EEVblog #1298 - $70 2000W Power Supply

hi some of my most popular videos over the last decade have been to do with that power supplies ever do-it-yourself ones or reviews of various low-cost power supplies and it's not surprising because apart from a multimeter a power supply is the essential bit of lab gear and it's always been the one that you make yourself you know you do it yourself lab so that's your one of your first projects is to build your own power supply and they're just incredibly useful you never have too many power supplies and over the last five that maybe you seven years or something like that there's been this influx of accompanies manufacturing these are like really low cost like sub hundred-dollar switch mode power supplies that just have like seriously good like user interfaces and they're like they cost hardly anything and we've looked at several over the years like little tiny module based ones and really the specs of these things are quite remarkable but you haven't seen anything yet let's take a look at this new series of Jun tech power supplies thank you very much John takes not actually the company I guess that's they're like public brand the company's actually hangs you Jun CJ you NCE instruments Aiko from China and they manufacture a power supply is another like arbitrary function Jen's another low-cost power supplies and what we're looking at here is if you thought the previous ones were impressive in terms of output power output current capability and user interfaces well this one's a 3,000 watt power supply this one here is near to 2000 watt power supply we're talking 70 US dollars for the 2000 watt job and about 135 Yankee bucks for this 3000 watt power supply and yes it comes with a funky little remote front panel for the thing I mean you can't operate it basically on here but if you want the really nice interface you know a voltage and current set readouts and you know knob and everything else um you can get this little wireless remote interface this is really remarkable so thank you very much I would just call them John tech for sending these ones in so let's take a look at them I mean 3000 watts obviously I'm there a switch mode converter there a buck converter but look at the size of those screw terminals that's just insane and yes they are the proper block ones - none of that little leaf spring rubbish and as is very common with these things there's several different models in each series this is the DP s series and this is the DP h series the DPH I assume H stands for high voltage because this is 0-2 96 volts so this is the DPS series here and this is 0 to 60 volts at 0 to 50 amps apparently yes it can handle the full 3000 Watts you know not sure about that but anyway that's its claim and this is the DPH series the higher voltage 1 0 to 96 volts and that's I don't know why 0 to 60 volts is fantastic you know because there's like 48 volt power supply systems out there and stuff like that so that would be very handy for that don't quite know why I'd want to go to 96 I don't know leave it in the comments down below if you've got an itch you know uses for anywhere from 60 to 96 our volts perhaps but anyway 0 to 96 volts at 20 amps so yeah these things are beefy so these are the different DPH models this is the one that we've got over here the DPH 89 20 it's the top of the range it's got rs-485 interface as well fantastic for remote controlling the stuff in like industrial environments here at 96 volts 0 to 20 amps output power claims up to nineteen hundred and twenty watts there you go so it's got TTL serial comms and for the regular one and rs-485 for this particular model that we've got here and presumably are these other models here are cheaper as well I mean yeah even getting the zero temp.1 is absolutely fantastic like you know that's better than most likely power supplies on the market that are like three amps and what 10 millivolts resolution current resolution on these models is one milliamp because they've got a lower output zero to basically ten amps these are when you go to the 20 amp model you'd want to have a good reason because you actually get less current resolution on there and output ripple I assume that's a full load less than 50 millivolts and efficiency 92% well yeah you'd want that because if you've got an eight percent loss in here at near 2000 Watts you're talking like a hundred and sixty watts that you have to dissipate in this case here yes it does have a our fan in it to get the airflow but you know that's a quite a significant amount amount of power to actually yaar dissipate so mm-hmm but these are certainly aren't precision supplies we're talking about a plus minus 2% plus a digit and current plus minus 5% so yeah these are not precision power slaves they're more like industrial high-voltage high-current type supplies but a good lab should have both of these types of supplies available for when you need it so I they only sent the manual for the DPH series here which is the smaller one that we got you can see that the the color user interface there and it's all in English and it actually seems quite well done it's got all the records that stuff that you actually need and there's a the display description looks like it can display all sorts of different stuff as valve voltage and current lower limit setting and stuff like that so you can actually use you don't need this user interface to actually set up all that sort of stuff you can just do that you know with the like crude user interface on the LCD and the four buttons that they got on there but yeah it's doable so you don't actually need to buy the extra front panel control so it's got an overheat protection when it gets to 80 degrees or if it's getting a degrees inside and a shorten the life of your I capsule and it is a plastic case but it's eventually going to get out enter could be a bit hot to touch but of course that's all going to depend on how much air flow you've got