Which electronic DC load to choose? - Page 1
Forum section: electronics / testgear

author: zapta
author_rank: Super Contributor
timestamp: June 15, 2014, 06:19:20 pm
content: I am looking for an DC electronic load for home/hobby use. At minimum I need 12V 4A and I have a strong preference to stand alone (110VAC) unit with front panel that does not require a hookup to a computer (though ability to control and/or log from a computer is a plus). I searched the threads here as well as ebay, amazon and the usual suspects and came up with these two candidates below.Any suggestion which one to pick? The Atten seems to have wider range (which I don't need), better price and simpler front panel. Other models I should consider?Mayuno M8811http://amzn.com/B00FKW04LS30V/5A/150W $460and Atten ATZ3710Ahttp://r.ebay.com/LiRAf0360V/30A/150W $354

author: HighVoltage
author_rank: Super Contributor
timestamp: June 15, 2014, 06:27:48 pm
content: The Maynuo you are showing is a Power Supply, not the DC LoadI have the Maynuo M9812 and also the M9811 and I am very happy with the instruments.Have been using them for the last 4 month or so and they work absolutely perfectly.The Software that comes with the instruments, also is very good to use.So, I would recommend you the M9811 or the M9812.

author: Kjelt
author_rank: Super Contributor
timestamp: June 15, 2014, 06:33:00 pm
content: Perhaps look at BK precision, they have some good loads (opinions vary though) but probably more expensive.

author: AndyC_772
author_rank: Super Contributor
timestamp: June 15, 2014, 06:40:10 pm
content: Consider a (used) HP/Agilent 6632B power supply, which also works as an electronic load and will switch seamlessly from sourcing current to sinking it.

author: zapta
author_rank: Super Contributor
timestamp: June 15, 2014, 06:40:46 pm
content: Thanks HV.Quote from: HighVoltage on June 15, 2014, 06:27:48 pmOops, I meant the 9811http://amzn.com/B00FKXKFJI(150V, 30A, 200W, $460).Quote from: HighVoltage on June 15, 2014, 06:27:48 pmCan the software both log and control? Is it available also for OSX/Linux? Is the protocol simple and open?Can it automatically alternate between two settings (e.g. two CC values) without a computer? (to test the step response of the source).What is the expected reliability compared to Atten? (I heard of Atten, never heard of Maynuo).

author: rodpp
author_rank: Frequent Contributor
timestamp: June 15, 2014, 08:44:24 pm
content: The Voltage/Current source Keithley 228A is capable of work in all four quadrants, and the range is 0-100V/0-10A. It has 100 memory positions where is defined the output voltage, output current, dwell time, sink only mode and modulation status. You can configure the source to single or continuous cycle the memory positions, so is is not necessary a computer to operate it properly. But it has a GPIB interface to configure, program, operate and log values from a computer if you need.It can invert the polarity without change cables and has a remote sense feature.It's old and big, but works very well in a test enviroment.

author: robrenz
author_rank: Super Contributor
timestamp: June 15, 2014, 09:23:06 pm
content: I have 4 quadrant supplies that I use as loads. But keep in mind they cannot by themselves do what a purpose built DC load can do. Such as setting a fixed resistance or wattage. Also the 4 quadrant supply will force the fixed current you set regardless of whether it needs to source or sink that current. It can get pretty confusing what is going on as I postedhere

author: saturation
author_rank: Super Contributor
timestamp: June 15, 2014, 09:32:22 pm
content: Almost carbon copy request of this forum archive:https://www.eevblog.com/forum/testgear/which-dc-electronic-load-to-get/The Maynuo is the better unit in terms of functionality and software. But I have strong doubts about the build quality of the hardware.OTAH, the Atten you link is actually an Array 3710a. It has horrible but usable software, basic firmware, but its claim to fame is high build quality hardware. You can get it from Amazon under another brand name as Array is the OEM for many brands. Its flawless if you use it as a stand alone instrument, and if you link it to a PC to gather data, its software is passable with a Grade of D, but it works.http://www.amazon.com/Tekpower-TP3710A-Programmable-Electronic-Watts/dp/B008NBGOM6/ref=sr_1_1?ie=UTF8&qid=1402865709&sr=8-1&keywords=tekpower+3710aA typical use is burn testing batteries to give you an example of the software and firmware.From eevblog forums, the Maynuo has a built in function, set the current drain and press "go"; when the battery reaches the cutoff voltage, it reads out the AH for you. Likewise, you can use the PC software.In my use, the Array will bleed the battery in CC, but it has no built in clock readout and the alarm is not loud at all when the test is over so when it cuts out you cannot calculate AH, so you must run the PC software, graph the output then calculate the AH manually when zero output time occurs. In practice, the graph is important as the shape tells you if the current you set is too high, but the Maynuo not only can do it stand alone for a quick check, but it can do just as the Array does but with greater control from its better software.That said, e-loads are wear-and-tear items, if you load items frequently and near rated wattage, the MOSFETs eventually burn out. You can use a 4 quadrant supply as an e-load but its expensive when it fails, and that is inevitable when used as an e-load. 2 things will preserve it, de-rating the critical parts in the design and keeping the unit very cool, both which the Array does well, and it does so at 2/3rd price of the Maynuo. The Array has been sold since 2002, so it has a history of hardware reliability.The Maynuo also has a richer set of tests it can run, whereas the Array only does CC, CP and CR.

