Inverter question regards arc welder use

I have purchased a small solid state arc welder off ebay, specifically for emerg repairs whilst travelling. It is a Lumix brand, circa $120, 0 - 160amp variable, 10 AMP plug. Its a cheapie but the first low cost. once in a lifetime use welder in this bracket.

I have a 3000W pure sine wave inverter, 6000w surge for 20 secs. I tried the welder this weekend and it barely raises a spark from even a 1.6mm rod running off the inverter. If I plug it into the mains, running off a 10amp fuse, welds beautifully.

Whats going on here? I know there is a temp amp rise at strike, however the inverter is not tripping out, simply appears to not have the 'power' to let this operate.

Appreciate any technical help I can get on this, and any alternate units that have been run off inverters. I have a 24-35V gasless mig welder already but its a handful getting the batteries connected etc and its large in size. this unit is not much bigger than a tissue box.

Sounds weird , is your inverter a elcheapo or cheap , the one I bought for the van would run the aircon unit no problem just not for more than 15 minutes .
I'll try my welder tomorrow on the car inverter it's also 3000 watt but elcheapo unit and see what happens .

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Originally Posted by GQtdauto

Sounds weird , is your inverter a elcheapo or cheap , the one I bought for the van would run the aircon unit no problem just not for more than 15 minutes .
I'll try my welder tomorrow on the car inverter it's also 3000 watt but elcheapo unit and see what happens .

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Its a chinese one, I think I paid around $500 - $600 for it. Pure sine wave, runs the 1700W coffee machine easily, power tools. I am wondering why it failed so dismally, and it appears to be operating well, fed directly off a 200A/Hr battery and 14.6V.

Mine was about that price but the one I have now was about $250? Ish .
I'll let you know if mine works but failing that is there any chance your earth was shitty when going through the inverter ?
Did you try cranking the amps up?

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Originally Posted by GQtdauto

Mine was about that price but the one I have now was about $250? Ish .
I'll let you know if mine works but failing that is there any chance your earth was shitty when going through the inverter ?
Did you try cranking the amps up?

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Dismal effect at all amperages. Vehicle is very well earthed, all connections used with conductive paste, and multiple around the vehicle - focus on ground plane effect for amateur radio use, so I think that,s not a focus area. I didn't have a problem with the coffee machine last time I used it either. I tried each of the three power outlets, but same outcome. However stranger things have happened, so I will hook up a jumper lead between the inverter earth, which goes to a body post, then to the battery, and run direct from inverter earth to battery. Away for the week again starting tomorrow, so will have to wait until next weekend for this unfortunately. Might be another great idea that fails in the detail due to some simple and fundamental oversight! Typical for me to be honest.

If your only chasing a stick welder why don't you just do a 24v setup.on a needs basis. Pull out the batteries and gook up to 24v with jumper leads or make purpose leads. Positive on the job and stick in the neg wire and your good to go.

This direct shorting of the battery buggers them in a very short period of time. Depending on the construction and age you could do permanent damage very quickly. The mig welder runs on either 24 or better 36v but it protects the battery integrity. I must admit I have tried this but had limited success. Hence looking for something that doesn't destroy itself if you get my meaning. Also there is no current regulation with this setup and I am guessing there might be times when a bit of fineness is required, such as thin metal repair or at the opposite a temp structural weld of quality

I'd have thought though you really only want the welder for the break down emergency. Your never going to set this up to undertake a project weld job surely? on that basis carrying a full sized welder in the car seems silly? also if you get the welding job done and your battery gets you home then its done its job. If it last another year then its even better.

When i did the Madigan TK in 2012 the hill with us had a shock collapse and break in the middle of nowhere. We has a 24v mig with us an it did the job with ease and ran off one of my batteries and a second from another car. I replaced that battery only last week. I put in on charge yesterday and the smart charger said it was fully charged..

I think for touring a set of Jumper leads will do the job you need and get you home. I like your idea but it seems like overkill.

