Running a Invertor Welder of an Invertor, Anyone Done It?

[resilientg]

Have any of you guys or gals run an inverter welder of an inverter?

If so what did you use welder and inverter wise.

I currently have a good 120 amp inverter welder that i use for just about everything, it runs of normal 240 volts.

I currently have about 480amps worth of batterys, with about 540 watts of solar and then the wind generator on top of that.

During the middle of the days im always having surplus power, and might just want to use the welder for short intermittent periods.

Long term i will be putting on extra solar panels to bring my total up to nearly 1000 watts, and will also be bringing the battery bank up to nearly 1000 amps too.

So i thought why not weld of a big inverter?

so thoughts and opinions please from the knowledgeable few out there,

thanks in advance

Matthew

[cat man do]

No idea but if it was that easy I would think these devices alowing welding onboard, would not have come about.


ENERGO-TEC 220V POWER SUPPLY

[Mr B]

I bought a pure sine wave invertor for just that reason,

5,000 watt, 10,000 watt surge, 12 volt - 240 volt,

I have a 170 amp CIG invertor welder with TIG attachment, but the invertor wont run it,

I had a 550 watt drill and 5 inch grinder running at the same time loaded, the invertor didnt even blink an eye at it, They both ran at full power,
It was connected to two 85 amp hour Gel batterys and a 12 volt lead truck battery, all connected together,
But the welder even on 60 amps for Stainless rods, just wouldnt fire up,

But you can buy a 240 volt alternater that runs off your motor, like the one above, that Cat Man Do put up, That will run the welder,

I had to replace my invertor any way, as it got drowned when I got wrecked, So I thought I will buy a decent big invertor,

But I will buy an alternater for the diesel that will run my welder, As I want to carry my welder with me,

[resilientg]

Thanks for the replies guys.

I dont want to buy a gen set as i already have one the i can mount on my motor, that will allow me to weld, but i was interested in the inverter welding as they are lighter than generators, and on a small boat every little bit of weight counts.

Maybe someone else out there has tried and been successful, lets wait and see.

Matthew

[Mr B]

I just looked at that gen set plus welder, above,

The alternator I am talking about looks like the alternator you have on a car and about the same size, It is set up for 240 volts,

It doesnt have motor or welder attached, They stick them on the end of a mobile welder for auxillary power.

About $400-00 the last time I priced one,

But I would like to know if any one can run the Invertor welder off an invertor also,

[Reefmagnet]

The problem with a welding machine, inverter or otherwise is twofold. Firstly, they are rated in a way that includes the duty cycle rating which means that the "on load" current draw through the primary is often much higher then the rating, and secondly, welders are like air compressors starting under load in that there is a double whammy of current draw where a) The inductive load of the circuit - power factor - and b) the high inrush current caused by shorting of the electrode in order to initiate the arc combime together to create high inrush loads. For this reason most generators, and I'm assuming inverter supplies, use a rather subtle "kVa" rating rather then a current / voltage output specification. This is because the kVa rating of a power source in the majority of cases refers to the absolute output, whereas a load will in most cases have an inrush, or startup loading, unless it is purely resistive e.g. a heater element. As an example, a welding machine can require up to three times the current draw of it's rating. This is no problem for the grid to supply momentarily, but can be a problem for anything else.

So to cut a long story short, unless the power source is designed to supply momentary startup loads that match the welding machine startup loads, it won't be up to the job.

As an alternative, regular alternators and batteries can be used for emergency welding. Typically a 24 VDC supply capable of supplying, say 60 amps minimum can be used make emergency repairs with welding electrodes. Using batteries alone simulates a constant voltage supply which is not ideal for stick welding (which needs a constant current supply) however I believe kits are available that allow alternator / battery systems to be used as makeshift constant current welding machines.

A more viable solution for those wanting to do a lot more welding would be to either get a suitable genset or to use an actual engine driven welder, which typically will also have a genset capability as well.

[denverd0n]

Originally Posted by Reefmagnet

I believe kits are available that allow alternator / battery systems to be used as makeshift constant current welding machines.

