I'm a data center electrician. I was installing L6-30R power for a clients cab. I lost control of the ground wire in a 4 panel PDU. It welded itself to the C bus in one of the panels. Alarms and lights were flashing, the L6-30 caught fire, and I was freaking. After the 3rd attempt to pull the wire off, with a insulated screwdriver, I was able to break the weld. The #10 copper wire insulation was melting all through the flex. I only had minor burns to my gloves and pants where the wire hit me after breaking the weld. Always stay safe!
This video fully explains what I'm looking for, the reason for isolating or not isolating the chassis ground connection while modifying these PSUs. Thanks a lot for the well-detailed explanation of the concept.
Hi Joshua, I just finished building my 12V/24v/Var supply based on your first video. I have to admit, it took research and perseverance to put it all together. It would be very nice to have a wiring diagram and operational instructions for the variable controller. That said, I did it and I am very happy with the results. Thanks!!
Finally got around to doing this during quarantine. My supplies were a little different. 4 attach points not 3 and all were the same height with no lip on the posts. I didn't even have to grind anything. Closing the lid was a little tight but not crazy. Ohm'd it out and checked voltages and G2G. Today's project is to replicate your ammo box. At least today is the first day of quarantine de-escalation here. Stay safe.
I built some of these 24V PSU’s many years ago for my Revolectrix PL8 charger as I needed 1450W of power. I floated the 12V ground for safety just as you’ve shown. Many guys float the 110V ground which is crazy because a couple of RC guys have died touching the metal exterior case and plugging it in at the same time. So just be careful and make sure electrically you know what you’re doing. People die all the time from opening up power supplies and touching the large capacitors as they hold a charge for days. Make sure you dump their charge before working around them internally. - Travis
@@brandonklaus2903 same question 🙋🏻♂️ here.. I guess using latex? gloves 🧤 and wearing proper shoes (rubber) and then using a wire cutter which has plastic / rubber where you are supposed to hold it. then just short circuit it. should give quite a "bang" if it's charged ?!
At 5:56 I think you're mistaken or at least what you say is incomplete. If the case on the right hand side became energized, then the ground line of the HIGH side supply would also be energized (the case is still grounded when we only cut the connection to earth at the plug level) Because of the series link between the two PSUs the 12V line of the left PSU became also energized and it will fry the left PSU. Two cases: - the left PSU exhibits a conductive path to ground/earth (a short circuit, for example due to a capacitor blowing up) then the breaker pops - the left PSU electronics cut the circuit to ground (for example a transistor blows) then the breaker doesn't pop. Remember that for the breaker what matters is the current between live and earth, not the voltage (which would be above 200V AC anyway). In my experience electrolytic capacitors (which are ubiquitous for decoupling in switching PSU) very often short circuit when they blow. So there's a good chance (higher than 50%) that the breaker pops instantly. But it's not guaranteed, just likely. This is to put in perpective with what you say in the video: that the case of the right PSU would remain energized no matter what.
I recently modified a 750 W version of this kind of supply. This one only needed one screw to be isolated. The other two screws were not connected to GND. This can easily be measured using a continuity tester (multimeter). So I only filed down the one standoff to put a nylon space under the PCB and one on the top. Since the hole and edges were not conductive I even could use a metal screw.
This is the first thing we learned ,basic electricity, electronic laws, when I was in Avionics school in the Navy, but not everyone has been in the Military.😁 Thanks for sharing Joshua.
Just bought a 24V 1200 watt extreme power supply on Banggood for just 80 bucks! Works awesome with my Icharger duo and have the advantage of having 4 output ports
DO NOT ISOLATE THE BACK SCREW. that is there for the class y capacitors, look up how a switch mode power supply is designed. you should have checked if it was connected to the low voltage side, anything on the high voltage side that is grounded should be grounded.
Can confirm it is not necessary to isolate the back screw. The DC ground is floated without isolating the back screw. Don't isolate ANYTHING unless it is absolutely necessary for the mod. Try a continuity test for yourself without isolating the back screw, you'll get the same results shown in the video.
Joshua, can you tell me why you also insulate the rear connection? If I measure between the front and rear, these are not connected to each other, how do you explain that?
I just connect two same pss and found out that minus is grounded. Before started to taking apart ps your video came out. save me a lot of trouble. thanks JB 💪
I have already done this mod but love your content and watched the video to its entirety and now I am helping a bit more with a comment. Keep up the great work. Hope this helps some folks do this the correct way.
Word of warning to everybody DO NOT TOUCH CAPACITORS IN POWER SUPPLY EVER!! not even when it is disconnected from mains! These suckers can kill if the unit doesn't have discharge circuit installed and one can never be sure it is there and it is functional.
yeah, im using brass sponge to sweep whole pcb, i know that may hurt psu but i rather hurt psu than me :D if you wanna do it safe way here it is: check high voltage caps on the mains side of switching power supply, remind that can be on standby so they are powered whole time when mains are connected. If you localised hiV caps, then take measurement of them and then discharge them by proper resistor according to ohms law. Thats it!
all you have to do to discharge one is touch them with a insulated screwdriver. guys that repair washing machines etc do that all the time. and those have a lot more juice stored in them.
@@blue03r6 the screwdriver has to to touch a ground like the chassis or use a insulated wire with a resistor or short out a positive and negative wire in the case. If removing psu from computer, unplug, remove cover hold in power button until green light on motherboard goes out. Having worked on microwave, tvs, air-conditioning whose capacitors store 3000 volts+, a mistake with a charged capacitor will stop your heart.