Fair enough, but you might have missed the comment this welder is the size of a tissue box, which is 1/4 the size of the 24v gas less mig in case. Right now I want to understand why it won't work, and then assess if I stay with it or it goes into the garage

Darren, just remembered my 24V mig, which is a Ready Welder 2, protects the batteries from internal arcing, hence if this was the same style of welder you used, would explain why perhaps there was no damage to the cells and your battery life remained unaffected.

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Originally Posted by PeeBee

Fair enough, but you might have missed the comment this welder is the size of a tissue box, which is 1/4 the size of the 24v gas less mig in case.

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Yep didn't get that. Nice and compact. I have often looked at the little carry ones and thought they'd be great too.

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Originally Posted by PeeBee

Darren, just remembered my 24V mig, which is a Ready Welder 2, protects the batteries from internal arcing, hence if this was the same style of welder you used, would explain why perhaps there was no damage to the cells and your battery life remained unaffected.

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If you have a Ready Welder why don't you stick with it? Do you want to sell it?

You will find it isnt reaching the advertised 6k watts. Sorter like those genpower 8kva gensets on ebay for $800 wont even run a small box a/c or start a fridge.
If you want to use a welder with an inverter then your going to need 5k watts normal running - which will require a hard wired sized inverter.
Ever seen the genset/ inverter system most portable welders use? There big for a reason :) doesn't matter what physical size the welder is it still takes the same amount of energy to start a spark and hold it (depending on wire size etc etc)

I never sell anything, just keep on buying!!! I am just looking at options I guess and whats simplest. If I didn't have to remove a couple of batteries and could simply plug in a welder to a socket and get moving, that would be my choice. Right now its simply about laziness I guess, as either should do the job, but I suspect the arc current at strike is exceeding the capacity of the 12V inverter and to overcome this I need a larger inverter, which for this frequency of use, being maybe never, isn't justified. From memory, my transformer welder at home requires a slow blow fuse of 40amp rating to cope with the inrush current. I understand this is reduced in the 'inverter style welders' but still around the 30amp I am guessing, hence the likely reason why I am not successful as my inverter will deliver 13amps continous and 26amps for 10 secs, but I am guessing so was looking for confirmation 'by someone' that this is the case.

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Originally Posted by johno90

You will find it isnt reaching the advertised 6k watts. Sorter like those genpower 8kva gensets on ebay for $800 wont even run a small box a/c or start a fridge.
If you want to use a welder with an inverter then your going to need 5k watts normal running - which will require a hard wired sized inverter.
Ever seen the genset/ inverter system most portable welders use? There big for a reason :) doesn't matter what physical size the welder is it still takes the same amount of energy to start a spark and hold it (depending on wire size etc etc)

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Thanks, I have done a bit of reading today and my strike current capacity is way down it seems. I am probably looking at sticking this new small welder on the garage shelf for another day and revert to using the ready welder mig when required, hassle being its a lot larger in size.

It would be interesting to see what sort of wave is produced by the inverter and what is happening, by using a scopemeter as you strike an arc.

I tried mine which is a bigger unit capable of AC-DC and high frequency but as soon as I select arc setting it trips the overload on the inverter , so I will get my son on the weekend when he's down to bring his smaller unit which is not much bigger than yours by the sound of it and will check again .

I am pretty sure the inverter will have some sort of protection that will stop it giving the instantaneous load that the welder.
You might be better off with a modified sine wave inverter.
Taking DC making into AC then back into DC is going to be inefficient.

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Originally Posted by GeeYou8

I am pretty sure the inverter will have some sort of protection that will stop it giving the instantaneous load that the welder.
You might be better off with a modified sine wave inverter.
Taking DC making into AC then back into DC is going to be inefficient.

