Thanks the review! I've ordered one. You've saved me some cash because I'll be able to use this over the missing power supply that my robot lawnmower manufacturer wants £180 for!!
Thanks for the review, it was very informative. I have just ordered one from BG to use as a general bench supply for low power digital and analogue circuits. I might be doing your switching noise fix when it arrives... but first I'll be changing those output terminals!
See the past/future: Fixing the LongWei LW-K3010D Bench Supply Noise Issue: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-WytDROmjWKQ.html&ab_channel=TheStuffMade
I have the same one, and I've had problems with the included wires (banana to clip, black and red). It could handle only about 3 amps in my case. Thanks for the great review!
Thanks, mine didn't come with any wires, just the mains cable, but it's a good test to short the wires and set the current to maximum, then see how much voltage drop you get. It should be very low, less than 1V for good wires.
@@TheStuffMade Right. I did the short test and almost immediately the wires got burning hot around 3amps. There was no voltage drop at that point, so Im pretty sure the cables were bad. ☺️
My one worked good for a year charging small batteries, model train testing and general light use. Charging a 18650 lithium ion when " BANG " . One of the large capacitors blew its end off. Replaced capacitors but it only reads to 1.5v then falls away. I am purchasing another make of power supply for a replacement.
That's a shame, mine still works fine after 4 years, it's always a lottery with cheap Chinese electronics. I did do a few modifications to mine to clean up the output. Cheers, Jake
Thanks! For adjusting the current there are 2 major use cases: 1. Current limiting is the most common. Here you use the current setting to limit the output current. This will prevent damage to the electronics project you are working on in case you short something by mistake. E.g . if you have the full 10A and you short a component, then you will most likely get a lot of smoke, however if you limit it to something like 250 mA, then nothing will get damaged. 2. If you want to charge e.g. a Li-ion battery, you would set the voltage to 4.2V and the current to e.g. 1A. Then when you connect the battery first the power supply will run in constant current mode and charging at 1A until it reaches 4.2V then it will switch to constant voltage mode and the battery will be fully charged once the current drops to near 0A.
@@TheStuffMade Thanks for the current explaination, I did not know this! This sounds like a great feature, one that I don't have in my many bench DC power supplies. Also, none of my power supplies adjust to 30vdc, nice for experimenting. I use my supplies for amateur radio; MFJ, Pyramid, Astron. I am going to order a 3010; your review sold me on it! Thanks again
@@TheStuffMade Thank you for the excellent review/explanation video and the answer above that allows me to finally understand how to use the 'constant current' aspect of my unit. I bought one of these many months ago and have used it a number of times but never understood how to set a constant current charge....the "instructions" that came with it are awful imo. Thanks again.
Just want to add something that I saw in my own model of this power supply : Check the earth wiring ! My one had its metal case not connected to earth at all ! The earth wiring was bad : from the rear mains socket the earth wire was only going to the pcb and via a pcb trace it was supposed to touch a metal stud which on turn was screwed to the rear of the case. But this had no connection at all because of the thick paint on the case surface ! Also the front earth terminal should have a better earth wire coming directly from the rear mains socket and not via a pcb trace. So here is what I did to improve the earth wiring : 1. make an earth wire from the rear mains socket directly to the metal case with an eye terminal fastened by a nut to a new and longer bolt in the rubber foot near the mains socket and scartch off some paint there for a good connection. 2. Leave the wire from the rear mains socket to the pcb. 3. make an earth wire from the mains socket directly to the earth output terminal at the front. 4. scratch off some paint on places where the metal cover is screwed on the metal case. (both sides) This ensures a good electrical earth connection everywhere and also a better shielding.
Thanks, I did check the earth wiring on mine and it was OK, both to casing and the front earth terminal. However as is with all cheap Chinese electronics the quality control is very bad and some people get a good product while others get a faulty or dangerous product. Thanks for highlighting this potential issue.
I had the same issue, no continuity from ground/earth to the case. I scratched off paint from the housing in the back where the upper circuit board (pcb) connects to the metal channel bar. This allowed the screw to pass continuity from the bar that it screws into and then into the case. Now I have continuity.