@@ng-iq4kx all the videos I've watched on repairing a washer the guy just touched the 2 inputs of the capacitor. ruclips.net/video/ZTQi5rTJIw8/видео.html
I had built this. It is as awesome as joshua says. I had one fail, still don't know why. I used same method on cheaper Chinese 12v 30a 360w supply. 24v 720w. I still have the 12v original and now I have 24v again and will most likely ever push its paces. Isolate the board from the case good to go
I think its important to note where the floated psu uses ground for reference and you removed that ground you removed that reference. So without restablishing -12 to 110v G you cant safly use the floated psu as a solo 12v supply.
arrrr, is that why when i testing mine before, it read a stable 12.3v and after the float mod, the volts were not stable and moving between 12v and 13v? then I done the 24v mod, and the total voltage output is around 25 and good
Just finished building my own 1500w, 63 amp power supply using 2 Dell N750P-SO server power supplies. DC float mod done on one of them coupled with the fan mod to slow them down! Cost me a grand total of £14! eBay is sometimes wonderful! Happy flying! 🧐
Thanks for this Joshua. I'm in the process of building one of these. I noticed the volt regulator in the video and the pictures. However, your blog doesn't list it nor does this or your other video speak about how it is wired into the system. Would it be possible to update the video or blog to include it? Thanks!
Hello Josh, I followed your video but floated both power supplies. Do you see any issues with this?. Also i read in a previous comment that the screw post on the board near the "mains" plug should not be isolated. Is this correct?. Thank you for any response..
@@JoshuaBardwell thanks a lot for all the video's. But i tried this today checked all and supllied 230v after 3 or4 seconds the led went out. No power anymore. Can you please help?
1. I put a dab of super glue on my nylon washer so it doesn't move while installing the nylon screws. 2. do you have to solder a resistor on both power supply to turn them both on, or just the modded one?
Picked up 2 of these used on the evilbays for $29 shipped lol. Same charger too except the DC only one. Saves $40 over the "pro" by not having the AC plug. Don't need the AC plug. 650Wx2 and 15 amps per channel for about $150 total... can't beat that...
You say that. But I picked up a pair of 2450W PSUs for $28 delivered. So once I finish running em in series, it'll be 4800W (24V 200A. The extra 50W was just a 5V 10A output that I doubt I'll use at all, maybe to power a Pi?) for $28. I've not seen anything remotely close to as cheap. And it's 92% efficient (80 Plus Gold rated). The PSUs are HUGE though. I have a server cabinet that houses all of my gear, so it's no problem for me. But it may be a bit difficult to fit on a workbench...
Two questions - 1) The power supplies I purchased look exactly the same as yours, but I have FOUR standoff screws. Do I insulate all four or is there one that shouldn't be insulated (per SuperBrainAK 6months ago - "DO NOT ISOLATE THE BACK SCREW.")? 2) How do I rewire the two 120 v power supplies to operate on 240 volts?
Only the front two screws should be isolated. I have learned that the back screws on the AC side should not be isolated. You cannot safely rewire a 120v supply to operate on 240v. At least not any way I know. But almost all of these supplies work on up to 240v if you look at the specs.
The correct wattage of the final PSU is 2400W. When you double the output voltage, you also double the output power. It does not matter if the PSU's are in parallel or in series, the output power is double in both cases. I hope you can correct the title to the correct power of 2400W
Great video! I have a different HP power supply and where you solder the resistor and where I soldered the resistor based on another tutorial are different. Basically my tutorial stated to solder a wire from pin 33 to the ground, then the resistor between pins 36 and 37. Is there a right and wrong way or is mine just different because it is a different power supply? They do power on in series and do provide 24.6v.
Great video! I'm a little late to the party and am going for the smaller rating of 750W so I'm closer to the optimum efficiency around 50% load of the units I'm using (94% for the 656363-B21 )...I was just wondering, what's the maths that determines the resistor size? Really appreciate any input....off to watch and like some more videos! Thanks for producing such great content. Michael
Go on ebay you can get these power supply for much cheaper on ebay used like probably $30 for both and I mean assuming you are not going to find 2 different Circuits to plug ini think 2 750s makes sense that's 1500 total and that's supposed to be output so input would be a little higher
Thank you, this was the info I was after. Question - Is using this method still safe if putting 4x power supplies in series for a 48v output? Ps- love your work.
Hi ! How are you today , Mr Woods here . I have made a 2400 watt ,power supply like yours . I have banana plugs in and 120 volt switch ! In .not wire up yet ! But i wonted to ask . about the watt and volt meter ! Will it just monitor .the power of the power supply .Our can i hook up 2 two of them .ONE FOR POWER SUPPLY ! AND 2 .FOR THE OUT GOING POWER ! TO THE CHARGER .FOR 24 VOLTS ! THANK YOU FOR YOUR TIME
Hello Joshua. I've got a problem, and I hope you can help me. I've got a Diatone gt-r90, and one of the motor bells feels a little bit lose. If I compare the sound of that motor to a normal motor, it sounds a bit different. But the motor doesn't get hotter than the others if I fly. Can I keep use it? Or should I take the motor apart? Or just replace it?
If you get a DPS1200FB-1 A, which is slightly different from the ones in the video (there are several variants of the DPS1200, mostly just diferent efficiency figures, operationally they're the same), you have to use a pretty low resistance. I tried 1K and they didn't power on. Tried 680 Ohm and they didn't power on. I didn't have any 330 ohm, so I just used two 680 Ohm in parallel, and that worked. So it seems like you need a 330 Ohm resistor for the FB-1 A variant. Other versions may not require such a low value, but 330 should work for all of them.
Josh, I just did the mod isolating all three screws. After completing modifications, I then did all your recommended safety tests and everthing checked out ok (continuity between AC ground pin and case, no continuity betw. hot & neutral pins to case, and no continuity between case and output neg/pos rails). Then I cranked up the power & got my 24 volts - great ! However, I did one more safety test after powering on - I measured 26 volts between case and DC output rails. Is having voltage at case normal when floating DC ground when power supplies are powered on ??
