EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: FriedMule on March 18, 2019, 02:41:09 am
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(https://www.eevblog.com/forum/testgear/review-of-the-korad-kel103-programmable-load/?action=dlattach;attach=679863;image)
We have all been there, in trying to test a power supply, solar panels or battery's, we budge something together that shall make it out to bee a reasonable load, often do we use a lot of time to make sure that our load is somewhat okay or at least simulates the reality fairly, but nothing do replace a dedicated load that are already made for the job.
Then what to choose? You could naturally just get a Kikusui that properly are the leading manufacturer but not all of us has that amount of money, you could also just get a cheap no-name Ebay model, but are you then much better of then DIY?
We all know the BK Precision, Maynuo and the Rigol, funny enough Siglent does not make any loads, but is that all, aren’t there more in that price rang or maybe even better? In my search for an answer to that, I’d stumbled upon the Korad KEL-103 that is the same brand as my often used Korad 3305P power supply. Unfortunately could I not find much about it, until I’d contacted https://www.sra-shops.com/ (https://www.sra-shops.com/) that have almost all what Korad are making for private consumers, including the KEL-103 electronic load.
(https://www.eevblog.com/forum/testgear/review-of-the-korad-kel103-programmable-load/?action=dlattach;attach=679869;image)
Many do all know what level of quality the Korad brand is and I would really like to know if the KEL-103 Electronic load was of high quality before buying / recommending the unit, so I contacted SRA Shops and asked if I could borrow a unit, and told them about my plan on reviewing it, before sending it back with thanks. SRA Shops was wary nice and liked my idea but offered me one for free, maybe knowing that after a tear-down, it may be worse off? When that is said, SRA Shops has in no way asked me to say anything in any particular way!
It has now been a month since I received the KEL-103 and I have tried to all from pampering to torturing it with some great and positive results.
But first, what do you get when buying the KEL-103 from SRA Shops?
The unit comes in a single layer cardboard box with nice padding to protect the unit. In the box, you get a professionally produced CD not that home copy stuff, a power cable, USB cable and a set of thick soft test cables. The manual is on the CD.
I have to say that the test cables caught my attention, they felt really solid and heavy I have no doubt that they can handle the 30A that KEL-103 can load, they have a really good feel to them and is wary bendable, down to 2 inch diameter without stressing them, pretty amazing.
The unit itself do also feel like a solid unit with a lot of holes in the bottom and back for the active cooling.
To me does the KEL-103 electronic load, looks a lot like the good old Keithly units, like the 2001, 2015 and so on.
KEL-103 has four feet's where the two in the front can fold out so the unit stands with a slight angel, that make it easy to use, the display is wary clear without been to bright, I feel that it has found the balance and you will have no problem reading the numbers on the front, not even outside in the sun.
So how good is the unit?
In the shortest possible way, can I only say that if you love your Korad PS, you’ll also be glad for the KEL-103 Electronic Load! They are of the same quality and build.
To test the unit I kept a constant room temperature at 21,5 °C = 70 °F I started by connecting my Korad power supply to the electronic load, so a Korad PSU to test a Korad load, what can be more fair?
I did a lot of tests with different configurations but the largest difference was when the unit did stay turned on from yesterday but in rest run and then work for 4 hours at 18V 20A where I got a fluctuation of 6mV over the entire period. That's pretty impressive.
Under the tests I did not find the unit to make to much noise, okay you should avoid to put it in your bedroom but for an electronic load, the noise is acceptable.
This unit has a lot of functions with 100 memory functions, 5 presets you can program for easy change to what you use most. The unit is fairly easy to use when you know how, what I am saying is that you have to read the manual to get any good usage out of it. It’s not a unit that you just put into your lab and start using, because there are some functions that you have to read how to use before you get frustrated. But after reading this thin 25 page manual, you should easily be able to use it.
I had looked forward to the tear down and I have taken some picture but every chip, capacitor and what not, is covered by a black epoxy that make it nearly impossible to get much out of the tear down.
(https://www.eevblog.com/forum/testgear/review-of-the-korad-kel103-programmable-load/?action=dlattach;attach=679881;image)
Conclusion: It is a unit you will like if you like the Korad brand, low noise and fairly stable, I do only not like that all components are without any kind of indemnification.
I think that this unit is worth the money and easily can compete with other brands like BK Precision and so on. The many functions and settings do make for a complete unit, you will not miss anything in your home-lab, unless you are working whit special advanced needs but then you may also own gear fare exiting this price range..
Facts:
(https://static.sra-solder.com/media/wysiwyg/Specs.JPG)
For more info, please visit: https://blog.sra-solder.com/article-categories/power-supplies (https://blog.sra-solder.com/article-categories/power-supplies)
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funny enough Siglent does not make any loads
One is coming:
(http://www.siglent.com/Chinese_website2014/picture/SDL1000X/SDL1020X111.png)
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So I've got one too (the KEL102, lower power one) and so far it seems to be a solid piece of kit, and surprisingly quiet one (and I think fan just stop at low load). The biggest annoyance I found is as FriedMule mentioned that using of any non-basic function pretty much requires a manual because display does not display enough info to be used without it.
For example some modes lets you specify amperes of load and A/us but for both steps it just displays A on screen so you have to remember the order or refer to manual.
Battery mode is also a bit... derpy because you *have* to set both time and Ah which means you can't make (or at least I haven't found a way) discharge that lasts more than 9999 seconds (typing 0 just changes it to 0.001). You can just use normal CC mode but that won't show you Ah consumed...
If someone wants me to test anything specific let me know :)
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funny enough Siglent does not make any loads
One is coming:
When? Weeks, months, years from now? :-//
My US vendor (as of last week) could provide no information at all as to when it will be available.
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@FriedMule Awesome review man!
I was on the verge of buying one of these and testing it out, but I happened to score a pretty fancy dc electronic load not too long after. I paid about 2.5x what this Korad costs, but it's a whole lotta dc load for one to handle ^-^. I'm still reading the manual on mine ;D
I'm glad this turned out to be a pretty sweet unit.
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funny enough Siglent does not make any loads
One is coming:
When? Weeks, months, years from now? :-//
As usual release date is a secret however mid (this) year was mentioned. So a couple of months or so. :(
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Why do so many loads have these stupid binding posts which don't take 4mm banana plugs? There are 4mm binding posts which are rated for 35A so that isn't the problem.
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Why do so many loads have these stupid binding posts which don't take 4mm banana plugs? There are 4mm binding posts which are rated for 35A so that isn't the problem.
I suspect that it is because EU safety rules requires fully-sheathed banana plugs, which makes also providing reasonably-sized binding posts difficult for smaller form factors and would make the product more expensive to produce.
I just discovered that the reason for this rule in the EU is because mainland European power outlets are a perfect receptacle for a 4mm banana plug -- and a match for the 19mm spacing of a dual banana plug connector.
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Thank you for the great review! :-+
Have been thinking about buying this one - this probably does it.. :-DD
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outside of ebay anybody knows where i could find it in the european union ?
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It looks like this RND brand is a rebrand of Korad. And that they can be bought from elfa: https://www.elfadistrelec.dk/da/programmable-electronic-dc-load-120v-150w-30a-rnd-lab-rnd-320-kel102/p/30126023?track=true. (https://www.elfadistrelec.dk/da/programmable-electronic-dc-load-120v-150w-30a-rnd-lab-rnd-320-kel102/p/30126023?track=true.)
Regards
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outside of ebay anybody knows where i could find it in the european union ?
Farnell got it rebranded as TENMA. Quite a good price. https://uk.farnell.com/tenma/72-13210/dc-electronic-load-prog-30a-120v/dp/2848407 (https://uk.farnell.com/tenma/72-13210/dc-electronic-load-prog-30a-120v/dp/2848407)
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It looks like this RND brand is a rebrand of Korad. And that they can be bought from elfa: https://www.elfadistrelec.dk/da/programmable-electronic-dc-load-120v-150w-30a-rnd-lab-rnd-320-kel102/p/30126023?track=true. (https://www.elfadistrelec.dk/da/programmable-electronic-dc-load-120v-150w-30a-rnd-lab-rnd-320-kel102/p/30126023?track=true.)
