300W DC Load: Korad KEL2010 or Tonghui TH8402A ? - Page 1
Forum section: electronics / testgear

author: nctnico
author_rank: Super Contributor
timestamp: July 19, 2023, 10:46:52 am
content: I'm contemplating on getting a DC load to replace my Agilent N3301 which is quite large and with it's 600W rating it is overkill for many jobs that I have.So I went looking around to see what kind of DC loads are out there. A hard requirement is to have banana jacks on the front. The Korad KEL2010 and Tonghui TH8402A caught my eye. Specs are in the same ballpark although the Tonghui has more functionality and in my mind Tonghui is a higher quality brand compared to Korad.Tonghui:Korad:A dillema with a purchase decission is that I can buy the Korad locally but the Tonghui is only available from Aliexpress. So if there is something wrong with the Korad, I can return it and/or get support. If there is something wrong with the Tonghui, I'm left with an expensive doorstop. And then there is also the more expensive (and bigger) Tonghui TH8202A which has 3 measurement ranges and might be more suitable for dealing with low currents.I have not been able to find any reviews so it is hard to tell which one is a good buy. Has anyone tried one of these loads?

author: trp806mo
author_rank: Regular Contributor
timestamp: July 19, 2023, 06:31:04 pm
content: I Have a multicomp (but it's a Korad). I made a review of the Sigelnt SDL too (in it's thread) so if you want a dedicated measure/feeback let me know.

author: PartialDischarge
author_rank: Super Contributor
timestamp: July 19, 2023, 06:54:31 pm
content: I'd get a Rigol DL3031 and add banana to spade adapters to the terminals if they are that important.I'm not recommending Siglent here as I have one (SDL1020) and it gives me random startup boot errors.

author: nctnico
author_rank: Super Contributor
timestamp: July 19, 2023, 07:38:12 pm
content: Quote from: PartialDischarge on July 19, 2023, 06:54:31 pmThe price for the DL3031 is about twice of that of the Korad / Tonghui for similar or even better specs.

author: tautech
author_rank: Super Contributor
timestamp: July 19, 2023, 07:47:26 pm
content: Quote from: PartialDischarge on July 19, 2023, 06:54:31 pmUsing which FW version ?It your running the latest ?https://int.siglent.com/download/firmwares/?CateIdss=12

author: PartialDischarge
author_rank: Super Contributor
timestamp: July 19, 2023, 08:15:40 pm
content: I have the 1.1.1.21R2, latest seem to be 1.1.1.22What happens is that randomly gives an error at startup, and then you have to turn off/on again until it works. The avarage is 2 times, not much, so I just don't care since I use it sparingly

author: tautech
author_rank: Super Contributor
timestamp: July 19, 2023, 08:19:02 pm
content: Quote from: PartialDischarge on July 19, 2023, 08:15:40 pmV1.1.1.22R1 actually.Suggest you install it.

author: PartialDischarge
author_rank: Super Contributor
timestamp: July 19, 2023, 08:36:10 pm
content: Quote from: nctnico on July 19, 2023, 07:38:12 pmWell I guess that’s the price to pay for probably a more widespread equipment, in any case I wouldn’t buy an equipment with a single character in Chinese in the UI, shows lack of commitment from them to sell abroad

author: Martin72
author_rank: Super Contributor
timestamp: July 19, 2023, 08:48:06 pm
content: Quote from: nctnico on July 19, 2023, 10:46:52 amOr here:https://www.globalmediapro.com/dp/A2MY50/Tonghui-TH8402-Programmable-DC-Electronic-Load/?setCountry=NL#Includeshttps://www.globalmediapro.com/content/aboutEdit: CrapFrom Korad we have exactly one DC-Supply, it´s a typically chinese cheap one.We also have 2 300W DC Loads from Rigol, good ones but complicated to use.