HI, JB. Quick question. At the end of the video, you only show the drawn diagram vs the final product with wires. Why are there (3) wire lead coming off the PS’s? Shouldn’t there only be 2? Or, do you have a pic of the final wiring assembly? Thanks! Edit: Never-mind....i think I got it. The positive lead is coming from PSU #! @ 24v and the negative lead is coming from PSU #1. Sound right?
you don't need the resister on the PSU FYI Simply just short them and it will power on the PSU, Also you won't get 1.2kw it states on the label you need to run over 200v to get the full 1200w per PSU
I just ordered a pair of the 750s from ebay for $22 shipped. I'm building a portable charging rig and if this works out nicely I'll build a bench charging supply out of the 1200 watt models.
Thanks for putting this one up. I’ve got a charger that I can’t use until I get a power supply something like the one you showed a build on. Even though I know I could just buy one part of the hobby for me is building stuff myself and learning through the process. On a separate note, do you know of any freestyle groups in the Greenville, SC area? I’m struggling to find anybody around that flys freestyle.
Instead of wiring up the resistor like that, could i put it across a switch so that when the switch is in the “on” position it turns on the power to both the power supplies?
It shouldn't matter which PSU gets it ground isolated. As long one in a pair has one isolated, you are golden. If you were to use 3 or 4 PSUs in series you'd need to isolate 2 of 3 or 3 or 4. Basically, only one will be left in tact.
How about current? Wouldn't the HIGH side PSU see twice the current it normally sees? But its elecotnic components (transistors, capacitors, inductors, resistors,...) aren't sized for twice the current.
This Is really cool ... But I'd really like to get into A portable Solar power Charging ring ... so that I can Plug a couple of chargers on the go ; something small a convenient not heavy and bulky . please help .
That would fail Ul but will work ... adding a single over load to handled both drivers or input detection on two independent normally open relays might make it safer. That way if one burns out they both shut off.
Hi JB just wanna ask. Is it fine to connect Multiple Chargers to 1 CCTV Power Supply 12v 360W 30A and the connector is XT60. Co'z I'm wondering if it's okay to connect 3 Chargers in that and use them at the same time 🤔🤔🤔
Go to HOMEdepot and paint the case with rubber dipp, paint a coat or two be done, or use 10 layers of scotch double stick, 15mm insulation should do., maybe 1 layer will do. Most likely wont wear.
I think you only get like 1800 watts with 120 volts and 2400 max watts if you run 240volt ac to them.if I understand correctly.tell me if I'm wrong. But 1800 is plenty lol.
If I do this, can I use it as a dual voltage supply? I mean take 24V from output of PSU 2 (with 0V from PSU 1), but also tap off 12V from output of PSU1?
So with the hp ps I have the resistor from fourth pad to first pad doesn't work. I have to go from second pad to second pad on bottom. (No resistor) I also had it going from third pad on bottom to the positive side. I took that off of the floater because it was now feeding that third pin underneath 25 v. Seems to be working now.
Should of started with discharging capacitors. Sorine built one using single psu, pedometer, vr, resistor, 24 volts adjustable amps, usb port using +5 wire.
Ordered it all lol. Couple of items on your web page list are "Not Available" on Amazon. There are plenty of other options that do the same thing ie the ac multimeter display, banana plugs. I'm mounting two isdt q6 pros on 24v with 12v and 24v constant and adjustable voltage below. Also will have 4 usb 5w 2a ports flush mounted on one side. In case I can find some flying buddies that might need a phone charged. I know this system is going to have way more than I'll need, but someday I might need to have 4 chargers and 20+ batteries charging at 5c lmao. What are your thoughts on going bigger. 36v adjustable ports by adding another 12v 1200w ps. I know it'll be capable of around 100a. My thinking was it is available if ever needed but could also serve as another channel of 0.1v thru 36v. Need a slightly bigger box for ease of work but could all have isolated bus bars routing to 12v/24v/36v circuits. Mount some battery terminals on back side for 12v bypass input(jumper cables)fused of course and switch. That moment when you plug in a creation, boom or relief, priceless I enjoy overdoing the already impressively dangerous stuff. I am tired of my little 12v 6a charger, 2+ hours to charge a bank at 1c.
@@JoshuaBardwell might be useful at a race or big rc day but not worth the extra expense. I'm just flying with my son, 24v is all I ordered for. And I'll never touch its limits. Thanks for all your work, I hope its getting your bills paid and much more! Ps thanks for the rdq video. I used them( through your link ofcourse). Special company there.
That 750w setup sounds better at 30 bucks. I went with a Meanwell 24v 600w power supply for a build a few months ago for about 115. Not as much capacity but no fiddling as well. I also appreciated the KwadBox boost of a 24v power supply from RDQ back in like November. That is a fairly cheap 24 PSU. For my big 24v setup about the most I will ever charge at is 15-18 amps into 4s packs when running two chargers at the same time.
750w version is a better buy for US folks at least. The 1200w one only actually puts out 1200w if you input 200-240V, otherwise it's limited to 900w. The difference between 1500w and 1800w ain't worth the price differential unless you really need all that power.. and you almost certainly don't. :-)
quick question, so the wattage on both psu add up. for example. my chargers max wattage is 1000w on 24v. therfore i would only need to combine two 500w power supplys?
Do the 5v rails and 3.3v rails also double up too 10v and 6.6v? Also can u use the 3.3v rail on the first psu as your ground and the 24v rail on the 2nd psu to get 20.7v?
