with a multimeter and test connectivity to the chassis. The other big one is positive. My PSU has both sides of PCB connected to either negative or positive, as you can see i soldered the large wire on both sides.
Now that you have soldered the jumper wire does this mean that whenever I plug the pc in the psu has power but then I press the PC case button it activates the pico that is being powered by the PSU?
Plug in = power on.
Looks good!
I have a question
How can i fix - and + kabels on this power supply?
I would like to use it as a adapter for my home sound system
You can buy adapters for these power supplies or solder on screw terminals.
Thanks for this video. I like to use these powersupplies for powering ledstrips in the house (a lot of them 1000 w +) for transporting the power i want to use 36 V and than bring it down to 12 using a buck converters. Is it possible to take 12 volts if you have 3 in series by using the + and - from the fist one? (used to power some local stuff) or you reccomment an different powersupply for this?
If its a minimal load, you can take 12V from the last of them. So you still have a reference to ground.
Do you isolate one or all 3 power supplies?
Here I isolated all 3. You can leave the last in the series at the negative end be grounded.
I have the same power supply and isolated the ground of one of them. (going to make a 24v charger power supply) after I floated the ground I'm measuring 6v between the case and ground. There is no continuity to the case or to mains ground. Is this normal?
Its normal with a high impedance measurement, try to add a little load like a resistor and it should be loaded down to nothing.
@KaizerPowerElectronicsDk thanks for the quick reply. With some load it drops to zero. While going over it I've noticed one of the diodes om the controle board marked AE (there's a bunch of them near the AC side) is blown but everything works so I'm gonna push my luck and see how it holds up with a full load lol.
I'm guessing it's a Transient Suppression diode that's not too essential
@@RubenRC94 yeah well.. you already bypassed a safety feature when removing the ground, which ruins the PELV class of the power supply :)
Since I'm pushing around 60A to charge large 12S lipo cells that's the least of my concern ;). I've found out the dioide is only linked to the fan controle so one of the 2 psu's skips over one of the intermediate fan speeds wich for me is no problem at all. Even after 5 years still a great video!
Do you have to isolate the grounds in order to run them in parallel?
Yes, Else you have to float mains ground and chassis can not touch each other. So its more dangerous.
Technical issue question. Are only certain HP power supply can be put in series? I tried to put HP power supply HSTNS-PL18 750w in series , 3 of them, but the power cord(s) began to burn up. Pls advise. Thx.
What burned up? With appropriate fuses in front of these and needed wire size on the DC side, you should never have smoking wires!
@@KaizerPowerElectronicsDk I figured out what was burning. The ground wire(s) of the mains that were powering the power supplies were burning. I have 6, 750W power supplies connected in series, and found out that only one unit/power supply can have ground wiring. I didn't go with disconnecting the ground wires inside the power supplies because I didn't want loose wires or floating wires. For any person that is looking to build a DIY power supply, make sure you have only one ground wiring for the series connection unit. And thank you Kaizer for putting up this instructional video that expanded my knowledge about series power supply DIY. Best.
P.S. Also, I have 3D printed my series power supply housing. Each power supply with custom cooling fan with lid (the top lid removed) and spacing.
Hi, I bought two of these to use in series, but both of them have nylon standoffs. Can I still use them as 24v psu? I thought of insulating the cases to make it safe but I do not know that much about electeonics
First check with a multimeter if output 0V is connected to ground /case.
@@KaizerPowerElectronicsDk by 0V you mean the middle pad here th-cam.com/video/xRAlXCzsY3Q/w-d-xo.html , right ? I'm still learning and don't want to mess anything up. If so, it shows no continuity.
Yes, how about continuity to mains plug ground pin?
Have these failed or are they still alive?
They are still alive, check out the latest videos where I use them: th-cam.com/video/Q3JOZFh0z_Y/w-d-xo.html and th-cam.com/video/VCfnuYSuDhc/w-d-xo.html and th-cam.com/video/8Xo6V50JdDw/w-d-xo.html
Thanks. I have the same supplies. Did you remove anything on the other side of the PSU? The other standoff screw, the mains earth ground wire that is green/yellow, or the black wire on the daughter board on the side of the supply? I’m asking because my negative is isolated when I check continuity, but when running, I can measure 6v dc between the case and dc negative.
@@BATTERY73 mains earth wire and standoff grounding point are left in place, since that is for protection of humans. The black wire to daughter board is removed.
Kaizer Power Electronics Just to confirm, there are two wires on that daughter board. Green and Black, both removed? I don’t have stable voltage if the cases touch. The black wire doesn’t have continuity to the DC side? I thought it was AC related.