Regards
RND is the Dätwyler group’s new house brand (as of a few years ago), so all the Distrelec companies as well as Reichelt, all being Dätwyler subsidiaries, now sell the RND products and push them heavily.
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I downloaded KEL103 programmable software here http://www.koradtechnology.com/nav/19.html. (http://www.koradtechnology.com/nav/19.html.) It contains:
KEL103.exe - a communication debugging utility, that can connect to my KEL103 over LAN and send commands to it. But it is not user friendly, it is just a test utility.
KEL103 software - this is user friendly software, but it can communicate with KEL103 only via serial port (or USB).
What software do you use to control KEL103 over LAN?
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Hello guys. I have this load and some of the components are burnt on mine. R155 and Q11 as well R166 but i know its 471 resistor. Can anyone share what components values are in Q11 and R155?
(https://i.ibb.co/qmHzzRx/2020-08-06-10-28-IMG-1774-Large.jpg) (https://ibb.co/qmHzzRx)
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outside of ebay anybody knows where i could find it in the european union ?
Farnell got it rebranded as TENMA. Quite a good price. https://uk.farnell.com/tenma/72-13210/dc-electronic-load-prog-30a-120v/dp/2848407 (https://uk.farnell.com/tenma/72-13210/dc-electronic-load-prog-30a-120v/dp/2848407)
CPC (basically less competent but cheaper farnell) is significantly cheaper for those in the UK:
https://cpc.farnell.com/tenma/72-13210/dc-electronic-load-prog-30a-120v/dp/IN07979?st=electronic%20load
Wish they had a higher voltage version though
Edit: Damnit now there is a good chance I'll ending up buying one to feed the TEA habit...
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found one of those for reasonable money on a returns shelf. It was still in the original packaging, so I could not resist.
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Can it make battery test (counting Ah) in constant power mode?
I would appreciate if someone could confirm this.
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Can it make battery test (counting Ah) in constant power mode?
I would appreciate if someone could confirm this.
You can always control it from a computer with TestController and do it that way.
https://www.eevblog.com/forum/testgear/program-that-can-log-from-many-multimeters/ (https://www.eevblog.com/forum/testgear/program-that-can-log-from-many-multimeters/)
Note: TestController do not have a definition for Korad KEL103 at the moment, but it is fairly easy to make (No programming required).
Note: TestController have support for Itech, Maynuo & B&K loads, this means with these you can measure Ah in constant power mode.
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Hello guys. I have this load and some of the components are burnt on mine. R155 and Q11 as well R166 but i know its 471 resistor. Can anyone share what components values are in Q11 and R155?
(https://i.ibb.co/qmHzzRx/2020-08-06-10-28-IMG-1774-Large.jpg) (https://ibb.co/qmHzzRx)
I don't have one (yet) so unfortunately can't help, but could you shed some light on what happened that cuased them to burn up? Was it just sitting there, or was a high voltage or something applied to the inputs that shouldn't have been? Asking as I'm considering buying one (in which case I'd open it and look at this area of course!)
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Hi,
Here are some snaps from mine.
Hope that helps.
/andreas
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Hi guys!
Q11 marked "1AM" is most probably a MMBT3904L NPN transistor: https://www.onsemi.com/pub/Collateral/MMBT3904LT1-D.PDF (https://www.onsemi.com/pub/Collateral/MMBT3904LT1-D.PDF)
From the picture it's clear that the gate drive circuitry of Q13 was affected. You should also check D11, D12, D13, U32 opamp and Q13, there are chances that some of these are be blown too.
As Hydron also asked, what had caused the failure? Wrong polarity connection to a battery?
Best regards,
rsx90
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Can it make battery test (counting Ah) in constant power mode?
I would appreciate if someone could confirm this.
No, battery test mode supports only CC. But ofc combined with a pc you can make your own tool that counts AH in any mode.
