Author Topic: Electronic Loads - Why so expensive?  (Read 9576 times)

0 Members and 1 Guest are viewing this topic.

Offline ElectronicCat

  • Contributor
  • Posts: 38
  • Country: gb
Electronic Loads - Why so expensive?
« on: March 22, 2017, 11:22:44 am »
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.
 

Offline Nusa

  • Super Contributor
  • ***
  • Posts: 1070
  • Country: us
Re: Electronic Loads - Why so expensive?
« Reply #1 on: March 22, 2017, 11:57:10 am »
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.
 
The following users thanked this post: TheWelly888

Offline rx8pilot

  • Super Contributor
  • ***
  • Posts: 3335
  • Country: us
  • If you want more money, be more valuable.
Re: Electronic Loads - Why so expensive?
« Reply #2 on: March 22, 2017, 12:40:18 pm »
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....

Factory400 - the worlds smallest factory. http://www.youtube.com/c/Factory400
 

Offline rx8pilot

  • Super Contributor
  • ***
  • Posts: 3335
  • Country: us
  • If you want more money, be more valuable.
Re: Electronic Loads - Why so expensive?
« Reply #3 on: March 22, 2017, 02:32:35 pm »
I'll give you another example. Take thermal wire strippers. Somebody tell me there is more to them than two soldering irons strapped together, and yet they are priced several multiples of even an expensive soldering station. Why?

As a side note, I got some Patco thermal strippers and they work well.Basic and low cost.
Factory400 - the worlds smallest factory. http://www.youtube.com/c/Factory400
 

Offline Zbig

  • Frequent Contributor
  • **
  • Posts: 795
  • Country: pl
Re: Electronic Loads - Why so expensive?
« Reply #4 on: March 22, 2017, 07:18:40 pm »
Have you checked Re:load Pro at arachnidlabs.com?
 

Offline ElectronicCat

  • Contributor
  • Posts: 38
  • Country: gb
Re: Electronic Loads - Why so expensive?
« Reply #5 on: March 22, 2017, 07:33:20 pm »
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.
Mainly 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.
Have you checked Re:load Pro at arachnidlabs.com?
I 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.
 

Offline usagi

  • Frequent Contributor
  • **
  • Posts: 341
  • Country: us
Re: Electronic Loads - Why so expensive?
« Reply #6 on: March 22, 2017, 07:51:26 pm »
I got one of these from amazon and for the price i've been satisfied with it.

300W dc electronic load  - $209
https://www.amazon.com/T-king-KL283-Channel-Adjustable-Electronic/dp/B015HM17MU/


Offline cowana

  • Frequent Contributor
  • **
  • Posts: 303
  • Country: gb
Re: Electronic Loads - Why so expensive?
« Reply #7 on: March 22, 2017, 09:40:14 pm »
Have you checked Re:load Pro at arachnidlabs.com?
I 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.

It 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!
 

Offline maukka

  • Supporter
  • ****
  • Posts: 73
  • Country: fi
Re: Electronic Loads - Why so expensive?
« Reply #8 on: March 23, 2017, 05:16:02 am »
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
 

Offline mcinque

  • Supporter
  • ****
  • Posts: 976
  • Country: it
  • I know one thing: that I know nothing
Re: Electronic Loads - Why so expensive?
« Reply #9 on: March 23, 2017, 09:05:32 am »
Have you checked Re:load Pro at arachnidlabs.com?
Agree, it's a good cheap load!
« Last Edit: March 23, 2017, 09:09:36 am by mcinque »
I'm basically still a rookie and because of this, even with the best intentions, I often say bullshit :)
 

Offline 2N3055

  • Super Contributor
  • ***
  • Posts: 1205
  • Country: hr
Re: Electronic Loads - Why so expensive?
« Reply #10 on: March 23, 2017, 09:38:12 am »
Have you checked Re:load Pro at arachnidlabs.com?
Agree, it's a good cheap load!

No, 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.