author: MarkL
author_rank: Unknown
timestamp: June 15, 2014, 09:35:12 pm
content: I can highly recommend the Array 372x series:http://www.array.sh/yq-3721e.htmIt's similar to the B&K 85xx series (and various look-alikes), but has an isolated true RS232 interface (no weird TTL isolation dongle), a sane user menu, and no bugs (at least none that I've found yet). All connections are on the front panel, including automatic sense input and trigger. Oh, and it's cheaper.It speaks SCPI so you can uses ASCII commands from Linux, and can bounce between 2 CC settings without a computer. It also has a controllable slew rate. I think it can even do more than 2 settings with the list feature, but I haven't used it.A GPIB or USB interface is optional if you want something other than RS232. I have an Array 3723A (200V 30A 350W) and speak to it from Linux via GPIB. No issues to report with reliability.

author: saturation
author_rank: Super Contributor
timestamp: June 15, 2014, 09:43:19 pm
content: Yes, the 372x series look very good, plus it has Array's reputation. But MarkL, I see those units in the $750 range.The 9811 Maynuo is $500, and Array 3710a is $350. They all have more functions are the price rises

author: Electro Fan
author_rank: Super Contributor
timestamp: June 15, 2014, 10:26:26 pm
content: +1 for MaynuoThe Maynuo has one particularly nice feature: It will show Volts, Amps, Watts, and Ohms simultaneously. See photo below showing Constant Resistance mode.If the Maynuo M9811 Programmable LED DC Electronic Load meets your requirements for all four values it's worth considering.

author: echen1024
author_rank: Super Contributor
timestamp: June 15, 2014, 10:54:51 pm
content: Kikusui also make some electronic loads, but they are generally quite old without the PC and plotting features, which is a primary use for a load.

author: mjkuwp
author_rank: Unknown
timestamp: June 16, 2014, 12:09:17 am
content: My company (in the USA) has a 300W load from this vendor.http://www.circuitspecialists.com/programmable-dc-electronic-loadsIt seems to work fine but I don't have anything to compare it to.

author: echen1024
author_rank: Super Contributor
timestamp: June 16, 2014, 12:20:02 am
content: Quote from: mjkuwp on June 16, 2014, 12:09:17 amThat's an Array load.

author: all_repair
author_rank: Frequent Contributor
timestamp: June 16, 2014, 12:49:38 am
content: Get the higher wattage you would not regret it.My experience is with Array for 5-6 years, no problem so far. Bought another set so I could load 2 rails sometime or parallel them to get 600W. So far I have no need to connect mt units to PC.

author: PedroDaGr8
author_rank: Super Contributor
timestamp: June 16, 2014, 04:49:37 am
content: If it matters, I have had a great experience with Array customer service. I had a heavily abused Circuit Specialist rebadged Array power supply. A banana plug was snapped off the front. Unable to find a source for matching bananas plugs, and being OCD, I contacted their support. A gentleman contacted me and sent two full sets of banana plugs for me to repair my device. Free of charge. I didn't even pay for shipping, I just had to wait for one of their usa distributors to make an order. He was very communicative through out, keeping me in the loop, letting me know when an order was placed, when they received it, etc. I couldn't imagine better support. Especially considering I purchased this power supply used.

