Raising the available mig welding current.

[normspanners]

Hi guys just a little tip I have toyed with for awhile, was doing some work with my little portable 160 but it was not doing it, felt like there was no power but I was on a VE----RY long extension. etc and needed more power.

I had the idea years ago but have never tried it till I was pushed I had a commercial battery in the back of the disco so with jumper leads put it in series with the earth ie welder earth to the pos. neg on battery to earth, so therefore raising the voltage by 12v. with a little adjustments lowering voltage and upping wire, It worked a treat.
I could easily weld 6mm the only downside is that the torch is semi live because the other side of the coil I say semi live it will spark slightly, so you have to watch that you dont ground it before hitting the trigger.
But it enabled me to weld whereas it was impossible before, you can still adjust voltage and wire enough to get a decent run. I did a fair amount of welds that day put the battery in the disco and forgot, then had flat battery on a car few days later still plenty of umph to start it.
So from that wouldnt have thought welding with it hammered the battery too much.

 

[normspanners]

PS just had a thought this might even help if HAVING to run a mig off a little geny ie on a rally in the field etc. because you are splitting the load
I have done emergency welds (you know sh1t or bust job) before running on a 2.5kv geny by getting my assistant to manually rev the geny as I hit the trigger a second after and then KEEP welding it did work, But not a nice or advisable trick. But the battery idea might work nicely with no reving

 

[Hitch]

I'd be a touch concerned about the battery popping....
I suppose it may have a similar effect on the battery to being overcharged .... Not ideal in itself.... If that's the case, It may be producing hydrogen, not a great gas to generate next to you welding.

 

[rtbcomp]

^^

The battery is in series with the welder, it's no worse than connecting 2 batteries in series, or 6 cells in series.

 

[the snooper]

^^

The battery is in series with the welder, it's no worse than connecting 2 batteries in series, or 6 cells in series.

I would agree with that as the current from welder and battery are being used, its not like the welder is supplying all its power to the battery only

 

[Rig Pig]

Battery's give off hydrogen and oxygen, make sure that there are no sparks going over the battery, they go with one hell of a bang!

 

[normspanners]

The battery didnt gas or even bubble because the welder is not charging it, and you can use a hand held mig http://readywelder.com/ that is designed to use two or three batteries, after all when you bang in a commercial starter it can be drawing 300amps/ 400amps easily.
I was thinking of developing the idea further by putting a solenoid in the connection to the battery so it clicked in as the contactor is energized then the torch would be non live.

 

[the snooper]

Battery's give off hydrogen and oxygen, make sure that there are no sparks going over the battery, they go with one hell of a bang!

been there done that, testing a starter across a battery the starter was blown up into the air, just missed me on its way back down and the top of the battery was no more, and it still had charge in it afterwards

 

[Rig Pig]

They have a nice habit of throwing acid everywhere when they go off as well!

 

[the snooper]

luckily that wasn't too bad, you lave and learn not to do that again

 

[normspanners]

To save any probs all that is needed is a piped vent battery with the pipe run away from ign source.

 

[Kent]

Battery's give off hydrogen and oxygen, make sure that there are no sparks going over the battery, they go with one hell of a bang!

Seen that one day - it cleared the welding bay pretty quick (someone decided from the machine shop decided we had most sockets and put his car battery on charge at break)

 

[AndyStobbs]

Interesting post norm. I'm thinking that really its an increase in Voltage primarily, ie. extra 12v in series with the welding power.
Of course you will then be able to move more current in the circuit with the increased potential, but I'm stuck with working out how much (in percentage terms) the battery will assist in additional current. Any thoughts?

 

[normspanners]

Sorry for the delay in reply
Yep raises the voltage considerably, my thoughts were if the battery was in the earth side ie neutral, the potential should travel into the work piece more, I cannot give you a percentage because of volt drop through the battery leads etc.
But all I can say is the welding power was increased possibly 40-50% and I had to raise the wire speed a fair amount so therefore the current was raised considerably.
BTW the welder nor battery seemed to suffer.
I have read about using the ready welder it uses two or three batteries but has no voltage control, bar for the jumper lead length or obviously dropping a battery out, people where saying that it could be a little fierce, for smaller jobs.
I had thought about the old type of battery where the bridging posts where at the top like a traction battery then you could raise the voltage by two each post.
But my idea allows adjustment through the welders tappings.
When I was struggling I think the current available was about 80a from a supposedly 160, it would not burn in and was just sticking the bead on the top, with the battery in line it burnt in nicely.
If you put some big capacitors in the circuit it raises the voltage by the rms of 24v ish so lifts it to 27-30 and does lift the current slightly, but not like having the battery in line which lifts it, by, I guess 10v ish whilst welding, all things taken in.
ps the live torch is caused by the battery +traveling through the transformer secondary to the torch there is not a lot of power to it coz of the massive volt drop. hence my idea of a solenoid in the earth energized by the welder wire feed.