Is anyone using an arc welder with an offgrid system

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doggy
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Re: Is anyone using an arc welder with an offgrid system

Post by doggy »

Hi Jordan,
Yes, the output is totally floating (insulated) from everything else so there is absolutely no problem.
Also, my unit continues to function beautifully.
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Re: Is anyone using an arc welder with an offgrid system

Post by paulvk »

a. Neutral link to ground.
b. Ground to existing house ground (copper stake).
NO definitely do not do this is against the rules you will have two earths on the neutral!!!!



With the newer units they have a relay for the neutral link.
If you are going to connect the inverter to a grid or generator with an existing neutral link you have to use a relay to switch the earth onto the neutral when the inverter is operating but to remove it when in by-pass and the grid or generator neutral earth is being passed through it is not allowed to have more than one earth on the neutral so only in stand alone no grid or generator with neutral link should you bond the output neutral to earth!
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Re: Is anyone using an arc welder with an offgrid system

Post by doggy »

Not sure you understand my setup.

The house is bonded in the normal manner. The grid does NOT connect to the inverter in any way. In other words I am NOT using the grid input (which is not connected) nor the ATS nor the inverter's charger.

Things connected to the inverter are totally separate from things connected to the grid. So they experience the neutral bonded to ground which is copper stake at the same location as the house ground.

Regds,
Dave
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Re: Is anyone using an arc welder with an offgrid system

Post by T1 Terry »

Skip the copper stake bit, that is to make a connection back to the transformer or the power generator. You have the power generator on board in the form of an inverter. If the generator is a plug in device and has a fault to the metal frame and that is sitting on the ground, the stake will make a circuit back to the generator and that will become the earth neutral link, or anyone touching the conductive body will become the earth neutral link if the are bare foot on wet ground.
If you are not going to connect to the shore power at any time then you can get your sparkie to make an earth/neutral bond after the inverter. Be very careful about connecting and earth wire to the inverter body itself unless it is in the specified spot, many inverters use a live shell inside the inverter that is isolated from the outer body, earth that and the smoke comes out big time.
Another way around the problem is to leave the system floating and fit an RVD after the inverter. These sense voltage rather than current on the earth circuit and switch the power off without any current needing to pass through the poor sod who got themselves tangled up in the active wires.
Please, keep in mind only one class 1 appliance can be safely connected to a floating supply, if that happens to be a generator plugged into the shore power socket, the RV is the first class 1 appliance in the circuit as it has the earth bonded to the conductive frame and panels. A short to the body from either line 1 or line 2 of a floating supply turns it into an earth/neutral supply and the other line becomes the active. A second appliance with a fault to the active that comes into contact with the user will not trip the circuit breaker nor will the user feel anything, but if the user also touches the conductive parts of the body work, they become another appliance with all the available current passing through them. The RCD does not see this as a fault, the user is just another appliance it needs to power.

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Re: Is anyone using an arc welder with an offgrid system

Post by BaronVonChickenPants »

Sorry for the thread hijack, i have started a new thread here: http://forums.aeva.asn.au/viewtopic.php?f=64&t=6226
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Re: Is anyone using an arc welder with an offgrid system

Post by Preator »

You must remember 200A @24v =200*24 over a period of 20 hours this is a standard rating given for batteries is lithium, lead acid or even capacitor storage. To get to 2000w constant @ 24v your cable will be 90mm² this is a constant 84 amp draw for the duration of the draw go with a 48v blend battery Maxwell 500F 48v and 10kw minimum lead or lithium two banks parallel. The cap will buffer the rush and buffer your lithium. Always work on thru-put on the inverter so 10kva pf1 with a high response and return.
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Re: Is anyone using an arc welder with an offgrid system

Post by jonescg »

Hopefully this is a useful place to put my query, considering if actually involves welders on battery-backed solar homes (but not off grid).

I'm considering a 10 kW hybrid inverter (transformerless) for my home, but in the shed I like to stick-weld, angle-grind and cut stuff with a honking big 2400 W cut-off wheel. Would these loads put undue strain on the inverter?

I have a feeling it won't because the inverters AC output is in parallel with the grid, so any voltage droop experienced by the inverter will be supplemented by the grid.

Also, considering the inverter is only good for about 3 kW AC per phase, what would happen if I tried to draw more than 20 amps? If I tried to charge my new EV at 7 kW, would the grid make up the difference?

TIA, Chris
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Re: Is anyone using an arc welder with an offgrid system

Post by doggy »

Hi Chris, I too have a 2400W angle grinder. Startup current is around 65amps.

Certainly if you were offgrid, I would not use a HF inverter for loads like that or for welding (at least using a transformer based rather than inverter based) welder. LF inverters can typically handle much higher surge currents.

Given you are grid-tied, I would have thought you would be okay. But if you had the inverter in the shed and the grid feed in the house, I would not weld or grind in the shed because of the impedance of the cabling between the house and the shed. I would think there would be a possibility of inverter damage in that case. However, if the inverter is in the vicinity of the lead-in and then the cabling runs to the shed, I would doubt you would have an issue.

Regds,
Dave
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Re: Is anyone using an arc welder with an offgrid system

Post by antiqueweb »

I saw someone recommended going with a Victron inverter for such off-grid requirement. I won't advise going with Victorn, reason most of their equipment is faulty and costly.....
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Re: Is anyone using an arc welder with an offgrid system

Post by jonescg »

antiqueweb wrote: Sat, 23 Sep 2023, 11:39 I saw someone recommended going with a Victron inverter for such off-grid requirement. I won't advise going with Victorn, reason most of their equipment is faulty and costly.....
Interesting - I've found Victron products to be pretty robust. Which ones have you had trouble with?
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Re: Is anyone using an arc welder with an offgrid system

Post by doggy »

I had a big Victron setup on my (then) 40tonne barge in France. Never a hiccup. Went for years. Could also sync it to a genny or shore power for a few more kW. Used it for all living plus welding, cutting and other "stuff". I had a separate motor-gen with 200A charger and 200A welder for really big stuff.

If I was doing an offgrid setup I would have Victron near the top of my list (unless they have gone downhill without my knowledge).
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Re: Is anyone using an arc welder with an offgrid system

Post by brunohill »

I did a bit of arc welding yesterday evening running off my Selectronic.
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Re: Is anyone using an arc welder with an offgrid system

Post by rhills »

antiqueweb wrote: Sat, 23 Sep 2023, 11:39 I saw someone recommended going with a Victron inverter for such off-grid requirement. .....
I'm not going to repeat the rest of what @antiqueweb said because, given this was their first post and it was an unusual twist to the main topic, I suspect they're reverse-spamming, ie trashing a competitor's products. It will be interesting to see if he returns to defend his comments with some evidence.

If not, I think the post should probably be deleted!
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Re: Is anyone using an arc welder with an offgrid system

Post by brendon_m »

The only complaint I've ever heard about Victron is the price
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