The heat sinks are sufficient enough for up to 30 amps. The problem is the circuit design. It either needs a better MOSFET with a lower RDSon and/or it needs a better driving circuit. These MOSFETs need to be slammed from cutoff to saturation and back again as fast as possible. If the MOSFET isn't driven hard and fast enough (you will notice this on a scope at the gates when you see a slope of more than 1us), the MOSFET will absorb more power and get hotter than it needs to be.
Don't get me wrong, it will do 30 amps. So technically they are not doing false advertising.
I don't like electronics that I can't touch because the skin will melt off of my fingers.
"To me" this specific PWM was not designed for 30 amps continuous duty for any significant length of time. (on the order of more than 30 minutes 'flat out'.)
Understood, but you have to expect heat sinks to get pretty hot anyway. The CPU in your PC can easily reach 150F degrees or more even with the heat sink fan; it's normal.
You're not really supposed to touch the heat sink anyway. If the temperature was running well over 200F degrees I would start to worry; but I'm sure it won't get that high.
Also bear in mind you will be using this under the hood of a car; the massive airflow should keep it quite cool, so it might not be much of a problem.
@lutherp40 I agree with jjenson2006 the MosFets must be Slammed on and off extremely fast, I have designed a DIY PWM base on Zero fossil Fuel CCPWM V2,
And have improved The PWM Drive to do just that. I am also working on a Small PWM Driver up grade, For Units like yours.
I would also agree with you that, excessive heat coming from electronic should not be. You should be able to touch them and not get burned!
I also burned the solder off the board under one of these heat sinks and it shut off. Has Zero's been tested for long duration? If we are using HHO gens on say a road trip it will require a day's long operation. Will a little fan be enough cooling? I hope to get back to a little RVing by using my new EBN gen.
Zero's PWM has a much larger heat sink than what I have here. I do not expect his to have this same heating issue.
As for the 'little fan', see my PWM temp fix video. I ran it with that fan for 12 hours straight at full bore, so it doesn't take much cooling to keep it from melting down.
I have the same PWM...I overheated it to the extreme when I used too much electrolyte one time...it melted the solder from underneath the sinks! Still working though. I was then surprised to see how little air you need to keep them cool....I have it next to my floor vent and even on low, that's more than enough. I'm going to do a CPU fan next so I can mount it in some spot. Good video!
Something is seriously wrong if it melted solder. Solder needs several hundred degrees before it starts to melt; so in order for the solder to melt, the heat sink would first have to reach several hundred degrees.
Its likely that this one got thru QC, try removing the syncs and make sure there is appropriate heat sync compond on it. the syncs look a little small to me anyway, maybe a fan IS in order. I bet the transistors( unlikely mosfets) are rated well above 100c. probably closer to 150-200 i would guess.
Running it like this will make it overheat, you need to place a fan on it, goto my page or my ebay auctions and you will see how I fix this problem. I'm not using a 30 amp I use the 15 amp PWm. You need max airflow to these heat sinks else yes they will overheat.
Yes I still have it, but it left a bad taste to say the least. Of course after seeing Zero's pwm, I might wait till he gets all the mods done and try to build that. Another yt I know also offered to help with circuit stuff too.
Anyway its all good - the building, the testing & learning.
The heat sinks are sufficient enough for up to 30 amps. The problem is the circuit design. It either needs a better MOSFET with a lower RDSon and/or it needs a better driving circuit. These MOSFETs need to be slammed from cutoff to saturation and back again as fast as possible. If the MOSFET isn't driven hard and fast enough (you will notice this on a scope at the gates when you see a slope of more than 1us), the MOSFET will absorb more power and get hotter than it needs to be.
jjenson2006 3 years ago
Thanks for the tip on the circuit design.
Don't get me wrong, it will do 30 amps. So technically they are not doing false advertising.
I don't like electronics that I can't touch because the skin will melt off of my fingers.
"To me" this specific PWM was not designed for 30 amps continuous duty for any significant length of time. (on the order of more than 30 minutes 'flat out'.)
lutherp40 3 years ago
Understood, but you have to expect heat sinks to get pretty hot anyway. The CPU in your PC can easily reach 150F degrees or more even with the heat sink fan; it's normal.
You're not really supposed to touch the heat sink anyway. If the temperature was running well over 200F degrees I would start to worry; but I'm sure it won't get that high.