Actually, you don't even need a kit. On an excursion with a Jeep club once I watched a guy do some crude stick welding by wiring 3 batteries in series to get 36 volts, using ordinary jumper cables, and then using more jumper cables to hold the electrode and make the negative connection. The weld was not very pretty, that's for sure, but it held together long enough to get the Jeep back home from way up in the Colorado mountains where it had broken.

Of course, this would really only be suitable for emergency welding. I'm thinking that the OP wants something more elegant and useful for non-emergency situations.

[Zanshin]

There is an interesting subject on welding using just the alternator:

see Emergency welding with a high output alternator

[Lake-Effect]

Apparently DC arc-welding with 1 to 3 12 v batteries is quite feasible:

- Build a Portable DC Arc Welder for $20
- Emergency Welding Using Automotive Batteries

Given all of the info so far, I'd much rather handle any occasional or emergency welding by just using the boat batteries, and avoid the hassle of needing a honking big inverter just for a welder.

disclaimer - I don't yet weld, but it's on my short-list of things to learn

[Mr B]

Originally Posted by Lake-Effect

Apparently DC arc-welding with 1 to 3 12 v batteries is quite feasible:

- Build a Portable DC Arc Welder for $20
- Emergency Welding Using Automotive Batteries

Given all of the info so far, I'd much rather handle any occasional or emergency welding by just using the boat batteries, and avoid the hassle of needing a honking big inverter just for a welder.

disclaimer - I don't yet weld, but it's on my short-list of things to learn

My stuffed 1800 watt invertor that needed replacing any way, Is just a tad larger than my new 5000 watt invertor,

Welding off the batterys is a pretty crude way to do things,

DLI XRay welder with fifty years of experience,

[popeye2818]

I weld for a living and I dont think either way you will be able to run them off the inverter unless you get the biggest one they make.A geny would be the way to go .You may burn overheat and burn out the inverter.Its hard enough for me to run a 20 foot ext cord to my 120v welder because of the amp loss.A small 120v tig may have the capacity as they run on a Internal inverter and you will be able to do nice stainless steel welds ,some do aluminum and you can stick weld also off them up to 1/4 inch .Im not to fond of sparks in tight spots from a mig.Stick welding is messy in a boat and is good if your trying to do a quick fix on a rudder shaft ,engine braket ect and get home,but thats it really.Like someone stated the initial burn in when you pull the trigger is the problem as it will be a shock to the inverter and the weld will just pop and not get hot enough.Hope this helps.


This is a milller dual voltage welder.120/230230 V, 25 A, 60 Hz, 1-Phase
120 V, 20 A, 60 Hz, 1-Phase

[Lake-Effect]

We ARE talking fiberglass sailing yachts, not workboats on oil rigs, right?

[Reefmagnet]

The other issue with an inverter welder is that they are not as robust as conventional transformer rectifiers. I also own a Weldskill 170 DC stick / TIG unit, which is a great bit of kit but I couldn't see it surviving on board a boat for too long without taking seriously to it's internals with polyurethane insulation spray. The other thing worth mentioning is that welding aluminium with the TIG process requires AC welding output which is much more tortuous on the primary supply, hip pocket and overall weight then it's DC only siblings. Interestingly enough, many years ago there were aluminium arc welding electrodes available. The flux looked for all the world like sea salt and it flaked off just by looking at it but none the less the bead of weld they laid wasn't that bad. It wouldn't surprise me if someone, somewhere is still making them?

And, oh yes, welding with batteries is for emergency use only, but it is commonly done in the 4wd world when things break that need welding repair in the middle of nowhere. You don't even need welding leads, as regular car jumper leads and a locking plier can be used. Just need to carry a handful of welding rods in the toolbox.

[Reefmagnet]

Originally Posted by Lake-Effect

We ARE talking fiberglass sailing yachts, not workboats on oil rigs, right?

Yep don't need to be a mechanic to swap out your oil, so it depends on what you need to do.

[hpeer]

Interesting, I just bought the same model Miller.

I have a little Harbor Freight 90A inverter welder, I can do only very limited work with it and then plugged in.

I have a 2000 watt Honda generator but have not tried that for the Miller or inverter welder yet. I suspect that itself is pretty tame for any serious welding but may withstand the inrush better than batteries. Don't have a gen set.