@@soldermecold7456 sorry, I meant the green, it just had so much crimp on it that I remebered as black, its shown at 2:30 in the video.
Where are you plugging in the 3 power cords without blowing the breaker?
In Denmark we have 230VAC with 10-13A fuses in the breaker panel, so I can run these three on a single mains outlet.
HI, I have connect four up power supplies (same model as yours) and isolated the dc ground on all four (exactly same as you've done) however only 3 supplies power up and the fourth does not. Note I have swapped the power supplies around and used spare ones, but the issue still happens....note always the first server in series (it's positive connected to next supply and it's negative to load)....any ideas please?
Could be some overvoltage condition or avalanche on a diode. Maybe the control circuit is not completely isolated at a higher voltage and you have more leakage or something. Never tried 4 in series.
@@KaizerPowerElectronicsDk HI, many thanks.....I have one idea, and will let you know if works....meanwhile curious....I have floated all my power supplies yet some forums say you only need to float those you connect to a master I.e. One grounded connected to my other 3 which would be floated.......what do you think plz....could this be the cause of my original issue?
@@lukebrown6913 It can only be the one sitting as the last in the negative end that can be grounded, as it is at the grounded end. I did not try that either, I floated all mine.
@@KaizerPowerElectronicsDk sorry, plz can I ask one final question please....each power supply is 750w, but putting four in series won't increase the wattage i.e. 2500w....series only increases the voltage ..is this right?
@@lukebrown6913 Power in Watt is P = U * I. Current in a string is the same all way through. Voltage is divided by each link in the series connection. So you have 62.5A from a single power supply, that current rating will be the same with more in series, but the voltage goes up. So from 1 power supply 12V * 62.5A = 750VA, but 3 power supplies 36V * 62.5A = 2250VA.
Would it be wise to use my 220v outlet for this? I think this will probably max out my 15A 120v circuit.
15A 120V is 1800W max, so yes you should use your 220V outlet if possible and the input voltage range of your power supplies allow for it.
Can you keep the first one grounded ??
You can keep the one with negative rail as output, grounded.
Power supply connect in series risks of insulation damage internal..?
How much power supply connected in series...?
3 is stable, 4 can fail, 5 is too much.
Maximum is 3
very helpful video thanks you
I got my 10 units and have been experimenting with them in series. I had some success, but could not get more than 3 in series working at a time. Even with the three, I have some interesting behavior. Without a load, as soon as I connect the 3rd one to the series, one of the fans slows way down. Similar behavior if I change order and swap entire units in and out. Adding a load, same behavior. Remove the third unit and the fans spin up due to the load. The output voltage and current is fine, but the fan just never spins up, even as the PS heats up. When I was trying 4 in series, I initially had success, but then started getting smoke out of the last unit (no load applied!). I tried swapping units in and out to get the 4 in series working, but either got a chip next to the fan overheating, or a supply shutting itself down right away. One power supply now has it's fan minimum speed permanently increased to about 30%. My thermal camera has been critical for these experiments! I feel like I need to make a whole video analysis of these power supplies.
Keeping in mind that these are built for 12V output, the power electronics part in the inverter is not rated for much. It could perhabs be 40 or 60V parts, if even that high. So if voltage sharing or grounding of the chained power supplies is not removed, you are pushing the parts above their limit or creating ground paths that makes them work against eachother. I assume you did remove all grounds of negative rail except on the last in the chain at the negative rail?
@@KaizerPowerElectronicsDk Thanks for the info. I'm fairly new to hooking up power supplies in series, so it's been a challenge understanding all of these oddities.
I removed all grounding on the secondary side in my first attempt. Then I tried grounding one secondary in the chain, and moved the grounded unit to all different places in the chain (1st, 2nd, 3rd, then last). I actually overheated and blew up a tiny diode connected to ground (there are 4 diodes connected to the earth wire near the fan). Using my FlIR One, I saw that the diode area heats up FAST when when the 4 are chained, and not at all when there are 3 or less. I made a video showing all the things I tried and the results. I'll try and post it tonight.
UPDATE: I disconnected the ground on the rear of the daughter board, and my 4 in series worked! It was a brief, unloaded test, so cannot confirm if there are any side effects. I was thinking of connecting that rear ground wire to the cut ground wire in the front since they are essentially connected in stock units via earth ground. If I was an electrical engineer, I'd know why this appears to have worked and the problems it could cause.
@@aromaticpillow I want to do the same as you, 4 in series. Are your setup still working? I have the HP HSTNS-PD18.
Looks good!
