[Solved - sorta] h801 dead

[bobbybeans]

Hey guys, I am wondering if you guys had this issue.
I have one of my H801s hooked up around my door in my room. I have rgb 5050 5 meter, warm white 4 meter and 5 meter for cool white attached to it.

last night i had them on like I normally do (only the CW ones) and it flickered then went out. after about 5 min i walked up to it to feel immense heat coming from the box. I took it off and looked at it, the white channel mosfet blew, completely black melted part of the case.
I looked up the specs and i dont believe I was driving it that hard especially only with CW on.
Looking at the datasheets on the 20N06L it can handle 20 amp continuous provided you can cool it, even at 100c its 10 amp. 5 meters should only be about 6 amp.
Upon inspection my h801 does not have 20N06L it has LR024N. The data sheet on that is 17 amps, I would assume they replace them as it was cheaper to use them.
I have a gauge of wire one gauge too small but I dont think that would have blown it?

Any suggestions? I am going to be buying small heatsinks and attaching to the rest of them. has this ever happen to you?
Also I am going to try and replace the mosfet dont know how successful ill be as I dont have a hot air gun. Anybody with electrical experience on how to get them off without a hot air gun? I do have a soldering iron

Edit: well I just replaced it with a new H801 and it did the same thing. So What I did was get ANOTHER one and remove all lights except white and it seems to have worked. The only thing I can think of as to why this happened maybe it short circuited and just started dumping tons of amps into the mosfet

I have now had my white light on and the mosfets arent even getting hot to the touch

Also since this has LR024N should I replace it with those? or I was going to by the 20N06L. it shouldn't matter technically as they originally had those ?

[Shardan]

Hello,

if you run your stripes consuming 5..6 amperes it's no matter if you use 20N06L or LR024N.
Both will run and both will blow when you short circuit an output.
There is another reason why i wouldn't change to 20N06L, see down.
Maybe a fuse in the cable to the outputs might be a better idea?

Some basics about MOSFET's:
The current you can put on a MOSFET depends not only on the type.
The most important factors are the voltage a MSOFET is driven with and how fast it raises and lowers.

And that gives problems!
If you use 12 V for LED stripes the driving voltage would be optimal in theory
as the MOSFET's usually need 10..15V to open up fully.
The H801 uses 5V for the driver - take a look how much power you can put
on a MOSFET with 5V at the gate... take a look into the data sheets.
The LR024N goes down to 11A max., the 20N06L goes down to 8 amperes.
This might be the reason why they swapped the MOSFETs in the box.
It's just the better choice for the given circuit.

Second, a really fast driver chip that can take 10..15 V for fully driving a MOSFET
like for example the ICL7667 is expensive. It costs 15 times more then a cheap 5V driver.
I don't know any cheap module using such drivers, I assume no one uses them due to the price.
The bad part: Cheap drivers might be slower. "Slow" says the "raise time", the time the voltage needs to
change from low to high and vice versa, is longer - the MOSFET has a longer time when it is "half opened".
This is critical as this heats up the MOSFET.
The faster the MOSFET is driven, the shorter is this "half open" time and the lower is the heat produced.
Usually the PWM for LEDs run on some KHz, so the MOSFET runs through the half-open phase some
thousand times per second - don't underestimate this.

As far as i have seen the H801 uses a 74HC245 bus driver to drive the MOSFETs. That chip should
be a fast one (Output transition time @5V about 15 ns). Anyways, it runs on 5 volts so this limits
the current you can put through the MOSFETs far more then the MOSFET type does.

Hope that helps.

Regards
Shardan

[bobbybeans]

Hello,

if you run your stripes consuming 5..6 amperes it's no matter if you use 20N06L or LR024N.
Both will run and both will blow when you short circuit an output.
There is another reason why i wouldn't change to 20N06L, see down.
Maybe a fuse in the cable to the outputs might be a better idea?

haha yes this is true. The reason I suggested short circuited is because from me testing it tonight that is the only logical conclusion. But it sort of baffles me to that extent because i have had that hooked up for months working 100% flawlessly, haven't touched it or moved it. nothing hits it and its relatively protected so i still dont know if that was the case bc i have the cold white lights (same strip) running on the same burnt h801 , on a different channel and its working fine. so i have no clue maybe a small wire magically moved IDK. When it went out I was sitting next to it about 1 meter away and nothing came in contact, seemed like it just felt like it.

Some basics about MOSFET's:
The current you can put on a MOSFET depends not only on the type.
The most important factors are the voltage a MSOFET is driven with and how fast it raises and lowers.

