HP HSTNS-PL11 psu Over Voltage Protection voltage increase? - Page 1
Forum section: electronics / projects

author: innkeeper
author_rank: Unknown
timestamp: July 14, 2020, 07:28:43 pm
content: I am trying to figure out how to increase the Over Voltage Protection voltage on this supply as I want to modify it for running at 13.8V with quickly varying loads (transmit/recieve) for ham radio operation and I do not want to trigger the OVP.I have the schematic and a pic of the mainboard, both are attached.Others have modified this for higher voltage, and that seems pretty straight forward from the schematic. However, they can't reach 13.8V for actual use under quickly varying loads without the OVP kicking in, They end up dropping the voltage down some to like 13v to keep it from happening. it would seem there is a little overshoot when the load drops quickly. This would seem to be resolvable if the OVP voltage could be raised a little.I've been studied the schematic for the way the supply does OVP is not apparent to me. Anyone have an idea of how it works?

author: eblc1388
author_rank: Frequent Contributor
timestamp: July 15, 2020, 12:19:21 pm
content: I have looked through the schematic and I may have good news for you.Apparently the power supply is using a microcontroller to monitor the +12V voltage level via its ADC input to provide the OVP function. In the attached photo, the +12V is divided down to below 3.3V and fed into the uP2 pin15. Thus reducing R901 would do the trick. You can do this by parallelling another high value resistor across R901 via trial and error.A better method is to measure the pin15 voltage along with the actual +12V output voltage and work out the divider ratio. Then it is a simple matter to increase the OVP to say 14.5V or 15V by changing the divisor ratio.Initially I couldn't find the MC9S08QG8 on the circuit board but then I noted from a chinese website that it is listed together with MQ64CDTE so they are equivalent. Hope all these helps in solving your problem. Do let us know of the result.

author: innkeeper
author_rank: Unknown
timestamp: July 15, 2020, 10:24:39 pm
content: eblc1388, Thanks, The Chinese version of the uP is a great find, I was assuming that was a uP but couldn't prove it out.I also saw that voltage divider going into the uP after i posted. That makes sense and I agree thats likely the place it gets detected, and glad that you think the same. I think that is the right track to go for. it also matches the flow diagram for what they call uP1There are 2 uP's on the board, one MC9S08QG4 and one MC9S08QG8. From the information you found, the MC9S08QG4 is the one we can see in the picture and the MC9S08QG8 is the one that the voltage divider of interest is connected to seems to be on another board in the PS that i do not have a picture of. I belive i found the board and it looks like that board is hard to see without removing the PS completely from the chassis. So that will be my next step.I've also made some sense of the labeling on the schematic of things like MB1 SB1SB2 etc. those indicate the board the components are on and the letters may mean the side of the board so SB1A is one side and SB1B is the other.The MC9S08QG8 would then be on board and side SB2A which judging form the number of components on the board would be that small board i don't have a picture of yet. unfortunately the boards are only labeled that way on the schematic and not the silk screen as best i can see. I did further conform the small board by finding the programming header jpm900 which is visible with a silk screen label on the that same small board.This looks very promising, I'll post my progress.

author: neuzpisk
author_rank: Newbie
timestamp: September 05, 2020, 06:04:52 pm
content: hi, i have same issue, but mine different MQG4CDTEdid you OVP voltage ?

author: eblc1388
author_rank: Frequent Contributor
timestamp: September 06, 2020, 05:07:03 am
content: The location of uP2 in my Reply#1 is wrong. The correct location is as follow. Noted that these power supplies have had many revisions and the actual position or MCU type might be different. Mine is PIC16F883 while others have reported PIC16F886. even getting the correct part numbers are difficult as most are blocked by other components.Once you have found this MCU, then you can carry out the OVP mod as in my reply#1.

author: neuzpisk
author_rank: Newbie
timestamp: September 06, 2020, 09:27:02 am
content: i even can't see what is tipe MCU is

author: ubrain
author_rank: Contributor
timestamp: December 21, 2020, 03:21:23 am
content: Hi guys, new here and to be honest, not very expert in the field, so apologies in advance for not being likely to be able to offer much advice... although I've got lots of enthusiasm if anyone needs any of that!I was wondering whether anyone did successfully manage to tweak the Over Voltage Protection of the HSTNS-PL11 in the end?I've managed to get the output voltage up to about 14v by winding it up gently. However, it won't start up with a voltage of over 13.75, and with a load in place, 13.4v is about the limit.I'd so love to push it up to about 14-14.4 but the OVP is getting in the way!

author: mamujim
author_rank: Newbie
timestamp: December 21, 2020, 06:05:59 pm
content: Hi All,Just purchased one of these and hoping to get the output voltage up to about 13.8v.Can someone please show how to adjust this psu to get it outputting around 13.8v.Many thanks

author: ubrain
author_rank: Contributor
timestamp: December 21, 2020, 07:00:48 pm
content: Ha - well after thinking I'd be no help to anyone here... I can answer thatOpen the box up: usual caveats about not being plugged in, and still watching out for inconvenient discharge from big capacitors.Add a 6.8K resistor between these 2 points. (don't copy me - I made a mess because I didn't have the right resistor handy)Turn the VR fully to the right (cw) before you start up, it should give about 13.2v. Slowly wind it up (ccw) until the over voltage protection kicks in.As I said above, I got it up to 14v but that was without a load so pretty useless. With a load on it, I'm getting it starting up OK at about 13.4v.I'd stillreallylike to know if anyone managed to solve the OVP issue though.

author: mamujim
author_rank: Newbie
timestamp: December 21, 2020, 07:14:31 pm
content: Excellent, many thanks, will give it a go and see how i get on.EDIT:thanks mate, got it workingadded a VR set to 6.8k across the points you mentioned

author: eblc1388
author_rank: Frequent Contributor
timestamp: December 22, 2020, 07:43:24 am
content: Quote from: ubrain on December 21, 2020, 07:00:48 pmTry this and report back.

author: ubrain
author_rank: Contributor
timestamp: December 22, 2020, 08:58:42 pm
content: Wow!It's a shame there's only one thanks button because I actually need to say it twice - in 2 different voices.Firstly: "Thanks for thateblc1388!" That was the biggest PITA fiddly messed up soldering job I've done in my life! Not being experienced with componentry this small, nor having a decent workbench, I broke and repaired 2 other things during the course of the job. Actually I appear to have broken 3 things as the power LED doesn't come on now - but I'll live with that.Secondly: "Thanks for thateblc1388!" It works! The tweaked VR now takes the voltage up to a max 14.41v so no idea if or when OVP would now cut in. It's now purring away, pumping a nice consistent 80A at 14v into the batteries.Win!It's worth noting, anyone else planning to try this: with the OVP out of the way, there's nothing to stop this box getting quite out of hand. At 14.4v it brazenly tried to chuck 150A at an empty battery and being LiFePO4, the battery was happy to take it. Fortunately the BMS was only willing to put up with that for a few seconds as I'm not sure how long a 1200w rated PSU would last pumping out over 2000w.