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My inverter is modified not pure sine , but the two gels are separated one under hood other in the back but close to inverter wiring is the stuff they used to run 5000 watt solar from roof to switch box etc which ways probably 20 metre run so pretty thick twin cable .
Wish I'd kept the one I had in the van and replaced with this crap one now .

Bloody hell, upgraded to a pure sine wave to try and overcome these issues with electric tools not liking modified sq wave. i know my grinder , power saw and drill are a lot noisier on Mod Sq wave than the pure sine wave. If this inverter has internal protection it doesnt indicate externally and certainly has not tripped a fuse.

I just had a close look at the nameplate and here in lies the problem. This thing is sold with a 10amp plug, but the nameplate says it can draw 25amps. What confuses me then is how this operates on a 10amp circuit, or is the 26amp so quick on start up that the fuses in the fuse box cope with the surge?

So this suggests the inverter size needs to be circa 7kw , but is this a normal load rating of simply the strike power rating (240V x 30A)? This does my head in to be honest. Might just stick with the readywelder2 and be done with it.

That will only be a start up (surge) rating as some appliances can use up to eight times there running current upon starting. Does it say anywhere that it has a soft starter incorporated in the circuit?

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Originally Posted by PeeBee

Bloody hell, upgraded to a pure sine wave to try and overcome these issues with electric tools not liking modified sq wave. i know my grinder , power saw and drill are a lot noisier on Mod Sq wave than the pure sine wave. If this inverter has internal protection it doesnt indicate externally and certainly has not tripped a fuse.

I just had a close look at the nameplate and here in lies the problem. This thing is sold with a 10amp plug, but the nameplate says it can draw 25amps. What confuses me then is how this operates on a 10amp circuit, or is the 26amp so quick on start up that the fuses in the fuse box cope with the surge?

So this suggests the inverter size needs to be circa 7kw , but is this a normal load rating of simply the strike power rating (240V x 30A)? This does my head in to be honest. Might just stick with the readywelder2 and be done with it.

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They do make a portable 12 volt mig which is very compact in size but expensive , can be used gas or gas less .

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Originally Posted by GQtdauto

They do make a portable 12 volt mig which is very compact in size but expensive , can be used gas or gas less .

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Yes I have the ReadyWelder2 that runs off 24/36Vdc and gassed or gasless already, looking for a package that is smaller

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Originally Posted by PeeBee

Yes I have the ReadyWelder2 that runs off 24/36Vdc and gassed or gasless already, looking for a package that is smaller

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I thought those things were ok and compact in size ? But yes they do hook up to batteries which is what you're trying to avoid .

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Originally Posted by GQtdauto

I thought those things were ok and compact in size ? But yes they do hook up to batteries which is what you're trying to avoid .

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I guess I could take it out of the plastic case, maybe just make do - still thinking, very s l o w l y.

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Originally Posted by mudnut

That will only be a start up (surge) rating as some appliances can use up to eight times there running current upon starting. Does it say anywhere that it has a soft starter incorporated in the circuit?

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Scant info in 'brochure ' , hardly an operating manual. I have emailed them regards recommended inverter size now that its identified as a problem, waiting to get a reply, maybe??/

Put a smaller SCA inverter welder on today and yeah you just get a weak spark .

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Originally Posted by GQtdauto

Put a smaller SCA inverter welder on today and yeah you just get a weak spark .

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Initial contact from supplier suggests 6 - 9kva generator - subject to confirmation - so waiting to hear what the actual size is.

Never tried to run a welder off my gennie 2000 watt peak but I think it would be a waste of time trying .

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Originally Posted by GQtdauto

Never tried to run a welder off my gennie 2000 watt peak but I think it would be a waste of time trying .

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From what we have found out recently it isn't going to work.

I run a 140 amp unit off a 5 kva but it is only Just ! If that's any help

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Originally Posted by Tip12345

I run a 140 amp unit off a 5 kva but it is only Just ! If that's any help

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Thanks, this is aligning with what the vendor has said, as mine is a 160amp unit.