And that gives problems!
If you use 12 V for LED stripes the driving voltage would be optimal in theory
as the MOSFET's usually need 10..15V to open up fully.
The H801 uses 5V for the driver - take a look how much power you can put
on a MOSFET with 5V at the gate... take a look into the data sheets.
The LR024N goes down to 11A max., the 20N06L goes down to 8 amperes.
This might be the reason why they swapped the MOSFETs in the box.
It's just the better choice for the given circuit.

Thanks this helps. i dont know much about mosfets I tried looking at the data sheets and understood maybe 5-10% of it which was only the main specs but how they operate on different voltages I didn't understand, ive never taken an electrical course. Even though i should. I was thinking actually once I move I switch to a 24 volt system as it would be more efficient, less heat loss, i can use lower gauge wire and I would assume the mosfets could cope better? if I understand what you're saying is correct below

Second, a really fast driver chip that can take 10..15 V for fully driving a MOSFET
like for example the ICL7667 is expensive. It costs 15 times more then a cheap 5V driver.
I don't know any cheap module using such drivers, I assume no one uses them due to the price.
The bad part: Cheap drivers might be slower. "Slow" says the "raise time", the time the voltage needs to
change from low to high and vice versa, is longer - the MOSFET has a longer time when it is "half opened".
This is critical as this heats up the MOSFET.
The faster the MOSFET is driven, the shorter is this "half open" time and the lower is the heat produced.
Usually the PWM for LEDs run on some KHz, so the MOSFET runs through the half-open phase some
thousand times per second - don't underestimate this.

As far as i have seen the H801 uses a 74HC245 bus driver to drive the MOSFETs. That chip should
be a fast one (Output transition time @5V about 15 ns). Anyways, it runs on 5 volts so this limits
the current you can put through the MOSFETs far more then the MOSFET type does.

Hope that helps.

Regards
Shardan

yes this does thanks. i read on some specs that the h801 is 4 amp rated per channel but that is only like ebay and ali express and personally i dont really ever trust the ratings when they say that because most of the ones I came across were completely wrong or different listings say 2 completely different things

I will buy the same mosfet and try to replace it, worst case scenario i screw it up and only have 4 channels RGBW instead of RGBWW. a pack of 20 from ali is 2 pounds
Any suggestions on replacing them? they are SMD and I watched a few videos that said /showed to flow solder around the pad then once hot enough move it away with tweezers

[Shardan]

For an understanding you may take a look at the datasheets.
There should be a diagram where
- X-axis is Vgs (Voltage Gate to Source). This is the voltage that the circuit uses for driving the MOSFET. With the H801 this is 5V.
- Y-axis is Id (Drain [to Source] current). This is the max. current the MOSFET can take with the given gate voltage.

Desoldering needs a doctor's degree in atomic physics and witchcraft

Use a standard electronic soldering iron with a not too big tip.
Use desoldering braid or a desoldering pump, and a small hook (Looks a bit like the thing used by a Dentist..) or twezers.

Make your life easier: As the old transistor is obviously broken you may use a small side cutter and cut off the two "legs".
Then you can desolder it "leg by leg".

Regards
Shardan

[bobbybeans]

Hey just an update really for anyone that has this issue in the future. i still have not figured out why they melted down. my best guess is a small wire from White Channel 1 touch either vcc or ground causing it to melt down. Even though I had it mounted out of the way with no one touching it for months.
ANYWAY bought some new mosfets for 1 pound off ali, waited a month. They arrived I took the old ones off and they worked.
One note about taking them off. If you had a meltdown like i did they will be black stuff around the melted mosfet. do NOT try and rip of the mosfet with pliers while heating it.
steps to take before doing anything
take a pair of snips and cut the legs off of it, BUT while you're doing this put your finger solidly pushing down on the body of it. the reason I say this is, if it melted enough where you see black stuff out of it most likely it has melted part of the board where the copper trace is attached to, making the copper trace very fragile. If you don't do this you risk ripping off the copper trace
after you snip the legs off put some flux and flow some solder onto it, again don't touch the mosfettill it moves freely by itself. I know this is probably over heating the board but both times i did it, i almost ripped off the trace even being very careful. So get a flat solder tip tin it, and heat the tab of the mosfet till you can push it around with the soldering iron. Quickly remove it with pliers or something
when putting on the new mosfet, tin the back of the mosfet and both legs. Tin the copper traces on the board of the lets and the back pad. put the mosfet on then heat it up till the solder flows on the main tab. Dont worry about the legs at that moment as long as they are relatively aligned then youll be fine. once solidly in place then solder the legs with a blob of solder and thats you sorted!
i tested them and they are working just as good as gold