2 inverters in 2 mos., both SMOKE!

[GinaParmesan]

Originally Posted by AtomicNo13

I would suspect a bad crimp on that lug.....
Nothing more than a simple poor contact will generate scary amounts of heat!

I personally solder all my lug connections.
Additionally, I always use specific electrical grease on all mechanical connections, it will ward off oxidation, which will eventually lead to poor connections, heat, then smoke!

@AtomicNo13: Thank you for the reply! Okay, possibly a bad crimp, got it. Another source said that a hammer or pin crimp was used and they agreed it's not the best.

[DaveP]

I can tell by the dimple in the lug sleeve that it was was the hammer/pin crimper. Easy not to get it right. When I did my upgrade, I paid $300 to get a good hex crimp tool to do the crimping and then tested each crimp. Worth every penny.

[GinaParmesan]

Originally Posted by uncle_bob

Hi

There's a couple of threads around here on crimp tools. The bottom line is that matching the tool to the connector is critical. Buying both from the guys who do $400 crimp tools vs $20 crimp tools is a really good idea. The difference between a good crimp and junk is not at all easy to spot after the fact. Again, a good reason to hire a competent guy (who has good tools) rather than some random bum named Bob ...

Bob (the guy with the junk tools ...)

@uncle_bob: Lol, thank you Bob! Yes, another source I spoke with today waxed poetical on the different kinds of crimping tools and had a bit to say about cheap ones. I went through a company with a good reputation, not a random Bob. ; My approach from the beginning was that a solar setup is only as good as the installation.

Other than this issue, the panels, charger, inverter etc. seem well planned and installed. It was a complicated job and not everything can go perfectly every time.

[Troutboy]

Originally Posted by DaveP

I can tell by the dimple in the lug sleeve that it was was the hammer/pin crimper. Easy not to get it right. When I did my upgrade, I paid $300 to get a good hex crimp tool to do the crimping and then tested each crimp. Worth every penny.

Same here. I bought the right tool based on research and recommendations from folks like Lewster that do this for s living. I am sure there many people that use the hammer crimp with no issues.

I also agree the crimp is likely not correct. It almost looks like the wire was not cut to the right size and forced to fit, so it has a kink as well.

I would have that entire wire redone. Crimped and measured to the proper length.

I know from my own install getting the measurement right takes effort if you are not a pro. I did several over because they were to long or too short.

[Al and Missy]

Yep, that's a bad crimp.

A minor semantics issue: KVA is not "energy". Energy is watt-hours.
Google KVA:
"A KVA is simply 1,000 volt amps. A volt is electrical pressure. An amp is electrical current. A term called apparent power (the absolute value of complex power, S) is equal to the product of the volts and amps. On the other hand, a watt (W) is a measurement of real power."

What the reference doesn't say is that real power is the apparent power multiplied by the power factor. Real power multiplied by time is energy.

Another 40+ year EE. My slide rule was a Post. I took an electrical measurements course in which one of the students asked the professor (probably in his 50's) if a particular technique could be used to measure milliamps. The professor's response was "Yes, but why wold you want to do that?

Al

[Snowy]

Is the wire getting hot on the source side, as in wire that goes to the battery, or the load side, as in the wire that goes to the inverter? Looks like load side from the pics which makes sense (to me). I'd bet you are getting a volt drop across that ANL fuse too. The Blue Sea fuse holder looks good, I find blue sea to offer quality products, however not sure about the fuse. I personally like the higher quality gold plated ANL fuses.

Personally I'd cut away that bundle of shrink wrap and electrical tape on that lug. Looks to me that it's the red electrical tape that's not rated for the temp.

Plus with the insulation cut away you will be able to inspect the lug fitting.

Replace with heavy duty marine shrink wrap rated for high temps. Ive use high temp 3M electrical tape without issue too but shrink wrap is better. Easy to do once the lug is unbolted.

Make sure the battery is disconnected before working on these cables.

[DaveP]

Originally Posted by troutboy

i know from my own install getting the measurement right takes effort if you are not a pro. I did several over because they were to long or too short.

2x!!!!

[GinaParmesan]

Originally Posted by Troutboy

Same here. I bought the right tool based on research and recommendations from folks like Lewster that do this for s living. I am sure there many people that use the hammer crimp with no issues.

I also agree the crimp is likely not correct. It almost looks like the wire was not cut to the right size and forced to fit, so it has a kink as well.

I would have that entire wire redone. Crimped and measured to the proper length.

I know from my own install getting the measurement right takes effort if you are not a pro. I did several over because they were to long or too short.

@Troutboy: Thank you! If the installer used an inferior crimping tool, then I'm wondering do I need to question ALL the crimps on ALL the wires?

I agree that the problem wire looks weird, like it might have a kink. The whole wire is about 4 in. from pin to pin, and it strikes me as odd that the actual wire is very, very short...basically a 1 in. nub is conducting all that energy. The lugs almost span the entire length by themselves. But maybe that's nothing.

I should note that another source mentioned the melt seems to be happening at the pad, not further up by the crimp...agreed?

[Snowy]

Wow, loads of posts between me reading the post with pics till me actually posting. You folks are fast.

I looked at the pics again. IMO, in addition to replacing that cable connection you should change out that ANL fuse too. That discoloration isn't good imo, it shouldn't look like that.

Blue sea does a ANL fuse which is well rated both electrically and thermally. I've never used one as they are pricey but for your setup it seems like a drop in the bucket.

[uncle_bob]

Hi

The bigger question is always - if the guy missed this, what else did he miss? Find a pro and let him go over the install.

