Detecting counterfeit 4110 mosfets

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Re: Detecting counterfeit 4110 mosfets

Postby The Mighty Volt » Sat Mar 17, 2012 10:09 am

On the left is a known genuine 4110 Mosfet as supplied by Methods. On the right is the first Mosfet in a controller. It purports to be a 4110. How does it look to you guys

Image


On the top of the photo is a series of known 4110 Mosfets, again supplied by Methods, in a plastic strip container. On the bottom, are visible are other Mosfets, purporting to be 4110 Mosfets, as arranged in a controller. One thing which caught my attention was that Methods mosfets have a distinctive copper hue. The ones in the controller do too, but it is just not as uniformly distinctive.

Now, that could be the aluminium heat-sink, or the yellow plastic tape, interfering. I don't know. I don't even know if it is that important.

Image

The best shot I could get of two Mosfets beside each other in the controller. Note the grubby nature of the prints on the Mosfets- but again that's not conclusive, because I took a known 4110 and rubbed it back between by thumb and index finger and it resulted in a faded, grubby appearance of the lettering. So who knows.

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Re: Detecting counterfeit 4110 mosfets

Postby The Mighty Volt » Sat Mar 17, 2012 10:13 am

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Re: Detecting counterfeit 4110 mosfets

Postby The Mighty Volt » Sat Mar 17, 2012 11:31 am

The two mosfets in this photo were fitted to an old controller by ES member "Monster".

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Re: Detecting counterfeit 4110 mosfets

Postby whatever » Fri Mar 23, 2012 4:14 am

look genuine to me
a- moulded centre part ( not present in some fakes)
b- rounded edges ( some fakes have very square edges, noticeably different)
printing looks genuine
I'd guess genuine, you can destructively check them also they have tiny tiny high amp wires inside, genuine have three tiny wires for the high current from memory
genuine.jpg
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Re: Detecting counterfeit 4110 mosfets

Postby Dave-s » Thu May 10, 2012 3:41 am

Hi,
Where can I purchase original 4110's?
Are all the ones sold on eBay from China fake?
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Re: Detecting counterfeit 4110 mosfets

Postby amberwolf » Fri May 11, 2012 4:08 am

No way to know until you get some and characterize them. ;)
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Re: Detecting counterfeit 4110 mosfets

Postby methods » Sun Jun 03, 2012 12:25 am

Did we get anywhere with this?

When I first saw those fets (in another thread) they instantly looked fake to me. Printing is at an angle.... I have probably looked at 10,000 4110 fets. I can't quite put my finger on it but those don't look genuine to me.

There have been some very good fakes on the market for some time now. Not sure if the old methods we used to compare them are still valid. Need to test.

4110's are a lot more affordable now then they used to be tho - so chances are higher that a Chinese supplier is actually bringing them in from a good source.

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Re: Detecting counterfeit 4110 mosfets

Postby methods » Sun Jun 03, 2012 12:32 am

Since I am here... time to share a little something with you guys.

First off - here is how you search for cheap parts. http://octopart.com/

Enter IRFB4110

You get this busy ass page: http://octopart.com/irfb4110pbf-international+rectifier-36192
Note that all of the major manufacturers are listed and all of the pricing is right there - across quantities.

Right away you can find Arrow carrying IRFB4110 fets for $1.53 each - even in quantities of 1 !!!
http://www.arrownac.com/parts/detail/42590206S7624301N3340

Dude... do you realize how awesome of a price that is guys?
Back when I was selling IRFB4110 fets here I had to commit to buying 12,000pcs to get similar prices.

So there you go. Discussion over... get um while they are hot. That is dirt f'ing cheap.

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Re: Detecting counterfeit 4110 mosfets

Postby John in CR » Sun Jun 03, 2012 2:32 am

Hey Methods,

You mentioned testing them. Is there something those of us with little in the way of tools more than a multimeter and even less know-how can do to test them other than using the controller and see how far it can be pushed?

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Re: Detecting counterfeit 4110 mosfets

Postby methods » Sun Jun 03, 2012 2:46 am

I dont have any direct experience here - so I am totally shooting at the hip.
If I was a regular guy with nothing but an iCharger I would do it like this:

1) Hook up a 12V source between the gate and the source to turn it on.
2) Set the icharger up for foam cut and turn the current up as far as it will go - say 20A
3) Hook the iCharger up across the mosfet - should work the same in either direction but try both.
4) Hook a good dmm as close to the legs of the fet as you can - set it to DC mV

V = I * R

We are looking for about 3 or 4 mohms right?
I figure a fake might be 10mohms?

