Electronic Loads - Why so expensive? - Page 1
Forum section: electronics / testgear

author: ElectronicCat
author_rank: Regular Contributor
timestamp: March 22, 2017, 12:22:44 am
content: So I was looking at electronic loads as they seem like they should be a fairly standard piece of test equipment for a lab, and I could use one for some upcoming projects. However, I haven't really been able to find any that I would consider to be affordable for casual hobbyists like myself, the cheapest that I could find is probably the BK Precision BK8540. It's pretty basic, only has CC, CV and CR modes and doesn't appear to have any data logging or modes for battery testing etc. Any yet despite being such a simple device it retails for around £470-500 here in the UK, which is more than a lot of low end scopes!I'm not sure if I'm missing something, but as far as I can tell they're relatively simple devices. Just a power FET or array to dissipate the power, heatsink/fan, microcontroller and some input circuitry. I've had a look for cheaper devices but all I can find is the really cheap chinese USB loads, or for slightly more there's some slightly beefier versions with a screw terminal but ultimately just the same bare PCB device with some 7-segment displays.Does there really not exist anything in the £60-200 range in terms of electronic loads? I know the cheap chinese ones would probably be good enough for my purposes or I could probably make one fairly easily, but I would ideally like something that I can buy off the shelf that comes pre-calibrated, in a nice bench case and at least semi-programmable. You can get linear dc bench power supplies within this range (and even fairly high end ones for less than the cheapest loads!) and as far as I can tell, loads aren't any more complex than this.

author: Nusa
author_rank: Super Contributor
timestamp: March 22, 2017, 12:57:10 am
content: I'd say it's simple economies of scale. Power supplies are far more popular than load testers.Everyone, from hobbyist to professional, wants and needs a quality power supply. Usually several of them.The audience for calibrated, precision, programmable electronic loads is far more limited. For most of us that's WAY down on the list of priority lab equipment. Throwing together non-precision manually changed loads on demand is often all people need. I guess that falls under "make your own", even if it's as simple as a couple light bulbs.

author: rx8pilot
author_rank: Super Contributor
timestamp: March 22, 2017, 01:40:18 am
content: Early on, I built a passive one with a bunch of resistors. It was well constructed and has 20 or so switches for each resistor. I also added capacitors to stress power supplies. It was very basic, but built largely from spare parts.As my interests and business started focusing more and more on power electronics specifically, I upgraded to an Array which was not hideous but not great and no option to automate.I sold that and got a Chroma mainframe with 8 load channels. That is what I really needed for power management testing. It is far more than a few fets and a microcontroller for sure - read up on Chroma systems just for fun.The question is what do you really need. What are you testing and what data do you need/want in the end? A light bulb is a DC load. A resistor is a load. The reason electronic options exist is for those who need very specific parameters, accuracy, and automation. That part costs money since they are generally designed for professional applications.Sent from my horrible mobile....

author: rx8pilot
author_rank: Super Contributor
timestamp: March 22, 2017, 03:32:35 am
content: Quote from: wilfred on March 22, 2017, 02:42:15 amAs a side note, I got some Patco thermal strippers and they work well.Basic and low cost.

author: Zbig
author_rank: Frequent Contributor
timestamp: March 22, 2017, 08:18:40 am
content: Have you checked Re:load Pro atarachnidlabs.com?

author: ElectronicCat
author_rank: Regular Contributor
timestamp: March 22, 2017, 08:33:20 am
content: Quote from: rx8pilot on March 22, 2017, 01:40:18 amMainly I'd be using it to test switched mode power supplies, both the output stability and thermal properties at different levels of load. Also to a lesser extent, probably battery charging simulation would be nice but I could do without. Logging C/V/R/P over time would also be nice but I suppose I could achieve the same thing with a data logging multimeter or two. Mostly I'm just looking for something with an adjustable level of load to save having to hook up a bunch of power resistors, and CC/CV/CP modes would be useful for testing different types of load which you can't do just with resistors.Quote from: Zbig on March 22, 2017, 08:18:40 amI hadn't! That looks pretty close to what I'm looking for actually. Only seems to have a CC mode, but I suppose I could live with that for the majority of my testing.

author: usagi
author_rank: Frequent Contributor
timestamp: March 22, 2017, 08:51:26 am
content: I got one of these from amazon and for the price i've been satisfied with it.300W dc electronic load - $209https://www.amazon.com/T-king-KL283-Channel-Adjustable-Electronic/dp/B015HM17MU/

author: cowana
author_rank: Frequent Contributor
timestamp: March 22, 2017, 10:40:14 am
content: Quote from: ElectronicCat on March 22, 2017, 08:33:20 amIt only has CC mode in hardware, but then has CV and CR modes in software. That means they're not quite as responsive/well controlled during transients - but fine for the majority of testing!

