Author Topic: Warning: Fake 100A Fotek Solid State Relays  (Read 3013 times)

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Offline gnif

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Warning: Fake 100A Fotek Solid State Relays
« on: August 21, 2019, 09:55:33 am »
Ordered a couple of Fotek solid state relays from eBay marked as being able to handle 100A (SSR-100 DD), I bought two figuring I would tear one down and verify they are indeed 100A modules before putting it into use. Here are the results.

[attach=2]

Yes, that's a 2SC4110, a 25A transistor.

Buyer beware!
« Last Edit: August 21, 2019, 01:26:55 pm by gnif »
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Offline Ian.M

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Re: Warning: Don't buy FOTEK Solid State Relays
« Reply #1 on: August 21, 2019, 10:24:02 am »
So its a fake, which isn't surprising on EBAY.  It looks like the whole SSR-nnDD product range uses the same housing, so it *MAY* simply be a remarked SSR-05DD or SSR-10DD, which would be consistent with the 60V voltage rating.  All the higher power SSRs in the range are rated for 120V DC.  Its also interesting to note that I couldn't find any reference to a SSR-100DD model on the Fotek website

http://www.fotek.com.tw/pdf/SSR-DD.pdf
 
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Offline wilfred

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Re: Warning: Don't buy FOTEK Solid State Relays
« Reply #2 on: August 21, 2019, 12:32:01 pm »
No link to the Ebay listing. Come on. Give us a fighting chance to make our own minds up.
 

Offline gnif

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Re: Warning: Don't buy FOTEK Solid State Relays
« Reply #3 on: August 21, 2019, 01:24:49 pm »
Whoops, sure: https://www.ebay.com.au/itm/133095376627

Edit: Just noticed that the label is completely different on the unit, so perhaps not Fotek's fault, but a fake/rebadged unit. I have re-titled the thread in accordance with this.
« Last Edit: August 21, 2019, 01:27:26 pm by gnif »
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Offline wilfred

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Re: Warning: Fake 100A Fotek Solid State Relays
« Reply #4 on: August 21, 2019, 02:24:47 pm »
Good one Gnif. Big Clive did a teardown of one of these things. @5:00 he notes the triac is not sufficient for the stated current.

 
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Offline thm_w

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Re: Warning: Fake 100A Fotek Solid State Relays
« Reply #5 on: August 23, 2019, 12:52:51 am »
That wasn't overly cheap too, $13 each.
Here are some genuine 40A for $6: https://lcsc.com/product-detail/Relays_CDG1-1DA-40A_C108612.html

There are lots of alix sellers but the reviews are not really useful, just lowish loads reported, none taken apart, so not clear if its genuine:
https://www.aliexpress.com/item/32845269143.html (one review saying it blew up but its not clear if it had appropriate heatsinking).
https://www.aliexpress.com/item/32865807659.html
https://www.aliexpress.com/item/32906876577.html
https://www.aliexpress.com/item/32842313085.html

Maybe its possible to measure the on resistance of output and get an idea of the internal FET?

Also in another thread it was mentioned the clearance of the fake was terrible: https://www.eevblog.com/forum/beginners/dc-ssr-wont-turn-off/
 

Online james_s

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Re: Warning: Fake 100A Fotek Solid State Relays
« Reply #6 on: August 23, 2019, 03:09:09 am »
This has been common knowledge for years. I'd expect a genuine 100A SSR to cost at least $50. Ebay is full of fake garbage that is nothing more than a commodity triac screwed to a piece of aluminum with a basic optocoupler circuit.
 

Online NiHaoMike

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Re: Warning: Fake 100A Fotek Solid State Relays
« Reply #7 on: August 23, 2019, 04:03:34 am »
I'm surprised they even bothered with the conformal coating.
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Offline vlady_2009

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Re: Warning: Fake 100A Fotek Solid State Relays
« Reply #8 on: November 07, 2019, 02:19:59 am »
Since these fakes so cheap (can be ~$4) thought I would check them out in any case.

