Author Topic: No brand/5500W inverter disaster porn  (Read 366 times)

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Offline lighthunter

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Re: No brand/5500W inverter disaster porn
« Reply #15 on: May 01, 2021, 07:35:50 am »
Hey ya'all, hope your having a good weekend, supposed to be hot here today 80ish might try starting the AC on this 8010 inverter.

So at the beginning of this thread i mentioned a PJ inverter that had run for years and control board quit... no blown fets, I WAS VERY MISTAKEN, it was blown fets, i was not home to hear the sound and there was almost zero visible evidence. A close up photo of the end fet shows a hairline fracture i never noticed and there are others like it. HA ive never seen so very little visible damage. This one had run for at least 4 years and so i must add that i am suspicious since i had made a change to the cooling only a day prior. The change was from 25c setpoint to 30c setpoint. The thermostat probe was fixed to one of the heatsinks directly. 

So was it the temp change from 25 to 30C?  Or was it totally a coincidence. My boss reminds me every so often that theres no such thing as a coincidence. Personally i dont believe that as ive often seen two unrelated events happen at the same time.

Its really not important now unless someone thinks i SHOULD have fan thermostat at 25C.  Sorry for the drama queen stuff
its just kinda nice to understand failures. :)

LH
LH

Offline Pete

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Re: No brand/5500W inverter disaster porn
« Reply #16 on: May 01, 2021, 05:44:04 pm »
I would have thought that 35 degrees would be well within the design limits of the components. It gets hotter than that just at ambient temperature in summer in lots of places.
Can't explain why the fets only just cracked though, normally they go bang in a big way. Possibly something else blew just in time to stop the usual fireworks.
Pete

Offline Pete

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Re: No brand/5500W inverter disaster porn
« Reply #17 on: May 01, 2021, 05:47:19 pm »
I just had a look at the Hy4008 spec sheet they say that the maximum junction temperature is 175 degrees C, so 35 degrees sounds very reasonable.
Pete

Offline noneyabussiness

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Re: No brand/5500W inverter disaster porn
« Reply #18 on: May 02, 2021, 04:34:03 pm »
Just remember junction temp doesn't have a whole lot to do with CASE temperature only " steady " temperature rises come into play there... the data sheet will have to J to C coefficient,  but an instant temp rise will still blow it to smithereens before the case even warms...

Ive had that happen to mosfets , cracking like that under failure... your lucky the energy in those capacitors usually make em go boom...

I don't think the 5 degree change SHOULD have made any difference,  unless you were at the limits... which sounds like you were not... maybe re-set it back to 25 and get some readings, a no contact temp probe are not expensive off of fleabay, check case temperature ( not heatsink ) under load  and post it here, can back track the junction temp using datasheet, will only give steady temp, not instant,  but give you some more info to track the issue down... 

Offline Pete

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Re: No brand/5500W inverter disaster porn
« Reply #19 on: May 02, 2021, 05:28:15 pm »
One thing that I have noticed on my powerjacks is that they don't use any heatsink compound on the mosfets. It may be fine if the inverter is not run too hard but with hard running and possibly an ill fitting transistor they could easily overheat.
I thought about adding heatsink compound during the repair I am doing on my 8000 but forgot , I may still undo the screws and put some compound on when I put the main capacitors back on.
Pete

Offline noneyabussiness

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Re: No brand/5500W inverter disaster porn
« Reply #20 on: May 03, 2021, 01:05:45 am »
Oz tested that at some earlier stage, said made no difference.. but up to you...

Offline Pete

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Re: No brand/5500W inverter disaster porn
« Reply #21 on: May 03, 2021, 02:22:28 am »
Thanks Noneya, I trust that Oz was enough of a tinkerer and blew up enough stuff to know what he was saying.
Will save me trying to undo those soft screws on the mosfets .
Cheers
Pete

Offline dochubert

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Re: No brand/5500W inverter disaster porn
« Reply #22 on: May 04, 2021, 08:52:44 pm »
Hi guys,
Pete, don't forget that it must be conductive heatsink compound behind those fets.
An illegitimate head of government based on a stolen election.
An illegitimate and corrupt legislation rubber stamped a stolen election and is currently demonizing anyone questioning it.
A corrupt court system that refuses to examine mountains of evidence.

USA = Banana Republic

---  dochubert --

Offline Pete

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Re: No brand/5500W inverter disaster porn
« Reply #23 on: May 04, 2021, 09:31:24 pm »
Thanks Doc, I have decided to take the advice of those more experienced and not bother to put heasink compound on.
Your point about conductive heatsink compound is probably why PowerJack don't put it on in the first place.
I should have realised that as the cables go directly to the heatsink that they are live
thanks
Pete

Offline lighthunter

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Re: No brand/5500W inverter disaster porn
« Reply #24 on: May 04, 2021, 10:10:02 pm »
Good discussion on the heat sink guys! Very important.