20A * 4mohms = 80mV
20A * 10mohms = 200mV

So as a totally gross test I propose that we could drive a constant current through the fet while it is biased completely on. We then look at the voltage that develops across the part to back calculate its rdson

Again - I am a mosfet retard so I am sure there are a ton of guys on here who know a lot more about it than me. I am a hack and that is how I would do it with the tools most guys have on hand. I have never gotten into the whole mosfet matching thing... I dont have the patience for that shit.

Hook it up
Ride
break it
fix it


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Re: Detecting counterfeit 4110 mosfets

Postby John in CR » Sun Jun 03, 2012 8:53 am

Perfect, thx. The iCharger is another tool I have, so that seems easy enough.

I can do 2/3rds of the other approach. Run it, break it are easy enough. I haven't had much success with the fixing part, not moset replacement anyway.

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Re: Detecting counterfeit 4110 mosfets

Postby whatever » Sun Jun 03, 2012 9:22 am

bottom of this page is very simple method to test fets
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=19585&p=289200&hilit=mosfet+testing#p289200
you can turn them half on/full on just with the voltage in your finger, maybe measuring the temperature of the fet once its on using a suitable light globe as current limiter would be useful thing as it will give some idea of internal resistance while its on.
Its not a switching current in this method but its really quick and simple, just need a 12v battery, 12v light globe and a couple of alligator clips. Its also a really good way to get an idea of how sensitive these devices are.
to methods: would icharger in foam cut mode be a switching current or its definitely a constant current?
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Re: Detecting counterfeit 4110 mosfets

Postby methods » Sun Jun 03, 2012 11:36 am

That is an interesting experiment but but in this case we are trying to quantify the RDSON of the fet so I dont think that experiment will do what we need.

Yes the Foam Cut mode is a constant DC current.
In this case we dont care about the switching characteristics of the mosfet. We are going to the presumption that a counterfeit mosfet would have inferior RDSON and looking to see if we can easily spot that.

-methods



whatever wrote:bottom of this page is very simple method to test fets
http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=19585&p=289200&hilit=mosfet+testing#p289200
you can turn them half on/full on just with the voltage in your finger, maybe measuring the temperature of the fet once its on using a suitable light globe as current limiter would be useful thing as it will give some idea of internal resistance while its on.
Its not a switching current in this method but its really quick and simple, just need a 12v battery, 12v light globe and a couple of alligator clips. Its also a really good way to get an idea of how sensitive these devices are.
to methods: would icharger in foam cut mode be a switching current or its definitely a constant current?
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Re: Detecting counterfeit 4110 mosfets

Postby methods » Sun Jun 03, 2012 11:59 am

I dont know... I bet you could do it if you wanted to.

When mosfets blow I do this:

* Grab DMM and measure form ground to Yellow, ground to Blue, Ground to Green. They should all be 10K. If one is 0 ohms we know that bank must be replaced

* Measure from VCC to Yellow, VCC to Blue, VCC to Green. Same thing - they should all be 10K and if any are short that bank gets replaced.

Lets say the first test failed for GND to Yellow
We flip it over and identify the big GND trace.
We identify the Yellow pad area

Now we identify the group we want. The number to be replaced will be:
12 fet 2pcs
18 fet 3pcs
24 fet 4pcs
36 fet 6pcs

Some times it is a bit confusing so you can grab a sharpie
draw a box around the group of fets that must be removed.

Ok - you probably knew all that and the real problem is the actual physical removal right?
Lots of ways to do this part... I will choose tools that you have.

Remove the fasteners from the 2,3,4, or 6 fets you need to drop out.
Dont even THINK about trying to swap 1 or 2 of them. SWAP THEM ALL. Not worth f'ing around here.
So remove the screws
Lean the fets forward a tad to break them free from the heat sink.

Now you can go about it a few ways.
First - if you have a heat gun that is probably the easiest.
It is a little awkward.. but try to set up the board so that you have access to the bottom
Grab a pair of long needle nose or some forceps or tweezers... or tie a little copper wire to the fets... so just something to pull them out when the solder reflows.
Fire up that hot air gun and heat up the solder. WATCH OUT -> That shit can burn a hole right through the PCB board so go slow and easy. The whole thing will need to heat up.
So you basically just re-flow the solder over the fets you are trying to pull and when you see it go liquid give them a little tug from underneath.

