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Old Jun 24, 2015, 08:30 PM
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This is very known issue. on mwc thread ..It happened to me too,,you burned the MOSFET assigned to that motor/.Need that FET replaced,
The rule of thumb ,,is if the motors are spinning when connect the battery,,the FET is burned.
The FET is burned when some obstacle on the propeller(grass outside carpet, doors walls ,too much weight on high throttle,...aso.),and the higher current is drawn.

for replacing the FET ,,is IRLML 2502 or equivalent.
http://www.ebay.com/sch/i.html?_odkw...+2502&_sacat=0

Another thing from what I see the quad is too heavy for this setup you have,How much weight has this frame all together?
If more than 40-42 grams you'll have problems.For this reason ressts drawn too much current because is heavy,Maybe for that reason you burned the fets also.Also you use 8.5mm which draw higher current maybe at limit of yout fets.You can use them but much lower weight.
Also the propeller used take a lot of current compared with normal 2 blades.I used Walkera QR propeller or Hubsan .
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Last edited by midelic; Jun 24, 2015 at 08:51 PM.
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Old Jun 24, 2015, 11:33 PM
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Quote:
Originally Posted by midelic View Post
This is very known issue. on mwc thread ..It happened to me too,,you burned the MOSFET assigned to that motor/.Need that FET replaced,
The rule of thumb ,,is if the motors are spinning when connect the battery,,the FET is burned.
The FET is burned when some obstacle on the propeller(grass outside carpet, doors walls ,too much weight on high throttle,...aso.),and the higher current is drawn.

for replacing the FET ,,is IRLML 2502 or equivalent.
http://www.ebay.com/sch/i.html?_odkw...+2502&_sacat=0

Another thing from what I see the quad is too heavy for this setup you have,How much weight has this frame all together?
If more than 40-42 grams you'll have problems.For this reason ressts drawn too much current because is heavy,Maybe for that reason you burned the fets also.Also you use 8.5mm which draw higher current maybe at limit of yout fets.You can use them but much lower weight.
Also the propeller used take a lot of current compared with normal 2 blades.I used Walkera QR propeller or Hubsan .
It's 57g with the battery. But there's nothing in it but Hasi's fc/rx, motors, and the battery. This is the frame from micro motor warehouse and is quite light. I can't imagine what I would have to do to get the weight down that far and have a quad there any fun at all. LOL
So... What do I need to do? Replace all of the FETs with higher capacity ones?
My fpv gear weighs 5g, including wires. I want to use that as well.
I have those people too, but let's face it, they won't make THAT much difference in draw. I want to be able to that this thing around and not worry if I'm going to smoke the FETs.
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Old Jun 25, 2015, 02:18 AM
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Replace only that defective fet you have for the moment(if only one motor spinning only one is defective).If you buy .buy FET higher current.You must replace also the propellers Better buy Hubsan ones or WalkeraQR.Your propellers are not good.

If you read the review of thes propellers you used (3 leaves) you'll see the are not good not enough power, and motor overheating means draw too much current.

http://www.banggood.com/Hubsan-X4-H1...-p-911713.html

http://www.banggood.com/Wholesale-3-...1-p-47127.html
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Last edited by midelic; Jun 25, 2015 at 03:29 AM.
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Old Jun 25, 2015, 03:11 AM
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These small batteries often can't deliver the rated c rate. Try it with another (newer) one.

About the fet, I included an extra one in the envelope. Just replace the damaged one and you should be good to go.

I also use the Hubsan propellers. They are the best/most efficient in this size.
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Old Jun 25, 2015, 03:45 AM
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I checked now .My FPV is heavier 11grams but my frame with battery..with 8.5mm motors is 47gramsWiith FPV is going on more or less 57 grams like yours.I have Walkera blades..my god so much torque..very fast, these motors very powerful 57 grams is like nothing ...so should your frame...with different blades and better battery.
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Last edited by midelic; Jun 25, 2015 at 04:07 AM.
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Old Jun 25, 2015, 04:47 AM
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OK, I'll replace the fet now, and change props to the hubsan ones. The battery is brand speaking new that I bought for this purpose, and I bought 4. I tried two. They are 30C, which is about as high a they come... I've only seen up to 35C for a 1S battery. I don't think that is the culprit. Let's see what props and new fet does. Thanks guys!
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Old Jun 25, 2015, 05:30 AM
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When you connect the lipo battery should be no spinning of the motors,If motors spinning that means one or more MOSFET are burned.
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Old Jun 26, 2015, 01:53 AM
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OK, I swapped out the FET and put on the hubsan props. It DID do a little better, but in the end, the result was the same. More specifically, the same sequence of events. First, when Plugged in the frame the #1 motor spun briefly, then all rest. I was able to lift off, but only for about 5-7 seconds before it fliped and landed, the #1 motor spinning briefly before stopping. I righted it again and tried one or two more times before again, the #1 motor stopped having this issue and the 3# motor would never stop.
In the very beginning when I connected this thing to the PC with the motors, none turned. The very first time I connected a battery, none turned until I gave it throttle (after armed). After the first reset is when the #1 motor would spin briefly (as in the video) on power up. If I continue to try, eventually that stops happening and the #3 motor is on permanent spin mode. LOL So... not sure what causes the brief spin of the #1 motor, but seems something is burning the #3 FET... if that is in fact what is happening - and that sort of makes sense. But why just this one?
I am going to do a test later tonight or tomorrow... I'm going to swap positions of the #2 and #3 motors to see if the problem is the motor. If the #2 FET burns out, then that's likely what's happening.
However, I'd like to get back to my question of replacing all of the FETs. Is it possible to put stronger FETs on it, to withstand high draw motors? BTW, these are the motors: http://goo.gl/9GWp0b
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Old Jun 26, 2015, 05:02 AM
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Check first the motors maybe that motor has a problem if burn the fet so easily.
Fet I used is IRLML 2502.
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Last edited by midelic; Jun 26, 2015 at 08:35 AM.
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Old Jun 29, 2015, 07:16 PM
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Is that the same FET you used on this board Hasi?

I finally got around to testing the motors. First I checked resistance with a multimeter and they are all around .5-.8 depending on where the motor stops. LOL But suffice to say, they are all the same. I then swapped out the offending motor with one of the working ones (swapped #3 and #2) and the problem didn't follow the motor.

OK, so, seems like maybe I might have fried something else. One time early on I did short the battery wire briefly by accident. Everything seemed fine though. At this point, it's the only thing I can think of. What can I check, and how? I have a good Fluke multi-meter... maybe I can check some parts using that? I just don't know what to check, or how to test. I was thinking maybe the dc booster, but if that was it, it wouldn't just keep frying the one FET. So maybe start with the resistor above that FET position that keeps burning and move in/outward from that? I'm out of FETs now, so will have to wait until more arrive.

I looked under powerful magnification, and other than that FET, nothing really looks abnormal.
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