anyway operating instructions and it's got all the various modes like I can't possibly go through all these art modes here I'm sure you can probably download the manual from somewhere and it's got a calibration functions as well so if it's not as accurate as you like from the factory looks like you can actually calibrate it if you've got the means to do so and it uses a Modbus communications protocol there as I said either over TTL or rs-485 and a wireless side controller uses 2.4 gig and yes it is rechargeable it's got a little charge light in there so that's obviously got some sort of lithium and USB charging little lithium ion controller so you know if you're walking around the factory and the whole idea is that you know you're standing there in the factory and you know you just hold in this thing and you can if you need to you know tweak anything on the factory floor you don't have to open up the rack cabinet or you know open up the bit of instrument and that's all power and you can just so that you know dial it in and yeah that's nice so I assume that you can set different channels are yes comms address there you go 0 to 100 it shows the internal temperature on the sleigh - that's very nice anyway it's got key lock functions and operating instructions so yeah that's a nice enough little manual and by the way these also come with a look a USB serial cable with the cables ready to plug wires ready to plug in to the terminal blocks absolutely fantastic and this thing I'm completely unlabeled no instructions I what is that a RS USB the rs-485 interface neat that's if you get the 485 our model they'd probably give that to you but anyway I'm very cool I won't try those out in this video though it's already long enough so let's start off with the DBH 89 20 I assume that all the others in this series will be identical we do have our first problem looks like she's been bending transport oh nothing worse than getting banged in transport yes if our plastic case there there's a little power switch down there it's a little bit how you doing it's not what you'd expect to find on it like a more industrial toy controller anyway these don't have the nice terminal blocks used on the other ones these were neonates some people might be a fanboy of those particular no blocks anyway I'm little fan in that we'll see how noisy that sucker is anyway input here and output over here and there's the ground and it looks like it has 5 volts as well I'm not sure what the output power capability of that 5 volts is it might only be you know it's not for serious our power and there your comms and the front panel user interface will whip that off there we go oh it's like a bought one and just four buttons and a two LED displays and you know you can as you saw in the manual it's pretty flexible but anyway even see our big-ass inductor in there already and our big-ass heatsink so it looks like the heatsink is actually nicely laid out in there with the fins so anyway let's crack it open and with the back panel off we've been mooned and our black solder mask give me a break anyway check this out they've had to increase rather than waste money I guess on like going for the 2 ounce or 4 ounce copper PCB I assume it's only like 1 ounce and then put the extra solder coat on top of the traces those they've left those bare and they've gone around and oh that's pretty how you're doing you can still see the residue that's not the nicest introduction to its power supplies at all but anyway yeah they're the high current up past obviously the input and the output and you know you've got the output filter caps and the switching and whatever as of course this is a our buck converter so it's not like you can feed in 5 volts and then get your 96 volts out you've got a feed in greater than your 90s and greater than whatever output voltage you're trying to do whatever the dropout voltage is and as you can see the minimum input is 20 volts and maximum 110 for a 96 volt out so it looks like it might have like at least 14 volts dropout voltage which is absolutely enormous yeah but anyway so if you want your 96 volts out you got to supply this with a hundred and 10 volt DC supply at the particular at whatever like a current based on the maximum output power that you want to do - the efficiency and we're in like Flynn and god I hate them bloody matte black solder mask anyway um I did actually bend at my switch here at actually when I took it out because the thing was protruding here I forgot about and just sort of lifted it out and lifted my switch up I just bent it back in place anyway it's obvious that here we've got that's our Wyatt 2.4 gig of eyeless interface is that yep that's just on its own little board there so can take that off and have a squiz nothing doing there it's actually black blood I don't think I've ever seen one of these with a a back black blob there there really you know they saved one sent there why not and then of course we've got our isolated rs-485 module it's a it's not nice that it's isolated of course there's our little own isolated DC to DC converter brick that's a little one what job' there that's 5 volt no.5 it stands for 5 volts in and o5 that stands for 5 volts out there so yeah that's pretty basic stuff so yes of course the that's isolator but these are not isolated supplies as you saw here here's our negative and here's our negative output over here if we flip those over you'll find that well they're not directly connected there because it looks like we've got is that a shunt and no that's going to be the bottom of the caps there's our shunt oh there we go there's our shunt so it's directly connected these are not isolated there we go through the shunt over to there so yes if you want to isolate a supply these aren't it but if you want high voltage high current high power capabilities really cheaply these things can't be beat so yeah check that out three current shunts in parallel there because well one that