These are server psu's, they do not supply 3.3 or 5v. You can find 5v on the left pins but it's for the control channel and standby not power output and is only rated at a few amps if there is a rating at all. If you need 3.3 and 5v a higher end desktop psu will be a better option or use a DC to DC step down to get what you need off of one of these.
Is it possible to use a 12v ATX 300W supply to get 24v of the same output? I just need a 30v that can put out at least 100w? Could i use a buck boost to achieve this?
Hi Joshua, I have an ISDT 20 charger rated at: charging current 0.2 to 20A x2. Max charging power: 500W x2. Parallel charge power and current: 800W/35A. I want to join 2 power supplies together as you show in your video for this charger. First question, you mention about using an appropriate cable to connect the two PSU'S together, it seems that 6 gauge copper wire is what I should use as it can handle the 70 amps you mention. Can you please verify, and is this what you recommend? Also, with XT60 connectors which the ISDT uses, will 12 or 14 AWG wires be suitable? Many thanks!
If you are looking up wire amp rating, bear in mind the length of the wire must be accounted for. Shorter wires will have less resistance. Personally I think 6 gauge is probably overkill. I think I used 2x 12 gauge? Does that equate to 6 gauge? I don't know. I guess do your own research in the end!
Lorenzo Chow You have to have 3 PS... you make 2 of them “floating ground” and the other leave it alone. Connect them into series and boom 36 volts. I have 4 of them and have 48V.
This particular model has a GitHub project too. The guy was trying to control it via Arduino and PWM. I don't think he got that working, but he sure does know how to hardware mod it. github.com/slundell/dps_charger#12vfb-tap
Is it allowed to make a terminal on the first PSU to have a 12V output besides the end 24V and use them at the same time? For example, if you have a charger wich only takes 12V and a 2nd charger wich goes up to 24V?
To isolate the DC negative of the PSU from the case, which is connected to mains-ground. When the two PSU are plugged in to the wall, they share a common mains-ground through the house electrical system. If the mains-ground is connected to the DC negative, then the DC negative of both PSU will be at the same voltage potential. It will not be possible to raise the DC-negative of one PSU to +12v, thereby turning the final output of the system into +24v.
@@JoshuaBardwell so this still allows the PSU with the isolated DC- to short to ground if the AC- wire shorts on the interior somehow? If this doesn't impact the performance or safety of the PSU, why is the DC- connected to ground to begin with?
It leaves the AC ground intact, yes. There is another technique for doing the same thing which isolates the AC ground, but in my opinion this technique is safer because mains ground is not compromised.
I'm a data center electrician. I was installing L6-30R power for a clients cab. I lost control of the ground wire in a 4 panel PDU. It welded itself to the C bus in one of the panels. Alarms and lights were flashing, the L6-30 caught fire, and I was freaking. After the 3rd attempt to pull the wire off, with a insulated screwdriver, I was able to break the weld. The #10 copper wire insulation was melting all through the flex. I only had minor burns to my gloves and pants where the wire hit me after breaking the weld. Always stay safe!
Thats heavy! thanks for your input I am going to build this and I am going to multi meter the poop out of it!
This video fully explains what I'm looking for, the reason for isolating or not isolating the chassis ground connection while modifying these PSUs. Thanks a lot for the well-detailed explanation of the concept.
Hi Joshua, I just finished building my 12V/24v/Var supply based on your first video. I have to admit, it took research and perseverance to put it all together. It would be very nice to have a wiring diagram and operational instructions for the variable controller. That said, I did it and I am very happy with the results. Thanks!!
Finally got around to doing this during quarantine. My supplies were a little different. 4 attach points not 3 and all were the same height with no lip on the posts. I didn't even have to grind anything. Closing the lid was a little tight but not crazy. Ohm'd it out and checked voltages and G2G. Today's project is to replicate your ammo box. At least today is the first day of quarantine de-escalation here. Stay safe.
What lenght screws do you need?
I built some of these 24V PSU’s many years ago for my Revolectrix PL8 charger as I needed 1450W of power. I floated the 12V ground for safety just as you’ve shown. Many guys float the 110V ground which is crazy because a couple of RC guys have died touching the metal exterior case and plugging it in at the same time. So just be careful and make sure electrically you know what you’re doing. People die all the time from opening up power supplies and touching the large capacitors as they hold a charge for days. Make sure you dump their charge before working around them internally.
- Travis
Thats why you earth everything that has a metall case
How would you suggest dumping the charge for this project?
@@brandonklaus2903 same question 🙋🏻♂️ here..
I guess using latex? gloves 🧤 and wearing proper shoes (rubber) and then using a wire cutter which has plastic / rubber where you are supposed to hold it.
then just short circuit it.
should give quite a "bang" if it's charged ?!
an nobody on youtube about these 24v conversion. Nobody have tested 24v they all have first part of video
Please make a video showing how you wired up the voltage regulator and display.
At 5:56 I think you're mistaken or at least what you say is incomplete. If the case on the right hand side became energized, then the ground line of the HIGH side supply would also be energized (the case is still grounded when we only cut the connection to earth at the plug level)
Because of the series link between the two PSUs the 12V line of the left PSU became also energized and it will fry the left PSU. Two cases:
- the left PSU exhibits a conductive path to ground/earth (a short circuit, for example due to a capacitor blowing up) then the breaker pops
- the left PSU electronics cut the circuit to ground (for example a transistor blows) then the breaker doesn't pop.
Remember that for the breaker what matters is the current between live and earth, not the voltage (which would be above 200V AC anyway).
In my experience electrolytic capacitors (which are ubiquitous for decoupling in switching PSU) very often short circuit when they blow. So there's a good chance (higher than 50%) that the breaker pops instantly. But it's not guaranteed, just likely. This is to put in perpective with what you say in the video: that the case of the right PSU would remain energized no matter what.
