Inverter got Fried!

quique

Attachment not found.I had an old inverter sitting around and I hooked it up to a battery bank which is wired up for 12V. I took the measurement of voltage before connecting it to the BB and confirmed 12.3V. So I proceeded to connect the black terminal first. But when I connected the red terminal, it sparked a bit and then the inverter made a frying sound and smoke came out of it

What else could be the problem besides the Voltage, which seems to be fine?

Here is the wiring diagram...

niel

Re: Inverter got Fried!

parts failure due to age or insects come to mind.

waynefromnscanada

Re: Inverter got Fried!

Reverse polarity is a definitely possibility. Or some internal part may have become defective since it was last fired up.

quique

Re: Inverter got Fried!

Reverse polarity as in -12.3 instead of 12.3....but I did get 12.3V

westbranch

Re: Inverter got Fried!

do you have some pics of the magic smoke and the inverter as hooked up?

quique

Re: Inverter got Fried!

No, unfortunately I wasn't ready with a camera when it happened. First it sparked, but then again it always sparks a little bit (right?). Then something inside fizzled, another fizzle, possibly a third fizzle and then smoke!

waynefromnscanada

Re: Inverter got Fried!

Any chance some liquid may have got spilled in it since when it was last used? A acidic or caustic liquid that may have caused internal corrosion? Other than that, my first thought remains the plus and minus reversed, but you say you checked that and was OK.
One other thought - - was anything at all, any wires, anything, connected to the AC output of the inverter when you tried it? Thinking if it's a MSW inverter and the "neutral" was grounded somewhere, that could well cause it's death.

gww1

Re: Inverter got Fried!

Doesn't your pickture show a 24 volt bank?
gww

waynefromnscanada

Re: Inverter got Fried!

gww1 wrote: »

Doesn't your picture show a 24 volt bank?
gww

Probably 6 volt batteries in series, as he states he checked the voltage before connecting the inverter and found 12.3 volts

gww1

Re: Inverter got Fried!

Whops, open mouth and insert foot. Note to self, "Pay attention"
Thanks
gww

NorthGuy

Re: Inverter got Fried!

quique wrote: »

No, unfortunately I wasn't ready with a camera when it happened.

You still can open the case and take pictures. You'll see what's fried and possibly why.

quique

Re: Inverter got Fried!

Nothing was connected to it. Well, except for the battery bank.

Great idea, I'll open it up

BB.

Re: Inverter got Fried!

If the input voltage was not exceeded and the polarity was correct--Possibly you lost the input filter capacitors (big electrolytic capacitors).

They can fail over time (dry out), and they could be damaged by input surge current (just connecting the battery bank) if they are already "weak/aged"... With larger computer systems, it is not unusual for a power supply failure to occur during normal servicing (tech powers down system--does some work--then attempts to power up). The initial power on stresses can be worse than day to day operation (not saying it happens often, but power restart failures happen often enough).

-Bill

KnowledgeSponge

Re: Inverter got Fried!

quique wrote: »

I had an old inverter sitting around

How old? What type? Manufacturer? Sitting around Where? How stored? Could bugs, liquid or even small hardware have found it's way inside the inverter?
Were the batteries 6Volt or 12Volt batteries?

quique wrote: »

and I hooked it up to a battery bank which is wired up for 12V.

Sounds ok so far....assuming 6 volt batteries. You have 4 rows of 2 batteries with each row connected in series, then the entire bank grouped as parallel.
If they were 12Volt batteries, you would have been supplying 24Volts.
BUT....you said you checked and it ws 12.3Volts....so you either had it connected correctly OR....VERY weak 12V batteries

quique wrote: »

I took the measurement of voltage before connecting it to the BB and confirmed 12.3V.

Still sounds like all systems go....(as long as they were 6 volt batteries.

quique wrote: »

So I proceeded to connect the black terminal first.

Yeah, I usually do that too.
How are your cables marked? Mine are all black and I had to buy RED electrical tape from Lowes and mark the positive cables to MAKE SURE I have a visual indicator.
It is SO easy to make a honest mistake.

quique wrote: »

But when I connected the red terminal, it sparked a bit

My brand new Xantrex Prowatt Inverter does that.

quique wrote: »

and then the inverter made a frying sound and smoke came out of it

I sure hope my brand new Xantrex does NOT do THAT !

quique wrote: »

What else could be the problem besides the Voltage, which seems to be fine?
Here is the wiring diagram...

Well, depending on HOW old and how it was stored, like others said it could be any number of things.
Short of a component failure or some foreign substance or smal metallic object accidentally entering the body through a fan opening
or something....not sure.