couldn't do the business so they had to put three of them that's actually really neat and tidy rather like that but yeah this is the 20 amp model as I said almost certainly a different current to shunt in there for the 10 amp model which has like half the power capability there we go I'll pull up the numbers for our parts in there there are they're our deities so I put up the datasheet for these these look like little our common cathode diodes in there and if we can get him out of the way it's flapping around in the breeze what do we got down there BD or 406 is it well your heavy work is being done by this sucker down in here so yeah NCE I don't know I'll pull up the datasheet for that so anyway um here's one of our main caps here what is it it's a its elite is that allele I'm not sure anyway 330 volt 200 volts and that is and that's 105 degree job as you'd expect and let's take a look on the other side here I think we've got identical ones there they close to the heatsink aren't they you know is a big-ass inductor wow that is a beefy anyway a typical buck configuration basically and you know they're reasonably efficient once what's that little job' right on the end there I don't know anyway I've got an extra hole in there don't know that's four um but I don't see any sort of thermocouple on that heatsink so they're not measuring the temperature directly on the heatsink that's not great they're trying to save costs there so I don't know can you I spy the thermocouple where's Willy where's Willy because they do give you a temperature readout of course but it's obviously not coming from the heatsink anyway it does look like you know really bare-bones type configuration let me get it under the mantas microscope and see if I can pull-a-part number four the main buck controller well spoiled all our fun look at that they've actually looks like they've like milled off look at the channels it's kind of like they've got like a milling drill bit or whatever and they're like arrays that erased from existence mongrels I'm and also the trend is over here look at these we can't even figure out what those poor little trainees are unbelievable and yeah they've rubbed the numbers off everything so what want wha that's hugely disappointing Wow yep not a sausage sorry there's a closer up shot of that that's remarkable so yep every single active part on there they have erased the numbers from I'm surprised that they didn't do it to the power devices as well anyway that's kind of like what you'd expect from like a $60 I carry a voltage power supply I still don't know where the temperature sensing element is got something budged looks like a diodes been hand budged down in there perhaps you can see they can see the residue on that I hope get the light at the right angle so yeah someone's had a someone's had a hairy hacker at that so anyway the question is are you going to be able to dissipate the claimed 160 watts maximum at think of that that claimed efficiency the loss that you're going to have is going to be it looks like at max 160 watts so I don't know or you power amp aficionados and all that who I do this is your daily bread and butter 160 watts with the fan with this little piddly fan in here maybe maybe so yeah for the price that's possible let's put it back together and see how she goes although I don't think I'm gonna like I don't have a 2000 watt power supply like DC power supply to be able to input to this thing to actually test it so mmm but looks like they don't care about your reverse engineering their display board alright so I'm feeding this room my new 200 watt well it's 800 watts total but if I wanted 800 watts I'd have to tie all four channels in parallel anyway 200 watts I've set it to 20 volts at 10 amps because this thing claims I'm 20 volts minimum input so let's set it to its minimum of voltage input and see what's what what found briefly turned on and yep it's shut off so obviously it's got a temperature controlled fan in it it was quite a loud a little were there not sure if you heard that because the microphones point it away anyway it's set for 5 volts at 3 amps so let's just go okay do we like I don't think that you know there's no output I don't think there's any output on/off is there or is that what that power made no that would be the that would be the actual power power that wouldn't be the output on/off oh no because our output here is some zero volts so yeah I guess we go okay there we go yep so that's our output be nice if they would have put you know out on off there as well anyway so that's that's obviously the set and obviously yeah obviously that's telling you what's on because we've got our constant voltage right there so five volts and set to five and we're getting pretty darn close to fire so that's pretty accurate no workers okay so I'm going to set this to our 5 volts constant current and let's turn it on sorry 3 amps yeah because we had our 3 amp current limit down there and sure enough I'm three amp card limits that's that's pretty bang armed I walk us okay so let's press it and we get into our voltage and we go down oh no no there we go oh this is where you have to read the manual there we go alright so we set that to twelve ants and now we're getting our ID what no we're supposed to have five amps constant-current yeah okay so what's going on here it's got constant it says it's in constant voltage mode seven point six volts why because we had that set to 5 volts what the heck is going on look there it is 5 volts it shouldn't go above 5 volts a 1012 ants that there there are set limits it's now saying 7.5 volts what the heck is going on can we know that's how mmm-hmm no let's just set up my what anyway a half a volt on our load but I am really puzzled as to why that says constant wearing constant voltage mode and seven volts at 4.1 amps like what the heck I don't get it and we're only dissipating to what's in our load limit all right I've gone back to one ampere