So far the 8010 inverter wins over powerjack in
1) efficiency
2) Quieter
3) Cheaper
4) Load volt regulation is better
5) power board design, compared to older pj


The only thing i dont like is the battery voltage regulation.
 ( i know AC volt regulation is load reg and bat reg, its all the same thing)
Maybe there is aomething i dont understand.

  49.0 thru 57.5 vdc = 120.7vAC solid
  48.2vdc = 118.7 vAC
  47.85 = 113.7vAC

   This might suggest the volt regulation range is
    at the lower edge, when below 48v it falls sharply,
    suggesting i need to add turns to the secondary of
transformer (or remove from primary)
 
What i dont get is the pj had no trouble
Holding 120v all the way down to 44v with this same transformer.  What could be the difference. Both are switching 48v through a transformer with an H bridge. Except,
one is using bipolar while the 8010 is unipolar. Maybe that explains the efficiency gain as well. Just guessin at this...



LH

Offline noneyabussiness

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Re: No brand/5500W inverter disaster porn
« Reply #25 on: May 04, 2021, 11:11:15 pm »
Oz discovered that earlier on... it doesn't have as good " dynamic range " as the PJ, why for a 48v system, the PJ is happy with a 32v/240v transformer,  but the eg8010 requires 28v/240v to be able to keep the voltage consistent over the lead acid usual voltage range..

However,  it doesn't mean it won't work,  voltage will just sag at lower voltages... how I got around it, was to lower final voltage ( 225v on a 32/240 transformer) it will hold that happily and I haven't had any connected devices complain.. grid voltages can fluctuate way more than this anyways...

Offline Pete

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Re: No brand/5500W inverter disaster porn
« Reply #26 on: May 05, 2021, 03:20:52 am »
Hi Noneaya , just wondering how you lowered the voltage on the 8010 unit. I have ordered one to try out and wondered how you went about adjusting it.
As the grid in Australia has aged and not been kept in such good condition then authorities have actually lowered our supply voltage guarantee to 230 volts anyway. Seems that they could not be bothered putting in bigger wires, cleaning connections etc.
So your 225 is well within the +/- 5% range that is required anyway.
Pete

Offline noneyabussiness

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Re: No brand/5500W inverter disaster porn
« Reply #27 on: May 05, 2021, 03:50:27 pm »
On my board, the variable resistor circled in pic is what adjusts the voltage.... yours may be different,  but the do come with a chinglish instructions which are easy to decipher...

Offline Pete

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Re: No brand/5500W inverter disaster porn
« Reply #28 on: May 05, 2021, 05:22:24 pm »
Thanks Noneya, I will see what mine looks like when it gets off the slow boat from China.
Seems that as our pollies poke a stick in to the ant nest that is the Chinese government, the freight slows down even more.
Pity that Australia stopped manufacturing electronic parts many years ago. With all the stupid talk of war with China, and anyone else the west decides is worthy of bombing that we had better ramp up our manufacturing.
Maybe the government here doesn't understand that all the electronics that runs our millitary and civilian industries comes from China.
Oh well, the madder the place gets the more being mad looks normal.
Pete

Offline lighthunter

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Re: No brand/5500W inverter disaster porn
« Reply #29 on: May 05, 2021, 06:35:53 pm »
Ha! yeah what a mess. The crazies of facebook were gonna try to decide if Trump is still banned from their website today. Too bad everybody dont just delete their account and vaporize social media.

Nonya, you were fortunate to find directions on your inverter. Mine had zero, i ended up using my phone camera and translator to figure it out.Pete just ask if you have any questions when it arrives. I only use 3 two pin plugs, one for on/off switch on the left, one for power in the middle marked - +  and the third on the end far right for feedback. I dont know if i have any current limit though, ive fuses for that anyway.

Noneya, thanks for the clarification of "dynamic range" thats a whopping lot of difference between the two. I cant help but wonder whats different. The only thing the 8010 can do to change voltage is vary the duty cycle. Seems odd they would be so different. Unless the bipolar thing makes a difference.

If i did the math right the power  difference d 110 Vac vs 120Vac
is 16%. Thats kinda huge for a compressor in an air conditioner.
a 10 volt drop at 235 to 225 is 8% power change. So its not that things wont work but the AC unit will draw more current and cool less. This time of year its not a big deal but when compressors are running at maximum it wont go unnoticed.  I may have to wrap more copper in my transformer.

As for the 8010 inverter its pretty darn good an pete your gonna like the power board simplicity.


LH