Bob

[GinaParmesan]

Originally Posted by Snowy

Is the wire getting hot on the source side, as in wire that goes to the battery, or the load side, as in the wire that goes to the inverter? Looks like load side from the pics which makes sense (to me). I'd bet you are getting a volt drop across that ANL fuse too. The Blue Sea fuse holder looks good, I find blue sea to offer quality products, however not sure about the fuse. I personally like the higher quality gold plated ANL fuses.

Personally I'd cut away that bundle of shrink wrap and electrical tape on that lug. Looks to me that it's the red electrical tape that's not rated for the temp.

Plus with the insulation cut away you will be able to inspect the lug fitting.

Replace with heavy duty marine shrink wrap rated for high temps. Ive use high temp 3M electrical tape without issue too but shrink wrap is better. Easy to do once the lug is unbolted.

Make sure the battery is disconnected before working on these cables.

@Snowy: Thanks! The fuse block is Blue Sea, not sure about the fuse itself. It does have gold ends & gold in the window, but I think you're recommending an all-metal one, without the black "window frame" (for lack of a better term). Will look into that.

The setup is like this: batteries > fuse block > *problem wire* > battery switch > inverter. See the attached image.

Good tip, I'll have the next person to inspect the install also dissect the problem wire.

[GinaParmesan]

Originally Posted by uncle_bob

Hi

The bigger question is always - if the guy missed this, what else did he miss? Find a pro and let him go over the install.

Bob

@uncle_bob: That's a hard truth.

[Troutboy]

I'm no expert, and I am sure ANL fuses are okay. I have two on the BMS for my lithiums. However, I was recommended a class T fuse for the inverter and wiring. Are class T better for this application?

[GinaParmesan]

Originally Posted by lewster

First, your 3000VA inverter is stated at 2400 watts, not at 3000 watts. Next, I would look at the load going from your batteries to your inverter. The cables are 4/0, which are fine, but do they extend into the batteries as well? There MUST be a solid connection here of 4/0AWG to transmit the power to your inverter.

Anything less will cause your amperage to increase beyond your ability to handle it, causing the over amperage condition to apply.

Check out the connection and let us know...............

@lewster: Thanks for your reply! VA vs. watts is a new one on me, but I'm clear now. I will make sure to stay below 2,400W.

The notes on my setup diagram say "One end of each #2 wire fitted with reduced-size #10 lugs for fuse block. Other end fitted with 5/16" lugs for battery." I believe there are two #2 wires connecting to the batteries, one black and one red...see attached photo.

[SSquared]

Another thought about replacing the bad wire section: That's a very short distance, and it looks like it is on the same plane. How about a piece of flat copper bar instead of a short wire? You can get flat copper bar that is intended for lightning ground systems. It can carry plenty of current, and it might be easier to work with here. Might be hard to get a nice shrink wrap insulation on it, though. (and probably not according to "code" for this application)

I agree with the previous posters regarding this point: If this crimp/wire was does wrong, what else was done wrong? hmmm.......

[lsbrodsky]

GinaP,

I have been thinking about all of these posts. The forum is a great resource and everyone tries to be helpful, but sometimes the advice is spot on, other times not so much.
People seem to have jumped on the hammer crimp as the root cause. Look hammer crimps are the inexpensive route but they are not necessarily bad. If the crimp is bad, that will be the point of high resistance and should be the hottest spot. In the one picture it appears that the insulation around the crimp is not getting as hot as the red tape next to it.
An earlier post suggested the red tape as the culprit. Another earlier post suggested an IR temp measurement. Clearly you should not be using your system until you get to the cause so wherever you are you should purchase or borrow an IR temp gauge. I have two; they are inexpensive. Energize your system and check the temps looking for the real hot spot.
To me it looks like the red tape was burning and that heat spread a bit. I do not see any evidence of that kind of heat on the insulation adjacent to the crimp, on either side. Nevertheless, it would appear that the real fix, now, is a new wire, new connectors, in that location. Don't reject the idea of a hammer crimp if you are near someone who can do that for you.
Larry

[cwf]

Everyone has personal experience and testing in their professional lives in shade tree and disciplined test. That experience cannot be discounted or discouraged. I have used the hammer crimp with proper tool to make lots of welding leads. Because exposed to weather, I hot dipped in solder pot... never a failure as long as secured against vibrations, or allowed to electrolysis...

I have also desired golf carts, without hot-potting, just hammer crimp... still running after 4 years of extensive use.

I should note.. most wiring I do is "overkill"...bigger wire than "minimally needed"... and so far no failure in that area.. except trying to get it to fit.

As mentioned above, a "copper" strap will do nicely and if it discolors you can see without guessing.

[Silver.Sanctuary]

Originally Posted by GCinSC2

Bob,

It's a sad day when you don't learn something.

I have associates degree in EET but back then we were carrying slide rules for math.

My specialty is 37 years in the clutch industry.

Gary

My slide rule still works!
My HP 50 has dead batteries...

[GCinSC2]

My Pickett model N-500-T with leather case and manual is on standby in the event of zombie apocalypse.

Also fun to show the "app" crowd a tool that helped put us in outer space.

[Troutboy]

Originally Posted by Silver.Sanctuary

My slide rule still works!

My HP 50 has dead batteries...

When I graduated with an engineering degree, for our final test we could bring two items to help in the test.

1- a sheet of paper with relevant formulas

2- a bucket of cold water to cool down the slide rule! There were a lot of questions....[emoji12]