author: zapta
author_rank: Super Contributor
timestamp: June 16, 2014, 08:06:37 pm
content: Thank everybody for the feedback. My main candidate now is Maynuo M9811. Anybody knows if it has any warranty service in the US?The Array one seems to have better support in the US and this may be the deciding factor for me.http://www.circuitspecialists.com/dc-electronic-load-csi3710a.html

author: HighVoltage
author_rank: Super Contributor
timestamp: June 16, 2014, 08:40:12 pm
content: Quote from: Electro Fan on June 15, 2014, 10:26:26 pmHello Electro Fan,May I ask, what kind of nice looking connectors you are using on your Maynuo in your picture?Who is the manufacturer?Thanks

author: Electro Fan
author_rank: Super Contributor
timestamp: June 17, 2014, 01:24:33 am
content: Quote from: HighVoltage on June 16, 2014, 08:40:12 pmHi HighVoltage,Those are from Cal Test Electronics.The Stacking Banana Plug Test Leads come in several varieties (these have a retractable sheath); you can specify cable length (10, 25, 50, 100, 150, 200 cm) and color (Black, Red, Yellow, Green, Blue, White):http://www.caltestelectronics.com/ctitem/110-plugs-banana-plug-test-leads-stacking-retractable-sleeve-plug-to-stacking-retractable-sleeve-plug/CT2148The DMM Probe Spade Lug Adapters are here:http://www.caltestelectronics.com/ctitem/38-probes-accessories-digital-multimeter-dmm-accessories/CT2553http://www.caltestelectronics.com/ctitem/38-probes-accessories-digital-multimeter-dmm-accessories/CT2661- two items above are similar; different colors and quantities in the packages... study carefully.If you look around on the Cal Test web site you can find lots of accessories including some kits:http://www.caltestelectronics.com/http://www.caltestelectronics.com/kitsIf you see something you like in a kit you can often order just the particular item, although some items have minimum quantities. Some times their web site search helps; other times you have to look carefully thru various small photos buried in product categories and sub-categories to find your item.You can buy directly from Cal Test or from distributors/dealers.http://www.amazon.com/Cal-Test-Electronics-CT2661-Multimeter/dp/B009QBF7UW/ref=sr_1_3?s=industrial&ie=UTF8&qid=1402969081&sr=1-3&keywords=cal+testAmazon can be very good but so can buying directly from Cal Test. Cal Test has pretty good phone sales support. From Europe/outside the U.S. it might be easier to contact them via web/email.EF

author: HighVoltage
author_rank: Super Contributor
timestamp: June 17, 2014, 07:24:53 am
content: That was very helpful,thanks, Electro FanIt would have been very nice, if Maynuo would have installed some 4 mm Banana jacks in addition to the huge screwed on connectors.For small loads, that would have been more than sufficient.But the spade connectors may be a good alternative.

author: zapta
author_rank: Super Contributor
timestamp: June 19, 2014, 03:11:32 pm
content: I ended up going with the Maynuo M9811. Could not find anybody in the US that provides Maynuo warranty service so ordered it directly from the manufacturer in China. They were very responsive, answered all my questions and the price with shipping to the US was reasonable.According the Maynuo, the M9710 which can be found on eBay for less is intended for the Chinese market only, possibly is of lower quality (my interpretation) and is not recommended for western companies (but should be ok for home use). In any case they would not sell me the M9710 with shipping to the US.The invoice mentioned an included 'USB interface'. Am not sure what it is but if it is this onehttp://r.ebay.com/jhLH4fthen the deal is even better than I expected.Thanks everybody for the info.

author: HighVoltage
author_rank: Super Contributor
timestamp: June 19, 2014, 03:47:06 pm
content: Without the USB connector, you can not hook the instrument up to the PC.So, it was a good choice to also get the adapter.@Electro FanThanks for the detailed explanation and links.I did order the spade connectors.

author: saturation
author_rank: Super Contributor
timestamp: June 20, 2014, 11:45:57 am
content: Congratulations. Give us a tear down when you get it.What was the price difference between the 9710, 9711 and 9811? Was it insured and how long to ship to the USA?Quote from: zapta on June 19, 2014, 03:11:32 pm

author: zapta
author_rank: Super Contributor
timestamp: July 02, 2014, 11:54:35 pm
content: The Maynuo M9811 arrived and I am very happy with it. Thanks everybody for the info. I got it directly from the manufacturer for $430 total, including the USB/Serial adapter and DHL to the US. Communication with the manufacturer was over email and they were very responsive. They wouldn't sell the 97xx outside of China so if you want the 97xx look somewhere else.Good points: clear display, more accuracy digits than I need, easy to operate, thin but nice paper manual, optional software installed smoothly on my Windows 7 box and looks nice and easy to operate (I am running now test of a Duracel AA, just for the hack of it), quite (I didn't notice any fan, but used in with 30W max) and it arrived with a detailed calibration sheet for this serial number (don't know how 'official' it is if you have formal calibration requirements, I don't).Bad points: rotating knob is hard to reach because of the oversized terminals would prefer banana terminals, when turning the knob, display update is sometimes slow and update every 2-3 clicks (though it does not miss clicks), no warranty service in the US (theoretically I can ship it to the manufacturer), larger than I would like (I don't really need 150W, 50W top).Overall it exceeds my expectations.Edit: the $430 was my total cost. Was not asked to pay custom or other taxes. Your locality may vary.