author: maukka
author_rank: Unknown
timestamp: March 22, 2017, 06:16:02 pm
content: This might fall under your category of cheap Chinese loads, but I've been happy with the ZKE EBD-A20H for the couple weeks I've been using it. Most importantly, it has USB control+logging and according to my cheap Fluke DMM it's reasonably precise.http://www.ebay.com/itm/252205821159

author: mcinque
author_rank: Unknown
timestamp: March 22, 2017, 10:05:32 pm
content: Quote from: Zbig on March 22, 2017, 08:18:40 amAgree, it's a good cheap load!

author: 2N3055
author_rank: Super Contributor
timestamp: March 22, 2017, 10:38:12 pm
content: Quote from: mcinque on March 22, 2017, 10:05:32 pmNo, that is a toy.. it has 25W capacity.. for 125 USD...Those "expensive" 500-600USd loads have 300W capacity. Programmability, computer control , CC, CV, CP, CR modes, battery capacity test ,.. etc...built in 5.5 Digit ampere meter and voltmeter, microampere resolution, etc, etc. They are a bargain for a professional tool.But if you don't need those features, handful of power resistors or halogen lamps will work much better that some toy. Or make your own, if nothing else, for learning experience.This one is should be OK too.. Simple, no programability but for basic load ok.Quote from: usagi on March 22, 2017, 08:51:26 am

author: Lbud4
author_rank: Newbie
timestamp: March 23, 2017, 12:59:03 am
content: Here is a good self powered load.http://www.saelig.com/TSTEQDC/M00154007.htm

author: HoracioDos
author_rank: Frequent Contributor
timestamp: March 23, 2017, 02:31:27 pm
content: Quote from: maukka on March 22, 2017, 06:16:02 pmThis is a similar model with battery charger. ($51)http://www.ebay.com/itm/332143888159Here is a review and follow up from Power Cartel.http://powercartel.com/tag/ebc-a05/He also found a small bug and reported to ZKE back in 2015. They promised a new firmware.

author: kwass
author_rank: Frequent Contributor
timestamp: March 23, 2017, 03:32:36 pm
content: Quote from: ElectronicCat on March 22, 2017, 12:22:44 amThe iTech IT8211 is identical to the BK8540 for about half the price on ebay and elsewhere. I bought one a few months ago and am quite pleased with it. While not remotely programmable you can enter in a short sequences of steps (LIST mode) for it to execute from the front panel. Admittedly these are not all that useful since they are a maximum of time of 25 seconds per step and a maximum of 25 steps per list with no ability to loop.I wonder if there's not someway, using the 9-pin D connection, in the back of this load to get into a remote access mode. The front panel allows you to set the address of this port but the manual says it's for factory use only. Weird!

author: kaktus
author_rank: Newbie
timestamp: March 25, 2017, 09:33:19 pm
content: I will make a shameless plug and point to my take on electronic load: 70 watts, 129 USD, constant power and constant voltage in hardware (CR, CP in software). But it is open-source so you can build it yourself.https://www.tindie.com/products/Kaktus/mightywatt-70w-electronic-load-for-arduinohttps://github.com/kaktus85/MightyWattR3

author: ebclr
author_rank: Super Contributor
timestamp: March 26, 2017, 06:53:51 am
content: 17 USD isn't that expensivehttps://pt.aliexpress.com/item/9-99A-60W-30V-Constant-Current-Electronic-Load-Discharge-Battery-Capacity-Tester/32776310672.html?spm=2114.10010308.1000016.1.7p1jeA&isOrigTitle=true

author: mcinque
author_rank: Unknown
timestamp: March 26, 2017, 08:07:25 am
content: Quote from: 2N3055 on March 22, 2017, 10:38:12 pmProbably the Re:load PRO.I was referring to the basic Re:load2 for only 20USD.