The Ghetto way is to bap the board on the table but... that can cause you trouble so proceed at your own risk.

Ok - that is the hot air method. Works better with a hot air rework station.

Second method involves connecting all 3 of the legs together with a blob of solder.
Try to rake back any "beef up" solder to keep it from heat sinking
Get a blob across all three pins with your soldering iron
Heat those bastards up and very lightly tug, tug, tug from below.

The biggest fail is tugging too hard or too early and ripping up pads on the top of the board. You really have to overheat the shit out of things.

Another method that you might like is the nip-tuck method
Get a pair of long skinny wire cutters (buy them - super long and skinny with a little nipper at the end) for tight spots
Reach in and nip the three fet legs
Then you have to heat them up from the back with a soldering iron and pull them out
Some times they have to go through the bottom and some times they have to go through the top... all depends on how you cut them and how deformed the copper is. Dont force either direction.

I hate that method... last hope of a desperate man but I will do it when I have to.

Once the fets are out I repair any damage (about 1 in 10 times I f up the PCB board)

I then try the bake and shake to clean the pads... I get the pads hot and reflow the solder and then shake the board really quick to try and fling the solder off. This saves me on solder wick. Alternately you can make "Ghetto Wick" by using some crappy old stranded wire to suck up the large portion of solder on the pads. Once you have 90% of the solder off the pads you can clean them up with solder wick AND FLUX. Flux is wonder lube - you cant use too much. Buy it in pen form and paint it on everything.

A hot iron and flux for the win.
Money well spent. 80W iron with adjustable heat
Real flux in a pen
Real lead solder

Assembling is easier...
Slide them in
Screw them in
Solder
Trim
Beef up.

-methods




John in CR wrote:Perfect, thx. The iCharger is another tool I have, so that seems easy enough.

I can do 2/3rds of the other approach. Run it, break it are easy enough. I haven't had much success with the fixing part, not moset replacement anyway.

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Re: Detecting counterfeit 4110 mosfets

Postby John in CR » Sun Jun 03, 2012 6:09 pm

Methods,

It's not that I can't, but me messing with electronics does absolutely nothing for the cause. If anything it's a negative, because I'm slow with an iron and that takes time away from areas where I might be able to contribute something worthwhile. I think it's better that I stockpile blown controllers, and as ebikes begin to show an inkling of momentum here I'll hook up with some electronics repair shops and get them familiar with controller repair. I actually had one try an upgrade of one with blown FETs to swap them all out using a set of those 4110's I got from you, but I didn't know and neither did he to be sure of no shorts between high and low side, so it didn't work out. At least we learned something, so the $8 I spent on his labor (hehehe, yeah some things are a real bargain down here :twisted:) wasn't in vain.

In the meantime, one of the best things I can do for the cause is ride my ebikes due to the positive attention they get. I've had people follow me to wherever I'm going just to inquire once I stop. I even had a young obviously carless family from the next town over waiting outside my gate one day just to ask where they could get one, and it was the wife asking about it.

My favorite was just the other day. I was unlocking the chain on SuperV at the grocery store, and walking by was a 2 year old with his grandmother. He planted his feet asked her what it was, and she said a moto-bici. Then he wouldn't budge until he got to see this thing in action, so I did a quick lap around the parking lot for him. When I came back around he had a big ole Luke style shlt eatin EV grin. Then he waved and turned to go inside. Giving someone an EV grin without even riding really made my day. Imagine the ebikes little tikes like him are going to get to have. :shock:

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Re: Detecting counterfeit 4110 mosfets

Postby texaspyro » Sun Jun 03, 2012 6:37 pm

John in CR wrote:he had a big ole Luke style shlt eatin EV grin.


I've always wondered why people grin when they eat shit? There was a little kid on our block when I was in 6th grade. He was a Batman like superhero crossed with Popeye. Beach towel for a cape, his super powers came not from spinach, but from eating dog crap. Grinned and giggled like a mofo when he did it...
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Re: Detecting counterfeit 4110 mosfets

Postby methods » Sun Jun 03, 2012 7:15 pm

Working on what you are best at is efficient.