constant current so let's just like increase this okay we've got two amps let's go to three amps okay three amps we're good four amps okay we're good okay no now we good again so what what was going on before what was going on before I don't let's I don't know six okay something weird was happening before you kiss as good as mine at this point certainly um confidence is not high at the moment I'm going up to a dance and I still don't have a problem down to nine ants and everything everything's hunky-dory oh I think I heard the boss some fan ramped up there up at night no we dropped out out do it and yep constant current mode we're dropped out I'm hearing a weird little clicking sound from this probably a fan bearing let me get the mic on that not sure if you can hear that dodgy fan bearing or something hmm anyway we are drawing sixty watts from this thing and the fans really worrying and it's it's pretty loud so yeah this thing's supposed to go to like 2,000 watts I don't know I wish I could push it all the way with LBJ but um as I said I don't think I have like a why certainly don't have like a a thousand watts our load my loads here are only a couple hundred watts each like two hundred watts and let alone the power source so I don't know leave your comments down below so I'm right up at nineteen point nine amps now that's our maximum output current and of course our voltages I dropped a bit from the nominal five volts because I'm not doing enough for terminal current sense on that so we get in even though I got big beefy gauge wire on there it's so we still getting some loss across that no workers so yet ninety-six watts and don't really feel any warm air coming out of that 92% they'll only be dissipating eight watts and the fans really going now full pelt so yeah I don't know anyway she's not getting the least bit warm at 100 watts but I am less than one I'm one twentieth of its maximum output power well I'll tell you one thing that's getting warm though and that's my output cable at 20 amps this is our fifteen AWG cable and yeah it's getting a little bit warm it's actually probe the noise on this thing at using a times 10 probe compensated of course and so a squiz well so much for their 50 milli volts peak-to-peak claim there and even on the lower frequency stuff I'm getting a hundred millivolts per division I'm seeing 150 50 milli volts peak-to-peak and most certainly got this high frequency bursts here so yes my probe is compensated shut capture that there we go that's what we're seeing and the excursions are quite large on that high-frequency stuff so yeah lots of ring in there wow I need some need some more chokes all right let's try and be a bit fairer to it I put a hundred in ceramic across the output and yeah okay we've dropped it to around about you know 200 millivolts but the peak to peak so yeah that's still four times more than what it's rated for of course they don't tell you at what it's rated they just say peak to peak so you've got to presume maximum over the entire performance range and that's with a hundred and a hundred Mike Louis our electro across the output alright let's try that without the electronic load because that could be impacting it we'll get a resistive load I've got my high-power 50 ohm load from my uh defibrillator here and defibrillator analyzer and I've now set the input voltage to 64 volts so we're getting 50 volts out so that should give us a 50 volts divided by 50 ohms should give us an air poor 50 Watts here so that's the output noise at 50 Watts with no output extra capacitance on there yeah we're still talking hundred millivolts per division you know a couple hundred milli volts peak-to-peak not including all those nasties those switching nasties in there but we can get rid of those so if we work a large at 100 N and a larger cap across the output that is what we get so we have actually reduced our low frequency output ripple it's probably now we're 50 millivolts per division so I don't know what's that you know 70 millivolts so it's getting closer towards its spec of 50 but certainly this higher frequency are content that's that's still there unfortunately we're not going to get rid of that without some inductor II goodness and that's the 0 to 5 volt switch on with that hundred Mike 100 n capacitive loads so it's clean as a whistle and that's the exact same a start-up but into a 10 ohm resistor flowed of course you can't start it up into an electronic load down here because these are dynamic buggers but I'll show you what happens when you do it at 20 amps with a constant current load okay just for kicks we'll set our 20 amp 19.9 load and a single-shot captured that let's go no helps if I probe it right here we go switch it on and bingo yeah that's what happens look at this we got out a little step here and so it's got some weird step for like 150 milliseconds Rises that better overshoot there and yeah well it's an electronic load so it's not going to perform the same as a resistive load Oh check it out I just set it to a constant power of 96 watts constant power load and a poor sucker is oscillating I might leave it doing that for a while just to see if we can kill it so yeah it's just the response loop of the power supply a response loop if the load plus the power supply is just yeah they're not gelling too well together so anyway we can wait let's go down to say 50 watts or something like that see if we can note it does not like that at all not it's still not gonna it's not gonna do that doesn't like constant power load at all hang on it finally settled down I just left it I'm like literally cameras off for 30 seconds and now I'm getting our constant power load let's try to ramp it up to 20 and see what happens so yeah we've got got a loop probably now it's fine now it's for now every everyone's a happy camper well it's a combination of both basically the response loop of both let's go let's go for 50 watts yeah it's stabilized now 96 watts yeah