Basic 5v Relay keeps failing (using lctech x2 relay)

Hi everyone !!

I am using a lctech x2 relay with my esp-01s for my home automation.
For some reason after approximately 24h of use, the relay (the components itself, not the board) broke down.
It is the second time I de-soldering and re-soldering a new relay. After changing it, every things is working fine until the next morning.

Once unsoldered, I test the failing relay by applying 5v to the pins, and I can confirm that the relay is dead because I don't heard any click from the relay.

The relay is used for opening and closing blinds, so it is off 99% of the time. It is activated only twice to 4 times a day during 10 to 30 seconds.

Do you guys have a idea ?
It has nothing to do with my esp programmation right? It maybe a electronical problem?

Best regards

Ps: English is not my first language, sorry if I made some mistakes. If needed I will be happy to make some clarification.

Don't assume that it is not the programming, assume it is :astonished:
Don't ask if it could be a electronic problem, assume it is :astonished:

I hope you still have that broken relay.
What is wrong with it ? Can you test it ?

I can try to make a list, but I prefer to have a lot more information (photo's, schematic, sketch, links to used modules, and so on).

  • Perhaps you require too much current from a ESP32 pin.
  • Perhaps the relay module requires 5V instead of 3.3V.
  • Sparks can melt the contacts.
  • The relay might have written 10A on it, but it might be only for 0.5A.

You can also forget about this and buy a Solid State Relay (SSR). Perhaps you used a relay module that was too cheap, then it is time to upgrade to something better.

Cheap, low quality, unreliable relay.

That's a guess, if you want a decent answer we need to know exactly what relay you have.

Yes when I apply 5v to them, I heard a small noise like it is trying to, but no click like it suppose to.

It is not a home made board, it is the lctech x2 relay for esp-01s

How can I prevent that ?

I confirm it is rated for 10A. I don't know my blinds in particular, but I think it need around 2A.

The marking on the relay is SRD-05VDC-SL-C and the brand is songle.

Never heard of them. That doesn't mean much there are so many manufacturers...
A link to where you bought it might help along with a data sheet.

That's a cheap hobby relay - many many Arduino relay boards use them - I'm looking at one right now. I would not expect them to last for years under heavy use, but a 24 hour lifespan suggests that something else is wrong.

Maybe you could kill it by switching it very frequently all day. Pulling a lot of current can weld the contacts together so it can't switch any more.

Try running a test with a LED or some other component that is stressful to make sure it isn't the board itself.

I bought it on aliexpress. But tech specs are available here

I am using those relay on a different board, but still to do the same thing, controlling my blinds, and those are running well (for the moment ...). The module in question is similar to this one 5 v 2 road 10 a optical coupling isolation relay module_chinalctech.
I am using the ictech one because it is "all in one board", esp+AM117+relay in one place.

Do you have any recommandation ? I would like to keep using the lctech board, so if you know one witch has the same factor than the one I am using, it would be perfect :wink:

I hope the others agree that we can make a conclusion:

It is too cheap. Those relays cause a lot of trouble. They can certainly not deal with 10A, probably not even 1A. That module is probably not according to the rules to be used with mains voltages. There are others on this forum that also run into problems when using those relays for something serious. It might be melted contacts or a overheated relay.
Sparks can be reduced with a RC snubber circuit, but the overall quality of the module is not good enough.

I think you have find something else. Something that is certified for using with mains voltages and preferably with a SSR. You need to step up to at least ten times better quality.


Tell me if I am wrong but (after a REALLY quick look on google) SSR doesn't seems to offer a "double throw" output (COM + NO + NC). And I really need this kind of output for my blinds.

For a board with a relay, sorry, no. If I want a relay I will most likely buy just a relay, bare, not on any board, from RS Components. I don't believe that's what you are looking for.

I agree with @Koepel about getting a quality relay. Sorry, not much help.

Because I am still in a process of learning how to make it work (because my long term project is to have a smart home without using proprietary tech), I prefer to take my chance my aliexpress.
If I broke something, or order the wrong object, the financial impact is less important.

So if I try with a SSR, what kind of SSR do I need?


Both should work if they are not fake. They probably are both fake.

0.76 euros for a real Omron SSR ? I don't think so.

Relays could weld their contacts together because the user failed to add a snubber circuit.

Can you show blinds motor data?!

What do you mean by "data" ? The Arduino code ?
Overwise there is neither data or logging.

A friend of mine tell me that I can try to add capacitor at the relay's output. What do you think ?
He tells me to use those one:

blinds Motor photo. and DC or AC power? :smiley:

The motor is hidden in the window's frame i have no access to it.
The motor is using AC power, 230v at approximatly 1A.

A 0.47µF might be damaged when the relay contacts suddenly put the mains voltage in the capacitor.