author: paulzedx636
author_rank: Newbie
timestamp: December 31, 2020, 06:18:45 pm
content: I have two HP HSTNS-PL11 and was wondering if anyone has done the voltage adjustment mod with the 6.8k resistor on the voltage adjust pot. And has someone also put the 12k resistor on the voltage regulators to override the OVP at the same time. Looking to find the max working output voltage before the OVP kicks in.

author: innkeeper
author_rank: Unknown
timestamp: January 01, 2021, 03:27:55 am
content: Quote from: eblc1388 on December 22, 2020, 07:43:24 amthanks

author: eblc1388
author_rank: Frequent Contributor
timestamp: January 03, 2021, 07:37:41 am
content: There's a lot of attentions on the HSTNS-PL11 with its small size but hefty 100A 12V output. As I've just put together an electronic 'wattmeter' (see image) using an AliExpress bought module, I might as well measure how these supplies perform on standby and idle. The following are my findings.The no load wattage shown are in the range of 42~44W for PL11, double checked with several PL11 power supplies. What it means is the power supply is consuming 44W with 12V but no load attached. This figure seems exceptionally high and unreasonable compares to different models of server power supply.It would be helpful if anyone with a HSTNS-PL11 and wattmeter can either confirm or rebute the figure using other makes of wattmeter.If it turns out to be correct, then it is definitely not a good choice if your application is mostly placing the supply on standby or very lightly loaded. However, its efficiency is still very good when loaded.The C7000 supply shows the best result. Before you even consider to go out and buy a C7000 power supply, be warned that there is no trim POT inside the power supply for output voltage trimming and access to circuitry is severely blocked by large components. Unless you are contented with 12.2V output, there is'nt any mention of voltage increase modification or OVP mod anywhere on the whole internet.Test Results: Server Power Supply Measurement==============================Measured with electronic wattmeter moduleAC mains voltage = 243VTest Conditions:AC ON: Supply +12V output disabledDC ON: Supply +12V output available, no LoadLoaded: Supply +12V output loaded1. 2450W Blade C7000 Power supply==============================AC On: 3.9WDC On: 14.6WLoaded: 12.2V 60.5A =738WWattmeter: 790W, PF=1Efficiency: 738/790 = 93.4%2. HSTNS-PL11 1200W supply=======================AC On: 8.12WDC On:42.3WLoaded: 12.3V 60A =738WWattmeter: 787W, PF=1Efficiency: 738/787 = 93.8%3. DPS-650EB 665W==============AC On: 9.7WDC On: 18.32WLoaded: 12.13V 59.3A =719W (overloaded, max 54A)Wattmeter: 823W, PF=1Efficiency: 719/823 = 87.4%

author: ubrain
author_rank: Contributor
timestamp: January 05, 2021, 01:47:38 pm
content: An update on my report above.This PSU seems highly resilient to abuse. It's not that I'm actively trying to blow it but I've really not been trying very hardnotto blow it and despite some quite bad treatment, it's still going strong.It was briefly pumping out 2000w (at about 12.8v) today slowly dropping to about 1300w over the course of 10mins as the battery took on charge. I've had it doing >1300w for over an hour with no sign of problems - yes the fan's running full pelt but nothing seems to be getting overly hot.My current issue though, is that there's not a perfect voltage to set it at, to cover the full range of the charge cycle. Set too high, then at the start, when the batteries are empty, we're trying to pump out 170A (or more) however, a voltage that gives a civilised output at this end, leaves us with, in effect, a trickle charge as we approach the 'full' end of the cycle.So there is a little bit of circuitry I'd like to build but I really don't know enough to design it myself as my knowledge is basic - for example: I know, in theory how transistors work but don't have a clue how to implement them in a circuit.Anyway...Everyone knows pins 33+36, bridged with <500R activates the PSU.Less well known is that pin 34, emits an 'indicator voltage' that represents the current output.For an output >20A the indicator voltage is roughly I x 0.032 - 0.4So 2.8v represents 100A, 2.0v is 75AAs above in this thread, I have a 'control resistance' between the trim pot and ground which, as it reduces, increases the output voltage (and hence the current) of the PSU.What I'd like to do is to automagically manage the control resistance based on this indicator voltage.eg. As the indicator starts to exceed 2.5v, increase the control resistance to bring the output back down.The thing is, I can think of ways toreducethe resistance as a result of increased voltage (eg. an LDR/optoisolator) but I don't know how to do the opposite. I assume this would be childsplay for many folk on this forum but I'm afraid I am 'enthusiastic but relatively clueless'.btw. if the answer is, "why are you even bothering? It would be much simpler toyour simple solution here" please do fire away...

author: MickeeYay
author_rank: Newbie
timestamp: January 09, 2021, 01:12:18 am
content: Quote from: eblc1388 on December 22, 2020, 07:43:24 amBrilliant. Worked for me. Thanks..

author: MickeeYay
author_rank: Newbie
timestamp: January 09, 2021, 01:20:36 am
content: Quote from: eblc1388 on January 03, 2021, 07:37:41 amI don't have a wattmeter but I measured the current draw on the mains side of my PL11 with DC on and I got 0.17A @ 230V = 39.1WThat is very high for idle use. The 6 LED downlights in my living room use less power.Surely it's not the fan drawing that much current?

author: eblc1388
author_rank: Frequent Contributor
timestamp: January 10, 2021, 07:06:51 am
content: Quote from: MickeeYay on January 09, 2021, 01:20:36 amThanks for the measurement. However, with DC ON and no load, the power factor is not unity, therefore a wattmeter is required to measure the actual power consumption.I don't think the fan would draw that much power, all other power supplies I tested have fans too.

author: eblc1388
author_rank: Frequent Contributor
timestamp: January 10, 2021, 07:35:10 am
content: Quote from: ubrain on January 05, 2021, 01:47:38 pmActually you've have got a very good idea and it might work, it just need a little twist in your thinking. Simply put, the power supply output voltage is sampled via a voltage divider, consists of a top and bottom resistor in series. You've already known how to change the sampled voltage by changing the value of the bottom resistor element. However, you can also do the same with the top element too. By reducing the value of the top element, you can mimic an increase in output voltage as the sampled voltage is now larger. The control circuit will then works to reduce the power supply output voltage as a result.However, will it actually works? Well one won't know if one don't try. I rigged up the few parts needed and tried it on my supply. In the schematic below, the current signal from edge connector pin#34 is fed to an emitter follower made up of NPN 2N3904, with the 470R trim POT as load. It is advisable to make sure the wiper is at the NPN emitter position before testing the circuit. This current limit can be totally disabled by setting the wiper to the fully clockwise(i.e. to GND) position. The parts like NPN, optocoupler and POT values are not critical. Mine works with a 5K POT but the control range is small.Yes, I can limit the current to 40A as the output voltage reduces from 12.2V down to 9.8V, with the POT wiper set at the fully anti-clockwise(i.e. at the NPN emiter) position. However, the current limit is gradual and it is difficult to conduct a proper test without an electronic load.