author: zapta
author_rank: Super Contributor
timestamp: July 03, 2014, 12:02:30 am
content: Quote from: saturation on June 20, 2014, 11:45:57 amThe manufacturer wouldn't ship the 97xx outside of China. Somebody mentioned in another thread that the 97xx has lower grade components and lower reliability but I don't know.DHL shipping from Singapore to my location was less than 3 days from pickup to delivery (they required signature, typically they don't). Not sure about the insurance. I didn't ask.

author: saturation
author_rank: Super Contributor
timestamp: July 03, 2014, 01:54:15 pm
content: Thanks, Zapta. Enjoy. If you only use it up to 50W and its rated for 150W, it should be very durable in your application.

author: K1JOS
author_rank: Regular Contributor
timestamp: September 08, 2014, 03:52:58 am
content: Zapta,How do you like the LCD display? ON all the pictures it looks pretty faint. Is it as blue 20x4 LCD??

author: HighVoltage
author_rank: Super Contributor
timestamp: September 08, 2014, 07:29:18 am
content: I have the 9811 and the display is OK. It is not too bright to be in your face but then it is also not Agilent quality.Since it has the additional information on the screen, compared to the BK Precision comparable unit, I like theMaynou screen even better. The real benefit of the Maynuo is the software and the GUI. For a China product, it isall extremely well built.

author: Uup
author_rank: Regular Contributor
timestamp: September 08, 2014, 07:44:15 am
content: Quote from: K1JOS on September 08, 2014, 03:52:58 amIt's actually a VFD screen, not an LCD. As Highvoltage said, it looks okay. Pehaps it is a little less bright than a typical VFD. Although, that may be due to the tinted display shield.

author: eurofox
author_rank: Unknown
timestamp: September 08, 2014, 08:12:56 am
content: I have the Vantek, work OK (for what I use it) but the PC software supplied is crap.http://www.precisegauge.com/index.php?main_page=product_info&cPath=111&products_id=501

author: forrestc
author_rank: Unknown
timestamp: September 08, 2014, 08:36:00 am
content: I'm using a circuit specialists branded dummy load made by ATTEN. Circuit Specialiasts model 3711A. In fact, it's burning off a few hundred watts right now doing a load test on a new product I'm development. Never had a problem with it, works well.There's a twin also on the manufacturing line which works just as well.-forrest

author: HighVoltage
author_rank: Super Contributor
timestamp: September 08, 2014, 10:49:59 am
content: Here is an instrument screen comparison to a BK-Precison 8500 to a Maynuo M9812 and screenshot of the Maynuo GUI

author: Kjelt
author_rank: Super Contributor
timestamp: September 08, 2014, 10:55:47 am
content: Quote from: HighVoltage on September 08, 2014, 10:49:59 amAre you implying it is the same instrument beside the display? Does anyone have comparison pictures from the inside of these devices?

author: mcinque
author_rank: Unknown
timestamp: September 08, 2014, 11:44:19 am
content: They are based on the same design (the original designer left Itech - bought from BK - and founded Maynuo).Google for some teardowns of the devices, internally they are almost identical, but the maynuo has some improvements, like 2 data lines and 4 field on the lcd. And it's cheaper

author: HighVoltage
author_rank: Super Contributor
timestamp: September 08, 2014, 12:16:39 pm
content: Quote from: Kjelt on September 08, 2014, 10:55:47 amYes, as mcinque already pointed out, they are almost identical.As both of my instruments are still under warranty, I have not open them up for comparison.But I have seen pictures from others on the internet that show the internals and they seemed to be almost the sameI have used both instruments extensively for some projects over the last few month and I like the Maynuo M9812 much more.Especially to run it from the GUI is a, lot better than the BKP.Both, the BKP and the Maynuo come with a RS232 to USB converterBoth converter look the same.But they are not interchangeable.It seem they are using different protocol settings, but I have not bothered of looking in to the details.