we can do it it's nice and stable now and of course down here I mean you know everything's everything's hunky-dory so yeah it just it really did not like that I'm gonna let me um actually switch it off and then back on yep yep it's doing the same thing yeah it does not like that the response loop of this is it's not having a borrow that income in combinational response loop of the loads now to be fair I've just hooked it up to my is super expensive up top-of-the-line lab rohde & schwarz power supply here and it's doing a similar sort of hiccup in a thing and of course this is how I've been able to kill power supplies in the past because it'll just like the response loop of the electronic lobe of the spawn slope of the power supply they're just playing tug-of-war and they're come any guts are a bit so I like the real test here is whether or not it actually kills the power supply or not and the john tech power supply seems to be holding up fine to that sort of oscillating even at 20 amps like 0 to max current so no problems at all it handles it but yeah that's interesting rohde & schwarz he does it do so if I go down below 1 watt something like that there we go it's settled down and then if we go up to 10 watts yeah we're all good and once it's settled down 50 watts yep exactly the same as what we got with the Jun tech it's once it's a hole locked in and settled down but it really doesn't like the transients when it switches on because it goes over current so then the power supply go goes briefly into our constant current mode and then the electronic load detects that and it'll switch back and modes and it'll add and it just goes it just goes haywire and so the to just play a merry little dance together let's 69 let's go to 69 good value and then we've got a 96 watts like we had before and everything's hunky-dory but if you switch the output off and then on again it's oh no it's gonna take night there we go it goes and does its merry little dance again so yeah Jon tech does the same thing there's nothing actually wrong with this and it actually it's surviving that quite well very impressed that it can oscillate between zero and 20 amps like that relatively quickly and it's not dying I mean I could leave it there all day doing that and see what happens but anyway it's pretty good all right here's the remote pen oh I've fully charged it and switched it on there you go so that is the power button I can't take off the stupid plastic thing it's protector it's wedged in there so anyway nice bright display it's um it's angles are really quite nice it's probably bigger than what it shows up on camera I think the purple kind of vanishes on camera there but I can still see it so yeah that's really quite nice they've got the readout voltage-current power and the set voltage is set current I love how they have set you here but they got V up here so you know looks like we've got a timer with a continuous R and P our display very nice the temperature of course and I've got to connect this thing but anyway I just wanted to show you that although it really does feel like chintzy plastic but what do you expect for the cost I mean I it's just like you get this with it if you buy it so like and the knob is the worst feeling knob it's like there's no gap between there and I can barely turn that and there's no it feels like there might be an indent in it but it's so damn tight against the case I cannot like that is just absolutely ridiculous so it's got an arrow on there anyway yeah that is just yeah that's awful don't know if it's just my unit or not but anyway looks like you can pair it up externally so the good thing about this is that if you want to I like put one of these into like a case you know you've got a case lying around or something you want to make your own sort of like high current high voltage do-it-yourselfer supply then you don't have to dig around like making out an exact cut out on the front panel and things like that or you've got well you don't even need the USB that's only for the charging so you can just you know but like stick this on the front panel with like double sided tape and then just have the like you know a cable coming out and going in it's not the most elegant thing but it's like really easy to assemble something like that but anyway let me see if I can get it talking and just quick squeeze inside for those playing log at home I you it looks like you could certainly put in a larger battery in there I suspect if you really wanted to anyway that's our interface uses the same little blob thing and what's the processor that's an ST something or other can't read that from here but I'm sure playing along at home you can so yeah nothing special about that you know charging circuitry here and Bob's your uncle and I'm not sure what type of plastic that actually is maybe somebody can tell out there but doesn't seem to be like usual ABS type plastic it doesn't feel like a really good quality plastic so not sure precisely sure but it almost feels like it's like 3d printed or something like that that's the kind of vibe I get from it but but it's not well that was easy or simply turn the power back on to this thing and the little comet LED there is flush in to indicate that it is connected there you go there's a wireless simple end there's our set voltage and current works a treat where it got that time that was maybe the pre no is it like a random time because I haven't actually done anything yet I haven't switched on the output at all so I don't know so if we switch that on boom there we go there's a slight delay there but mimics that precisely OOP nope it's jumping back and forth looks like it's 5 millivolts ah sorry 50 millivolts resolution there okay so let's see if it's any easier to use this without having read the manual which is probably pretty foolish thing to do set mo that toggles between there no that's the setting those I would guess anyway let's just press voltage volt V low oh