author: ubrain
author_rank: Contributor
timestamp: January 10, 2021, 04:43:44 pm
content: Uh!eblc1388, You are an absolute legend!I had spent quite a lot of time researching and learning, trying to figure this out from basics, but at a certain point my brain was feeling a bit full, I wasn't sure I was getting anywhere and I was using time that I should really have been spending on work and well, one needs to be careful not to get obsessedHowever... thank you for your reassurance and actually I was getting pretty close - it is fair to say that I have understood your explanation much better for the learning that I've done over the past few days so it's a WIN after allI need to get the bits ordered - annoyingly, having just discovered I had an electronics store within easy reach, within 48hrs it had closed for lockdown!If only Amazon did 2hr delivery on transistors.

author: ubrain
author_rank: Contributor
timestamp: January 11, 2021, 12:13:30 am
content: Quote from: paulzedx636 on December 31, 2020, 06:18:45 pmI did both changes. The voltage goes up to 14.41v (which was my target) and the OVP doesn't kick in by then.How far did you want to go?

author: paulzedx636
author_rank: Newbie
timestamp: January 11, 2021, 04:11:36 am
content: Thanks for the reply I've done both mods too. I'm trying to get 14.41v I'm getting 14.32 under load without shutting down. I think it may be since my 6.8k resistor measures at 6.9k I'm not sure if I need to go a little lower or higher in resistance to get get to 14.41v. 😅

author: ubrain
author_rank: Contributor
timestamp: January 11, 2021, 11:14:07 am
content: Yes, reduce it a little to go up further.I didn't have a 6k8 handy so actually used a 5k7 + 1k in series and got exactly what you're trying to get to.btw. I was experimenting last night and wound the voltage up to 15.5v without OVP kicking in. There was no load at the time though so I don't know how much use that info is.

author: paulzedx636
author_rank: Newbie
timestamp: January 11, 2021, 06:13:40 pm
content: Thank you for the information, I will try it on the one l haven't modded yet. I think 16.68v is the upper limit without further mods, as I had solder grounding on the pot where you place the 6.8k resistor. In this scenario I had no adjustability and have corrected the problem. If someone was to take the voltage that high they would have to change the output capacitors to 25v as their only rated for 16v. 😁

author: ubrain
author_rank: Contributor
timestamp: January 16, 2021, 01:14:21 am
content: Quote from: eblc1388 on January 10, 2021, 07:35:10 amThis is BRILLIANT!All the bits arrived a couple of days ago, and I've put them together on a prototype board, so I could mess around with it a bit and maybe even learn something.The only changes I made: I used a PC817 rather than a PC817A as that's what I could get quickly. Also I swapped the 22k out for a 17k to get the transistor to trigger a little earlier in the range.You say you got it working at 40A but with the 22k I wasn't seeing any life until >80A.So, I have just run a full charge cycle: that's 285AH of charge put into the batteries in just 3hrs withoutanymanual input from meKicking off at just over 100A, current very slowly dropped toward 90A as the voltage rose. But this is OK because critically, the power output remained consistent - within the range of 1212-1250w the whole way. This is the optimal resultI had tried to set the range to max out just before full and so at about 97-98% charge, the optocoupler went fully open and current started tailing off over the last minute or so, dropping to about 50A by the time I hit 100%.This is such a fantastic mod! And I think we're the first to have done it. Now I just need to do the final build - if only my work was as neat as yours!Respectfor your skills Sir andthanksfor your efforts putting the circuit together.I should probably stop here as I've achieved the objective but... you know how mission creep goes, right?So meanwhile, one of these just arrived today:eBay auction: #https://www.ebay.co.uk/itm/HP-704604-001-ProLiant-DL580-G8-G9-1500W-Common-Slot-Hot-Swap-PSU-684532-B21/401795623783?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649(They accepted £30 as an offer)It's platinum rated so 94% efficient and has a double fan to dissipate more heat. Of course the Pinout is the same.I liked the idea of 1500w instead of 1200w / 120A instead of 90A. Am I being greedy?I hope I can figure out how to adapt the HSTNS-PL11 mods we've done here over to the HSTNS-PL33. I mean, the model number's almost the same, so how hard could it be, eh?

author: Squidster
author_rank: Newbie
timestamp: January 16, 2021, 05:04:41 am
content: What a fantastic thread! I bought two of the HSTNS-PL11 Power Supplies for my ham radio shack that I am trying to do as inexpensively as possible. So far, I've spent $37.00 for two of these power supplies. I'm waiting for some resistors to arrive and will get cracking on these mods as I need a solid 13.8v for the first radio I am installing. BUT, I want the OVP to let me go up to 14.0 - 14.2, approx. to allow for the voltage spikes when transmitting on the highest wattage for this radio and have it stay on and not let the OVP to 'protect' it.Soon as I get the required items I will put it together and report back.As a avionics technician in the Navy I am having to chisel off the dust that is sitting on my electronics knowledge and experience from 30 years ago.HUGE THANK YOU toeblc1388- definitely a master. BIG thank you to all who have contributed & those who have tried and reported back - ALL of this has made me excited about the ham shack, and, not paying $145 for something that I can do for about $45 and a bit of time. Thanks to all of you, of course.

author: eblc1388
author_rank: Frequent Contributor
timestamp: January 16, 2021, 07:42:32 am
content: Quote from: Squidster on January 16, 2021, 05:04:41 amIf you're not as courageous as ubrain which want 14.4V output or more, then you should do the OVP mod with a different resistor value. First, connect a voltmeter to point A and slowly increase the output voltage. Record the voltage increase until the unit is tripped by OVP. This might be 13.5V or more. Turn the voltage adjust POT back a bit.Now power off and solder a 50K VR to replace the 12K resistor(as per the above OVP mod). Power ON and the OVP would now operate with a slightly higher output voltage. Repeats the process by gradually trimming down the VR value until the OVP trips at 14.5V or whatever voltage you desire. Remove the VR and replace it with a resistor.

author: eblc1388
author_rank: Frequent Contributor
timestamp: January 16, 2021, 08:07:51 am
content: Quote from: ubrain on January 16, 2021, 01:14:21 amGreat. Please do a tear down with lots of photos. Maybe their constructions are similar and the above mods can be carried out without much changes.

author: ubrain
author_rank: Contributor
timestamp: January 16, 2021, 04:10:26 pm
content: Quote from: innkeeper on July 14, 2020, 07:28:43 pmDo you happen to remember where you got the schematic?- I'm trying to find one for the HSTNS-PL33

author: ubrain
author_rank: Contributor
timestamp: January 20, 2021, 03:14:59 am
content: Back to the original project, the HSTNS-PL11.My circumstance is that I'd really like to leave the PSU wired up to the batteries permanently but of course, as soon as the mains is disconnected, back-current kicks in.My first thought was diode but to cover 100amps it would need to be quite a big one and then there's the voltage drop.So I went relay withone of these. Weirdly though, although I bought them from that ad, I only paid £7 each. The prices seem to yoyo quite a bit on them and exactly the same thing can cost between £6 and about £25 depending which ad you click.Anyway, I fed it with the 12v standby signal so as soon as the power is plugged in, it clicks on. When the PSU is powered though, it seems to hold its ground and there's no back-current problem.It pulls the 12v signal down to about 11.85v which affectseblc1388's balancing circuit (which uses the same 12v feed) but only a small amount... a tweak of the VR covers it.Being a novice though, I was wondering whether there's anything silly about what I'm doing?For example, should I be putting a resistor in line with the relay coil or anything?