I recently modified a 750 W version of this kind of supply. This one only needed one screw to be isolated. The other two screws were not connected to GND. This can easily be measured using a continuity tester (multimeter). So I only filed down the one standoff to put a nylon space under the PCB and one on the top. Since the hole and edges were not conductive I even could use a metal screw.
This is the first thing we learned ,basic electricity, electronic laws, when I was in Avionics school in the Navy, but not everyone has been in the Military.😁
Thanks for sharing Joshua.
Just bought a 24V 1200 watt extreme power supply on Banggood for just 80 bucks! Works awesome with my Icharger duo and have the advantage of having 4 output ports
Splash FPV do u have a link?
DO NOT ISOLATE THE BACK SCREW. that is there for the class y capacitors, look up how a switch mode power supply is designed. you should have checked if it was connected to the low voltage side, anything on the high voltage side that is grounded should be grounded.
Oh shoot. I better put back the metal screw then 🤣🤣
Hello is this a for sure?? Please reply with detail TKS
Can confirm it is not necessary to isolate the back screw. The DC ground is floated without isolating the back screw. Don't isolate ANYTHING unless it is absolutely necessary for the mod. Try a continuity test for yourself without isolating the back screw, you'll get the same results shown in the video.
Joshua, can you tell me why you also insulate the rear connection?
If I measure between the front and rear, these are not connected to each other, how do you explain that?
I just connect two same pss and found out that minus is grounded. Before started to taking apart ps your video came out. save me a lot of trouble. thanks JB 💪
I have already done this mod but love your content and watched the video to its entirety and now I am helping a bit more with a comment. Keep up the great work. Hope this helps some folks do this the correct way.
Yes they are GOOD power supplies. I used to work(RnD) with this PS. Even tried injecting 2kv at the input. They survive.
you can just do a straight wire from the pins to turn it on, i used to mine ethereum with like 8 of these.
Word of warning to everybody DO NOT TOUCH CAPACITORS IN POWER SUPPLY EVER!! not even when it is disconnected from mains! These suckers can kill if the unit doesn't have discharge circuit installed and one can never be sure it is there and it is functional.
Oh yes. When I was a teenager an unplugged PSU did bite me heavily when i tried to repair it.
yeah, im using brass sponge to sweep whole pcb, i know that may hurt psu but i rather hurt psu than me :D if you wanna do it safe way here it is:
check high voltage caps on the mains side of switching power supply, remind that can be on standby so they are powered whole time when mains are connected. If you localised hiV caps, then take measurement of them and then discharge them by proper resistor according to ohms law. Thats it!
all you have to do to discharge one is touch them with a insulated screwdriver. guys that repair washing machines etc do that all the time. and those have a lot more juice stored in them.
@@blue03r6 the screwdriver has to to touch a ground like the chassis or use a insulated wire with a resistor or short out a positive and negative wire in the case. If removing psu from computer, unplug, remove cover hold in power button until green light on motherboard goes out. Having worked on microwave, tvs, air-conditioning whose capacitors store 3000 volts+, a mistake with a charged capacitor will stop your heart.
@@ng-iq4kx all the videos I've watched on repairing a washer the guy just touched the 2 inputs of the capacitor. ruclips.net/video/ZTQi5rTJIw8/видео.html
Thank you for this guide! And thank you for telling the people cuting the ground at the AC side is a bad idea!
I had built this. It is as awesome as joshua says. I had one fail, still don't know why. I used same method on cheaper Chinese 12v 30a 360w supply. 24v 720w. I still have the 12v original and now I have 24v again and will most likely ever push its paces. Isolate the board from the case good to go
I think its important to note where the floated psu uses ground for reference and you removed that ground you removed that reference. So without restablishing -12 to 110v G you cant safly use the floated psu as a solo 12v supply.
It depends on the design, there are many PSU that have floating outputs.
arrrr, is that why when i testing mine before, it read a stable 12.3v and after the float mod, the volts were not stable and moving between 12v and 13v? then I done the 24v mod, and the total voltage output is around 25 and good
Just finished building my own 1500w, 63 amp power supply using 2 Dell N750P-SO server power supplies. DC float mod done on one of them coupled with the fan mod to slow them down! Cost me a grand total of £14! eBay is sometimes wonderful! Happy flying! 🧐
L stands for "line" not "load", also when crossing lines in a line diagram bump out your line makes interpretation much easier. Nice video jb....
We'll turn him into an electrician in no time... He's already using Klein tools :)
Thanks for this Joshua. I'm in the process of building one of these. I noticed the volt regulator in the video and the pictures. However, your blog doesn't list it nor does this or your other video speak about how it is wired into the system. Would it be possible to update the video or blog to include it? Thanks!
Fantastic video nice to see a fellow Lefty showing people how it’s done
HaHaHa i emailed JB last night and i woke up and he had pointed me to this video woo hooo thank you Mr Bardwell!!
Hello Josh, I followed your video but floated both power supplies. Do you see any issues with this?. Also i read in a previous comment that the screw post on the board near the "mains" plug should not be isolated. Is this correct?. Thank you for any response..
Is it correct that with this method it is safe to let the two metal cases (of the combined 24V PSU) touch? Or will it go zap?
It's safe. Thats why you isolate the ground.
@@JoshuaBardwell thanks a lot for all the video's. But i tried this today checked all and supllied 230v after 3 or4 seconds the led went out. No power anymore. Can you please help?
omg i never thought you would post a video on how to make one, thank you
Jumpstart rc so you always thought he was going to post this video? You have a double negative in your sentence.
@@fatal510 I'll fix it
1. I put a dab of super glue on my nylon washer so it doesn't move while installing the nylon screws. 2. do you have to solder a resistor on both power supply to turn them both on, or just the modded one?
