2 inverters in 2 mos., both SMOKE!

[uncle_bob]

Hi

Ok so now I'm confused. Does the battery bank have 4 110AH 6V batteries to give 220AH as stated earlier? Does it have 4 6V T-105's at 220AH each? Is it something else entirely?

Bob

[Troutboy]

I also have the same unit, brand new never smoked using microwave,and also using AC. By the way, your unit is not 3000W, it's more like 2400W. The 3000 is kva, as Victron uses metric system units.

I would be very scared when using this if it smoked. Do you have proper ventilation? Can you exchange air through the closet or is it sealed. The fan on the unit alone will not cool it, unless you have fresh cool air access.

Does the smoke happen right away, or after it runs for a bit. Have you measured the temp in the closet before and after? Sounds like you may be overheating in that small space.

[GinaParmesan]

Originally Posted by uncle_bob

Hi

At 5' of cable, 4/0 should be ok. it certainly is big enough that it will not smoke running a 1.5KW load. That does not let the cabling off the hook as the source of the smoke, just the wire (the connections are still in the running). The idea that a brand new inverter sends out clouds of smoke is bunk. That goes double for a well known and respected brand. It goes at least double that when run at 1/2 the rated load. So, no this is not some sort of "expected result" running an inverter.

Backing up a bit, 3KW at 90% and 12V gets you to 275A. That's running your batteries at a discharge rate above their amp hour rating. That 200 AH rating is likely at a 10 or 20A rate. At 200A, there rating might be 120AH rather than 200AH. Simply put, your battery bank is a bit small for a 3KW inverter. It *will* drop voltage under load pretty fast. Consider tripping the number of batteries in the bank if you want to get 5 or 6 years use out of them and will be running the full or near full output on a regular basis.

Smoke generally means 451F is being approached. (Yes, it's a Sci Fi reference ... sorry about that). Normal electronics should never get above about 150F. Wire and cable - same thing. You will get steam at 220F, but that's not smoke. If it's getting hot enough to generate smoke, it *will* leave a trace. If that trace is not obvious, an infrared camera or cheap IR thermometer (< $30) will likely spot it for you. If you don't mind getting burned, poking here and there will spot it as well. BE VERY CAREFUL OF 120V LINES if you do the poke method.

My guess is it's not the inverter at all. They generally have high temperature shut down features that kill them when they go hot. I'd bet on a poorly done connection somewhere or a cable that has a deep gouge in it. A really scary thought is that it's not on the 12V side but on the 110 V side of things ... yikes !!!

Bob

@uncle_bob: I OWE YOU A WARM SIX PACK, SIR, because I just found a half-melted connection between the 400A fuse and the battery switch. It was hidden under the fuse cover. I wrote out a long reply, went for a bike ride, then decided to poke around before posting and boom, there it was. I can't believe the guy who installed the new inverter last week didn't see it! What a relief to know the cause at last, and clearly I'm lucky not to have had a fire. I'll be getting that wire replaced pronto. Thank you Bob x1,000,000!

So now my big question is, do you think the inverter was/is/will be fine?

[GinaParmesan]

Originally Posted by nwclassic

Your battery bank (composed of 4 6v @220Ah) will deliver 440Ah wired for 12v, not 880Ah, right? AND, discharging <50% now limits draw to 220Ah. You're asking your bank to do more than it should (which could only be managed by trimming the minutes (seconds?) of use. I wonder if you demonstrated the smoking behavior to your technician that looked it over. There is no safe circumstance where electrically generated smoke (of ANY kind) is acceptable in an RV. Your system is capable of harming you. Be cautious/get help with this.

@nwclassic: Correct, I have 4 6V Lifeline sealed AGM batteries wired in series and parallel, so it's a 12V system that can deliver 440Ah (220 usable). No, I didn't demonstrate smoking to the second tech. I did test all appliances including kettle, a/c etc. after the new unit went in, with no smoke, which is why I thought everything was hunky dory. Until the next morning trying to make coffee... Thank you for your contribution, I did find the source of the problem (bad connection) and will get it fixed pronto!!

[GinaParmesan]

Originally Posted by Troutboy

I also have the same unit, brand new never smoked using microwave,and also using AC. By the way, your unit is not 3000W, it's more like 2400W. The 3000 is kva, as Victron uses metric system units.

I would be very scared when using this if it smoked. Do you have proper ventilation? Can you exchange air through the closet or is it sealed. The fan on the unit alone will not cool it, unless you have fresh cool air access.

Does the smoke happen right away, or after it runs for a bit. Have you measured the temp in the closet before and after? Sounds like you may be overheating in that small space.

@Troutboy: Thank you very much for the reply! Yes, scary indeed. I just discovered it was a bad connection, hidden under a fuse cover. It was a bit warm in the closet but nothing crazy. There is decent ventilation. That's new info about the wattage though...very glad you mentioned it. Still beats me why we aren't on the metric system too.

[uncle_bob]

Originally Posted by GinaParmesan

......
So now my big question is, do you think the inverter was/is/will be fine?

Hi

You have a good brand of inverter. It should self protect (shut down) before there is damage. I would not worry about it at all.

Glad you found the problem !!!

Bob

[lsbrodsky]

Me, too! Your inverter is fine. Enjoy
Larry

[GinaParmesan]

Originally Posted by lsbrodsky

Me, too! Your inverter is fine. Enjoy
Larry

@lsbrodsky: Thank you so much, Larry!