author: Squidster
author_rank: Newbie
timestamp: January 20, 2021, 03:27:02 am
content: I received my resistor kit today, so I am ready to make the mods on the PL11 P/S. But... I gotta share this laughable moment.I open the little plastic box and on the top of the little sealable bags is the first batch of resistors. See attached photos...Last time I checked, 0 ohms is a straight wire.MIC (Made In China)Pretty funny!Soon as I get it all put together, I will report back on how it all went for me.

author: eblc1388
author_rank: Frequent Contributor
timestamp: January 20, 2021, 07:12:08 am
content: Quote from: ubrain on January 20, 2021, 03:14:59 amThe 12V auxiliary power supply is 2.5A regulated. Pulling it down to 11.85V means that the relay coil has overloaded the regulator current output capacity. This is definitely not good. Please reports back thecoil resistance. The relay coil is dissipating 5W of power(relay specifications, but I seriously doubted it) and is sealed within such a small enclosure. Needless to say, this relay(like all other similar car starter relays) is meant and rated for short time operation only. You'll risk melting the relay or start a fire if you keep it energised.Quote from: ubrain on January 20, 2021, 03:14:59 amNormally, there are already beefy diodes installed in parallel at the output of the power supply. These diodes should block the back feed into the power supply should its AC input goes off.I did a check on mine and found the PL-11 takes some 200mA from external 12.2V source. The most likely cause is the 12V cooling fan, which runs under this condition. This PL-11 supply is a bit different from other models, which takes only 20mA or nearly none at all via back feed if the input AC is off.I would suggest the following test. With AC off, open the case and unplugged cooling fan from its pcb socket. Then apply 12V to the power supply output via an ammeter to see if the total back feed current drops to 20mA or less. If it drops then you can use a small 12V relay to switch the cooling fan off via the 12V aux supply if the AC input is off.Regarding to your problem of 200mA back feeding, I think you may have to live with it. I'm sorry I can not propose a cheaper and better solution.

author: ubrain
author_rank: Contributor
timestamp: January 20, 2021, 03:57:09 pm
content: Quote from: eblc1388 on January 20, 2021, 07:12:08 amI've checked again. I was measuring via a pin on the bread board. If I go direct to the 12v output pin on the PSU itself, I'm getting 11.92vQuote from: eblc1388 on January 20, 2021, 07:12:08 amIt measures about 33R cold and about 43R when it's warm.Quote from: eblc1388 on January 20, 2021, 07:12:08 amIt appears to be drawing 0.27A so at 11.85v that's 3.2wQuote from: eblc1388 on January 20, 2021, 07:12:08 amNoted.I just set it up and left it energised for about 40 minutes, checking regularly. Yes, it got warm but not seriously hot. After 20 mins I could still touch it and hold my hand on it without discomfort. It doesn't seem to get hotter than that.Quote from: eblc1388 on January 20, 2021, 07:12:08 amNo worries - thanks for your suggestions.I can always put a manual isolator switch in if I have to. It's just that it's one more thing to remember, and hence, that I'm likely to forget sometimes. So if I can set an automated solution up that's far preferable.

author: Arq1983
author_rank: Newbie
timestamp: March 29, 2021, 04:40:01 pm
content: Big thank you eblc1388 and all of you for help. I Have problem to start psu. What resistor did you put between pins 33 and 36? I tried 1k but wouldn't start some times. Thanks

author: ubrain
author_rank: Contributor
timestamp: March 29, 2021, 04:42:44 pm
content: It needs to be less than 0.5k. 470R should work

author: Arq1983
author_rank: Newbie
timestamp: March 29, 2021, 05:21:30 pm
content: Thank you

author: gwhaley
author_rank: Newbie
timestamp: April 15, 2021, 10:15:04 am
content: Hieblc1388- sorry to party hijack a thread here - when you say you have a DPS-650EB...Quote from: eblc1388 on January 03, 2021, 07:37:41 amwould that be the server power supply block like those from an 'RM Dual' server. Quite rare I think - but, I happen to have a pair here and have been trying to power them up outside the server. See my github page where I've documented what little I've found so far:https://github.com/grahamwhaley/Delta_DPS_650EB.If those are the same as the one you have, do you have details on how to power it up or the pinout? I've tried a lot of searching and comparing with similar Delta supplies, but I've not found any really comparable, or a pinout that works. My next step would be to follow a well known published multimeter procedure and start putting 1k resistors across the likely candidate pins, but that might get a touch laborious (and I need to re-solder a header I attached to do it effectively).Any hints tips or clues appreciated - and I'll update the github pages with anything found etc.

author: eblc1388
author_rank: Frequent Contributor
timestamp: April 16, 2021, 10:27:40 am
content: On two of my DPS-650EB units, I did the following to turn it on.I place a short on pin T21 to 0V. Then to control the +12V main output On/Off, I just connect pin T20 to 0V via a Dupont connector. If the connector is open, the power supply's +12V is turned off. To turn on the +12V, I just push in the removable connector to the metal pin which is connected also to 0V. See image.

author: gwhaley
author_rank: Newbie
timestamp: April 16, 2021, 01:37:42 pm
content: Thanks @eblc1388 - I can confirm that works here on my 650EB!Well, it works on one of them. The other has the relay click on and off and immediately goes into 'orange light' error mode. I suspect I may have damaged that one during my investigations. I think that one is destined to become 'spare parts' :-(The one that does power up then spins its fans up pretty fast after a few seconds, and they seem to stay at that speed (much as they do when used in the server chassis), even with no load attached. Not the quietest PSU I think.I'll go update my github docs now. Many thanks!

author: eblc1388
author_rank: Frequent Contributor
timestamp: April 16, 2021, 04:24:56 pm
content: One of my units does this too, but to a lesser degree.With the +12V output off (T20 not connected to 0V), the green power LED flashes, but no relay sounds. I then enable the +12V output and I can then hear the internal relay clicks several times and unit powers ON. It will then remain quite normal even if I turn on/off the 12V output, with the mains connected. It does this again if I left it power off for a few weeks. I suspect there is some electrical leakage on the PCB causing this, mostly across those voltage sensing smd resistors string.I recommend to try to startup several times with only the T21 pin shorted and see if the green LED would lit steady and no orange warning LED.Yes, the fan in my unit spins at full speed too when I turn the +12V output ON.