I got one of these from amazon and for the price i've been satisfied with it.
300W dc electronic load  - $209
https://www.amazon.com/T-king-KL283-Channel-Adjustable-Electronic/dp/B015HM17MU/

 

Offline Lbud4

  • Contributor
  • Posts: 8
Re: Electronic Loads - Why so expensive?
« Reply #11 on: March 23, 2017, 11:59:03 am »
 Here is a good self powered load.

http://www.saelig.com/TSTEQDC/M00154007.htm
 

Offline HoracioDos

  • Frequent Contributor
  • **
  • Posts: 293
  • Country: ar
  • Just an IT monkey with a DSO
Re: Electronic Loads - Why so expensive?
« Reply #12 on: March 24, 2017, 01:31:27 am »
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

This is a similar model with battery charger. ($51)
http://www.ebay.com/itm/332143888159

Here 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.
« Last Edit: March 24, 2017, 01:40:52 am by HoracioDos »
 

Offline kwass

  • Frequent Contributor
  • **
  • Posts: 321
  • Country: us
Re: Electronic Loads - Why so expensive?
« Reply #13 on: March 24, 2017, 02:32:36 am »
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!

The 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!
-katie
 
The following users thanked this post: Kremmen

Offline kaktus

  • Newbie
  • Posts: 3
  • Country: cz
Re: Electronic Loads - Why so expensive?
« Reply #14 on: March 26, 2017, 08:33:19 am »
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-arduino
https://github.com/kaktus85/MightyWattR3
 


Offline mcinque

  • Supporter
  • ****
  • Posts: 976
  • Country: it
  • I know one thing: that I know nothing
Re: Electronic Loads - Why so expensive?
« Reply #16 on: March 26, 2017, 07:07:25 pm »
No, that is a toy.. it has 25W capacity.. for 125 USD...
Probably the Re:load PRO.
I was referring to the basic Re:load2 for only 20USD.
I'm basically still a rookie and because of this, even with the best intentions, I often say bullshit :)
 

Offline Fraser

  • Super Contributor
  • ***
  • Posts: 7528
  • Country: gb
Re: Electronic Loads - Why so expensive?
« Reply #17 on: March 29, 2017, 02:49:49 am »
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

 

Offline Fraser

  • Super Contributor
  • ***
  • Posts: 7528
  • Country: gb
Re: Electronic Loads - Why so expensive?
« Reply #18 on: March 29, 2017, 03:14:08 am »
Some pictures of the earlier version of the EBC-A05 taken from this file repository :

https://yadi.sk/d/v387M6gEjCTNX

ZKE appear to have tidied up their design.
« Last Edit: March 29, 2017, 03:25:34 am by Fraser »
 

Offline Zbig

  • Frequent Contributor
  • **
  • Posts: 795
  • Country: pl
Re: Electronic Loads - Why so expensive?
« Reply #19 on: March 29, 2017, 03:32:24 am »
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.
 

Offline Fraser

  • Super Contributor
  • ***
  • Posts: 7528
  • Country: gb
Re: Electronic Loads - Why so expensive?
« Reply #20 on: March 29, 2017, 03:40:02 am »
Yes, a forced air blow & suck cooling system. I like that idea as well.

Fraser
 

Offline ebclr

  • Super Contributor
  • ***
  • Posts: 1628
  • Country: 00
 

Offline Fraser

  • Super Contributor
  • ***
  • Posts: 7528
  • Country: gb
Re: Electronic Loads - Why so expensive?
« Reply #22 on: March 29, 2017, 07:20:11 am »
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
« Last Edit: March 29, 2017, 07:23:13 am by Fraser »
 

Offline serggio

  • Regular Contributor
  • *
  • Posts: 147
  • Country: ru
Re: Electronic Loads - Why so expensive?
« Reply #23 on: March 29, 2017, 08:03:15 am »
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".

 

Offline HoracioDos

  • Frequent Contributor
  • **
  • Posts: 293
  • Country: ar
  • Just an IT monkey with a DSO
Re: Electronic Loads - Why so expensive?
« Reply #24 on: March 30, 2017, 10:35:15 am »
For anyone interested, I just received a new and shiny ZKE EBC-A05+.

I 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.
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf