Magic Smoke Incident!

[freejuice]

Yep the Magic smoke came out my AIMS inverter today....groan.
 I think it was this South Carolina humidity  which did it in. The setup was in the garage and had not been ran in about three days, I went out ther to cut it on after the grid power was knocked out and """zzzzzzcrick curck,ssssssssss" I threw the switch off , disconnected the battery cables and took it apart...it looks like two oversized fets burned up. But everything looked very dry inside??

I will contact Aims and see what they charge to either repair it or give it a proper burial.

I will have to rig something up that allows that inverter to "breath with the cooling fan" but also keep the humidity out of it!
 Any ideas on that one folks?
 I could bring the inverterinside but everything would have to be moved...battery bank, cabling from the 17 footer would have to be dug up and re-routed, etc etc.

[TrackerJack]

Well Crap... I bought a aims mw 5000 and a psw 1000 about 2 years ago. I brought them out of storage, brand new to use as a back up.
Forgot I even had them. Never even heard of aims. After searching net, I found 3 units that where exactly the same as the aims but with
different badges. Me thinks you can buy these a 1000 at a time. Have some stickers made up, a good web site and your in business.
Now after reading your post  I am thinking that its to big to be a paper weight, maybe a door stop or an anchor for my boat.
But I don't think I want to take the chance of a big o firework. By the way, what size inverter is it?

[rossw]

I had a reply all typed up before.... but deleted it because it wasn't politically correct.
I'll type it in again, as a "watered down, sanitised" version, and leave out the comments about the specified brand.

To minimise the risks with humidity in your (relatively low) voltage application, you don't need specifically to dry the air (or relocate it inside) - the biggest single thing is to ensure your equipment doesn't fall below the dewpoint of the air you have.

For example, if you've got 95% relative humidity, and it's 30 degrees C, any surface that's below 29.1 degrees will have water condensing out on it!!

If its been slightly cooler overnight say, and the day warms up and humidity increases rapidly, the extra mass of your equipment can easily keep it below the dewpoint and you will get water condensing on things. Bad karma. Magic smoke.

Keeping the equipment slightly warmer than the ambient temperature of the air will prevent the problem. If you're on-grid and have cheap, plentiful power, you don't need much of a heater to achieve that. The battery charger itself is probably enough. Or a small incandescent lamp. Anything. Only needs to take the chill off.

[kitestrings]

fj,

How's that quote go..."there's nothing like the smell..."?

Majic smoke and burning brakes pads all leave you with a lasting impression.  Seriously, sorry to here this.  We have a very small AIMs inverter - SW, I think it is 180 watts.  We've used it to run our demand water heater, which is really just the ignition and exhaust motor (freeze protection on rare ocassion).  It keeps our main inverter from running all day, and thus has lower standby losses.  So far no problems with it.  We've had it about 2-3 years.

One thought - There's quite a bit of heat generated from the diodes of the rectifier (I'm assuming you have wind?).  Perhaps that could be recylced to provide the needed temperature rise.  This or another source of waste heat might be woth considering.

I've also seen small resistive elements (and even AC) in larger, industrial control panels, but that seems overkill here.  Extreme cold temps are more often the problem where we live.

Good luck with it.

~kitestrings

[DanG]

I have a Mylar sheet with a resistance trace painted on it - 1 watts at 120VAC that came out of a refrigerator door, it was used on the cold water dispenser to halt exterior condensation... If you have utility power to that area and want it for the next unit it's yours.

[madlabs]

I've blown a couple of AIMS. One was apparently due to grounding issues and the other just bit it for no reason. That one was replaced by the place I bought it at (theinverterstore, no affiliation but they were prompt with replacement). So I wouldn't assume it was humidty, they don't seem to be the most rugged inverters out there. Of course, it could have been the humidity. Now, wasn't I just very helpful? :-0

Jonathan

[dnix71]

Not just humidity. The church I attend was nearly burned down by an old school microwave oven with a mechanical dial. A bug (probably ant) crawled in and turned it on empty with the door closed at night until it caught fire.

I've had ants destroy a GFCI in the bathroom by crawling inside, too and watched a microwave oven circuit board catch fire when the door was closed because a triac failed gate to hot.

That one came out of a preschool I did maintenance at. Some things are just better left unplugged when they are not in use. No way to keep ants out. They have invaded my place again now that it's raining in south Florida.

