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Forum Index : Electronics : Grey Beards and HY4008W
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Dougie Analog Newbie  Joined: 21/02/2025 Location: AustraliaPosts: 14 |
After reading and being inspired by this forum for years, I caught the inverter bug and bought a Chinese EGS002 4 MOSFET/leg board to experiment with. The inevitable MOSFET blow-ups ensued... Education is not free... In October 2021, I ordered and received 20 x HY4008W MOSFETs form Aoweziic at AliExpress for $1.93AU each, including shipping and tax. They tested as per the datasheet. I'm very happy with those devices. Those replacement MOSFETS are powering my off-grid, inner city home to this day. So yes, like others on this forum Aoweziic for MOSFETs at Ali has been a good experience. However.... I have heard the warnings about less than honourable sellers on Ali but I have had so many great purchases over the years, so why not test the boundaries and go down market a little and see what I get? Early this month I ordered and received 30 x HY4008W MOSFETs form GSXDZ-ic Store at AliExpress for $1.57AU each including shipping and tax. These MOSFETs look similar to the genuine ones but have a higher RDSon. All of the Aoweziic ones tested at 2.9mΩ, which is bang on the typical datasheet figure. The GSXDZ-ic ones tested from 3.9mΩ to 4.1mΩ , which is higher than the datasheet maximum figure. I won't use these new MOSFETs and will place a dispute on Ali and probably order some new ones from Aoweziic. Having said all that, 3.9mΩ to 4.1mΩ are respectable numbers for these large MOSFETs, just not what I was expecting. Looking at them closely, I can see the font and kerning is different and also slight differences in the case moulding and plastic case texture. The back and the pins look very similar. I wonder if these are from the same factory and are binned as "out of spec"? Maybe someone has acquired them for the right price and independently re-labelled them as spec devices? They may work perfectly fine but perhaps slightly warmer, but I'm concerned that there may be other out of spec issues like turn on threshold, total capacitance etc. Executive summary: When it comes to MOSFETs for inverters, listen to the grey beards on here and order from a reputable vendor. For some reason the grey beards know what they are talking about ;) Cheers da |
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oreo Regular Member  Joined: 11/12/2020 Location: CanadaPosts: 97 |
Thanks for sharing. This is a problem that most of us have run into. FYI, right now LCSC Electronics has HY4008W's in stock and their pricing at 30pcs is the same as your purchase from the Aoweziic store. HY4008W Not sure about others, but I have had very good experiences with LCSC and of course Digikey here in the USA. Greg |
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| Dougie Analog Newbie Joined: 21/02/2025 Location: AustraliaPosts: 14 |
 A side by side... |
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Revlac Guru  Joined: 31/12/2016 Location: AustraliaPosts: 1114 |
Welcome to the Forum Dougie Analog, Here is a picture of a genuine one from Aoweziic a few years ago...... looks identical?  Have to go back to work. Cheers Aaron Off The Grid |
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| Dougie Analog Newbie Joined: 21/02/2025 Location: AustraliaPosts: 14 |
I checked out the LCSC website for 30pcs HY4008W MOSFETS. Including the cheapest shipping, were $41.95USD. That is $66.03AU or $2.20AU each. Australian $ were not accepted so there may be an extra currency conversion charge and I don't know if they tag on the Australian sales tax (10%) at the end of check out? Ali have a sale on at the moment so Aoweziic have 20pcs HY4008W MOSFETS for $38.61AU or $1.93 each including shipping and tax. Thanks oreo, I appreciate you and your suggestion and link but I think I'll go with Ali this time. cheers da |
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| Dougie Analog Newbie Joined: 21/02/2025 Location: AustraliaPosts: 14 |
Here is a better close up of the 2 MOSFETs.  Revlac said: "Here is a picture of a genuine one from Aoweziic a few years ago... looks identical?" Does anyone know if hooyi change the way they mark their devices over different batches? Revlac, thanks for sharing the picture. The font on yours looks more like the higher RDSon (3.9mΩ) MOSFET that I have. Could it be true that in fact the 3.9mΩ to 4.1mΩ devices are genuine and that hooyi are a bit loose with their devices conforming to their datasheet and a lack of conformity over different batch runs? da |
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| Revlac Guru Joined: 31/12/2016 Location: AustraliaPosts: 1114 |