[uncle_bob]

Hi

Ok just a clarification:

KVA = volts times amps. In an AC circuit that may or may not be power due to phase shift between the voltage and current. Technically it's the "energy" into the load.

Power = KVA times power factor. It's the "work" (heat) delivered to the load. Power factor takes the phase angle between voltage and current into consideration.

If your load is purely resistive (coffee pot) the two numbers (KVA and power) are the same. If your load is a motor (think compressor motor) they probably are not the same (KVA is higher than power).

Another bit of confusion comes with "peak power". Some loads pull a "surge" of power when they start up (agin compressor motor). Depending on who writes the ad copy, you may see *that* as the number on an inverter. There is no standard for how long an inverter needs to deliver "peak". It may be one cycle (1/60 second). It may be 10 seconds, it could be 10 minutes. I believe the converter we are talking about is rated at 6KW peak (which is a good number).

Yes, there's a lot of confusing numbers tossed around on these gizmos. It's a bit like comparing a 30' Airstream to a 30' SOB ... they aren't measuring the same thing but they both use feet

Bob

[GCinSC2]

This is a great example of reaching out and darn good responses, contributors nicely done.

I'd like to see the look in the installer techs face when he sees that wall hanger burn up.

And looks like several posters have strong professional electrical experience. Is that correct Bob?

Also this sure beats a call to the fire dept. OP glad for you this is on its way to happy camping again.

Gary

[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...............

[uncle_bob]

Originally Posted by GCinSC2

And looks like several posters have strong professional electrical experience. Is that correct Bob?


Gary

Hi

.... only about 50 years of experience as a EE (which is *not* the same as a Master Electrician, don't let anybody *ever* tell you it is. They know a lot of stuff I'll never know.) ... still learning new stuff every day

Bob

[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

[Snowy]

I think you already found your issue, the ANL fuse right? While you have correctly sized wire all the amps run through a single fuse based on your description. The ANL fuses get stupidly hot at the sort of amps you are drawing.

I've run into a similar issue with a portable inverter setup used to power an air compressor. The inverter is a 3000watt with 6000w surge. Tested using a shunt, I see 150amps constant draw while the compressor is running. The ANL fuse would heat up and actually started melting the "cheap" ANL fuse housing.

My solution was to move to a parallel fuse setup. When you do this each fuse is lower rated by the division of the number of fuses in parallel. In your case I think you said you were using a 400 amp fuse, putting two 200 amps in parallel would be the same.

I'm sure the electricians on the forum will have a fit over this solution. I'd love to know if there is another recommended solution. Maybe it's simply a better ANL fuse housing.

[uncle_bob]

Hi

You *can* get the parallel fuse setup to work. It's a pain to wire it so the current properly splits between the fuses. There are a number of fuse types that will easily handle a few hundred (or a few thousand) amps. They aren't small and they aren't cheap.

At 300A and 12V you will be passing around 3.6 KW through the fuse. If they consume 25W at max current, that sounds like a lot. Compared to 3.6KW, it's < 1%.

Here's the bigger issue - 25W *is* a lot of heat. Put into any small device, the temperature will go up quite a bit. The holders are designed on the assumption that they will not be buried under something. At half current you should see < 1/4 the heat, so it's not as big a problem under "typical" conditions.

Bob

[rmkrum]

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

(Sigh). I still own my original K&E slide rule and an original copy of the book.

[GinaParmesan]

Contributors, thank you all for your help with this issue! I now know the smoke was coming from a hidden connecting wire all along, not the inverter.

The problem wire connects the 400A fuse to the battery switch. Can anyone diagnose from the attached photos what about the connection is causing the wire to overheat?

I've checked the four bolts connecting wires to the 400A fuse, and I couldn't tighten any of them by hand at all. Unsurprisingly, the wire gets very hot to the touch when a heavier load runs.

I want to find out as much info as possible before I call the installer. (I'm 2/3 of the way across the country from them so they can't check it over personally.) Thanks again!

[GinaParmesan]

Originally Posted by Snowy

I think you already found your issue, the ANL fuse right? While you have correctly sized wire all the amps run through a single fuse based on your description. The ANL fuses get stupidly hot at the sort of amps you are drawing.

I've run into a similar issue with a portable inverter setup used to power an air compressor. The inverter is a 3000watt with 6000w surge. Tested using a shunt, I see 150amps constant draw while the compressor is running. The ANL fuse would heat up and actually started melting the "cheap" ANL fuse housing.

My solution was to move to a parallel fuse setup. When you do this each fuse is lower rated by the division of the number of fuses in parallel. In your case I think you said you were using a 400 amp fuse, putting two 200 amps in parallel would be the same.

I'm sure the electricians on the forum will have a fit over this solution. I'd love to know if there is another recommended solution. Maybe it's simply a better ANL fuse housing.

@Snowy: Your portable scenario sounds like what I'm seeing. The smoke is coming from a melted point on a wire, but I'm unsure whether the fuse is the actual root cause.

There's no evidence of melting on either the fuse window or the plastic base. I do see discoloration on half the metal on the fuse. The top half that's closest to the melted wire, and inside the fuse window, are now copper color. The metal part on the bottom of the fuse is gold. All parts are gold on the replacement fuse.

It could be the discoloration on the fuse is just from being so close to the wire (heat source) but maybe it's the other way around and the fuse is the heat source?

[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!

[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 ...

Also consider that the fuse and holder may be getting quite hot, but be high temperature materials. The temperature rating on the wire or connectors may be much lower.

Easy approach - leave it all out in the open and turn on the coffee pot. See where the smoke comes from ...

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