okay there jumped over there so sit there's our set there you go and we can change our cursor position there that's all right it's not too shabby there you go let's go up to 10 volts shall we and then we'll go 19 amps okay and we switched our output on and every it's updated everything's hunky-dory so let's put a load on see if the temperature goes up well there you go there's the update speed for it I've got it in a silly bugger constant power mode again and yeah it's jumping around the shop I've got a jumping up to like you know 19 amps or whatever so yeah it's still not killing it it's a robust little beast guess one of my only complaints about the user interface is that like really when you switch us to constant current and constant voltage to constant current it's not really obvious yeah the dot there changes but like it would have been nice if it like just highlighted say in CV or CC you're not change the entire display or something rather than just changing the little bullet dot there perhaps it's just you know it's just not obvious that it seemed constant like at a glance at its seen constant current mode well I've had it run in at a hundred and fifty watts for a little bit now and it got up to 41 just a second ago before I hit record dropped down to 40 degrees there but that fan really is are worried it's like it is quite loud and oh it's a hard to hear with the mic pointed away from it but yeah it's really distracting you know you wouldn't want that on your bench you know it's fine but the whole idea of these bricks is that you you know lock them away in some you know rack cabinet or something like that they're more for industrial type thing than for lab use so would have been nicer if it had a larger fan and just you know like could run to the lower speakers that you're gonna remember this is supposedly although I can't read Aliyar test it a 2000 watt capable power supply we're only running at a hundred and fifty watts here so it's more than an order of magnitude less than what it's capable of and it's still at 40 degrees and the fan she and I were in pretty loud so yeah they're from a thermal point of view it would have been nicer to sort of like engineer that a bit better but you could remember this is like engineered down door cost what is this likes less than 70 Yankee bucks um the bang for buck is just incredible really now it's time for this 3000 watt job' there we go like a bought 100 I just don't play with those bad boys all day look at that it's practically pornographic d monetized it so anyway this is I don't know if this has a 485 model available but I don't think it is anyways the DPM 8650 which is the 50 amp model so there's our like our 5 volt output and our serial icons as well once again there's a little dinky on/off switch I don't know why you'd even bother with that on such an industrial type unit anyway this cracka dome and again we've got another one damaged in transit again we've been mooned and again that we've got the makeshift high current traces with the solder on the bottom so and once again not isolated there's your negative and there's your negative how does it get over there three a big current jumper links again this is 50 amps as we saw before but yeah anyway so I'm there power high current that's all all our high current piles in there that's all there is to it and again we've got our matte black solder mask anyway there's our wireless module exactly the same as before what's this little what's this little bad boy over here we've got a little sock 23 is that like that is that like the temperature sensor maybe like is that like an I squared C temperature sensor perhaps anyway yeah well let's actually speaking of which let's see here's our heatsink I don't see any thermocouple attached to the heatsink so once again you know they're not measuring the heat sink temperature which is what you'd expect in a top quality power supply but anyway once again it's built down to a price they've removed the solder mask on the look at all the vias look at all the vias there you know that via stitching Wow somebody had fun that's incredible and also in there as well so they yeah they really want to stitch its together you don't have to do that it's not really helping by doing all that stitching because most of it's taken on the traces on the top and the bottom anyway what bad boys do we have in there I put up some data sheets I've got a mixture of international rectifier and a and IM see yep like it looks like there's two pairs there and the caps 2200 mike hundred volt once again no there ain't no eight a different brand is that we didn't have our chins in in the other one did we anyway I'm the year not exactly Panasonic's or anything like that so anyway that's you know it's built down to a price what do you expect really close to the heatsink they're not a big fan of that but yeah we've got two big bad boy inductors in there they're absolutely enormous probably got the same ST processor and the other one probably running almost identical firmware to the other one anyway you can have a you can update that's probably your programming interface there once again regulator flapping around in the breeze there what does that just a local that's probably just local regulation something like that perhaps anyway there's our current jumpers one of them's a bit how you doing off on the side you can't bend that one back no siree Bob you've got no chance in hell of doing that but yeah they're really beefy and once again this is a 50 amp unit so yeah they're using three current shunt leaks there yeah so what we've got in here this is our rs-485 double slash serial output that's our that's a DC to DC convertor isolator which isolates the whole thing from the rest of it don't really see a huge amount of clearance on there I'm not sure what the actual voltage isolation is between the output and the serial here I don't see anything hugely on the bottom bloody black solder mask pain in