[freejuice]

Well Crap... I bought a aims mw 5000 and a psw 1000 about 2 years ago. I brought them out of storage, brand new to use as a back up.
Forgot I even had them. Never even heard of aims. After searching net, I found 3 units that where exactly the same as the aims but with
different badges. Me thinks you can buy these a 1000 at a time. Have some stickers made up, a good web site and your in business.
Now after reading your post  I am thinking that its to big to be a paper weight, maybe a door stop or an anchor for my boat.
But I don't think I want to take the chance of a big o firework. By the way, what size inverter is it?

Its a monster, 48V 7000 watt industrial version

[freejuice]

I had a reply all typed up before.... but deleted it because it wasn't politically correct.
I'll type it in again, as a "watered down, sanitised" version, and leave out the comments about the specified brand.

To minimise the risks with humidity in your (relatively low) voltage application, you don't need specifically to dry the air (or relocate it inside) - the biggest single thing is to ensure your equipment doesn't fall below the dewpoint of the air you have.

For example, if you've got 95% relative humidity, and it's 30 degrees C, any surface that's below 29.1 degrees will have water condensing out on it!!

If its been slightly cooler overnight say, and the day warms up and humidity increases rapidly, the extra mass of your equipment can easily keep it below the dewpoint and you will get water condensing on things. Bad karma. Magic smoke.

Keeping the equipment slightly warmer than the ambient temperature of the air will prevent the problem. If you're on-grid and have cheap, plentiful power, you don't need much of a heater to achieve that. The battery charger itself is probably enough. Or a small incandescent lamp. Anything. Only needs to take the chill off.

Thanks Ross, your explantion makes perfect sense!

[freejuice]

Hi Dnix71,
I was thinking it could have bee a criiter before I opened it up...but didnt see any evidence of a suicide inverter bomber...but the was it hissed and sparked it could have complelty dissappered.
 Hi madlabs,
The interternal of the Aims appaers to be fairly rugged...well at least to my untrained  eye   However, what makes this such a puzzle is that it appeared to be dry inside and out, but the humidity aorund here is my likely suspect...but like you say it could have simply been time to go.

 Hi DanG, where would I place it? The inverter is fairly large...its about 8-10 inches wide, about 6 inches tall and about 30 inches long

[David HK]

Can you identify the company/manufacturer that made the failed components - as shown normally on the item concerned.

That may give a hint as to why things went up in smoke. The manufacturers name is one thing, the suppliers name is another. a  surreptitious copier of a product is another and so on.

Your machine may have a mixture of good and inferior products.

David in HK

[TomW]

Electronics are funny devices. It could last the millenium or pop the smoke the next power cycle. Not easy to predict which in consumer goods.

Lots of components can sizzle when they fail. Some literally explode after a bacon frying sound.

It could just have been "its time". Meaning no external cause.

The real kicker on DIY repair is the obviously failed (fried) part will more than likely not be the actual cause so tossing in new FETs will likely be tossing money on the fire so to speak when they fail on power up from another failure that took out the FETs.

[Boss]

I had a reply all typed up before.... but deleted it because it wasn't politically correct.

Now you have my curiosity heightened? What could be politically incorrect about humidity? Or was it the ...? Ah come on tell us?

[freejuice]

Hi Boss,
  If not mistaken I think it had something to do with a debate over inverter voltage ( 12v vs 24v vs 48v)...maybe a year ago...it had a lot of comments and a lot of hits.


David HK,

Hopefully some photos will follow soon....busy (groan)
I took the inverter apart again and took the heat sinks  off the offending "oversized fets" I call them oversized fets because I'm no electronic guru...just ask Ghurd, he'll tell ya how rich he could be right now if he had charged me a nickle a question!
 Here is the information on the four smoked(fets?)
as printed on the component:

OIXYS
IXTK80N25
SS0542
DS3778
KOREA


Since the AIMS unit is made in Korea it looks like they also shopped for the components in their home country.
 If I can finally free myself up for a weekend around here I may just try to replace these....if the local electronics store has them and they are not too pricey....I will toss twenty or so more bucks at this unit if comes back to life,...its either that or dig deep and ....exhale halfway and squeeze the trigger on an Outback!

[freejuice]

Inverter with the lid off...just left of center, top of the lower unit you will see a heat sink missing...I took it off, this is the area which got "smoked" the next heat sink to the immediate right also has one or two more smoked "fets?"
 Thats all the damage I can see....I did not take the board out...maybe more damage on the reverse side?