author: Jerycho
author_rank: Newbie
timestamp: May 28, 2021, 07:58:12 pm
content: Hello. Thats probably my first post.Since I have been interested in converting server power supplies to achieve cc / cv function. I came to the conclusion that to achieve this, it is enough to change the reference voltage compared to the sampled voltage from the current measurement. I like liteon server power supplies because technical documents and diagrams are available. In addition, the power supplies are available in various power options from 460w to 1200w. The price is also affordable. New power supplies can be purchased for just £ 5 apiece for the 460w option. The best thing is that each power option has the same control system, the pcb can only differ and the location of the components.Let's get to the point.In the picture I present an example of a control loop for the power supply.My suggestion is to cut the reference voltage output path before the 1k resistor and change to an adjustable reference voltage, the easiest option is tl431 + potentiometer and a small capacitor. A more advanced option is to use a dac + microcontroller. Tried to use esp32 (adc as output voltage measurement + current measurement + op amp as filter, 34 pin is 60mv / A current monitor output and built-in dac as reference voltage followed by opamp). Unfortunately. The ADC in this microcontroller is very inaccurate or I just made a bad low-pass filter but achieved current regulation from 1A to the maximum. The power supply performed well, it did not squeal or make any strange sounds. I also have the test results in the form of the Vref vs output current and voltage table somewhere, and I do not have equipment for precise measurements such as an oscilloscope, dummy load etc.In the pictures I present pcb pictures with the location of the reference voltage inputs for the current control loop and some pictures of the relative pcb boards with the location of the inputs. If there are interested people who would like to develop the topic, I can provide more details about my research and unearthed schematics.Not quite accurate schematics for PS-2122http://www.sector.biz.ua/docs/power_supply_schemes_10/HP_HSTNS-PL11_PS-2122-1C.pdfSchematisc for PS-2142 in attachement.BTW. Anyone know why compensation is made at the reference voltage input instead of at the reference voltage input? I have looked through many documents, diagrams on the control loop and have not seen a similar solution anywhere.Regards.

author: eblc1388
author_rank: Frequent Contributor
timestamp: May 31, 2021, 07:57:15 am
content: Quote from: Jerycho on May 28, 2021, 07:58:12 pmThat's very affordable. Are you sure they are really new, and not just cleaned and refurbished units?Quote from: Jerycho on May 28, 2021, 07:58:12 pmYes, it will work. I have uploaded a modified schematic so others can make the modification change if they wish. I wonder if you can still maintain the same current with the power supply output connected to a very low impedance(e.g. short circuit)? Does the power supply complaints of the low output voltage and shutdown?Quote from: Jerycho on May 28, 2021, 07:58:12 pmThanks for the schematic. They are difficult to find on the internet. If you have more of the schematics by the same manufacturer, please upload them here.Quote from: Jerycho on May 28, 2021, 07:58:12 pmAre you asking why compensation is added at the reference voltage input instead of the actual output voltage input? My understanding is that compensation is usually added between the op amp's output and the inverting input terminal or else there will be a possibility of positive feedback if done otherwise. The connection of signals does not determine which pin should be used for compensation. Many op amps also has separate compensation pins besides the two input pins.

author: Jerycho
author_rank: Newbie
timestamp: June 02, 2021, 05:07:17 pm
content: QuoteI think these were spare parts. Considering the reliability and the number of these power supplies, it is very likely. I bought Astec AA23340 for £ 15 which was 100% unused.QuoteAs I mentioned before, I didn't do too many tests because I don't have the necessary equipment, my test was to connect 6 car bulbs 60w each in parallel.The power supply worked well, it only sizzled slightly when the reference voltage was close to 0v, I suspect it was due to the quality of the pcb. The power supply did not turn off at low voltage because I turned off the uvp protection, so voltages close to 1v were available when the reference voltage was also lowQuoteSure, I took some time to do it, it was not very pleasant because I was wandering around Chinese forums typing keywords in Chinese search engines but I found interesting documents. Unfortunately, only preview demos are available, the service on which I found the documents is payable at the moment, when I was doing the search, they were available in full.http://ishare.iask.sina.com.cn/f/5075532.htmlishare.iask.sina.com.cn/f/5075393.htmlhttp://ishare.iask.sina.com.cn/f/5080334.htmlhttp://ishare.iask.sina.com.cn/f/5075478.htmlhttp://m.ishare.iask.sina.com.cn/f/5074978.htmlhttp://ishare.iask.sina.com.cn/u/53b4cea411e0ee10dc4a362f/Here is directory indexhttp://ishare.iask.sina.com.cn/u/53b4cea411e0ee10dc4a362f_downNum_pdf_1/Also see atachement.I also found a Chinese forum where someone managed to convert the power supply, but unfortunately the person does not want to share the method.https://www.mydigit.cn/forum.php?mod=viewthread&tid=183810https://www.mydigit.cn/forum.php?mod=viewthread&tid=229111&extra=&page=1https://www.mydigit.cn/forum.php?mod=viewthread&tid=217015QuoteThanks for the answer.

author: iz1fks
author_rank: Newbie
timestamp: August 04, 2021, 04:46:48 pm
content: Quote from: eblc1388 on September 06, 2020, 05:07:03 amHello, since a few years I have had a HSTNS-PL12 never solved the issue of modify the overvoltage protection to go up to 13.8V output. Now I have read your great mod but PL12 board is slighlty different and PIC 16F883 is located on the other side of the small pcb (the external side near the chassis). So i can't apply your mod using the posted photo only; which is the adc input used on the PIC16F883 for voltage monitoring? Attached the small pcb external side photo.

author: eblc1388
author_rank: Frequent Contributor
timestamp: August 04, 2021, 06:25:13 pm
content: You can try the following steps:1. find out which pin of the 18-pin (2x9)connector between small PCB and main PCB is directly connected to the +12 V output2. follow this pin to locate one end of a certain resistor, of which the other end of the resistor is connected to PIC and a resistor to 0V. In effect, locate this +12V voltage divider resistors pair. The junction of this voltage divider should connect to one of the following PIC pin 2,3,4,5,7 or 21~26.3. with the power supply output +12V, measure the voltage on the voltage divider or at the PIC pin.4. parallel a suitable resistor on the 0V leg of the voltage divider, such that the PIC pin voltage is the same as measured in step(3) when you adjust the output voltage to +13.8V

author: iz1fks
author_rank: Newbie
timestamp: August 04, 2021, 07:22:12 pm
content: Quote from: eblc1388 on August 04, 2021, 06:25:13 pmthanks for your quick reply.Already tried both step1 and 2 but not easy to perform and to find the voltage divider. I know that output +12 voltage is located on pin 4 from left upper row of that 2x9 connector and detected the first resistor that it's in a very difficult to reach area of the pcb (internal side); if I remeber well it's a 1kOhm resistor, but unable to be sure which is the next resistor to 0V. For this reason it could be useful to know which is the pin used on the PIC maybe it's the same on PL11, i don't know. It's not a easy pcb to investigate without other information. I could try to put a resistor between the resistor leg and the 0V, 12kOhm is the value you suggest isn'it ? I should solder on the internal side but this is very very difficult , it would be better find the trace on the external side or perhaps removing the pcb from main board desoldering 2x9 connector but not so easy task anyway...

author: eblc1388
author_rank: Frequent Contributor
timestamp: August 05, 2021, 05:01:24 am
content: Yes, it is a bit difficult. Unfortunately, your attached image of the board is not sufficiently clear to enable tracing of the circuit.There is another method.We know that the output voltage signal after the voltage divider must only goes into one of the ADC pins of the PIC. This limited the possible PIC pins to eleven(see previous post). First you carefully set the output voltage to exactly 12V, and measure voltage on these pins. Then you increase the output voltage to +13.5V or as high as you could without tripping the unit and do the measurement again. Any pins of which the voltage is between 2.0V to 3.5V and increased by proportion to the output voltage increase will be the likely target. Hope this help.