Could be, Murphy's friend did a lot of testing on these a long time back, for the most part people report these as all within spec as more were bought, there earlier purchases did require some testing though I don't remember if they were from the same supplier back then.....too long ago.  Cheers Aaron Off The Grid |
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| Dougie Analog Newbie Joined: 21/02/2025 Location: AustraliaPosts: 14 |
Yeah Revlac, roger that.. FWIW this is the RDSon test process I used. Pretty sure it was inspired by someone here years ago but sorry to that person, I can't recall now. May serve as a refresher for others. Connections: Heatsink the MOSFET under test Power Supply #1 and Power Supply #2 Grounds and MOSFET Source joined Power Supply #1 (+10V) to Electronic load Positive Power Supply #2 (+10V) to MOSFET Gate Electronic Load Negative to MOSFET Drain DMM Positive to MOSFET Drain Test Process: Power Supply #1, Increase Voltage from Zero to 10V (1.1 Amps CC) Power Supply #2, Increase Voltage from Zero to 10V Initiate the Electronic Load (1 Amp) Measure the voltage over Drain to Source (VDS) Calculate the resistance: Resistance = Volts / Current (RDSon = VDS / IDS) Example: If 0.01V is measured with a 1A load, then: RDSon = 0.01/1 = 0.01Ω or 10mΩ   Cheers da |
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phil99 Guru Joined: 11/02/2018 Location: AustraliaPosts: 2407 |
Fake devices are seldom just a little bit out of tolerance. To know for sure that they do or don't meet the specification it may be necessary to replicate the manufacturers test method. Their procedure is often in the datasheet somewhere. Using your own test that replicates what you are going to use them for allows you to pick the best ones for that project, regardless of who made them. . Edited 2025-02-24 08:31 by phil99 |
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| Dougie Analog Newbie Joined: 21/02/2025 Location: AustraliaPosts: 14 |
Good point phil99, thank you. If that's the case then perhaps I'll give these MOSFETs a try on a working inverter and see how they perform. There is always this tension between a pragmatist and an absolutest in electronic projects. Where to pitch it in terms of effort and money. Saving a couple of $$ on MOSFETs is probably not worth it in the scheme of things. I'm struggling atm about buying differential oscilloscope probes. There is a huge range in prices in them and should I buy two of them? So an interesting perspective there... Dropping a $1000 on test gear compared to saving a couple of $$ on MOSFETs. Thanks again, da |
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| Dougie Analog Newbie Joined: 21/02/2025 Location: AustraliaPosts: 14 |
I'm re-reading, making my way through old threads from 2017 to the present. Trawling for MOSFET posts. I'm up to 2022. WOW! There is a universe in here!! So much great material... "MOSFET Testing Jig" thread was a good one https://www.thebackshed.com/forum/ViewTopic.php?FID=4&TID=15062 Contributed by lots of the usual gurus, 5 stars... Paraphrasing Donald Rumsfeld's quote: Known knowns - things we know we know. Known unknowns - we know there are some things we do not know. Unknown unknowns - we don't know we don't know. In this off-grid inverter world, I starting out at "Unknown unknowns". I've graduated to "Known unknowns" along with many others. The Gurus and the collective hive mind here have "Known knowns" covered. That's why this forum rocks! I couldn't have gotten this far without other people's generosity. Thank you, thank you... da |
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| Dougie Analog Newbie Joined: 21/02/2025 Location: AustraliaPosts: 14 |
I ended up buying a bunch of HY4008Ws from the LCSC website. Thank you oreo for your suggestion. You were right. Even with the currency exchange, they were the best price and shipped very fast. The best part is that after testing a few of these MOSFETs, they tested at 2.7mΩ. That's the best yet and lower than the typical figure in the data sheet. So yes, LCSC gets a recommendation from me on these MOSFETs. Does anybody have pictures of the inside to see the chip size. I didn't think to keep my dead ones to split open. I found this picture online but I can't verify that it is a HY4008W.  Here is a picture inside of a TO-247 MOSFET found online.  The chip in this unknown TO-247 is bigger than the one above but I have no reference for what the real one looks like. I guess I could sacrifice a couple of working ones to find out but if the picture exist elsewhere than that would be good to see. Cheers, da |
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