You could super glue the nylon washers in place
Picked up 2 of these used on the evilbays for $29 shipped lol. Same charger too except the DC only one. Saves $40 over the "pro" by not having the AC plug. Don't need the AC plug. 650Wx2 and 15 amps per channel for about $150 total... can't beat that...
You say that. But I picked up a pair of 2450W PSUs for $28 delivered. So once I finish running em in series, it'll be 4800W (24V 200A. The extra 50W was just a 5V 10A output that I doubt I'll use at all, maybe to power a Pi?) for $28. I've not seen anything remotely close to as cheap. And it's 92% efficient (80 Plus Gold rated). The PSUs are HUGE though. I have a server cabinet that houses all of my gear, so it's no problem for me. But it may be a bit difficult to fit on a workbench...
Two questions - 1) The power supplies I purchased look exactly the same as yours, but I have FOUR standoff screws. Do I insulate all four or is there one that shouldn't be insulated (per SuperBrainAK 6months ago - "DO NOT ISOLATE THE BACK SCREW.")?
2) How do I rewire the two 120 v power supplies to operate on 240 volts?
Only the front two screws should be isolated. I have learned that the back screws on the AC side should not be isolated.
You cannot safely rewire a 120v supply to operate on 240v. At least not any way I know. But almost all of these supplies work on up to 240v if you look at the specs.
The correct wattage of the final PSU is 2400W. When you double the output voltage, you also double the output power. It does not matter if the PSU's are in parallel or in series, the output power is double in both cases. I hope you can correct the title to the correct power of 2400W
Great video! I have a different HP power supply and where you solder the resistor and where I soldered the resistor based on another tutorial are different. Basically my tutorial stated to solder a wire from pin 33 to the ground, then the resistor between pins 36 and 37. Is there a right and wrong way or is mine just different because it is a different power supply? They do power on in series and do provide 24.6v.
12:00 the Pin 5 + 6 are connected as well ? Looks like they are connected by solderthin
to make it easier first super glue nylon washers to circuit board
1200w is only on 240v in (12v x 100A), 120v "only" gives 900w (12v x 75A). I picked up 3 of these a few years ago for about $50 total
That'll still be 1800w with the two together.
I just paid $29 for 2 lol. Gonna float one and then throw two 120mm fans on either end of a small toolbox and put them in there.
Thank you for posting. Best to have good information out there. Great how you show what to do and how to test.
JB, you do an amazing job.
Joshua Bardwell ASMR. I love this format
Great video!
I'm a little late to the party and am going for the smaller rating of 750W so I'm closer to the optimum efficiency around 50% load of the units I'm using (94% for the 656363-B21
)...I was just wondering, what's the maths that determines the resistor size?
Really appreciate any input....off to watch and like some more videos! Thanks for producing such great content.
Michael
Go on ebay you can get these power supply for much cheaper on ebay used like probably $30 for both and I mean assuming you are not going to find 2 different Circuits to plug ini think 2 750s makes sense that's 1500 total and that's supposed to be output so input would be a little higher
Thank you, this was the info I was after.
Question - Is using this method still safe if putting 4x power supplies in series for a 48v output?
Ps- love your work.
Hi ! How are you today , Mr Woods here . I have made a 2400 watt ,power supply like yours . I have banana plugs in and 120 volt switch ! In .not wire up yet ! But i wonted to ask . about the watt and volt meter ! Will it just monitor .the power of the power supply .Our can i hook up 2 two of them .ONE FOR POWER SUPPLY ! AND 2 .FOR THE OUT GOING POWER ! TO THE CHARGER .FOR 24 VOLTS ! THANK YOU FOR YOUR TIME
Back pcb screw should be left metal. Also led can be easily pushed in. Inside there is springy hooks that can be moved with screwdriver.
Hello Joshua. I've got a problem, and I hope you can help me. I've got a Diatone gt-r90, and one of the motor bells feels a little bit lose. If I compare the sound of that motor to a normal motor, it sounds a bit different. But the motor doesn't get hotter than the others if I fly. Can I keep use it? Or should I take the motor apart? Or just replace it?
If you get a DPS1200FB-1 A, which is slightly different from the ones in the video (there are several variants of the DPS1200, mostly just diferent efficiency figures, operationally they're the same), you have to use a pretty low resistance. I tried 1K and they didn't power on. Tried 680 Ohm and they didn't power on. I didn't have any 330 ohm, so I just used two 680 Ohm in parallel, and that worked. So it seems like you need a 330 Ohm resistor for the FB-1 A variant. Other versions may not require such a low value, but 330 should work for all of them.
Josh, I just did the mod isolating all three screws. After completing modifications, I then did all your recommended safety tests and everthing checked out ok (continuity between AC ground pin and case, no continuity betw. hot & neutral pins to case, and no continuity between case and output neg/pos rails). Then I cranked up the power & got my 24 volts - great ! However, I did one more safety test after powering on - I measured 26 volts between case and DC output rails. Is having voltage at case normal when floating DC ground when power supplies are powered on ??
Hello ???
HI, JB. Quick question. At the end of the video, you only show the drawn diagram vs the final product with wires. Why are there (3) wire lead coming off the PS’s? Shouldn’t there only be 2? Or, do you have a pic of the final wiring assembly? Thanks!
Edit: Never-mind....i think I got it. The positive lead is coming from PSU #! @ 24v and the negative lead is coming from PSU #1. Sound right?
For the LED, just push against it with your thumb and it will easily push in allowing you to remove the entire board. I got 2 1200w for $24 shipped :)
you can use a dab of hot glue to position the washer on the board or the case to get things to line up easier
you don't need the resister on the PSU FYI Simply just short them and it will power on the PSU, Also you won't get 1.2kw it states on the label you need to run over 200v to get the full 1200w per PSU
you have a blob of solder between pads 5 and 6. Is that part of the fix for both of them? tnx
For a Q6+ charger, just use a $22 24V/15A PSU from Amazon/Eagwell. No fiddling and smaller/lighter/cheaper.