A great and very thorough review. I just got one for my self to use mainly for charging batteries and other DIY projects. The single turn Current Control Pot as you demonstrated is very hard to set especially in low settings, i.e. micro amps. Thinking abut replacing it with a multi-turn pot. Read from other users that they used the WXD3-13 2W 10K style pot. Will this be a proper replacement? Looking at the three wires can you comment which wires goes were on the replacement pot? Thank you.
Thanks, that pot looks like a good replacement if it fits inside, just solder the wires in the same order you removed them from the original pot. If the adjustment goes in the wrong directio you just swap wire 1 and 3 to resolve that. Let me know how it works out for you. Cheers, Jake
@@TheStuffMade Received the pots (ordered two for the price of one at less than $2 each) and installed one today. It's a perfect fit although a little tight. But with little maneuvering it'll get in without having to dismount other components. The wiring is basically the same if you number the old single pot terminals as 1, 2, and 3 starting from the left with the pot's stem facing up or facing towards you. Wires are marked as dots, "x's" and dashes and corresponds to terminals 1, 2, and 3 respectively. And these all transfer to the new pot terminal numbering as well. Current control is more positive and about the same control as the Voltage control. One thing I missed is the length of the stem of the new pot, it's about quarter inch longer than the old one. I didn't notice until the end and was just too lazy to dismount it again to cut it. So now the current knob is sticking out about 1/4 inch compare to the voltage knob. Maybe I can cut it later with a little dremel cutting tool. Cheers.
How would I calibrate the voltage and current output display when they do not match my external meter? I see there are adjustment pots on the inside but not sure which ones to adjust.
I haven't done it but I'd try the 2 trim pots on the display board in the front of the unit (see 23:35), And of course be very careful you will have lethal high voltage on the main board and exposed metal like heat sinks etc.
Hey, just got mine today. I am using it for testing and repair of diy quadcopter components. In your opinion do you think this will be good enough for such things? Thanks for the vid and info
Great video, good review and lots of valuable info for a non-electrical guy like me. I received the same power supply this afternoon and you just thought me how to use it. THX. :) Wondering though, what is it with the piece of cardboard?
BTW, I'm not going to use it as a measuring or testing unit, the 3010D is going to power up/heat up a homemade Nichrome wired acrylics bending table. I need more amperage for that than the max 2A that my old 240V AC Variac can deliver. And it's safer too (DC output). At least, I hope.
Thanks, I believe the piece of cardboard was something left inside by mistake during assembly, it doesn't serve any purpose or do any harm, just a bit sloppy.
@@TheStuffMade I thought so too, but then I noticed a similar piece of cardboard at the same spot in another review video. see here at 8:20 > ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-dAT6hTXeVfw.html The Chinese must have a purpose for it, probably want people to note that allthough pretty well made, it still is a Chinese device. And I just opened mine, that I received yesterday, and there is a piece of cardboard in it too! It must be a feature! LOL And it looks to be there on purpose, to shield the PCB from the inductor. But at further inspection I don't believe it is cardboard, a pair of tweezers couldn't scratch or damage it and it's pretty sturdy, so I guess I just leave it there. Did you remove it?