author: HighVoltage
author_rank: Super Contributor
timestamp: September 10, 2014, 09:55:27 am
content: I just bought an Agilent 6632B PSU on ebay GermanyThis unit:http://www.keysight.com/en/pd-838596-pn-6632B/100-watt-system-power-supply-20v-5a?cc=US&lc=engAnd just now I found out that it can be used as a current sink and DC loadHow great is that!May be this is an alternative to a Maynuo or BKP?

author: mcinque
author_rank: Unknown
timestamp: September 10, 2014, 11:21:09 am
content: It's the same unit of the BK, even if it's ITECH branded. It's the same company, same design, same engineering.

author: Artraze
author_rank: Contributor
timestamp: September 10, 2014, 06:56:16 pm
content: Quote from: HighVoltage on September 10, 2014, 09:55:27 amIt's very great, if for no other reason than it's a dual use (supply+sink) device for less than half the price (depending on your luck!).That said, it's very limited compared to a true electronic load:*) Much lower limits (20V vs 150V, 5A vs 30A, 100W vs 200W)*) No Constant Resistance or Constant Power settings.*) It willsourcecurrent if, say, whatever you're loading turns off.*) For the 663xA version, the sink current limit accuracy is pretty bad.Still, it's quite usable in a lot of cases and for me, at least, has made a proper electronic load more of a luxury rather than a necessity.

author: mcinque
author_rank: Unknown
timestamp: September 10, 2014, 10:04:12 pm
content: Quote from: gazelle on September 10, 2014, 11:27:28 amSure, but generally, if you pay less, you get less. In this case it could be the after sale service I guess.I've googled itech it8152 europe and these are the first two europeans resellershttp://www.caltest.co.uk/product/476/electronic-load-dc/it8512http://www.es-france.com/produit4657/product_info.html

author: Electro Fan
author_rank: Super Contributor
timestamp: September 11, 2014, 12:33:00 am
content: Quote from: HighVoltage on September 10, 2014, 09:55:27 amThe price is "Starting From US$ 2,792"?Seems like you could buy the Maynuo and decent power supply for half that price. Or you could buy the Maynuo and variety of entry level 30V, 5A power supplies for under $1,000.

author: HighVoltage
author_rank: Super Contributor
timestamp: September 11, 2014, 08:56:44 am
content: Quote from: Electro Fan on September 11, 2014, 12:33:00 amYes, the new list price is ludicrously high.I got it for Euro 149 in mint condition and that price is acceptable.How good it will even work as a load, I have no idea.I guess I will stay with my Maynou or BKP anyways for the DC load since both of these units are made for it.And as was said already, the Agilent is very limited in current and voltage.

author: AndyC_772
author_rank: Super Contributor
timestamp: September 12, 2014, 07:02:36 am
content: It works very well, I use mine regularly as a load.What the 663xB series does particularly well is emulate a rechargeable battery. Many times I've used two 663xB's together; one to simulate the battery of a portable product, and the other to act as that product's charging supply.Switch the "charger" on and off, and the "battery" swaps seamlessly between sinking current and supplying it, and I'm not aware of any other piece of equipment that can do this. The fact that it has a usefully accurate voltmeter and ammeter built in as well is a major bonus too.

author: zapta
author_rank: Super Contributor
timestamp: September 14, 2014, 03:33:08 pm
content: Quote from: K1JOS on September 08, 2014, 03:52:58 amDisplay is excellent. It's not a LED, it's one of those greenish high voltage displays.I used the unit often since I bought it and am very happy with it.

author: tkline98
author_rank: Contributor
timestamp: October 20, 2014, 02:45:55 pm
content: Quote from: zapta on July 02, 2014, 11:54:35 pmI'm looking to get one of the M9811 units too. I see them on eBay (supposedly new) for $420 from China, and tequipment.net has them for $625. How is it that there is such a price difference? I realize I can return it to tequipment if need be and I'd be stuck with it if I bought it from China, but is there any thing else I should be wary of?Zpata, did you buy from eBay or just send them an email directly? I don't see any online sales via their website.

author: zapta
author_rank: Super Contributor
timestamp: October 20, 2014, 03:47:13 pm
content: I ordered directly from the manufacturer. I think it's safer than ordering from an arbitrary ebay seller. If you buy from tequipment (there is a discount for eevblog users) ask them if they provide warranty.My order order:M9811 Electronic load (200w,0-30A,150V),with USB // 'USB' means that USB adapter/cable to connect to a computerUS$430 including shipping with DHL (typically takes 2-3 days, China to US).

author: tkline98
author_rank: Contributor
timestamp: October 20, 2014, 03:51:46 pm
content: tequipment quoted me the discount, but it's 3-4 weeks lead time.Thanks for the info. Maybe I'll email them.