Also here some clarification about the unit/manual:
The manual is garbage. For example...in battery test mode you have to specify (even if you dont need it) a max discharge time limit and consumed AH limit. The manual states that this is in seconds (discharge time) but this is wrong. You can set the max time to 9999, but this is minutes and not seconds. The same with AH, its 9999 AH.
The manual is also wrong/confusing with different other things.
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I have blown up my KEL103. 12V Lead Acid batteries should not be connected the wrong way.
I have replaced one of the 5W resistors on the input.
Now U8, a 7812 +12V regulator goes burning hot and nothing works. Looking closely on the pcb I see C135, C136 and C 137 are burned up (?).
Anyone know their value? If you have a KEL103, can you measure them?
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Did you check for shorts? I'm not familiar with this device, but for sure there is a short somewhere.
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Yes, I am looking for a short. Not found one so far, only the broken caps.
There is some resistance (kohms) between output of the 7812 and ground, so no "hard" short. I came across those broken caps while searching for the short.
I will keep looking for that short. I am considering solder out the 7812 and insert probes between output of the 7812 to see power draw.
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I was rather interested in this load: Cheap with build-in network and serial connection.
I got one and have added it to TextController https://www.eevblog.com/forum/testgear/program-that-can-log-from-many-multimeters/ (https://www.eevblog.com/forum/testgear/program-that-can-log-from-many-multimeters/)
(http://lygte-info.dk/pic/Projects/TestController/Screens/KEL103.png)
(http://lygte-info.dk/pic/Projects/TestController/Screens/KEL103a.png)
I like it uses a LED display. The network interface uses UDP, that is not the best for instrument control, but I got it working.
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Newark (Farnell) has rebranded the Korad loads from Tenma to MulticompPro.
Currently the 300W unit (Korad KEL103) (https://www.newark.com/multicomp-pro/mp710259-us/dc-electronic-load-300w-120v-30a/dp/52AH6649) is $255
The 150W model (https://www.newark.com/multicomp-pro/mp710258-us/dc-electronic-load-150w-120v-30a/dp/52AH6648) is $205
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Other rebrands/rebadges are Stamos Soldering S-LS-60 and S-LS-61, respectively 150W/300W.
Got mine via german ebay, also sold on Amazon.
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Newark (Farnell) has rebranded the Korad loads from Tenma to MulticompPro.
Currently the 300W unit (Korad KEL103) (https://www.newark.com/multicomp-pro/mp710259-us/dc-electronic-load-300w-120v-30a/dp/52AH6649) is $255
The 150W model (https://www.newark.com/multicomp-pro/mp710258-us/dc-electronic-load-150w-120v-30a/dp/52AH6648) is $205
Those are pretty nice prices. They must be overstocked or something.
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Those prices are similar to CPC's (basically farnell's budget division), and have been around that mark for quite a while. The only reason I didn't get one myself is I wanted higher voltage capability (which meant going for one of the banggood options and then making some mods).
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I emailed Shenzhen Korad Technology Co., Ltd. yesterday and asked them to send me the latest version of the manual for the KEL103. Krissy Yang emailed me version 2.10 of the Korad KEL102 & KEL103 electronic load manual (http://chrisgrossman.com/manuals/korad/Korad_KEL102_KEL103_english_user_manual-V2.10.pdf) a few hours ago. It seems to be a newer version than anything I could find online.
The pages are in a odd jumble of an order, but seem to be all there.
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I would like to get the Korad KEL103. I am in Italy. Can someone suggest a reliable source where to buy the KEL103. Thanks a lot,
Tod
p.s. Is it possible to buy this directly from Shenzhen Korad Technology Co., Ltd?
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I'm also from italy, and i've bought mine from eleshop.nl.
By now it not has too good prices.
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does Reichelt deliver to Italy ? they usually have it in stock (it's where I got mine)
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At the current moment I see these prices:
KEL102 KEL103
Reichelt 256 Eu 400 Eu
Eleshop 299 Eu 349 Eu
These prices include VAT but exclude shipping. Too much. AliExpress prices are more convenient and I am tempted to try it...