Even though I suggest doing this shit work I can not stand doing it myself. That is why I pawn it off on Matthew..... I can do about 2 or 3 hours of it a month and I have to have a real boner to get started on it.

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Re: Detecting counterfeit 4110 mosfets

Postby amberwolf » Sun Jun 03, 2012 10:05 pm

methods wrote:When mosfets blow I do this:

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Re: Detecting counterfeit 4110 mosfets

Postby liveforphysics » Sun Jun 03, 2012 10:11 pm

I have the ability to measure Rds down to fractional uOhm's on devices that can handle high currents.

It's actually pretty neat to have the resolution to watch the uOhm's climbing up rapidly as the silicon warms and bond wires warm etc, then after a minute (depending on the current you're running and how well sinked the part is of course), you can see it increase a whole mOhm, after 5 minutes (or whatever), you see the resistance is double or even 2.5x where it started, because the chip is reaching maximum operating temp.
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Re: Detecting counterfeit 4110 mosfets

Postby methods » Mon Jun 04, 2012 3:14 am

liveforphysics wrote:I have the ability to measure Rds down to fractional uOhm's on devices that can handle high currents.


That is just a matter of running the same procedure I just described but at 100A and measuring voltage with a standard 6 digit meter.

Stop showing off or I will have to bring out an arduino and show you that I can make the LED blink. :mrgreen:

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Re: Detecting counterfeit 4110 mosfets

Postby Gordo » Mon Jun 04, 2012 8:27 pm

methods wrote:
liveforphysics wrote:I have the ability to measure Rds down to fractional uOhm's on devices that can handle high currents.


That is just a matter of running the same procedure I just described but at 100A and measuring voltage with a standard 6 digit meter.

Stop showing off or I will have to bring out an arduino and show you that I can make the LED blink. :mrgreen:

-methods


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Re: Detecting counterfeit 4110 mosfets

Postby methods » Tue Jun 05, 2012 11:39 am

The last time I used a 555 timer it was to convert a semiautomatic paintball gun to full auto.

Full Auto Conversion

Image

I used a microphone and LabView to run an FFT so I could graph the firing rate in real time. 15 rounds per second limited by the internal circuit board.

You can tell by the video quality how dated this is :mrgreen:

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Re: Detecting counterfeit 4110 mosfets

Postby liveforphysics » Tue Jun 05, 2012 3:47 pm

I hate to be the guy that gets back on topic, but I actually think it would be a valuable resource for ES and the rest of the world doing anything with power electronics to test various real and counterfit FETs and make big shared document providing all the results.


I think helpful, easy, consistent tests for all potential suitable controller FETs would be something like this:


Short the gate low, and put the drain tab on an ice-cube, stick a precision 1mA power supply in series with a ~100-250vdc supply, and slowly ramp up voltage until you see the device start to conduct (the 1mA supply will drop out of CV mode into CC mode when you hit it, then you add the two supplies voltages together).

Now do the same test, but with the drain tab on a hot plate set to 140degC.

Then we have a kinda-sorta ball park range on how much voltage overhead a "100v" fet really has. I've heard stories of folks running real IRFB4110's at >110vdc, and having it work. It would be valuable to know where the real limits are so we can see what margin we've really got.

Then testing the real current handling would be nice too. Not just datasheet Rds numbers * Rth numbers with no thermal pad going to a magical perfect heat-sink, but something real. For example, bolt that thing to a controller case with a typical thermal pad in the stack-up, give it 1 minute of 50amps, see what happens. Then give it 1 minute of 75amps and see what happens. Then give it 1 minute of 100amps and see what happens. I don't expect any TO220 package devices to survive past 75amps for 1 minute, I would be pleasantly surprised if they make it past 50amps for 1 minute. Regardless of when they blow though, it would just be good data to have for everyone doing EV builds.
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Re: Detecting counterfeit 4110 mosfets

Postby John in CR » Tue Jun 05, 2012 4:19 pm

Sounds good. You're the one with the fancy tool and the know-how, so I elect you. :mrgreen:

It sure is fun to make commitments of the valuable time of others. :lol:
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Re: Detecting counterfeit 4110 mosfets

Postby CamLight » Wed Jun 06, 2012 5:11 am

John in CR wrote:Sounds good. You're the one with the fancy tool and the know-how, so I elect you. :mrgreen:

It sure is fun to make commitments of the valuable time of others. :lol:

I second that motion.
This is awesome...democracy at work! :mrgreen:
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