author: iz1fks
author_rank: Newbie
timestamp: August 05, 2021, 07:24:53 pm
content: Quote from: eblc1388 on August 05, 2021, 05:01:24 amok, I perfomed a bit more test on pcb trace and found the ADC pin used is AN9 (pin 24 of PIC16F883) on HSTNS-PL12. I have soldered a 22k to ground ground and now 13.8V can supply amps without overvoltage shutdown; voltage on pin 24 3.36V. I don't know the exact overvoltage threshold becuase the modification for voltage adjustment doesn't permit more than 13.9V ouput, i will try if i can remove the mod and perform the same mod as described here with 6.8kOhm (now the 01B resistor is removed and I'm not sure about its value).I will post an image with the solder point for the resistor near the PIC. Thanks a lot for your support. Now I will try to reduce output riplle and rfi noise if possibile.

author: eblc1388
author_rank: Frequent Contributor
timestamp: August 06, 2021, 05:03:22 am
content: Quote from: iz1fks on August 05, 2021, 07:24:53 pmI'm glad the method works. You must be an ham trying to use the power supply on communication equipment at 13.8V and worry about noise. These 13.8V equipment are designed to work on mobile vehicle too so they can withstand quite some input over voltages like unstable and noisy DC power from a vehicle.Your target of overvoltage protection for the PL12 should be set at 14.6V or a bit more, as too close to 13.8V would likely resulted in many unexpected trips if output loading suddenly changes, like when you key a transmitter on and off.

author: iz1fks
author_rank: Newbie
timestamp: August 07, 2021, 06:34:01 pm
content: ok, I removed any mod and with 12V ouput, ADC voltage is 3.1V. Installed the new voltage mod according to reply#8 by ubrain user, and the 22k resistor from adc pin 24 to ground and with 3.3V @13.8V ouput no OVP issue varing voltage up to 14.54V (max available).Don't have power resistor to perform test with high current but I will test on field with my transceivers requiring more than 20A (yes, you're right I'm an ham!), eventually changing the resistor to raise the OVP, but quite sure that it's ok yet.About the rf noise, it depends on several fators, equipments, frequencies used etc. usually a common mode filter wounded on ferrite on the ouput could help with conducted emi in hf or low vhf range. A ripple up to 100mV is easily visible with oscillocope on the output and also high frequency noise unfortunately; this is a drawback of these items, but I have not understood if it's due to a poor filters to reduce ripple and hf nosie (not need for application they are designed for) or due to a circuit design topology. I have seen similar issue on my dps-600 power supply.I attach a couple of images to help any PL12 owner that need to perferm the mod (of course I don't take any responsability for the mod, people need to know that these power supplies can be very dangerous items!)I would like to use a quieter fan, anybody know the pinout of the 4 wire pwm connector?

author: eblc1388
author_rank: Frequent Contributor
timestamp: August 08, 2021, 04:58:32 am
content: Quote from: iz1fks on August 07, 2021, 06:34:01 pmThe industry standard for PC PWM controlled fans all follows the same connections, though the color of the wires might be different. These 4-wire fans will also run at full speed in a 3-pin connection. Starting from pin1 to pin 4 are:Gnd, +12V, tacho feedback, PWM control input. It would be out of the ordinary that those fans on the power supplies would use difference connections but check to be sure.

author: eblc1388
author_rank: Frequent Contributor
timestamp: September 21, 2021, 12:09:38 pm
content: Quote from: Jerycho on May 28, 2021, 07:58:12 pmHi, Jerycho. Have got the remaining pages of the power supply you have posted in your first post, i.e. the PS-3601-1F? If so, can you upload a copy to the forum?I visited the various links you have provided but unfortunately it only allow visitor(me) to view the first two pages of that particular schematic.Thanks.

author: Jerycho
author_rank: Newbie
timestamp: September 21, 2021, 12:43:34 pm
content: Of course. I found a method to get the first 30 pages of documents on ishare.iask.sina.com.cn, but I need some time to build the index as my method requires getting an image from ishare.iask.sina.com.cn and splitting the image file by the address of the pattern found in image. The link includes an example file representing the first 30 pages of the document. You can open the file in your favorite hex editor and see what I mean by searching for "JFIF". I think by the end of this week I will be able to deliver about 10 power supply schematics worth your attention.https://mega.nz/file/v1AixLpT#Pj421U9LQQVkBPhbi0hopAWHadVfBRhdHok4hvij0K0

author: eblc1388
author_rank: Frequent Contributor
timestamp: September 21, 2021, 01:21:53 pm
content: Thanks for your effort.I downloaded the file from mega.nz and examined it in a HEX editor. My first impression is the file is a collection of many jpeg files concatenated together into a large file. If we can find out the starting address of each individual file, then we can extract the individual jpeg files and then convert them back into a pdf.Interesting.p.s. Success. I search the net a bit and find out a way to automatically split out the individual jpeg files, using the awk command under Linux. Just create a temporary directory and place the merged jpeg file into it. Then execute the command with the correct filename to match with the merged filename. I got all 50 jpeg files. Attached is the schematic in pdf format.Code:awk 'BEGIN {RS="\xFF\xD8\xFF\xE0\x00\x10\x4A\x46\x49\x46"; FILENUM=-1} {FILENUM++; if (FILENUM == 0) {next}; FILENAME="image0"FILENUM".jpg"; printf "%s",RS$0 > FILENAME;}' PS-3601-1F.jpg

author: Jerycho
author_rank: Newbie
timestamp: September 21, 2021, 02:40:11 pm
content: So basically if you found something interesing you need to get link to image rendered on main page ie:https://swf.ishare.down.sina.com.cn/avumxnYYL7B.jpg?ssig=0UZsQwnRAS&Expires=1637313011&KID=sina,ishare&range=0-63922Then you need to remove last parametr from url, so you can get mostly all documents. Sometimes just svg format is available.Cheers

author: eblc1388
author_rank: Frequent Contributor
timestamp: September 21, 2021, 03:30:14 pm
content: I tried downloading several documents and the method works. You rocks.If you have Linux, have you tried the "awk" extraction method I mentioned above?

author: Jerycho
author_rank: Newbie
timestamp: September 21, 2021, 03:52:43 pm
content: I have somewhere python script for spliting file into images. I'm currently not using linux systems. Btw I have done some dc simulation of control boards. In the simulation, affecting voltage references affects voltage/current limits. I beginning thinking about design some control board based on mcu and some dac (in my way is a pic24fj64gb002 (build in 1x 10bit adc muxed up to 14 channels) and mcp4527 12 bit dac's for voltage/current adjustment, but I'm currenlty studying many books from ti, analog about theory and calculations and have some time shortage.