Closeup:

[fabricator]

I had a reply all typed up before.... but deleted it because it wasn't politically correct.

Now you have my curiosity heightened? What could be politically incorrect about humidity? Or was it the ...? Ah come on tell us?

Ross doesn't believe in anything but high dollar true sine wave inverters, his reply was gonna be something on the order of you get what you pay for, to each his own, everybody has the right to his own opinion.

[Southbuck]

Ross does not have a blown inverter. I just wish I could go medium dollar stuff.
High dollar stuff usually ends up what you pay for, quality and service.

Southbuck

[dnix71]

http://webcache.googleusercontent.com/search?q=cache:j8gfWMkYyRgJ:parts.digikey.com/1/parts/1714503-mosfet-n-ch-250v-80a-264-ixtk80n25.html+IXTK80N25&cd=5&hl=en&ct=clnk&gl=us&client=firefox-a&source=www.google.com

That's a HIGH power mosfet 540 watts max. Over $10 each if Digikey actually had any. Me thinks the heat sink is not big enough for 1/2 KW.

http://www.ixyspower.com/store/PartDetails.aspx?pid=748&r=1

http://components.arrow.com/part/detail/43897171S9596511N2198?region=na&whereFrom=partDetailClickThrough  16 weeks lead time to get any. Maybe someone here has an inverter to sell or loan you.

That mosfet is military grade.

[freejuice]

[That's a HIGH power mosfet 540 watts max. Over $10 each if Digikey actually had any. Me thinks the heat sink is not big enough for 1/2 KW.

That mosfet is military grade.

Ok sounds like AIMS used some quality components...but the heat sinks might be small....hum interesting.... you might have a point ....each heat sink covers TWO of these fets so it is actually trying to dissapate close to 1100 watts!
 the heat sinks are roughly  about 3/16ths ( 5 mm) thick  x .750 ( 19mm) x 1.5 inches long( 31 mm)....that possibly could have been the culprit...but the rub in this theory was the inverter had been off for about three days and it blew the moment I flipped the switch.

[boB]

Yeah, unfortunately the power dissipation rating of the part doesn't have a lot to do with how much power the inverter is good for.
All that means is that if you keep the case of the FET at 25 degrees C, the silicon die inside will be at it's maximum rated temperature
at that dissipated Wattage.   However, the bigger the number, the better the part is, usually.  These are not too bad of parts, but there
are better.

 In a real application you will only get a few Watts dissipated from a FET before it goes to toast mode.  A few meaning MAYBE around 10 watts
or so depending on the heat sinking capability and ambient temperature the unit is in.

If the FET drive is OK, and nothing else is broken or shorted, you might be able to fix it.

boB

[kurt]

.exhale halfway and squeeze the trigger on an Outback!

if you go for an outback take a look at there sealed units that will pretty much eliminate any humidity and insect problems.

[rossw]

Ross doesn't believe in anything but high dollar true sine wave inverters

Pull your head in, You delliberately misrepresent the facts in order to stir up trouble.

Boss: for the record, I was going to make a comment about the brand from comments others have made. I've never owned one of "those" and never will.
I purchased ONE inverter when I built here, about 7 years ago. It's still running, been running 24/7.

[fabricator]

Calm down Ross, did I not say everybody deserves an opinion? Who was it that mentioned having a reply all typed up that was not politically correct, which lead to the curiosity of some posters? Take a chill pill brother.

[joestue]

are the fets individually driven or are all the gates paralleled into one massive driver?

[rossw]

Calm down Ross, did I not say everybody deserves an opinion? Who was it that mentioned having a reply all typed up that was not politically correct, which lead to the curiosity of some posters? Take a chill pill brother.

You are trying to re-ignite the old war. You know as well as I do (if you care to admit it, which I doubt) - that my main argument was with squarewave inverters and all their implied problems (that includes marketing-hype-bull$#|+-terms like "MSW" deliberately chosen to mislead the uninformed into thinking somehow "square waves with bumps" are not really square waves), and that 12V is not a suitable supply for high-power applications.

Your "mate" who made such a venomous attack against me doesn't seem to have admitted in public that he's dumped his precious aims inverters and now has bought some *shock horror* expensive xantrex units.

I won't partake of your games. People can buy what they like. I will spare any sympathy for those who have failures, and especially those who suffer multiple failures, from using unsuitable technology for the task at hand.