author: nctnico
author_rank: Super Contributor
timestamp: July 19, 2023, 09:10:21 pm
content: Quote from: PartialDischarge on July 19, 2023, 08:36:10 pmThe menu language on the Tonghui can be switched to English and there are English manuals available from Tonghui that show the screens in English. So there is no lack of commitment to sell abroad. Tonghui has been around for nearly 30 years already.Quote from: Martin72 on July 19, 2023, 08:48:06 pmThanks for looking and the comment about the UI of the Rigols. I've found Globalmediapro as well but without any mention of name & contact address it looks like a super shady business which seems to be located in New Zealand. Also online reviews aren't stellar. I'd rather buy from Aliexpress

author: Martin72
author_rank: Super Contributor
timestamp: July 19, 2023, 09:25:10 pm
content: Aha, you might be right.Because everything they offer is always in stock...That can't be right, so forget my post before that.Then the decision would be clear for me.You can get Korad on every corner, in our country even at Reichelt and Conrad Electronic.And then would be for me for exactly the reasons you had already mentioned, the Tonghui out.So if it is to decide between Korad and Tonghui.Just order, test and if that's nothing, back again and spend a little more money.As mentioned, the Rigol loads are good, but the menu navigation makes you crazy....

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 19, 2023, 09:28:03 pm
content: IME Tonghui makes good quality hardware. However, if you don't buy it directly from them, forget about ANY kind of support. A lot of Tonghui products are rebranded and sold by other parties with the same hardware. If you really want that TH8402A, see if it's sold through any other brands like Sourcetronic.

author: Martin72
author_rank: Super Contributor
timestamp: July 19, 2023, 09:35:06 pm
content: QuoteAlready did this....No DC-Loads from Sourcetronic.

author: KungFuJosh
author_rank: Super Contributor
timestamp: July 19, 2023, 10:47:18 pm
content: Quote from: Martin72 on July 19, 2023, 09:35:06 pmI'll mention it to the reps I've been speaking with. 😉

author: trp806mo
author_rank: Regular Contributor
timestamp: July 20, 2023, 12:18:09 pm
content: I don't have any boot failure on my (home) Siglent but I'm more annoying with its high (normal?) ripple during the regulation.Regarding Tonghui we wanted to buy one DC load too some years ago but we couldn't do it as they haven't any CE certificate for the office.@Nctnico, what do you want to know/be checked on the Korad model ?

author: nctnico
author_rank: Super Contributor
timestamp: July 20, 2023, 01:28:08 pm
content: Quote from: trp806mo on July 20, 2023, 12:18:09 pmAbout the Korad model: I'm interested to know whether it works and if there are any kind of known issues (firmware bugs). I noticed the Korad can be connected to a network. Do you have any experiences to share on how that works?

author: Martin72
author_rank: Super Contributor
timestamp: July 20, 2023, 01:35:24 pm
content: QuoteDepends on the regulation type.

author: trp806mo
author_rank: Regular Contributor
timestamp: July 20, 2023, 04:21:04 pm
content: ok, I'll upload a short review this week

author: nctnico
author_rank: Super Contributor
timestamp: July 20, 2023, 04:55:58 pm
content: Quote from: Martin72 on July 20, 2023, 01:35:24 pmI checked the Siglent SDL1000 manual but can't find any way to adjust loop bandwidth. Then again, a current sink/source has a very high impedance to start with so it is hard to stabilise the voltage using a voltage control loop. If the voltage control loop hasn't been dampened enough, a true current sink will make it oscillate quite easely. In other words, the ripple is likely an effect of the source and load interfering. I have experienced this before using cheaper DC loads.BTW: I used to have a self built DC load that used transistors as an open-loop (no feedback) near ideal current sink. This thing was handy to test the regulation of power supplies. Unfortunately I blew it up and couldn't find suitable replacement transistor as the transistors I used came from a switching PSU and where custom parts / marked with custom part numbers. In hindsight I got super lucky that these transistors worked at all in a linear application; these transistors must have had an exceptional DC SOA area!

author: Martin72
author_rank: Super Contributor
timestamp: July 20, 2023, 05:46:36 pm
content: Would like to see what he meant, is it while a loadstep...

author: tautech
author_rank: Super Contributor
timestamp: July 20, 2023, 07:54:02 pm
content: Quote from: trp806mo on July 20, 2023, 04:21:04 pmBe sure you have the latest FW installed for it to mean anything.