Also do you think rebranded Tenma from Farnell is good quality?
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I emailed Shenzhen Korad Technology Co., Ltd. yesterday and asked them to send me the latest version of the manual for the KEL103. Krissy Yang emailed me version 2.10 of the Korad KEL102 & KEL103 electronic load manual (http://chrisgrossman.com/manuals/korad/Korad_KEL102_KEL103_english_user_manual-V2.10.pdf) a few hours ago. It seems to be a newer version than anything I could find online.
The pages are in a odd jumble of an order, but seem to be all there.
They are sorted in a way that they can be printed and then stapled together to get a brochure ;-)
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At the current moment I see these prices:
KEL102 KEL103
Reichelt 256 Eu 400 Eu
Eleshop 299 Eu 349 Eu
These prices include VAT but exclude shipping. Too much. AliExpress prices are more convenient and I am tempted to try it...
Also do you think rebranded Tenma from Farnell is good quality?
My KEL02 is also rebranded, and as I took it apart, it seemed to be only cosmetic stuff like exchanging the label on the front and changing the ident string from the electronics...
So I would guess that the other rebrands/rebadges also uphold a certain quality.
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Hello is there a pious soul who could share a link with the Korad Kel103 CD software? I bought mine from AliExpress and it arrived without any CD. I could not find anything in Internet by Googling.
Thanks a lot,
Tod
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Hello is there a pious soul who could share a link with the Korad Kel103 CD software? I bought mine from AliExpress and it arrived without any CD. I could not find anything in Internet by Googling.
You could install this software: https://www.eevblog.com/forum/testgear/program-that-can-log-from-many-multimeters/ (https://www.eevblog.com/forum/testgear/program-that-can-log-from-many-multimeters/)
It supports the KEL103 and a few hundred other pieces of test equipment.
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@HKJ Thanks, I will try it :-+
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I have a Multicomp MP710259 (which I assume is equivalent to the KEL103 and the Tenma 72-13210). The software supplied on CD ROM was version 4.1 and is useable now, but it took some experimenting. I am using the supplied USB cable. One help is to open the folder found in Program Files (x86) and change the permissions by right clicking the Configuration settings files, select Properties, then Security, then Users, then Edit, then Users and finally Allow so those files can be written to by the program.
When using the graphs, you can click on the min and max values and change the scales. Also, you can right-click a chart and then clear it.
I hope some others discover more about this software as it seems at least somewhat useful. Thus far, I am liking this electronic load a lot!
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I hope some others discover more about this software as it seems at least somewhat useful. Thus far, I am liking this electronic load a lot!
For another software check https://www.eevblog.com/forum/testgear/program-that-can-log-from-many-multimeters/ (https://www.eevblog.com/forum/testgear/program-that-can-log-from-many-multimeters/)
The current version do not support the load, but next version will (It only requires a small change in a definition file and information about it is posted in reply #1526).
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Also here some clarification about the unit/manual:
The manual is garbage. For example...in battery test mode you have to specify (even if you dont need it) a max discharge time limit and consumed AH limit. The manual states that this is in seconds (discharge time) but this is wrong. You can set the max time to 9999, but this is minutes and not seconds. The same with AH, its 9999 AH.
The manual is also wrong/confusing with different other things.
Yep, it quite confused me cause it counts somewhat like seconds right to the dot but these are actual hundredth of a minute.
I like the unit with the simple and very clear segment display.
A bit annoying is the fan on the heatsink at the front area that turns on 100% when going above 2 A load. Is that some kind of shunt / measuring construction?
Also sometimes the main fan is not switched off although load is turned off and the heatsink is cooled down. Don't understand the magic behind this yet. ^^
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Yes it is possible to buy from the factory for US$309 excluding shipping. I think it will be cheaper from Ali or Bangood.
If you going to buy from Ali, ask the store if they have stock for immediate dispatch, otherwise you will end up like me, & have to cancel the order & wait for a refund because they can't get stock in time.