Question on the LED lights. I’m using this currently to top off a 24v LiFePo battery which has a max charge current of 28.8v. I set the voltage at 28.8 and 10a to charge but the red LED for c current comes on. If I lower the voltage it lights the c voltage LED. I need 28.8v to charge to full but would like the current to taper when approaching full. With c current the current doesn’t taper down is that correct? If I turn the voltage down for c voltage it isnt enough to top off the battery. I’m very much a novice and would like to understand the operation of this power supply Thanks
Hi, the power supply behavior is correct. During charging you want constant current first, then it will switch to constant voltage until be battery is fully charged. Eg: in your case, lets say your battery is fully discharged down to 18V, then you want to set the power supply to max voltage for your battery (28.8V in your case) and dial the current to full before connecting the battery. Then you will see the power supply voltage display showing e.g. 25V (depends on the battery internal resistance and the resistance of the wires you are using to hook up the battery) while the current display shows ~10A, and the red LED will be on. Then while charging you will see the voltage display rising slowly until it reaches the set 28.8V and the power supply will switch to constant voltage mode, as in it will keep the output at the set 28.8V. During the constant voltage stage of the charging you will see the current display go from the max 10A down to 0A. Once 0A or close to 0A is reached the battery is fully charged. Make sure you use reasonably short cables with low resistance and good connections when charging at 10A otherwise it will take a lot longer to charge your battery. Hope this helps. Cheers, Jake
No it's fine for general use. If the noise is a concern then I did a video on how to implement a simple mod to get rid of the noise. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-WytDROmjWKQ.html Cheers, Jake
Hello sir, may I please ask what is your educational background? Interested in working with electronic devices and do not want to damage phone PCB! Any guidance/ courses / books you can recommend would be appreciated! Cheers
I too have this power supply but it leaves a lot to be desired since it does not deliver any amper when I try to power something. I adjust the voltage but I don't display any amper value!!! How come?
Try set the voltage to 5 V, then short the output of the power supply and adjust the current knob until it shows a value, e.g. 1A, (note the voltage will show close to 0V while doing this) if you can't do this then the power supply is faulty. BTW: make sure you connect your power supply leads to the two outside holes. The center hole is earth ground. Cheers, Jake
Are your outlet grounded? I just bought a same model (manufacturer name rddspon), measured I didn't get so deep spikes of the amplitude. Only in range about 0-40mV with short circuit load.
Yes, my outlets are grounded, but it wouldn't make any difference to the switching noise. When you do this measurement make sure you use a scope capable of 100MHz, have all bandwidth limiting switched off. I have a follow up video showing how to fix the switching noise issue if you search my older videos. Cheers, Jake
@@TheStuffMade well for increasing better results of the measurment is not only a scope Max freq capability. A results of the noise are just spectrum domain summ. So you should be using a spectrum analyser (expensive stuff) or just some of cheap sdr. Conducted noises up to 30MHz can be solved with scope of course
@@xxvytas For power supply noise measurements it's common practice to use a scope, but sure, a spectrum analyzer is also useful if you care about the frequency range of the noise. Anyway, check the video I did on how to fix the noise with a few basic components. It will give you more details on the noise from this power supply and where it comes from: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-WytDROmjWKQ.html Cheers, Jake
Does anyone know what is the Filter Choke Inductor (L6) on the bottom? It has no info on it only number "3" on the left and "HY" on the right. Thank you very much for any help. My power supply immediately blow when I plug it in even while it was turn off and the input AC was set right.
Hi Robert, do you mean the common mode choke between the two yellow capacitors? Try contact the seller for a refund, quality control and consistency is always a problem with cheap Chinese products, some people get a good one while others get a faulty one.
@@TheStuffMade Hi. Yes, I mean the common choke as you say. I have contacted the seller but its from Aliexpress and they dont care so... I have to try to replace it. I have found packs by 5 for about 2$ but the only thing I know its the size 10x13 mm and I dont know what value to chose, they are mostly 10mH or 20mH or 30mH. The only info I have now is from google when someone did calculation for 410V 10A power supply and it is 30mH so I guess Im gonna try the 20mH and 30mH and hope one of them its gonna work. I have EU Czechia 220V 16A 50Hz.
@@robertzeman4301 You should still open a dispute on Aliexpress, I've gotten refunds for damaged and broken items in the past. Anyway, I'll take mine apart today and try measure the inductance of the choke. Did your choke open up? If it did then it's likely because something after the choke is shorted, these rarely fail on their own. If you have another current limited bench supply you can try disconnect from AC line and inject a low DC voltage e.g. 24V on the output side of the rectifier and see if that starts up the power supply or if it's shorted.
@@robertzeman4301 I measured mine and both coils measure 1.1mH with an Rs of 60 milliohm @ 50 Hz, however the exact value is not critical, it's just part of the input filter, if your choke is open then you can just bypass each coil with a wire for testing.