Lol. For real. Thats what i did. I think i bought mine on ebay but about the same price.
Buy 4xQ6+ and you have a 4 channel 60A charger for less than 250 bucks!
Which one?
This approach I'd for those who want MAXIMUM POWAH
@Michael Benjamin true. Lol. Extra powah
So you’ve shown how to make it 24v 1200w and of you was to make it parrellel instead of series it would be 12v 2400w right???
Today I learned Bardwell is a lefty. Hello fellow lefty.
I'm a lefty too! Yay lefties!
The only ones in our right minds.
Left handed.. hopefully not left wing
hello fellow lefty!
I am a lefty too!!!
I just ordered a pair of the 750s from ebay for $22 shipped. I'm building a portable charging rig and if this works out nicely I'll build a bench charging supply out of the 1200 watt models.
Hey question, 220Ohm 5watt also oke? They are same Ohm but more watt, think you got 0.5 to 1 Watt, but i got 5Watt?
Thanks for putting this one up. I’ve got a charger that I can’t use until I get a power supply something like the one you showed a build on. Even though I know I could just buy one part of the hobby for me is building stuff myself and learning through the process. On a separate note, do you know of any freestyle groups in the Greenville, SC area? I’m struggling to find anybody around that flys freestyle.
Followed through. Checked ground isolation. Plugged in, led lights for 3secs then goes out - no output. Help please!
Same issue here, dont know what happend either. Any1 any ideas pls
@@iopuk8206 It was faulty - they sent another one
@@randallpatrickc thanks man, ill try the same than. You got it working than?
@@iopuk8206 I have some that power themselves off as well. Guessing I am SOL?
@@quinnfoster4671 ive received a new one, now they are ok. Internally they didn't look the same. I had one good built one the other was very bad parts
Instead of wiring up the resistor like that, could i put it across a switch so that when the switch is in the “on” position it turns on the power to both the power supplies?
Yes that's fine.
Whew this is a rather über useful info! Thanks, Master!!
@joshua Bardwell, Great video! Thank you!
May I ask why did you bridge pin 5 and 6 @11:55 ?
I assume you could daisy chain more of them for 36v and 48v? Eg 4*750w ones would give you 48v 3000w
It shouldn't matter which PSU gets it ground isolated. As long one in a pair has one isolated, you are golden. If you were to use 3 or 4 PSUs in series you'd need to isolate 2 of 3 or 3 or 4. Basically, only one will be left in tact.
How about current? Wouldn't the HIGH side PSU see twice the current it normally sees?
But its elecotnic components (transistors, capacitors, inductors, resistors,...) aren't sized for twice the current.
If the metal cases are touching each other, wouldn't taking the ground pin off be ok?
That runs the risk of having a case energized with mains voltage and not knowing. Too dangerous.
Great video Josh! Show us more cool stuff like this! 👌
This Is really cool ... But I'd really like to get into A portable Solar power Charging ring ...
so that I can Plug a couple of chargers on the go ; something small a convenient not heavy and bulky . please help .
Good job I have a few old rack mount servers laying around.
That would fail Ul but will work ... adding a single over load to handled both drivers or input detection on two independent normally open relays might make it safer. That way if one burns out they both shut off.
why rerister needed where completing circuit for power, without load it wont up?
Great tutorial, very good info
Hey there one questions for dummies! I want to buy the ISDT T8 1000w charger can I feed it with more than 1000w?
yes but the charger won't be able to use all of those Watts
@@hrhodes2768 ok thank you
Hi JB just wanna ask.
Is it fine to connect Multiple Chargers to 1 CCTV Power Supply 12v 360W 30A and the connector is XT60.
Co'z I'm wondering if it's okay to connect 3 Chargers in that and use them at the same time 🤔🤔🤔
Sure just build a big Y adapter.
Finally! And neat! I have 8 of these. :)
Go to HOMEdepot and paint the case with rubber dipp, paint a coat or two be done, or use 10 layers of scotch double stick, 15mm insulation should do., maybe 1 layer will do. Most likely wont wear.
I am by far not an electrical expert but, wouldn't putting a large diode on the ground side be a much easier?
I guess it could work but It would need to be rated for tens of amps and over 1000 watts.
I think you only get like 1800 watts with 120 volts and 2400 max watts if you run 240volt ac to them.if I understand correctly.tell me if I'm wrong. But 1800 is plenty lol.
If I do this, can I use it as a dual voltage supply? I mean take 24V from output of PSU 2 (with 0V from PSU 1), but also tap off 12V from output of PSU1?
Yes definitely.
So with the hp ps I have the resistor from fourth pad to first pad doesn't work. I have to go from second pad to second pad on bottom. (No resistor) I also had it going from third pad on bottom to the positive side. I took that off of the floater because it was now feeding that third pin underneath 25 v. Seems to be working now.
Nice video. You should have some circuit board that could warn you if the DC ground and Ground gets connected.
The PSU will shut down if that were to happen.
Should of started with discharging capacitors. Sorine built one using single psu, pedometer, vr, resistor, 24 volts adjustable amps, usb port using +5 wire.
Ordered it all lol. Couple of items on your web page list are "Not Available" on Amazon. There are plenty of other options that do the same thing ie the ac multimeter display, banana plugs. I'm mounting two isdt q6 pros on 24v with 12v and 24v constant and adjustable voltage below. Also will have 4 usb 5w 2a ports flush mounted on one side. In case I can find some flying buddies that might need a phone charged. I know this system is going to have way more than I'll need, but someday I might need to have 4 chargers and 20+ batteries charging at 5c lmao.
