Teardown of an eBay 25A Solid State Relay. (SSR)

Only just come across this, and I imagine that at time of watching (Dec 2023) any SS relay on eBay priced at under £5,- isn't even going to have a 10A TRIAC in it. 100mA or even 1A perhaps (Whatever will just about withstand a 30s inbound test on a 20A load) but definitely not 10A! 📦💸😉

That aside; Living in an all-electric flat I'm struggling a lot with cost of heating and I keep considering ideas like running TRIACs and ICs close to their upper tolerances and benefitting from the heat this will give off as a biproduct. Even if I have to swap in new TRIACs every week it's probably still going to work out a lot cheaper than running my 3kW convection heater at the present 36p/kWh for a few hours each day! ⚡🔥💡

costs 30cents on aliexpress

I use something similar with my. Snake vivarium ceramic bulb and a low voltage digital thermostat,,
Mine is heavy and I've used a heatsink to be on the safe side

It's fascinating to see what I've been using for the last six years! I'm glad now that I acted on impulse and used them conservatively, and only for personal projects. But they have worked without complaint.

Thanks for posting, it's good to see the insides. I used an SS40DD (to switch a DC 3A load) controlled by an arduino GPIO pin. I was using it well within spec, but it got very hot indeed and all the case melted and twisted. I built my own after that :) :)

There are "real" ones and fakes that are nearly identical. Slight differences in the label. I'm using one with a cheap Chinese PID controller in my fish smoker with a 1500 Watt 120 V heater. If you know what you're really getting, They can be useful. Just don't take the ratings too seriously. But, 1 degree C control for less than $ 50 in electronics is not too bad. I call it the smoke-o-matic. And yes, it's overkill.

One thing you didn't test is the turn on voltage. Triacs are not the same gate turn on in all quadrants. You will see that below 3V (2.2 - 2.7V) the SSR will only be half wave. That could damage some AC devices which are inductive and that may be very close for 3.3V devices. More expensive SSR like CRYDOM use a constant current circuit and LED drive current will be a constant 2ma from 3-32V. You get what you pay for.

are all of them this shitty?

I used one on my off grid solar set up to turn the immersion heater on when the batteries were full.

That is a counterfeit Fotek relay

I usually cut any current rating from a chinese product in half, and usually that is even not enough.

I'm looking at using one of these with a raspberry pico (3.3v device). All the electromechanical relay modules I've used come with 3 inputs (VCC, GND, IN) but this only has two inputs. How would I control this?

I have an original Idec RSSDN-25A that has blown. I disassembled it and it's nothing like the one you have there. If you want I can send you some pictures of it. It does not carry a Triac like that. let me know.

I know you are focus on a somewhat more intellectualy evolved audience but for us novices and such could you please add notes for when you are being for ex,cheeky,witty,or just being plain ole sarcastic because o am gaining so much from your presentation but dont want to go off and think that your "that's reasonable" is normal when it really isn't,lol.thank you great video.

I have a few of these and need a few more.
BUT..... I thought about just making my own, but as it turns out, the cost of parts and time, outweigh the cost of these units......

OR AT LEAST IT USED TO. LOL

Just last year, at a local store, I bought the "40Amp" version for about $8.

So I just now checked stock at that store and the THIEVES now want $30 for the same freak'n units!

Not only has the pandemic caused to much pain in people, but it's revealed how companies are just taking advantage of it to make extra $$$$.

sigh.

👍 I've watched this a few times. Clyde can you do a real one and maybe also compare a couple of those high current 100A ones? That would be really interesting. And I wonder what's inside the 40A version. Do you think the resin is for isolation or for heat? Isn't there a version of the triac that has a snubber built in?

It's a fake Fotek. They're everywhere. The triac is way under the rating.

Nice explanation man, tnx for all of the info.

jumping back 7 yrs in time now. im guessing the yt algo chose this due to the words resin used so many times so that would be a logical grouping as well as triac which would then bump up the relevance.

I wonder if that is the current rating of the imported/no heat sink on triac .Some triacs show you 2 ratings free air and potted .The heat sink will make a huge difference in ampacity .I have used the same ones but never had gone over 12 amps at 120V .Great for controlling heating elements on my mini still

Great stuff,i would like to see inside a proper non clonned one,just for reference.Cheers Clive,love your vids.