Please post photos of the inside and if you get a chance to answer my questions at the top of the post.
It might help everyone help you figure it out.

Sorry about the inverter....hopefully it was not a very expensive one.
This thread has caused me to consider a VERY important aspect of a New Xantrex Inverter I just bought however.

It is brand new but was manufactured 4 YEARS ago. The huge capacitor inside has already lived a significant
amount of it's "shelf life" sitting on a shelf. But I'll post a thread on that topic.

quique

Re: Inverter got Fried!

Here they are. I know absolutely nothing about electronics so I have no idea what to look for. I did look for anything charred black but couldnt really find anything.

I did notice that one of those cylinder looking things (which I guess could be capacitor) was missing its silver cover. The silver cover was actually floating around elsewhere, loose, inside the inverter.

I also noticed some white paste which looked like something had melted but it could simply be that its the way it was from the beginning.

It had been stored in a warehouse. Its chinese, we bought them a couple of years back. The 3 ones installed work fine.

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BB.

Re: Inverter got Fried!

Yep, electrolytic capacitor "blew" (and there is a clear liquid electrolyte inside the cans too--probably slightly corrosive if not washed off the components/board).

Notice the "cut marks" in the top of the larger capacitors--Those are "pressure relief" points (split at the cuts rather than blow the whole can off like a rocket). So, they do have to plan for failures.

The white paste on the sides (under power transistors) should be just "thermal grease" used to help transfer heat from the hot transistors to the aluminum heat sink.

-Bill

NorthGuy

Re: Inverter got Fried!

quique wrote: »

Here they are.

In addition to what Bill said, a mosfet (or diode) bolted to the heat sink north of the big inductor looks like it might be burned down, but it's hard to see.

niel

Re: Inverter got Fried!

NorthGuy wrote: »

In addition to what Bill said, a mosfet (or diode) bolted to the heat sink north of the big inductor looks like it might be burned down, but it's hard to see.

i agree as it looks a tad crispy, but it could also be corroded. the bottom line is the inverter is defective.

waynefromnscanada

Re: Inverter got Fried!

quique wrote: »

I did notice that one of those (capacitors) was missing its silver cover. The silver cover was actually floating around elsewhere, loose, inside the inverter.

Oh oh, that end cap off the capacitor, floating around among all that electronics could very easily cause short circuits, and in turn very serious damage

KnowledgeSponge

Re: Inverter got Fried!

Preventative measures anyone ?

Could he have possibly opened the Inverter (having been stored and inactive for an extended time) and maybe seen a bulging capacitor?

Is there such thing as giving an Inverter a "Physical" before putting it back into service?

inetdog

Re: Inverter got Fried!

KnowledgeSponge wrote: »

Preventative measures anyone ?

Could he have possibly opened the Inverter (having been stored and inactive for an extended time) and maybe seen a bulging capacitor?

Is there such thing as giving an Inverter a "Physical" before putting it back into service?

Usually a bad electrolytic capacitor will not show any physical symptoms until voltage is applied. Same way that a light bulb will always fail while the power is on. :-)

But if you see actual signs of fluid leakage, such as dry residue around the base, that would be bad.

One way to increase the odds for electrolytic capacitors which have sat unused for a long time is to apply voltage to them slowly and to cycle the applied voltage up and down for awhile before going to full voltage. But it is hard to do that when the capacitor is in circuit and it is not connected directly to the input.

waynefromnscanada

Re: Inverter got Fried!

Certainly if he had noticed anything rattling around inside, (the end cap off the capacitor) it would have been a very good indication the cover should come off to see what was going on. Beyond that, I too would have just hooked it up to see if it was still working. And right or wrong, the only other reason I would have taken the cover off would be to have a look for cobwebs and to see how well made it appeared to be. A well made device is to me a true work of art that I tend to admire.
Unfortunately, the OP due to his lack of experience, wouldn't have recognized a capacitor, bulging or not. And even if he had noticed what to him looked like a bulge, he wouldn't have questioned it. It's different for us who have many years experience/training in electronics.

mike95490

Re: Inverter got Fried!

photo #4 shows a cap with the case blown off ? (next to 3 good looking ones) No way to prevent that except QA at the factory.

The good news is, that with the inverter dead, the transistors clamped to the heat sink, via their plastic cases, will
never have a chance to die. When the case material heats up, the pop-rivet "clamp" is not going to provide the proper tension, and the transistors will eventually overheat.

Mike "not going to fly that in space" Burgess.