Also bear in mind you will be using this under the hood of a car; the massive airflow should keep it quite cool, so it might not be much of a problem.
jjenson2006 3 years ago
@lutherp40 I agree with jjenson2006 the MosFets must be Slammed on and off extremely fast, I have designed a DIY PWM base on Zero fossil Fuel CCPWM V2,
And have improved The PWM Drive to do just that. I am also working on a Small PWM Driver up grade, For Units like yours.
I would also agree with you that, excessive heat coming from electronic should not be. You should be able to touch them and not get burned!
H2O2FromH20 1 year ago
I also burned the solder off the board under one of these heat sinks and it shut off. Has Zero's been tested for long duration? If we are using HHO gens on say a road trip it will require a day's long operation. Will a little fan be enough cooling? I hope to get back to a little RVing by using my new EBN gen.
ed121249 3 years ago
Zero's PWM has a much larger heat sink than what I have here. I do not expect his to have this same heating issue.
As for the 'little fan', see my PWM temp fix video. I ran it with that fan for 12 hours straight at full bore, so it doesn't take much cooling to keep it from melting down.
lutherp40 3 years ago
I have the same PWM...I overheated it to the extreme when I used too much electrolyte one time...it melted the solder from underneath the sinks! Still working though. I was then surprised to see how little air you need to keep them cool....I have it next to my floor vent and even on low, that's more than enough. I'm going to do a CPU fan next so I can mount it in some spot. Good video!
WesNowBetter 3 years ago
Something is seriously wrong if it melted solder. Solder needs several hundred degrees before it starts to melt; so in order for the solder to melt, the heat sink would first have to reach several hundred degrees.
jjenson2006 3 years ago
Its likely that this one got thru QC, try removing the syncs and make sure there is appropriate heat sync compond on it. the syncs look a little small to me anyway, maybe a fan IS in order. I bet the transistors( unlikely mosfets) are rated well above 100c. probably closer to 150-200 i would guess.
EmotepOraca 3 years ago
I do not believe that this is the case.
You have to consider that these things were originally designed as controllers for robots, electric trains and such. Toys basically.
They were never intended for 100% duty cycles pulling 30 and 40 amps continuous for hours on end like when we are driving an electrolysis process.
These are a good design, but originally intended for a different kind of application where they were more than adequate.
This is not the case now.
lutherp40 3 years ago
This has been flagged as spam show
Check out my fan controller that solves the overheating on your HHO cell. Eliminategas(dotcom
eliminategas 3 years ago
Running it like this will make it overheat, you need to place a fan on it, goto my page or my ebay auctions and you will see how I fix this problem. I'm not using a 30 amp I use the 15 amp PWm. You need max airflow to these heat sinks else yes they will overheat.
eliminategas 3 years ago
what is the max operating temp of the mosfet?
You might just be able to get a 12 volt fan and mount on the top of those two heat sinks and cool it down.
KyHighlander59 3 years ago
I am not sure about the max temperature is.
All I know is that if I touch it and I leave skin behind, "Its too hot!" ;-)
I added a fan to mine this evening.
I am a bit happier with it now. Ran it at 19 amps for about 10 minutes and it only gained a degree or two.
See my 'temp fix' video posted after this one.
lutherp40 3 years ago
I think that is what happened to my "cheapie" - I know before I installed it in my vehicle I did duration tests for about an hour max at 20 amps.
Then when I put it in my vehicle my fuses would keep blowing. Well I took out the pwm and the system worked (darn cheapie pwm).
I'm not sorry I got it, but I did learn a lesson... dont buy a cheap pwm.
thanks for posting Luther.
Keep up the good work.
AH
AlmostHydrogen 3 years ago
I already posted my temporary fix for this issue. So.... Don't throw it away. You may still be able to salvage it. (and upgrade it at the same time)
Electrically, the circuit is pretty good, the problem is with the implementation.
It just needs a little help managing heat, that all.
lutherp40 3 years ago
Yes I still have it, but it left a bad taste to say the least. Of course after seeing Zero's pwm, I might wait till he gets all the mods done and try to build that. Another yt I know also offered to help with circuit stuff too.
Anyway its all good - the building, the testing & learning.
Thanks for posting & the reply.
AlmostHydrogen 3 years ago
I will have to admit that ZeroFossilFuel's PWM is very desirable.
In particular the current limiting feature. I want that really bad!! ;-)
The way I am looking at it, the "cheapie" PWM can stay on the test bench. Zero's PWM will go in the car.
It won't go to waste.
lutherp40 3 years ago
I agree.
I have a few things that I "want for christmas"
;)
AlmostHydrogen 3 years ago