Hey men. How are you? I have some problems here. I did the modification, and when turm on, they don't gave me the 12volts. I read like 5 volts, 3 volts, 6 volts. The 3 power supplys the same thing. If i reconnect the green terminal to the chassis then 12 volts. Do you know what can be wrong??
Did you check that each power supply work on its own before modifying them? Sounds like one or more are broken and its continuously starting up/shutting down from under/over-current or -voltage.
Hey I am having problems as well. Hope you figure something out. HSTNS-PD18 some are not isolating with the standoffs and green wire removed idk why...
@@KaizerPowerElectronicsDk yes I check each psu before modifying, and all works grate. I think maybe here in Venezuela, uses 110volt outlets with only two terminals, I think that I need the ground of the 3rd terminal. Tomorrow I will try in my office. Thank you very much for your reply. Very good videos. Best wishes for you.
I tried with 4 to get 48V but the last one sparked in the fan area. I think its broken now, but the other three still work in series (36V). Is 48V just too much for the internal parts?
You are not the first to report these failures with 4 in series, so it is safe to say that it pushing them too far.
I burned a few of mine this way too. The power going to the fan passes through a set of TINY diodes (on the board near the fan). Those diodes get hot fast and quickly burn. The neg side of the fan is connected directly to ground (small wire with screw terminal on the board near the fan). I'm no expert, but it seems to me like that area is seeing the high series voltage due to that ground. To try and solve it, I connected the ground wire we removed from the front to this ground wire near the fan to make the fan use our isolated "ground". It improved strange fan behaviors I saw with 3 in series, but I have not yet been brave enough to try 4 again. I bought a cheap astec 42v 6000 watt power supply around that time (35$ shipped), so no longer needed the 4 HPs in series.
I just realized I posted about this "fix" in these comments 9 months ago, but I had no clue why it worked at the time. I must have gotten a little smarter in 9 months. According to my 9 month old comment, I DID get 4 working in series with no magic smoke. Nice!
@@aromaticpillow Was wondering if you could possibly answer a few questions on those Cisco Astec power supplies. Is the C13 computer plug proper for these? Do you have to do anything special to get them to start up? I see the connectors in back, are they labeled?..IE, 3.3v and 12v...If you can, much appreciated.
Did you try to connect them in parallel? I have a plan to connect a couple of 19V laptop chargers in parallel to run some cordless tools. I know that I should protect each charger by diode, could anyone advice what kind of diode should I use? Could this parallel connection actualy work? Thanks.
That was the right question for the right guy! I made a 2kW series/parallel power supply from 12 old laptop power charges, abused it as power supply for a induction heater and it regulated very well: th-cam.com/video/5iMFYdDMfXo/w-d-xo.html
@@KaizerPowerElectronicsDk Thank you. I have already watched your videos. It seems it works without diodes but I would prefer to use them. Could you please explain the purpose of capacitors in your setup? How to connect them and what capacity to use? Maximum output current of my project will be 50A at 19,5V
@@martinrob7230 The idea of adding capacitors was to have some surge current supply from changing loads in the induction heater, to give the power supplies more time to regulate to load.
Hello thanks fo the video
my hp1500w power supply heats up quite a bit at 40% load
I wanted to know if this is normal?
I have other hp1200w power supplies which are much cooler.
What is the normal temperature of the power metal cases?
Thanks in advance :)
Server PSU are designed small and have to run with high fan speed, to disdipate the heat. If you can still touch it by hand, its no problem.
@@KaizerPowerElectronicsDk thank you for the answer
I check by touch and it is possible to touch it between 5 and 10 seconds maximum
so is it normally good?
@@mehdi660 server psu are designed from 5 to 50 degree inlet temperature, above 44 degrees you will start feeling pain www.jm.com/en/blog/2015/february/too-hot-to-handle/
@@KaizerPowerElectronicsDk thank you very much for the explanation and the link.
I must be between 44 and 48°c
Do you know how to increase the voltage on the hntns-pd18... I think you can get 13.8vdc on them somehow.
The best I can give you, but I have not tried myself. www.rcgroups.com/forums/showpost.php?p=25149870&postcount=2238 and th-cam.com/video/4P1-lpzYV1Y/w-d-xo.html
@@KaizerPowerElectronicsDk You can increase the voltage using several methods ... they work a short period of time... and guess what they randomly fail. Ive been selling these Psus way to long and just when i think i figured it out and got something solid.. I go to put it on the market and I have to warranty returns because they dont fail on my bench or load station after hours of testing they fail randomly with the end user. Most of the time when users are requesting 13.8 they really dont have a good reason to other than it would be nice but the wattage gains arent worth it vs having the units run at their native voltage of 12.3... they can go to 12.6 without issue via a trim pot thats built into certain models but when you got for those higher voltages where you have to defeat the OVP and resistor trickery... Its always ended up being a fail in the real world for my users.