author: Fraser
author_rank: Super Contributor
timestamp: March 28, 2017, 03:49:49 pm
content: For anyone interested, I just received a new and shiny ZKE EBC-A05+.I have already had is lid off and all looks to be in order inside the unit. Neat little design that looks suitable for my requirement. I have electronic loads and battery analysers but I wanted a battery exerciser that would charge, discharge, and then charge again with a record of performance. I have loads of spare laptops to dedicate to the unit so i will have a dedicated battery exercise station. The only real limitation is the 10V maximum charge rather than a more useful 16V which would have coped with a broader range of battery packs.I found the software and English User manual. I attach the user manual for those who need it.My unit is Firmware version 3.0.2 with a date code of 16-11-01. That could be 01 Nov 2016 or 11 Jan 2016 depending upon which format they use for date info.I attach some internal pictures of this latest version.Fraser

author: Fraser
author_rank: Super Contributor
timestamp: March 28, 2017, 04:14:08 pm
content: Some pictures of the earlier version of the EBC-A05 taken from this file repository :https://yadi.sk/d/v387M6gEjCTNXZKE appear to have tidied up their design.

author: Zbig
author_rank: Frequent Contributor
timestamp: March 28, 2017, 04:32:24 pm
content: At first I wondered where the air intake/outlet vents for the fans are, then realized they are a "complementary pair" mounted in the opposite directions with one blowing and the other one sucking air. Clever, I don't think I saw this before.

author: Fraser
author_rank: Super Contributor
timestamp: March 28, 2017, 04:40:02 pm
content: Yes, a forced air blow & suck cooling system. I like that idea as well.Fraser

author: ebclr
author_rank: Super Contributor
timestamp: March 28, 2017, 08:16:00 pm
content: 30 Buckshttps://world.taobao.com/item/40566539149.htm?spm=a312a.7700714.0.0.9JQ3QP#detail

author: Fraser
author_rank: Super Contributor
timestamp: March 28, 2017, 08:20:11 pm
content: Yep, plus shipping. I believe Franky's shop could get them to a customer in the west for $60.You need to be careful to ensure that cheap units come with a PSU and USB to RS232 cable as some sellers do not include these in order to advertise a lower price.I paid $51 delivered and the stock was in the UK so it arrived in less than a week. My unit came with both PSU and data cable but no instructions or software. Those may be downloaded online.Fraser

author: serggio
author_rank: Regular Contributor
timestamp: March 28, 2017, 09:03:15 pm
content: I more than satisfied with this cheap electronic load:http://www.ebay.com/itm/361872115003?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT.Unbelievable precision with load current and voltage support and measurement. Can be even calibrated by user.Used it many times for discharging lead-acid batteries with up to 60W load, no any problems with this "toys".

author: HoracioDos
author_rank: Frequent Contributor
timestamp: March 29, 2017, 11:35:15 pm
content: Quote from: Fraser on March 28, 2017, 03:49:49 pmI bought the same unit last week to use it as a electronics load for a linear PSU and for capacitor discharge. I don't know if it's possible. It's in the mail now and will arrive in two months or more.I've read that firmware can be upgraded from user's software. Also found a USB protocol document but it's un russian.Software version is V1.8.5 build 2017-02-16. It seems to work in linux under wine.

author: plazma
author_rank: Frequent Contributor
timestamp: April 05, 2017, 06:47:25 am
content: Quote from: Fraser on March 28, 2017, 03:49:49 pmWhere is the PC SW available? Is there any FW updates?

author: ralphrmartin
author_rank: Frequent Contributor
timestamp: April 05, 2017, 09:25:26 am
content: Quote from: Fraser on March 28, 2017, 03:49:49 pmIt is standard for everything in China to write dates logically, i.e. year month day.(I say logically as eg. in 2016-03-09, for example the 2 is the most significant digit, on the left, and 9 is the least significant digit, on the right, just like when you write an integer like 413).

author: HoracioDos
author_rank: Frequent Contributor
timestamp: April 05, 2017, 12:34:52 pm
content: Quote from: plazma on April 05, 2017, 06:47:25 amLast item from the table. The one that says EB V1.8.5 English Version Download. AFAIK firmware can be updated from this software.http://www.zketech.com/nd.jsp?id=15&_np=101_304

author: smile
author_rank: Regular Contributor
timestamp: October 14, 2017, 02:00:57 pm
content: There is a nice hacked 150W ZKETECH load here EBC-A10-150W:https://pt.aliexpress.com/item/EBC-A10-150W-aluminum-alloy-electronic-load-capacity-tester-18650-minute-capacity-cycle-charging-and-discharging/32813597066.htmlThe only electronic loads from ZKETECH that have charger is EBC-A10 60W; EBC-A05 60W;

author: smile
author_rank: Regular Contributor
timestamp: October 14, 2017, 02:09:35 pm
content: Seems like the only good one is CBA IV Pro with capability to use external chargers of your choice, and extendability up to 2000W makes it no brainer IMO.The other option is maynuo m9711 / 9712. But can it be made into charger (battery maintainer) with external lab power supply? Yes it's more expensive but if you buy direct from China then half the cost.

