Emergency welding using Batteries
- Thread starter Genesis V
- Start date
The bare minimum voltage for welding is around 36V. If you have a bank of batteries that you can switch to connect in "series" it can be done. Preferably if you have Golf Cart batteries to withstand the load.
I once helped an "old" guy weld some fence posts in the field using a 8D battery on the truck (might have left the engine running, 150 amp alternator) using jumper cables. No fancy welding rods, this guy used coat hangers, pretty crappy weld, more like a cold solder joint. It was good enough to keep the cows on their side. I don't believe I'd have any faith in it's strength on a boat.
There are several reasons that it is not a good idea. You have no control over the voltage, so the welds run really hot, tending to cause burn through and lots of spatter.
The other reason is that you have connected two batteries together to make 24VDC, and then made as high a current short as you can. The likelihood of catastrophic battery failure is as high as it ever will be. And, since this is supposedly an emergency, you likely aren't wearing enough PPE to really protect you doing this job in this environment. If you have a catastrophic battery event you will also likely have ignited all the excess hydrogen that you were producing, creating a really bad day.
AWalker said: ↑"...you will also likely have ignited all the excess hydrogen that you were producing, creating a really bad day....."
Not so much...., I don't think so, Hydrogen is only created when charging the battery. If you want to understand the reaction here is a good explanation. http://www.tpub.com/doeelecscience/electricalscience278.htm
Otherwise, I think his demonstration is spot on. This is "real world". The inductor (wires wrapped on bolt) aids in the start of the plasma when he strikes the arc (Δi/Δt). Notice he said"stuck in the middle of the Atlantic". This is only as a last resort and a pretty cool idea. I would vacuum pack the electrodes as the flux will go bad if you don't. A typical Group 29, 12v battery can discharge 8,000 Joules (watt/seconds). I'll stick to a battery - save my boat bucks for boat parts. One less thing to buy and store. Cheers.
Not so much...., I don't think so, Hydrogen is only created when charging the battery. If you want to understand the reaction here is a good explanation. http://www.tpub.com/doeelecscience/electricalscience278.htm
Otherwise, I think his demonstration is spot on. This is "real world". The inductor (wires wrapped on bolt) aids in the start of the plasma when he strikes the arc (Δi/Δt). Notice he said"stuck in the middle of the Atlantic". This is only as a last resort and a pretty cool idea. I would vacuum pack the electrodes as the flux will go bad if you don't. A typical Group 29, 12v battery can discharge 8,000 Joules (watt/seconds). I'll stick to a battery - save my boat bucks for boat parts. One less thing to buy and store. Cheers.
Yes but remember, welding voltage is generally in the 20 vdc range, you have connected two different batteries together which, unless identical batteries already paired together, have a different state of charge. Generally you are going to use a house and starting battery, so one will always be discharging and one will be charging.
If you think it is a good idea knock yourself out. Generally what happens is that you ruin a part that a competent welder can fix as well as the spark damage to your boat from not having welding blankets, and inevitably get battery acid on yourself and your boat.
Offshore, creating a jury rig after being dismasted a thousand miles from anywhere is one thing, for most others find a better way to get home and doa good job of the repair.
If you think it is a good idea knock yourself out. Generally what happens is that you ruin a part that a competent welder can fix as well as the spark damage to your boat from not having welding blankets, and inevitably get battery acid on yourself and your boat.
Offshore, creating a jury rig after being dismasted a thousand miles from anywhere is one thing, for most others find a better way to get home and doa good job of the repair.