@@icecube578 I heard 13.6 is the maximum you can set it to without it failing, 13.8 is too much, that was your fault for not knowing
Any idea what pins for hp 750ab ?
Use the method I show here, on how to find the correct pins: th-cam.com/video/Xyzi64OPUOg/w-d-xo.html
Its very good
I need buy
Look for a "Cisco WS-CAC-6000W". There are versions of 3000 / 6000 or even 9000 Watt! You can get them very cheap of off ebay and are quite easy to modifiy from 38...52 V output at over 100 Amps! You can read about modifications in the MFK-forum over here: forum.mosfetkiller.de/viewtopic.php?f=2&t=63559&p=284968#p284968
Just ordered one for 30$ incl shipping. It has a 42v output stock! My 3 HP supplies run OK in series for 36v, but they exhibit some strange fan behavior that i am not 100% comfortable with.
Sure, quite easy you say..It's all in German.
has anyone attempted to communicate with the ps with the PMBus protocol?
Not yet, but thanks for the suggestion
I got a few HP 723600-201 power supplies but can't seem to find a video on jumping the power on traces. It has ten thin traces on top and ten on the bottom. Anyone worked with this style of pin outs. It might be the one where you jump pins 1 to 4 with a 220ohm resister or the other method is jumping pin 30 and 31 which are on the top and bottom. The problem is that one PSU has 6 pins and the other has 8 . Mine has 10 so there should be a way to do it. The far right pin on top (near the long negative pin) is labeled S20
It may have to do with that being a hot plug power supply. I read a thread about removing something on a hot plug power supply, so I made sure I didn't get a hot plug supply. Did you figure it out?
Could I instead putting a jumper between the starting pins, a switch on the not modefied power supply, to start that way all power supplys together ? 🤔
Would be nice If someone would make a video how that could be done. 😊
Hi great job but here a challenge to you. Can you hack a hp-dps 750ab-3 to 14.6V?
No, the maximum voltage these can be pushed to is somewhere around 13.5 to 14.0 VDC
Sir can you help me model hp1400 power supply how to on
See if you can find a similar power supply here: www.rcgroups.com/forums/showthread.php?1292514-How-to-convert-Server-Power-Supplies
Many of the capacitors are like 16volts max internally, that isn't a problem?
As long as the capacitance variance is no larger than each capacitor in the string would see below its rated voltage. You do know about capacitive voltage divider?
@@KaizerPowerElectronicsDk Ok so sounds like it's ok, I saw another video mention it so wasn't sure. & No I don't know anything, but I am reading about it now
@@gg-gn3re I wrote a small article about it, for large electrolytic and other DC bus capacitors in series or parallel: kaizerpowerelectronics.dk/tesla-coils/drsstc-design-guide/dc-bus-capacitor/
How do you run 2 of these in parallel to get 100+ amp capability @12v ???
You can put them in parallel without problems. You do not need to remove the negative side grounding for that. You could add diodes on each positive lead to avoid one power supply pushing power into the other, which can give funny regulation results.
@@KaizerPowerElectronicsDk I have a breakout board for hst pl11 with 8 16awg wires connecting to a distribution bolt. so I could add another one and connect it to the same bolt to get more capacity for my car audio amplifiers
Add Schottky diodes as shown in this article: power-topics.blogspot.com/2014/03/when-should-external-diodes-be-used.html
Assalam O Alaikum Mujhe Server Supply chahiye HP ki zyada watt wali agr kisi bhai ko pata hai kahan se milegi mujhe zrur btaen
Hi thanks for the video I have a delta dps-600sb psu.
Does any one have the pinouts for it thanks.
Your best bet would be the rcforums, but I did check there and google. Best approach would be to find a picture of one with similar pad layout and then try to make the short circuit with a 1K5 resistor to limit the current if you hit something wrong.
@@KaizerPowerElectronicsDk thanks
why not just use one Telecom rectifier power supply - they output 53v and 30-35A - with CANbus control upto 50- 60A
Probably because they are $2,000 ea compared to $24...What do ya think?
@@MrDLRu depends on from where you get it, I purchase them as a used retired item.
@@JawadAhmadsahibzada Sure that's all good, please, tell us all where to get one for $24. As 1200w, 12v, 100A power supplies can be had today for that price on ebay.
I bought a 2kw psu for 10$ lol