author: ramjet1953
author_rank: Newbie
timestamp: February 03, 2018, 04:37:51 am
content: I have been using the ZKE EBC-A05+ for a while now.For those Linux users, the ZKE software works fine in Linux, under WINE.Just install the software and the driver in WINE.You will then need to make a symbolic link to com2 .To do this, just open a terminal in your directory:/home/[your home directory]/.wine/dosdevicesThen type in the following command:sudo ln -s /dev/ttyUSB0 com2Enter your sudo password when prompted and you should be good to go.You may need to change the USB and com port numbers, depending upon your Linux distribution and hardware.

author: ez24
author_rank: Super Contributor
timestamp: February 03, 2018, 05:51:09 am
content: What did the OP get?I got one of these, lasted 15 minutes at 100 watts.https://www.aliexpress.com/item/Battery-Capacity-Tester-Digital-voltmeter-adjustable-Constant-Current-Electronic-Load-charger-usb-volt-ameter-meter/32821857011.htmlUsing power rheostats now.

author: eurofox
author_rank: Unknown
timestamp: February 03, 2018, 08:52:52 am
content: I got this one, very good price/qualityhttps://www.benl.ebay.be/itm/DE-SHIP-M9710-USB-Programmable-DC-Electronic-Load-150W-220V-DHL-BLITZVERSAND-/162547257806?

author: ChrisLX200
author_rank: Unknown
timestamp: February 03, 2018, 11:16:53 am
content: I just bought the same one as ^ , comes without the propriatry USB/Serial interface (unlike the 9711) but that can be bought seperately if required. Controlling via a computer is much easier that working through the menus on the device..

author: Mechatrommer
author_rank: Super Contributor
timestamp: February 03, 2018, 08:21:28 pm
content: if you have problem with price or the spec or the UI (rotary encoder that requires many many turns)... build your own...

author: ElectronicCat
author_rank: Regular Contributor
timestamp: March 02, 2018, 11:41:23 am
content: Quote from: ez24 on February 03, 2018, 05:51:09 amStill haven't got one as I've managed to do without for now. Looking back through the thread there's a few good options I might consider but I'd ideally like one with at least CC, CC and data logging. Programmable discharge profiles or battery simulation would be ideal but none of the cheap ones seem to support this. The ZKE or Arachnid Labs ones probably look like the best options for me.

author: ziplock9000
author_rank: Regular Contributor
timestamp: June 12, 2018, 02:39:48 pm
content: I'm tempted to get the EBC-A05+ but as someone else pointed out, I'd like it to at least be able to support 12v+. Possibly even 24v+Do they have other models that support this?

author: HoracioDos
author_rank: Frequent Contributor
timestamp: June 12, 2018, 03:38:18 pm
content: Quote from: ziplock9000 on June 12, 2018, 02:39:48 pmAFAIK it supports 12v @ 5A for discharge mode and 10v for charging mode.

author: batou
author_rank: Contributor
timestamp: June 13, 2018, 07:49:37 am
content: Quote from: ez24 on February 03, 2018, 05:51:09 amI also got one of these - didn't last 2 minutes at 100W. The main FET is toast - and what's worse is that it fails short so you've potentially got a fire on your hands if you are testing unprotected Li-Ion.Got a 50% refund from AE, and have now replaced the FET and its working again, but i'd like to know exactly what the limit is and/or how to protect it.Anyone got any insights? Is there a thread for these somewhere? Maybe I'll start one

author: wraper
author_rank: Unknown
timestamp: June 13, 2018, 08:04:38 am
content: Quote from: Mechatrommer on February 03, 2018, 08:21:28 pmI'd like to know how in the hell TIP142 can be interchangeable with IRF540 as written in the circuit? And why TIP142 is drawn as a MOSFET when it's a Darlington BJT?

author: Jester
author_rank: Frequent Contributor
timestamp: June 13, 2018, 12:43:03 pm
content: Quote from: kwass on March 23, 2017, 03:32:36 pmI picked up the BK version of these recently and am quite pleased with it so far. Its very quiet unless heavily loaded and the 1mA resolution is a must for me. The current scale is quite accurate, however the voltage scale is not as accurate as I would like, does anyone know how to calibrate the V scale?