I will say - I'm probably totally unqualified to comment on inverters. I've only been living totally offgrid for 7 years, so quite a n00b. I've also only ever purchased one inverter. That inverter runs all the computers and "sensitive" electronics, my lathes and grinders and welders and pumps etc. It interacts with my generator, turbine and solar arrays, it logs stuff and has a plethora of adjustable parameters. It was moderately expensive, but it was at a time when time was short - after the promised grid connection was undelivered and undeliverable. Against that, I've had zero downtime with it running 24 hours a day, 7 days a week since I bolted it to the wall. I doubt my time was wasted with the research I did into what was available *worldwide*, fault/problem reports of each from users and my own gut feelings about the specifications and manufacturers claims of each.  I doubt there are too many who can (honestly) say the same.

[freejuice]

are the fets individually driven or are all the gates paralleled into one massive driver?

Joe,
 I wish I could answer that question....I'm far from an electronics guru

[wpowokal]

Ok sounds like AIMS used some quality components...but the heat sinks might be small....hum interesting.... you might have a point ....each heat sink covers TWO of these fets so it is actually trying to dissapate close to 1100 watts!

They are not trying to sink that wattage the figure relates to their max handling wattage, it seems that only some of the MOSFET's on that half are zapped which to me indicates a fault localized to them, dust and humidity will do it, so will old age, now where did I put that walking stick. While I also am no expert if you clean up the chared area so there are no shorts and power it up no more smoke should escape if all else is well, try a small load if that seems Ok replace the smoked MOSFET's. I know its hard without the right monitoring gear but give it a try.

A MOSFET that is correctly driven should generate little heat on it's own, however in most inverters there are many so heat is developed.

And while I am at it although I see little sense in debating inverter quality in this thread I as with Ross rely on my inverter totally and for that duty one gets what one pays for, I also have a cheep MSW inverter I used/abused on the farm for fencing etc and it still works but for my house I put my hand deep in my pocket $10,000 OZ dollars for my current unit, same as I had on the farm, but there are many variations on peoples budget and requirements, having informed people they can buy what suits them for their application and budget. Real inverters have transformers in them.

Allan of the jungle

[Boss]

Boss: for the record, I was going to make a comment about the brand from comments others have made. I've never owned one of "those" and never will.

Gotcha, thanks for the clarification, I was hoping for something juicier. Nevertheless this is still a informative thread
 

[freejuice]

Ok sounds like AIMS used some quality components...but the heat sinks might be small....hum interesting.... you might have a point ....each heat sink covers TWO of these fets so it is actually trying to dissapate close to 1100 watts!

They are not trying to sink that wattage the figure relates to their max handling wattage, it seems that only some of the MOSFET's on that half are zapped which to me indicates a fault localized to them, dust and humidity will do it, so will old age, now where did I put that walking stick. While I also am no expert if you clean up the chared area so there are no shorts and power it up no more smoke should escape if all else is well, try a small load if that seems Ok replace the smoked MOSFET's. I know its hard without the right monitoring gear but give it a try.

A MOSFET that is correctly driven should generate little heat on it's own, however in most inverters there are many so heat is developed.

And while I am at it although I see little sense in debating inverter quality in this thread I as with Ross rely on my inverter totally and for that duty one gets what one pays for, I also have a cheep MSW inverter I used/abused on the farm for fencing etc and it still works but for my house I put my hand deep in my pocket $10,000 OZ dollars for my current unit, same as I had on the farm, but there are many variations on peoples budget and requirements, having informed people they can buy what suits them for their application and budget. Real inverters have transformers in them.

Allan of the jungle

Thanks for the clairification Allan!
 What kind of inverters do you folks use "down there"?
 A  few folks I have spoke to in PMs mention Outbacks...I understand their customer service is top notch...I dont want to open up a peeing contest over this inverter V. that inverter...each person has their justification on the economic scale alone, and quality appears to vary widely and I have discovered in my application that AIMS might not be my best option
 I guess I'm now looking for success stories before I make my decision on my next inverter. As of now I'm 100% grid power...groan.
 as a side note ... here's my situation:
my system is 48v and I need to be able to switch back and forth from grid to battery bank through my transfer switch....so my inverter will need to be grounded back into my service panel which has the common and neutral together I wont prejudge anybody on their choice, I'm looking for reliability alone. Thanks for any and all replies!
 All the best,
 Gavin