Two RC constants in the circuity is using two time constants or double time constants is to make full use of the triac for more efficacy. Thus making use of the negative and positive parts of the sine wave

I've got an analogue version of this "brand" SSR, rated 40A and connected to the 4-20mA output of Siemens PLC on my educational panel, and controlling the water kettle, maybe it was a good idea not to trust the listing, and buy one rated 40A for 10A load. I didn't know they even fake SSR ratings. Also i doubt that PLC output will handle reverse 230V RMS AC in case of isolation breakdown:(

so...is it proper to simply apply a low impeadance voltage source directly to the input of an SSR WITHOUT an external current-liminting resistor??? I am planning to use 12v to 24VDC from a battery. I have always been in some doubt about applyig a straight input voltage WITHOUT a resistor?
THIS WILL ANSWER A LONG-AWATING QUESTION FOR ME!! THANKS MUCH.
THUMBS UP WITH SUBSCRIBE!

They used a 12A TRIAC inside the SSR and rated it as 25A? typical Chinese goods off ebay. I teared apart a 40A one and the TRIAC inside of it was 25A. :D

Good video. Anyway to get rid of the lights flickering when using these for PID control?

So if i understand this correctly these relays would as you say be used to switch power on and off on say a AC single phase or AC 3 phase big foxtrot motor/pumps etc and then that would mean that the other side of the relay could use a much smaller dc or even ac voltage, switch and wires negating the need for big Foxtrot cables, wires running through to the switch and cabinets etc. Great idea really, I guess you just leave the switch in the on position until you want to turn it off, way safer way to handle all the switches inside cabinets on low voltages and smaller cabling... always wondered how they worked Thanks Clive...

Zero crossing is not great for inductive loads. I've used these FOTEK relays quite a bit, however I generally use them @ 1/10 spec. Doing that I have never had any trouble and they are cheap enough that such over-specing is very affordable.

potting of components with epoxy isn't as important as potting the transistor or thyristor ,SCR to a good base with an insulator and heat sink compound .then potting the SSR onto another heat sink with fins .I have a very good SSR 3 phase 24 to 400 vac max .Came out of a hot table .With 3 heating elements in wye configuration and 24 v digital control
.Believe it or not the hot table rotted through and the SSR and control were perfectly fine .the heating elements were done .Fuses popped .But SSR was fine .The heat sink for that units was huge 12x12 finned anodised aluminium plate .Current rating was 25 amps per phase .The base plate on the SSR was 1/4 inch thick copper !was made by crydom .could not believe it diddnt blow when elements went .usually the don't like that hi amperage instantaneous short.Alway wonderd how fast you can switch them on and off and if you can use them as a VFD /Ac motor speed control

Can anyone anywhere find the datasheet for the Berme BEM-14840DA, which is the OTHER cheap one you can end up with?

I bought a couple of these several years ago for a brew fermentation controller (BrewPi). Hooked it up to my old fridge and when the fridge should have turned on I heard the sound of something from the compressor but it didn't start up. I assumed the compressor must have seized up after being idle for months so gave it a few whacks with a rubber hammer but still the same,

Something then made me think to check the SSR and turned out it had a crazy on resistance so when hooked to the fridge, the output was something like under 100V rather than 220ish. Swapped it out for the other SSR I had and it worked fine... Invested in regular relays for that project instead.

I do understand there are no shortage of fake FOTEK SSRs that likely you and I found for bargain basement prices, but the genuine FOTEKs are more reliable. What about ordering one from CPC or the like and seeing if that's any different?

Clive, thx for exposing this farce of an SSR. As usual the only way to get what the label says is to buy at least 2X what you need and hope that you get what you need.

So, let me see if my math is rusty, BTA12, 12A Triac == 25A triac. I guess in some universe this is true. What a crock of crap.

The way they did the board about the isolation shows that the designer has no or little HV experience.

I wonder why they didn't choose a conformal coating instead of the resin. If all you're doing is coating the components then one is as good as the other. Typically the resin fill is to keep prying eyes outta your circuit. Seems in this case it was just a copy cat without a brain behind it.

Hey, China you could've just used conformal coating at a tenth of the price of resin. Come on, get with the cheapness.

So now, the biggest question is, did Fotek authorize this design or did the Chinese totally rip of Fotek ? It's like how many licks to the Tootsie Pop center, the world may never know.

Again, thx clive for sharing.

Do you think if i bought one then used x2 mosfets in parralel it would take more current? i need 40 amps :)

is it normal that when I plug in 220V AC to the output terminals without any input, I get around 120V passing through? Shouldn't it be flat 0V?

I think the trick is to find a genuine Fotek item - they are OK. Sadly, the vast majority are snide copies and are varying degrees of garbage.

Nice vid, what makes this device zero crossing? Only the steering of the led in the coupler?

Are these able to switch DC loads?

i have one of these am using one of these rated also 40 amps but 220 v DC but and it seem to be on all the time i mean the 2 contact is closed all the time no matter what the light is on or off , what do you think the issue is ?