For anything "serious" obviously not worth the risk, but if used highly derated, potentially useful, especially when "her in doors" frowns upon every dollar spent on "frivolous hobbies"  ::) .

I use a notional 40A SSR for a 10A load (a DIY steam generator for essential oil extraction based on a 2400W element) - the teardown of the actual SSR showed a 24A triac used - and working OK so far.

Here is summary of results of the testing for any interested.
www . youtube . com/watch?v=rgW8L2LaAlU
 

Offline Ivanko1

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Re: Warning: Fake 100A Fotek Solid State Relays
« Reply #9 on: March 22, 2021, 10:47:07 pm »
I ordered SSR-60 DA on aliexpress, and LED light bolb still glowing (faded) after regulated voltage disconnected. Is it concidered as a fake and money can be refund?
 

Offline Ian.M

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Re: Warning: Fake 100A Fotek Solid State Relays
« Reply #10 on: March 22, 2021, 11:02:59 pm »
According to the Fotek SSR-xxDA series datasheet, the max. off state leakage current is 5mA, which is more than enough to light a LED bulb.
 
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Online james_s

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Re: Warning: Fake 100A Fotek Solid State Relays
« Reply #11 on: March 23, 2021, 02:26:11 am »
Look on the back and see if you can see the screw hole where the TO-220 triac is attached. Genuine will not have this.
 

Offline Ivanko1

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Re: Warning: Fake 100A Fotek Solid State Relays
« Reply #12 on: March 23, 2021, 08:31:22 am »
It have some
 

Online james_s

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Re: Warning: Fake 100A Fotek Solid State Relays
« Reply #13 on: March 23, 2021, 05:30:31 pm »
It's very dark in those photos but that looks like there's a screw to me. If you paid less than about $50 for a 100A SSR it's fake. You could also try putting it on a heatsink and put perhaps a 30-50A load on it, it will probably fail almost instantly and then you know it's fake.
 

Offline Ivanko1

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Re: Warning: Fake 100A Fotek Solid State Relays
« Reply #14 on: March 24, 2021, 09:54:16 am »
Yes it have screw hole. I pay $10 for two SSR 60DA on aliexpress. I need it for REX-C100 and <1000W load on 220V.
 

Online james_s

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Re: Warning: Fake 100A Fotek Solid State Relays
« Reply #15 on: March 25, 2021, 12:13:24 am »
If they are that cheap they are fake, period. Good for around 10 Amps or so typically, regardless of what the label says. Good quality name brand SSRs are much more expensive.
 

Online coppercone2

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Re: Warning: Fake 100A Fotek Solid State Relays
« Reply #16 on: March 25, 2021, 03:17:25 am »
I recommend getting panasonic brand on digikey for heat related projects (SMD oven). Yes its like $50 but you can easily fry 4x that on a PCB if it fails short during a reflow and you get tired of watching it. I just don't trust the cheap ones.
 

Offline floobydust

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Re: Warning: Fake 100A Fotek Solid State Relays
« Reply #17 on: March 25, 2021, 05:08:13 am »
Everyone, don't forget a (triac) SSR dissipates about 1W per A.
They aren't really practical above say 60A because the required heatsink+fan is huge and thermal resistance of the SSR and mounting hardware is a problem. This is when people go with (or add) a mechanical contactor.

A 60A SSR will dissipate 60W and buying higher current-rated say 100A SSR doesn't mean it runs any cooler.

Crydom are the best because they mount the triac die right on the thermal slab (patent) for very low thermal resistance. But really expensive now.
 

Offline BreakingOhmsLaw

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Re: Warning: Fake 100A Fotek Solid State Relays
« Reply #18 on: March 26, 2021, 09:25:22 pm »
It could be even worse. The manufacturer of that fake SSR will take little care where they source their components. If that 12A Triac is actually a relabelled part itself with even less true rating than that, you might end up with a 6A Triac in a "40 A" SSR.
« Last Edit: March 26, 2021, 09:38:25 pm by BreakingOhmsLaw »
 


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