author: Jerycho
author_rank: Newbie
timestamp: December 11, 2021, 09:03:47 am
content: Quote from: gwhaley on April 16, 2021, 01:37:42 pmHello. I found doc about server chassis which contains this psu.https://www.intel.com/content/dam/support/us/en/documents/motherboards/server/chassis/sc5650/sb/e39531004_sc5650_tps_r1_2.pdfPinout is on page 45

author: VA3HDL
author_rank: Newbie
timestamp: April 05, 2022, 01:40:13 pm
content: Hello everyone,I have the HP HSTNS-PL11 psu made the two mods and everything is good for setting up the 13.8V needed for ham radio and not tripping the OVP.However, I have two issues that I will need some direction on how to fix or adjust:1. The OVP triggers at very high voltage for my use case - Close to 17v - How do I bring this down to 14.5v max under load?2. I noticed that since I made the mode, the PSU fan goes really quiet and down in speed when the PSU is under load. Quite the opposite behavior before the mod. Any ideas?Thank you,Pablo

author: eblc1388
author_rank: Frequent Contributor
timestamp: April 05, 2022, 04:25:35 pm
content: Quote from: VA3HDL on April 05, 2022, 01:40:13 pmIf you have added the 13K resistor to increase the OVP trip point, then you can increase the value of this resistor to lower the tripping voltage level to the original trip point(by using a very high value resistor) or any level in between 17V and 13V. You can try 22K for a start to see if the unit operates correctly with 13.8V load.Quote from: VA3HDL on April 05, 2022, 01:40:13 pmMine does that too but it has nothing to do with the modification. The fan speed will increase automatically when the internal temperature goes up.

author: VA3HDL
author_rank: Newbie
timestamp: April 07, 2022, 11:57:38 am
content: Thanks eblc1388For #1I will try with a variable resistor to find the right voltage spot, then switch to fix one.For #2The fan was working as it should before the mod, going up with load and temp and going down without any load. The issue is now when PS is under load the fan goes down, instead of going up as it was doing before.Thanks.

author: PA3VOS
author_rank: Newbie
timestamp: April 21, 2022, 12:26:50 pm
content: Hi all,With a big THANKS to eblc1388 I modified the OVP on a 460W version that has a custom-made PIC called A4315-1. it is also a 28-pin IC. the PCB does look somewhat different from what I have seen here in this thread. I added a 33K resistor between pin 24 en GND and it worked for me perfectly!73's PA3VOS

author: eblc1388
author_rank: Frequent Contributor
timestamp: April 21, 2022, 05:41:30 pm
content: The power supply mentioned above is the 460W HP HSTNS-PL14.Thanks PA3VOS for letting us know about the modification.

author: PA3VOS
author_rank: Newbie
timestamp: April 23, 2022, 09:05:38 pm
content: Edit:I had to increase the resistor value to 33K to ensure the OVP was increased to 14,5V.

author: Ignatovd
author_rank: Newbie
timestamp: May 20, 2023, 10:31:59 am
content: Hello to all!have PL11 rev 16 and I can't get an OVP of 14.5V.In this revision there is a PIC called A4315-1Photo as in the post of 21.04.2022Without load my power supply picks up the voltage to 14,4V , but as soon as I connect the load the voltage drops to 13,6V and changing the resistance has no effect on the voltage. With the load and at 13,6V my power supply makes a noise, but this noise comes from the board and not from the cooler.- problem in this videoMaybe you have a solution for my PL11 rev16 power supply?

author: eblc1388
author_rank: Frequent Contributor
timestamp: May 20, 2023, 01:53:01 pm
content: Quote from: Ignatovd on May 20, 2023, 10:31:59 amIt sounded like your power supply has entered output current limiting mode. How much current loading are trying to draw from it?For a 1200W 12V power supply, it is rated at 100A max. As you have now increased the output voltage to 14.4V, the maximum current it can provide will be lower at 1200W/14.4V = 83.3A.From the image of your supply label, it stated a max current of 160A which is wrong. It is unthinkable for a genuine big company like Lite-On to have made such a big mistake on the label of its product and not being discovered before the product has left the factory. This led me to suspect that the power unit is possibly a fake one and so had a even much lower output power.

author: Jerycho
author_rank: Newbie
timestamp: May 21, 2023, 12:03:45 am
content: I think you're using too long potentiometer cable, feeedback path is very fragile to noise. Try to use fixed resistor or make shorter you pot connection cables.

author: hardocp
author_rank: Newbie
timestamp: June 11, 2023, 12:46:05 pm
content: Hi everyone,with help from this thread, I managed to modify a Lite-on PS-2751-2F-LF to output 14.4V, the control board is very similar (maybe even identical). The OVP circuit is different but I found the right resistor to change to fix it - let me know if a picture of the mod would help anyone.The issue that I have now is similar to the one reported by Ignatovd: over 11A @14.4V, the power supply cuts output to ~13.6V and starts buzzing. This behavior continued up to 23A and above probably - I did not have a bigger load to test with.Any ideas on how to debug this further?

author: Ignatovd
author_rank: Newbie
timestamp: August 29, 2023, 06:36:08 pm
content: Thanks for pointing out the incorrect specifications on the label!The author in the comment under this video also suggested that it is a fake: "Another possibility is that you may have purchased a fake power supply. Genuine power supplies typically have serial numbers starting from 1, whereas yours starts from 3."In this video, the power supply has all the refinements removed. With no load, the voltage is 12.4 volts. It operates at 75-76 amps at 12 volts. But when you try to increase the load over 80 amps, the protection kicks in and the power supply shuts down.Conclusions:- I did not damage the unit during modification, it works;- the 1200 watt power indicated on the cover does not correspond to reality, so the unit is most likely fake.And I'm still looking for a way to bypass the OVP to about 14.5 volts.Quote from: hardocp on June 11, 2023, 12:46:05 pmGlad to know that my problem is not an isolated one. Maybe you have found a solution in the intervening time?

author: Ignatovd
author_rank: Newbie
timestamp: September 04, 2023, 05:32:41 pm
content: Quote from: Jerycho on May 21, 2023, 12:03:45 amI checked your position, soldered the permanent resistors and without using wires. Unfortunately, it continues to buzz at voltages above 13.5-13.6V under load.

author: dimon_ua
author_rank: Newbie
timestamp: November 01, 2023, 09:39:42 pm
content: Good day.Tried to replicate your mod using the PC817 on the PL11 unit. But somehow it turns out strangely. The output voltage is 3.72V.It is worth disconnecting PC817 from the board, as the voltage again becomes 14.6VTell me where I'm wrong.Thank you!

author: eblc1388
author_rank: Frequent Contributor
timestamp: November 02, 2023, 02:03:38 pm
content: Quote from: dimon_ua on November 01, 2023, 09:39:42 pmYou have got the opto-coupler PC817 input/output side reversed.I've reviewed the original picture of the mod and noted that there is some dirt on the underside of the opto-coupler, which you probably mistook as the round "dot" for pin #1. The schematic shows the correct connection though. I'm sorry for the unclear picture which led you to have connected the opto-coupler incorrectly. I've also updated the original picture to indicate clearly where pin#1 of the opto-couple is located.

author: dimon_ua
author_rank: Newbie
timestamp: November 06, 2023, 04:03:16 pm
content: Thank you friend!The scheme worked. It is possible to adjust the current starting from 50A and above.Although honestly speaking, I thought there would be a wider range.For example, adding a variable resistor in parallel with the 802Ω resistor, on the board near the left potentiometer, allows you to adjust the current starting from 30A. The lower the resistance, the lower the current. But even a short circuit gives a current reduction of at least 30A.Therefore, it is not at all clear how in China they manage to adjust the current starting from 1A

author: eblc1388
author_rank: Frequent Contributor
timestamp: November 06, 2023, 09:53:35 pm
content: Quote from: dimon_ua on November 06, 2023, 04:03:16 pmThis modification is a simple maximum current limiter, and is not meant to be adjustable once trimmed to the required current value.If you want a very wild range of adjustable constant current setting, you can refer to the method in Reply#41~42 of this thread kindly offered by forum member Jerycho. He did managed to set the current down from maximum to about 1A.