[Bruce S]

ALL;
Those who currently posting here THAT is NOT directly involved with helping with a way to fix or temp repairs.
NEED to STOP and of right now otherwise further action will be taken to remove your posting rights known as Time-out.
I for one will NOT allow this diatribe to continue on this posting!!
FAB , RossW with due respect to the OP--- NO more of this on this post.
IT does no one any good and detracts from helping.
Others are trying to ignore this.
Bruce S

[ChrisOlson]

A  few folks I have spoke to in PMs mention Outbacks...I understand their customer service is top notch...I dont want to open up a peeing contest over this inverter V. that inverter...each person has their justification on the economic scale alone, and quality appears to vary widely and I have discovered in my application that AIMS might not be my best option

Gavin, this is my experience with buying a quality pure sine inverter when we made the jump to 120/240 volt split phase power.

I think the Outback is a very good unit and it is relatively inexpensive compared to the Xantrex.  When I went to buy inverters I decided I am going to buy them from a brick and mortar store where I can walk in and talk to somebody who knows what's going on.  I was originally going to buy an Outback Flexpower TWO so I called Outback Power Systems in Arlington, WA and asked them who my closest authorized dealer is.  I gave them my zip code and then spent five minutes waiting on the phone and they finally gave me a phone number for some guy in Ohio.  I called the guy and he didn't even answer the phone.  I decided this is not going to work and I will not buy another inverter online.

I called Schneider Electric and asked them who my closest Xantrex dealer is and they gave me the phone number for a local dealer only two hours away that has been servicing Trace/Xantrex inverters since before Outback was even invented.  I went there to see what they got and was immediately impressed - they stock EVERYTHING.  After drooling all over their stuff I wrote them out a check that really hurt the finances and left with a written guarantee that if anything goes wrong with my new inverters they will be here same day, holidays and weekends included, and have that inverter back up and running in one visit.  They stock everything for it, including a complete replacement unit if it blows right off the wall and lands on the floor in a smoldering heap.  They were here the next day and installed my equipment.

The Outback guy called me back the afternoon when I got my new Xantrex units installed.  For me, the Xantrex was "The Smart Choice For Power".

You can argue the merits of the Outback units vs Xantrex vs Magnum, etc..  It all boils down to what you need, where your local service center is and how qualified they are, and how much you want to spend.  In my opinion the big Xantex is the "Cadillac" if you need 120/240.  It is also not cheap - you'll drop $7 Grand on it with all the bells and whistles.  You can probably install an Outback for around $2 Grand.
--
Chris

[freejuice]

Ok sounds like AIMS used some quality components...but the heat sinks might be small....hum interesting.... you might have a point ....each heat sink covers TWO of these fets so it is actually trying to dissapate close to 1100 watts!

They are not trying to sink that wattage the figure relates to their max handling wattage, it seems that only some of the MOSFET's on that half are zapped which to me indicates a fault localized to them, dust and humidity will do it, so will old age, now where did I put that walking stick. While I also am no expert if you clean up the chared area so there are no shorts and power it up no more smoke should escape if all else is well, try a small load if that seems Ok replace the smoked MOSFET's. I know its hard without the right monitoring gear but give it a try.



Allan of the jungle

Well I be darned! I did just what you said... hey what the heck nothing to loose right??...I took an old toothbrush and scrubbed up the old soot nice and clean....snipped off the three burnt fets and screwed it all back together...and believe it or not it works! I plugged up a circular saw to it and it started without a problem.
 Now what load it can handle now I don't know but it appears to be working, I do however need to increase the load a bit more....I'm with Tom on this, I might be throwing good money after bad if I replace those fets, but my stubborn logic is telling me to give it a fools try
 IF all this works out I might be back in business for the short term, however I still need to improve my inverter status a bit....maybe keep this ol dog on a shelf for a backup inverter!
 Thanks again!
 Gavin

[freejuice]

Chris that sounds like excellent customer service...while I could eek out  the 7 grand, it would hurt...so much in fact I would probably see the wife out in the back yard with a set of post hole diggers just going to town with them....being naturally curious I would have to inquire with the "bitter-half" as what she was doing...she would probably snap back ' I'm going to place a pole here and this is what I'm going to tie you to when I shoot your A$$"
 I probably need to keep it in the 2000 dollar range so I won't get perforated.