What are your thoughts on going bigger. 36v adjustable ports by adding another 12v 1200w ps. I know it'll be capable of around 100a. My thinking was it is available if ever needed but could also serve as another channel of 0.1v thru 36v. Need a slightly bigger box for ease of work but could all have isolated bus bars routing to 12v/24v/36v circuits. Mount some battery terminals on back side for 12v bypass input(jumper cables)fused of course and switch. That moment when you plug in a creation, boom or relief, priceless
I enjoy overdoing the already impressively dangerous stuff. I am tired of my little 12v 6a charger, 2+ hours to charge a bank at 1c.
I don't see much point I going to 36v. 24v is enough to max out the charger, and the additional watts are probably not going to be used.
@@JoshuaBardwell might be useful at a race or big rc day but not worth the extra expense. I'm just flying with my son, 24v is all I ordered for. And I'll never touch its limits. Thanks for all your work, I hope its getting your bills paid and much more!
Ps thanks for the rdq video. I used them( through your link ofcourse). Special company there.
What Gauge wire do you use?
That 750w setup sounds better at 30 bucks.
I went with a Meanwell 24v 600w power supply for a build a few months ago for about 115. Not as much capacity but no fiddling as well.
I also appreciated the KwadBox boost of a 24v power supply from RDQ back in like November. That is a fairly cheap 24 PSU.
For my big 24v setup about the most I will ever charge at is 15-18 amps into 4s packs when running two chargers at the same time.
750w version is a better buy for US folks at least. The 1200w one only actually puts out 1200w if you input 200-240V, otherwise it's limited to 900w. The difference between 1500w and 1800w ain't worth the price differential unless you really need all that power.. and you almost certainly don't. :-)
quick question, so the wattage on both psu add up. for example. my chargers max wattage is 1000w on 24v. therfore i would only need to combine two 500w power supplys?
What is the difference between the power supply you used and some of the other hp power supplies that look similar.
I couldn't be sure but many of them are identical.
Joshua why is a resistor used.
Why not just some 22gauge wire?
Serious question
I don't know the real reason. Presumably it's to limit current flow, but I doubt the circuit would burn out if you used a wire.
Do the 5v rails and 3.3v rails also double up too 10v and 6.6v? Also can u use the 3.3v rail on the first psu as your ground and the 24v rail on the 2nd psu to get 20.7v?
These are server psu's, they do not supply 3.3 or 5v. You can find 5v on the left pins but it's for the control channel and standby not power output and is only rated at a few amps if there is a rating at all. If you need 3.3 and 5v a higher end desktop psu will be a better option or use a DC to DC step down to get what you need off of one of these.
Is it possible to use a 12v ATX 300W supply to get 24v of the same output?
I just need a 30v that can put out at least 100w?
Could i use a buck boost to achieve this?
Hi Joshua, I have an ISDT 20 charger rated at: charging current 0.2 to 20A x2. Max charging power: 500W x2. Parallel charge power and current: 800W/35A. I want to join 2 power supplies together as you show in your video for this charger. First question, you mention about using an appropriate cable to connect the two PSU'S together, it seems that 6 gauge copper wire is what I should use as it can handle the 70 amps you mention. Can you please verify, and is this what you recommend?
Also, with XT60 connectors which the ISDT uses, will 12 or 14 AWG wires be suitable? Many thanks!
If you are looking up wire amp rating, bear in mind the length of the wire must be accounted for. Shorter wires will have less resistance. Personally I think 6 gauge is probably overkill. I think I used 2x 12 gauge? Does that equate to 6 gauge? I don't know. I guess do your own research in the end!
Thanks. 2x 12 gauge equates to 9 gauge...
What if you want to connect three power supplies in series to get 36 volts? Do you undo the dc grounds from two psu's and leave one alone?
Lorenzo Chow You have to have 3 PS... you make 2 of them “floating ground” and the other leave it alone. Connect them into series and boom 36 volts. I have 4 of them and have 48V.
Looks like it's only 900w max on 110v-120v. Not nitpicking just an observation from when I was building a power supply
That'll still be 1800w with the two power supplies.
And there's a great thread on rcgroups with settings etc for lots of different psu's.
This particular model has a GitHub project too. The guy was trying to control it via Arduino and PWM. I don't think he got that working, but he sure does know how to hardware mod it. github.com/slundell/dps_charger#12vfb-tap
Question instead of doing two of those to get 24v ...what if i added dc-dc converter 24v will the amps increase?
I mean watts
Hello can I use psu 750w to be 24v to ?
Or will it be able to output it 14.4volts?
Is it allowed to make a terminal on the first PSU to have a 12V output besides the end 24V and use them at the same time? For example, if you have a charger wich only takes 12V and a 2nd charger wich goes up to 24V?
Yes, absolutely you can do that.
Hi Joshua,
Can you confirm the reason for installing the nylon washers? I'm a bit stuck on their purpose.
To isolate the DC negative of the PSU from the case, which is connected to mains-ground. When the two PSU are plugged in to the wall, they share a common mains-ground through the house electrical system. If the mains-ground is connected to the DC negative, then the DC negative of both PSU will be at the same voltage potential. It will not be possible to raise the DC-negative of one PSU to +12v, thereby turning the final output of the system into +24v.
@@JoshuaBardwell so this still allows the PSU with the isolated DC- to short to ground if the AC- wire shorts on the interior somehow? If this doesn't impact the performance or safety of the PSU, why is the DC- connected to ground to begin with?
It leaves the AC ground intact, yes. There is another technique for doing the same thing which isolates the AC ground, but in my opinion this technique is safer because mains ground is not compromised.