author: deadlistcach
author_rank: Newbie
timestamp: January 10, 2024, 05:41:19 pm
content: Hello I read most of comments videos etc.I have some questions.I have 2 PL11 rev10 psu. I did OVP and 14.4v mod already. they work seperately very good.I wanted to use them in series configuration. because of this I floated one of them. and made 24v. I mean 28.8v.as series right now its working without any load.I noticed something when I test in home one of (non isolated + goes to isolated psu -) isolated psu get more hot then not isolated. I mean not very hot, one of them like ıce other little warm. I watchend BBI on youtube he do serious parallel configurations. and I know these psu's have load sharing.Can I do series connection and load sharing in same time?or I needed to do this?thank you who read and give answer.

author: eblc1388
author_rank: Frequent Contributor
timestamp: January 10, 2024, 10:56:20 pm
content: Load sharing only applies to power supplies connected in parallel. e.g. two 40A power supplies providing 60A to a load. You don't want the situation of 40A+20A from the supplies so you connect them up with load sharing. This will equalize the loading and each power supply will then provide 30A.In case of series power supply connection in your case, there is only one load current value for both supplies, and this is the same for the two power supplies.You don't need any current sharing. In fact the only thing you can do is output power adjustment by changing the output voltage on one of the supplies.

author: deadlistcach
author_rank: Newbie
timestamp: January 11, 2024, 06:57:48 pm
content: Thank you for fast reply.if I dont need load share its good.(I just saw on internet and wonder) Today I test 30A load at 5 min everthing ok right now.when I do voltage increase with resistor, one of supply 14.3 other became 14.35-38v with 5k resistor.I check 2 small potentiometer before do anything one psu 53-24 second 48-56 there was different. So I open 2 of them and set 14.40v at idle.Do I need to do someting about starting psu's. just put switch ac power?

author: eblc1388
author_rank: Frequent Contributor
timestamp: January 11, 2024, 11:04:15 pm
content: Quote from: deadlistcach on January 11, 2024, 06:57:48 pmMost people just switch On/Off the mains ac power to these supplies via a single switch, and they work fine. Most will find no problem in doing so.However, the proper way to do it would be to add reversed-polarity diodes at output of the supplies to deal with the difference in timing regarding powering up/shutdown of each supply. Please read the following thread about how to wire it up.https://www.eevblog.com/forum/beginners/can-this-power-distribution-board-will-handle-1200w/

author: deadlistcach
author_rank: Newbie
timestamp: January 16, 2024, 07:45:51 pm
content: Hello,As you said I added reclifier, its 35a I will add one more paralel if I need(my load will be max 45A), but i dont understand how it works because we do bridge from 12+ to other psu negativeto 24v electric can stil go. Anyway I read most of your comments you know these issueI willchange cables if everything ok tomorrow load test.

author: eblc1388
author_rank: Frequent Contributor
timestamp: January 16, 2024, 11:00:12 pm
content: The added 35A rectifier(goods for up to 70A loading) is more than sufficient for the protection purpose, and you definitely does not need to add more in parallel.The added diodes(bridge rectifier) is a form of protection to prevent the components inside each power supply from reversed polarity voltage, when one power supply starts up faster than the remaining one. This condition exists for a brief moment during power up, through the connected load, a reversed voltage will be present across the output of the remaining one. It may or may not damage the component immediately in the short term, but there is a risk it could after more power up sequences. As a form of protections, user will not notice any difference without these diodes being connected.

author: deadlistcach
author_rank: Newbie
timestamp: January 18, 2024, 05:50:33 pm
content: Thank you for explanation, today I could do test. (half hour) I was trying to run PWM Solar Charger as dc dc charger, with 2 PL11 power supply works good.my batteries was not full but they had 26v. I also open some lights I wast 15A max on test. Thank you for helpingdo you have knowledge about pwm chargers? I also have some questions.

author: eblc1388
author_rank: Frequent Contributor
timestamp: January 18, 2024, 10:23:54 pm
content: Glad it all work out ok.You can start a new thread on problems with PWM Solar Chargers and I'm sure many members here can offer their help.

author: AirShox
author_rank: Newbie
timestamp: January 26, 2024, 02:06:38 pm
content: Greetings,I have PL11 with version 14 and 16. Unfortunately they do not have the same components and I cannot overcome the OVP. I can only power them ON to test if they are not dead on arrival.Does someone have used version greater than 13 (I have one and it works flawlessly) with success?

author: pienari
author_rank: Regular Contributor
timestamp: January 26, 2024, 04:13:15 pm
content: We need pictures.

author: AirShox
author_rank: Newbie
timestamp: January 30, 2024, 06:06:53 pm
content: Thank you in advance!PL11 ver16

author: AirShox
author_rank: Newbie
timestamp: January 30, 2024, 06:07:35 pm
content: Sticker as well

author: sp3rat
author_rank: Newbie
timestamp: August 13, 2024, 01:53:33 pm
content: Hello Pablo.I have the same problem with my fan.Without load, it works quickly and noisily, and with load, it works slowly and very quietly.Have you already solved this problem?Greetings to everyone.Jurek sp3rat

author: Mr Henkey
author_rank: Newbie
timestamp: November 06, 2024, 08:57:59 pm
content: Hi, I have two PL11 (rev 9 and 12). I going to use them as chargers for my battery. I've made mod from post #8, I used resistor 4,7k. To brake OVP I used different solution, I've replaced resistor 4,9k (R900 on scheme) to 5,6k. As a result, all works well, but... If I start charging with 14,4v 110a, power supply shutdown, I guess this is some kind of total power protection. I've made ocp mod, add resistor and have tried to set limit 60A, my BMS show charging current as 60a, but pl11 start buzzing and shutdown in 5-8sec, green led turn of.Could you please help me? Does my ovp wrong? Or this ocp is not fit for my situation? Thanks!

author: Reymond Josue
author_rank: Newbie
timestamp: April 28, 2025, 04:09:01 am
content: En vez de la resistencia de 12k coloca una de 5,1k esto para ovp y en los puntos del potenciometro y el punto GND coloca una de 6,7k yo lo hice y puedo variar el voltaje entre 13,33 y 14,65 sin ningun problema de que la fuente se apague aparte la fuente tiene 2 mosfets en su parte de rectificacion de voltaje los cuales por configuracion de fabrica no trae yo e sacado los 6 mosfets y e agregado los 2 mosfets faltantes e puesto los IRFB4110 estos soportan 100v y 180 amperes por lo cual la fuente quedara aun mas potente tambien con este cambio seria bueno cambiar el fusible de entrada a uno de 15 o 20 amperes no recuerdo bien el valor del fusible que trae originalmente si es de 10 amp poner de 15 y si es de 15 amp poner de 20 amp saludos desde costa rica