Have used 25 amp solid state relays but when load was more then 3 amps would mount it on a heat sink and use heat conducting paste. Have just used a 6 by 6" aluminum plate that was 1/4" thick for loads up to 50% of label. Nice vid.

Never purchase or use ANY test or safety equipment LEDS electrical items or tools from scum bag cheating lack of quality control communist china. They are great at miss labeling products. Were making 25 amp relays that were actually only 10 amp products. Were making great looking boot leg home circuit breaker s that were faulty

Watching this was interesting I just replaced one on my T-shirt heat press, fully repaired for a few pounds.

The better high power SSR's use back to back SCR's rather than TRIACS because SCR's are more reliable when driving large inductors like motors. I talked to Motarola years ago and they told me you have to overdrive TRIACS to reliable switch high inductance loads in all four quadrants. This is easy to do if you know what voltage your going to be driving from but can be more problematic if you really do have to have a wide input control voltage. We were buiding our own SSR's so we controlled the input switching voltage and could set the gate driving voltage and thus the current.

Is the triac electrically isolated from the back plate?

We actually use similar relays. Allen bradley drives switch it to power a 120 volt brake on sew eurodrive motor. Works great. Great video as usual Big Clive ⚡️🏴󠁧󠁢󠁳󠁣󠁴󠁿⚡️
Our relays are allen bradley or omron.

I don't know what is the norm, but I tore open a US brand SSR once, and it was basically a chip and wire hybrid, bonded to the copper base plate. No PCB, no packaged components, just chips, bus wires, covered with clear silicone. The circuit was stupid simple, too, like 3 chips and no passives.

Just don't buy from China

Very interesting and helpful! Any chance you would consider doing a similar teardown of one of those resistance controlled AC SSR's also widely found on ebay? I suspect they might use a capacitor dropper + full wave rectifier bridge as you described in the "Random high voltage eBay "thing"".

Thank you for sacrificing this relay to show us how it works. I am concerned that when there is 240V AC on the relay it is showing about 10V AC between the backplate and ground or neutral. I wanted to bolt this to a grounded chassis but with a potential between them it sounds like a bad idea.

In fear of the cheap Chinese ssr reputation I bought a Crydom from Arrow. Got a 90A version and it heats up twice faster than the 40A chinese that I paid 1/20 of the price. really disappointed.

Here is a reply I received from an Amazon seller after leaving a review of their fake SSR. It's a pretty sad excuse.

"I'm very sorry. I know our mistake made you a little disappointed, but please give me a few minutes to explain that，this product is from OEM and delivered within the period of novel coronavirus pneumonia ,at that time China is lack of raw materials and lack employee .Most of the worker, including engineers, was on vacation. Only a few people stayed in the factory. (originally, SSR-25AA used BAT24 Chip,SSR-40AA used BTA41A ) Due to the fact that engineers can't get to the company in time, many employees can't go to work in time because of pneumonia in China. Pneumonia affects the closure of the city) which leads to the following mistakes. Originally, our brand is eqiek, but due to the negligence of the printing staff, they make the label FOTEK instead of EQIEK . But we confirmed that there is only a batch of part labeled printed wrong. In fact, the main drawing of our products is eqiek(Pls check OEM brand EQIEK as attachment ) We have confirmed with the factory that we have ordered 1000 pieces of ssr25da and ssr25aa respectively. More than 900 pieces are produced with bat24a. Only a few dozen pieces are produced by BTA12A within a period of novel coronavirus pneumonia , engineer can't back to office immediately ,one worker mistaked BTA12 instead by bta24a, When we found out, more than 1000 goods had been delivered to Amazon's warehouse. We contacted Amazon to return the goods. However, due to the impact of pneumonia in the United States, there was no reply. Last , we have no idea to deal with returning the goods. .AMZ service answered :Because 1000pcs SSR-25DA with SSR-25AA have been diverted by AMZ warehouse .we feel very helpless about this matter. But we will be responsible for our every customers.Please Believe us, we only do honest business, we will not deceive every customer. On behalf of our company, I apologize to you. Now our company proposes two solutions: we will refund the money to you, or we will send you replenishment from China (this time we promise SSR-25AA 100% function and with BTA24A chip ) ,However, the US postal service is very slow and may not be able to deliver it to you in time as the spread of pneumonia in USA ,so hope your advice to us . Hope you can forgive us and hope you can give us a chance to service for you .We will cherish this chance .we are willing to return payments for you .Thanks for your time to read this long email .
All best wishes for you and your family
Happy everyday
JESSICA"