@@TheStuffMade Well I have soldered out the chokes and Ive tried bypass it with external power supply as you recommended (dc dc step down converter) and I have burned the converter as well heh, at least its just 5$, now I have also order P channel mosfests for the power supplies protection, it has been to many that I have burned :). I was checking the circuit on the LW-3010D with flash light if I can see anything burned and I checked few components with diode beep test but unfortunately I cant make it work. It has been more than 60+15 days for the Aliexpress so I cant open dispute now but I may have order new one and open dispute at the new one if you know what I mean. Definitely thank you very much for the tip with the external power supply and help with values, you have saved me about 2 months of waiting for new chokes and few bucks. Btw the flash light from behind the circuit makes it really nice to see all the components, you could try it in your videos.
Either your multimeter or your power supply is our of calibration, impossible to say which one without more information. The Amp meter will always show 0 A until you attach a load.
You might be able to remove a little more of the high frequency switching noise, but the ripple and the sine wave oscillation would remain the same. The unit already got filtering on the output with both chokes and capacitors. However the noise is not a big deal, it's to be expected from a switch mode power supply.
@@TheStuffMade Maybe remove the caps used for ripple and run a wire from there adding a few more electrolytic caps in parallel, may not look professional, but may help that ripple.
@@MrBrymstond I wouldn't recommend adding a lot of capacitance on the output of a bench power supply, it will ruin it's capability to limit the output current.
@@MrBrymstond That is unlikely to make any difference on the output noise. Best you could do is probably to change the existing electrolytics with high quality low ESR types designed for switch mode applications, but I doubt it's worth the effort.
I don't remember calling it an exhaust fan, but if I did then that is not correct. However it would be a better design if the fan was an exhaust fan sucking in cold air on both sides of the circuit board. Cheers, Jake
Sir i need your help because my Longwei power is same ad yours but the Auxillary Fan i dont know if its working or No? Please Tell me if your Power Supply Fan Is turn On everytime you use it or you need to wait an Hour before it will Automatically Turn On Please answer me sir🙏🙏🙏
Hello, this sounds normal, the fan is temperature controlled and will only switch on/off, there is no RPM/speed control. It will turn on when the power supply gets hot. If you just run the power supply with no load then the fan will only switch on occasionally for a short time. But under high load the fan will run more frequently. Hope it makes sense. Cheers, Jake
hi, i'm having this, now blinking when switched on, it turn on 1/10 second with fan but immediately turn off, fading, two second latter it turn on again and immediately off, fading, repeatedly, i we stored it months then at first try it worked, lasted 2 hours before it failed, doing this again... depending on voltage potentiometer position, the big transformer make a kind of tick tack, maybe just a result, nothing burned inside. Damn cheap thing, have an idea?
Hello, unfortunately quality control is always an issue with these cheap chinese products. It's really hard to say what the problem is without poking around with a multimeter and an oscilloscope. It sounds like it's either going into some kind of protection mode or it's losing power on the secondary side for the control circuitry. Does it have any voltage on the output? Cheers, Jake
@@TheStuffMade Yep, nice to see your interest. A dedicated voltmeter is able to see kind of pics at each restart, too fast for device to allow him correct reading i guess, it show randomly voltage from 0 to 6V anyway the V potentimeter is turned from min to max. Maybe i'll try some reading, at the end it will more probably end with a nice hammer tool to fix this thing destiny. what those Volts at output can tell? thx
I wouldn't worry, these bench power supplies are very rugged and designed to be nearly impossible to destroy, you can short the output as much as you like. Unless you do something silly like connecting the output to the mains then you will be fine. Cheers, Jake
It's very easy to change it, just remove the power plug, then use a flat screwdriver in the slot in the middle to pull out the small drawer with the fuse in it. Replace and push it back in place. Cheers, Jake
Yes, I recommend it as a general purpose bench power supply. I'm using mine regularly and I haven't experienced any issues. However it's not a power supply suited for low noise circuity, for that you need a decent quality linear power supply.
The no load test is to see what the switch on behavior is like. It's the worst case scenario for a bench power supply to see if it over shoots the voltage.