the ass but no all the grounds like flood filled over the whole thing so it's nuts not like they've actually cleared the grounds or anything like that did a whole separate one looks like it's all it's all just one big flood field so ah that's a bit disappointing but you know I can't even think they get a spec for that so me it's isolated in quote marks I think the fire I don't think they even have a spec on what current the 5-volt out there I think it's just for like interface purposes and stuff like that so you know maybe a couple hundred milliamps tops perhaps but as you can see you're pretty simplistic what you'd expect in like well this one's what a hundred and thirty Yankee bucks or something like that but yeah 50 amp job so let's pair it up once again this is three a thousand watts so and the efficiency I believe is identical at ninety two percent so once again with this one at three thousand watts at 92 percent we're talking about well eight percent are lost in well everything in here I'm including the heatsink and the inductors and all their people what we are they would have been nice to put some silastic on that really yeah see how you're doing anyway what do you expect for the price but how much does silastic cost you know it's a it's a human operation somebody's got to have the celesta gun they're on the production line and they've got to gunk it all up and all that but yeah it's you know these things are built down on a price anyway we're talking eight percent two hundred and forty Watts has to be dissipated in this thing with once again the tie I think the fan is a little bit bigger than we had in the other one but still pretty chintzy and again they've rubbed the numbers off all the chippies all the active semi is on here so that's all hang on yeah oh no no no they're being rubbed off too I think yeah yep unbelievable secret squirrel okay let's power this one up with the same 20 volt input as we had before I got around the right way I think so once again little fan burst as we powered on powered on 5 volts three answers probably what they lost tested at the factory let's switch okay on and yep 5.00 5.00 to no workers and we're in constant current mode three amps 2.0 3.0 oh good enough Ross trailer alright I go to output in 25 amps at the moment there we go constant current and no workers whatsoever and yeah my wires once again might get a little bit worn ski but even though even 15 gauge um he's gonna get a bit warm at 25 amps oh yeah I can feel it starting to warm up now he need hang on that just when Burke Oh for a second and alright load just said over current protection input disabled ah okay you up you up okay I changed it to 10 volts output and um it's now fine like 175 let's go to 195 okay what what what happen there well it's it's resetting is that resetting that's it's it's resetting over current protection input disabled and that I got pretty sure that was recent in the family for it like it rebooted right that wasn't me being silly was it and silly me dole I had that set to 300 watts current limit and my input power supply over here is 200 watts current limit said this was briefly dropping out causing this thing to reset so there's actually nothing wrong with this at all so yeah no worries okay I think what might be happening here with this over current protection input disabled I think that word ins a bit off it's trying to protect the input it's not that the protection has been disabled it's the input has being disabled because of the protection I believe that's what it means so I think what might have happened here is that the large output capacitors here if they're low ESR there jumping current into the load and the load has protection against that to try and like to want to protect itself and so the capacitors are trying to wear and when it changes over into constant current mode they're trying to those capacitors trying to slam that current into the load which is you know basically just shorting out pretty much and it's just protecting itself so I think that's what the deal is there as so technically that's an issue with the rygel power supply but this is what happens when you have large output caps on your power supply the energy or current in those caps can get dumped into your load for a brief period when you enter that constant current mode so yeah power supply lab at power supply design good lab power supply design tries to minimize the output capacitance but these ones let's go back in and actually have a look to see that they're actually smack on the output and back inside again and here's our two caps there and there this is our input here so obviously our one cap is for the input one big 2200 mic there but the other one is look directly on the output pins and it's even after the current shunt here so that's absolutely nothing stopping all these huge tracks absolutely nothing stopping all the energy from this huge output cap from being dumped over into your load so yeah as I said these things aren't the best as a precision lab power supply kits a good precision lab power supply well a good lab power supply doesn't have to be precision good lab power supply will minimize the amount of output capacitance that gets dumped into your load and I've mentioned this many times in my power supply yard design tutorials and stuff like that so that's what's happening here the current are from the output caps is being dumped into the load and the current limit down here it looks like it's set to its maximum of 70 amps it's actually it's got a good electronic load like this will have these overcurrent over-voltage protections so that which will kick in to actually protect it so these things are actually hard to kill or that's the intention of it and so that overcurrent protection is kicking in and yeah all that current is being dumped out of those and out of that big output cap so yeah just take that into account of anything that you're using this for in this particular