author: nctnico
author_rank: Super Contributor
timestamp: July 21, 2023, 09:36:23 pm
content: I've found out Tonghui has a Youtube channel with videos showcasing most of their instruments:https://www.youtube.com/@changzhoutonghuielectronic3305/videosIncluding one that shows a bit about how their DC loads work:

author: trp806mo
author_rank: Regular Contributor
timestamp: July 23, 2023, 02:00:01 pm
content: I uploaded my reviewcheck the topic Korad KEL2010 / Multicomp MP710771 review

author: danils
author_rank: Contributor
timestamp: July 24, 2023, 12:11:46 pm
content: Hello there,I have a Tonghui DC load 8411. When I received it the firmware was very bugged, constant power mode was not working at all. The company answered in half a day and they sent me via email a new, working, firmware.It still has some problems like the meter showing a DC offset also if it is disconnected (could be a problem of my unit).About the rest it's a well built unit with some premium components inside (ST MOSFETs), I'd say it's a bargain for the price.

author: luudee
author_rank: Frequent Contributor
timestamp: July 24, 2023, 12:24:52 pm
content: Hi Nico,I, personally, will never buy anything from Tonghui again.Sure, the HW may be just fine, but boy, if you ever need a bug fix, or any other type of support, FORGET IT !!!(As you kow I have their LCR meter, and regret that purchase)I own an iTech IT8513C+. A bit more than what you are looking for, but I really like the unit:Rating: 600W, 120V/120AAbout $1200 USD @AliExpressiTech also makes smaller (<600W) variation if this is overkill for you ...The UI takes a bit getting used to, but now I can set it up and am ready for work within seconds!Cheers,luudee

author: nctnico
author_rank: Super Contributor
timestamp: July 24, 2023, 01:05:52 pm
content: Quote from: danils on July 24, 2023, 12:11:46 pmThat is usefull information. How long do you have the 8411? And from who/where did you buy it? From Aliexpress or a seller in Europe?@Ludee: also thanks for your input. I appreciate it a lot.I have send Tonghui a few emails asking about European distributors but no response so far.

author: trp806mo
author_rank: Regular Contributor
timestamp: July 25, 2023, 06:20:01 pm
content: I uploaded the manual of the th8200 which is not the same type as what you are looking just for example.I had those contacts in mid 2021 :commercial thhongkong@hotmail.com (Linda Song) which warned me that the product was not EC (and so perhaps it's your issue for not having a distributor)and a technical guy who answered to all my questions :Clint HanChangzhou Tonghui Electronic Co.,LtdNo.1, Xinzhu Road, New District, ChangZhou, JiangSu, ChinaTel: +86 519 85195566Fax: +86 519 85109972Mobile/WhatsApp: +86 18801509216Email: dx.han@tonghui.com.cnIt's just for information as I have any clue of the "quality" of a Tonghui's Dc Load

author: nctnico
author_rank: Super Contributor
timestamp: July 25, 2023, 06:54:45 pm
content: I've send a message to Batterfly (Italy) about the TH8402A because Batterfly sells a lot of other Tonghui equipment. Their price is reasonable but I got no response yet on lead time and whether I can return it if it doesn't work as advertised.About CE: The smaller Tonghui DC loads seem to have a CE mark while the bigger ones don't.

author: nctnico
author_rank: Super Contributor
timestamp: August 05, 2023, 09:01:02 pm
content: No reply from Batterfly about lead time & return policy (yet) so I decided that I'm going to order the Korad KEL2010 and see how it works. Meanwhile I have also found out that some of the Tonghui DC loads I have looked at are sold under BK Precision models BK8550 (175W) and BK8551 (300W). Unfortunately no European supplier has any stock at this moment.

author: electr_peter
author_rank: Unknown
timestamp: August 29, 2023, 08:14:43 pm
content: Quote from: nctnico on July 19, 2023, 07:38:12 pmCheck price of DL3021 insteadFYI, Rigol DL3000 electronic load series can be modified easily (all models have same HW)dl3021-to-dl3031-conversion-discussionFor 300W, I would go with Itech/BK Precision (in my experience Itech e-loads work well). Newer units have very nice binding posts with integrated 4mm banana sockets. Something likeBK8500B