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Hey,
This topic has some time now, but I made last week a review on the KEL102 (comparing also with KEL103) if anyone is interested.
https://www.youtube.com/watch?v=-b9t5dqwSC8 (https://www.youtube.com/watch?v=-b9t5dqwSC8)
and the written article
https://techcorner.tv/eletronics/korad-kel102-kel103-programmable-dc-electronic-load/ (https://techcorner.tv/eletronics/korad-kel102-kel103-programmable-dc-electronic-load/)
I liked a lot, is part of my workbench now. In europe you can have your delivere (KEL102) for 162€ with free shipping. I believe it delivers also in USA for the same value ~ $190...
Links on the article and in the video description.
Cheers,
Hugo
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Hi,
just a silly question - what is adjustment resolution in CR mode? I can't find it reviewed in any video. It is very useful in testing limit of SMPS.
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Does anyone have experience of the dynamic CC capability of the KEL102/103? I am looking to make transient response tests for some power supplies. I have a DC load here whose dynamic mode does not meet its advertised spec by a long way and is incapable of generating a transient that a PSU notices... (maybe for another thread.)
Is the Korad capable of generating useful transients?
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Does anyone have experience of the dynamic CC capability of the KEL102/103? I am looking to make transient response tests for some power supplies. I have a DC load here whose dynamic mode does not meet its advertised spec by a long way and is incapable of generating a transient that a PSU notices... (maybe for another thread.)
Is the Korad capable of generating useful transients?
Wouldn't happen to be an EastTester or Dingchen unit would it?
I second the interest in this - I'd also like something affordable that can do this as advertised.
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I want to add that the device can be used as current limiting device. In Constant Current Mode, the voltage drop across it without Current limiting acting is almost 0v. I've had the need to test a device using it's Power supply and I've had the need to Current limit it. The response to sudden load changes is quite fast. Can do something that isn't designer for. Quite Happy with it. Excluding the user interface😅
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I want to add that the device can be used as current limiting device. In Constant Current Mode, the voltage drop across it without Current limiting acting is almost 0v.
DC loads can be used in more advanced situations, you described one of them. DC load in conjunction with PSU can test DC chargers (charger sees positive or negative current depending on voltage). Be mindful of allowable parameters in full setup.
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Hi,
just a silly question - what is adjustment resolution in CR mode? I can't find it reviewed in any video. It is very useful in testing limit of SMPS.
Hi. It's been some long time, but I saw your question only now.
I have KEL102, and the adjustment resolution in CR depends on the range:
- 0 - 9.9999 R the resolution is 0.0001 R
- 10 - 99.999R it is 0.001 R
- 1000 - 9999.9R it is 0.1 R
Maximum is 7500 R. Minimum is 0.05 R.
0.0001 R is crazy resolution. I tried to confirm it really works, using Keysight 34461A and Li-Ion battery (the most stable voltage supply I have right now), but the lowest I saw the difference was 0.01 R. Everything below 1 mA was noise. Perhaps with better setup it could be measured.
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Digging up and old thread here, but it's the correct place for this question.
Anybody know what the ripple / noise is on the KEL103 while under load?
An important parameter for testing PSU's. It's quite large on some of the cheaper loads like the KP184.
Thanks.
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This is with 100mA CC load (from a linear 5V supply). The ripple is from magnetic coupling from the (shielded) transformer to the shunt and/or the amplifier circuitry.
Ripple gets worse when either fan starts up (at 2A+, or when the temperature of the main heatsink rises too high).
Edit: has anyone else had issues with getting DHCP to stay on, or to connect with TestController? I think there might be a new revision and I'm not having any luck with those things, which ontop of the transformer/fan noise is a bit annoying.
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I want to add that the device can be used as current limiting device. In Constant Current Mode, the voltage drop across it without Current limiting acting is almost 0v. I've had the need to test a device using it's Power supply and I've had the need to Current limit it. The response to sudden load changes is quite fast. Can do something that isn't designer for. Quite Happy with it. Excluding the user interface😅
That is good idea!
I have one more good use case, it can do short circuit (shift + short), in this mode load can be used as 30 Amp ammeter.