case because we're cycling their into constant current constant voltage mode boom all that currents available to be dumped out and because the load was thinking because this is an electronic load takes time to respond and things like that it just sets the output transistors like a really low impedance and that will effectively short the output of the cap cause all the current to be dumped into this load and trip the output or the input current over current protection system so yeah that's just a quirk of testing these sorts of things but that can of course have very real consequences for the product that you're actually powering with this thing and you could come a gut so it could blow the ice out of your product so yeah that's why LED power supplies try to minimize the output cap and therein lies one of the things like even this a small unit here is way beyond that the capabilities of any DC power supply that I have in my lab any DC source I believe any way unless I get lots of them and parallel them all up to try and do that so you know really the limitation of these is your input power source you really need if you want to get the 2,000 watts out of this or the 3000 watts out of that which is more than the 2400 watts available on a standard 10 amp may 240 volts and slash 230 volt mains power supply here in Australia this thing even if you rectified that to DC at a suitable voltage you can't obviously go up to like you can't just bring to rectify the mains and feed it in here you're going to blow the ice out of this thing because it's got a maximum DC input voltage you think this one's 110 volts isn't it anyway even if you were able to like rectify the mains and you got the full power available and it was a big beefy thing you still wouldn't reach the capability of this thing so it's you know it's it's remarkable anyway even this one is really hard to like really thoroughly test out because you need the DC input source these things aren't AC powered and you can't just buy a plug pack and whack it in or a simple transformer ain't that easy so there you go thank you very much John tech for sending these things in there you know they built down to a price but they are really remarkable bang per buck products so you just can't help but give those a thumbs up from a like bang per buck viewpoint really um is there anything similar to these things out there maybe there is I don't know I'm not nothing keeping up with the power supply market but yeah incredible bang per buck so yeah unless you got something specific you don't need to shell out for this big unit here like the smaller units they do have other models that are even cheaper I think it's this cheap is like 52 bucks or something like that and Yankee bucks that is and yeah really remarkable so yeah probably worth while hanging around but you've got to have a suitable DC input source but if you can salvage that as I said in my previous videos on those these buck power supply modules is that yeah you can salvage like like old gear old industrial gear and things like that and get switch my power supply's out of them you can maybe of like an old PC power supply but things like PC power supplies aren't good enough because they're only like what 12 volts is the highest output on those and things like that but you know you get a good industrial one and you can get like a maybe like a 24 volt output or something like that and even then that's incredibly are useful you can still get like a 0 to 12 volt power supply at some higher current so yeah what worth looking into so we're like less than an order of magnitude like of this the capability of this 3000 watt power supply yeah maybe more testing are required if this are more mucking around I mean you could probably do comprehensive performance sweeps of you know various current and voltage modes and things like that and oh man it's a huge amount of work to gather all that data but anyway I could spend hours on this this video has been long enough already so thank you very much John tech for us sending in these power supplies remarkable or you know bang per buck value for money and even the little control panel it's just like it's there's lots of uses for these things like less so for the lab or something like that but as I said if you want a high current high voltage supply we haven't even tested at any of their high voltage input or output capabilities yet or anywhere near their power capabilities but anyway maybe somebody else with the ready loads and things like that can I give these things a full workout maybe someone on the eevblog forum can have a crack at it I can maybe I call something together but anyway not for this video so we'll call it quits there but yeah interesting I'm a new player in the market these John Tech one Sun and as I said they have lots of other stuff including an oscilloscope with a power supply built-in so leave it in the comments if you want me to get a hold of one of those scopes with the power supply and function generator built in and never squeeze but like at less than 70 US dollars with I believe it comes with the wireless remote for that incredible value for money so not the solution for a precision lab power supplier that we've seen in other videos and things like that but if you certainly want high-voltage high-current and you should have a high-voltage high-current power supply yep well worth checking out so I'll leave the I believe you can buy them on Aliexpress I'll leave the links in down below check them out thank you very much John tech as always if you liked that please give it a big thumbs up leave your comments down below and over on my library channel as well catch you next time you

Channel: EEVblog

Views: 155,061

Rating: 4.847918 out of 5

Keywords: eevblog, video, power supply, lab power supply, juntek, juntek power supply, power supply review, bench power supply

Id: GUxszz_lo14

Length: 55min 24sec (3324 seconds)

Published: Mon Apr 06 2020