New thought on Onboard Welder

[Chevy1925]

ive wanted an onboard welder for my tracker for some time but this thing is "compact" and budget built. Ive used the Premier Power Welders before on a couple buddies rigs but they had the room for the alternator supplied, i dont under my hood. ive also used the Ready Welder's but that requires guys taking out their rigs battery to be used. Seen guys make welders out of alternators like the Premier setup but again, im space limited under the hood.

So i started looking at maybe getting a Ready Welder and just dealing with getting other guys batteries till i found a youtube video of a guy who used a car battery and then a lithium jump box with it. he has 0 issues with the lithum battery self igniting and actually went on to try some other setups.

Eventually he tried the old school arc welder trick with 2 and then 3 jump boxes only. 2 wasnt quite enough (even just car batteries, 2 usually isnt enough) but 3 made that thing buzz along well. To the point all 3 boxes were doing a steady 200amps of output.

Now obviously, this isnt exactly "safe". No way this would stay in my tracker during welding. i figured it will all stay in an ammo can of mine and come out when needed for welding. This is all "testing". i have a 12v plug at the back that will keep the batteries topped off and ill plug it in before a trip to charge them assuming this works

These things are cheap enough, i bought 3 jump boxes off amazon, leather welding hood, 2ga jumper cables, arc welder stinger to connect to one of the jumper cable ends, some 6011 rod (seems to work best in off road conditions and crap prep lol), and eventually ill order some connections to daisy chain the jump boxes. for the time being, ill just use the clamps to see how it works out.

so who wants to see me blow some shit up? :roflmao: if this works well enough, ill probably pick up a ready welder and put it in the back. varying wire speed on the ready welder can kinda vary the heat and it only needs 2 batteries to weld nicely.

basically i figured you guys might want to follow along as i screw with this.

 

[1FastBrick]

In for the magic!!! :happy2:

 

[Mike L.]

In for the magic!!! :happy2:

Like this?

 

[Chevy1925]

its going to be entertaining for sure :roflmao:

here is the guy i found on youtube. This one they use a ready welder on 24v and two jump starters. it does well even on that 1/2" or 3/4" steel they are welding on

[youtube]o9_z7Nb4SJc&t=833s[/youtube]

 

[TheBac]

oh boy....

 

[AJH]

I’d set up the jumpers so the are permanently attached to the battery side and use Anderson plugs to make “quick” connections on the trail. May also be able to run some battery cable to the back and use the battery’s if you have a dead truck but a need to winch situation. Not sure how your wheeler is set up.

https://powerwerx.com/anderson-power-powerpole-sb-connectors

 

[Cougar281]

Instead of going withe a commercial jump box of varying capacity, you could build your own LiFePo4 battery like this: https://m.youtube.com/watch?v=5IPnQieycyA



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[2004LB7]

James, what kind of current and duty cycle are you needing or wanting? These two are going to dictate what you can use and how well it will work.

 

[Chevy1925]

James, what kind of current and duty cycle are you needing or wanting? These two are going to dictate what you can use and how well it will work.

Honestly, I’d think 30% at 150amps would be more than enough for a trail fix. Most migs are higher rated than that on 220v but not really what I’m after

I’d set up the jumpers so the are permanently attached to the battery side and use Anderson plugs to make “quick” connections on the trail. May also be able to run some battery cable to the back and use the battery’s if you have a dead truck but a need to winch situation. Not sure how your wheeler is set up.

https://powerwerx.com/anderson-power-powerpole-sb-connectors

That’s what I was planning on if all goes well!

Instead of going withe a commercial jump box of varying capacity, you could build your own LiFePo4 battery like this: https://m.youtube.com/watch?v=5IPnQieycyA



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I contemplated that but I have to look into the cost vs bang for the buck with the jump starts

 

[2004LB7]

What about using a bank of super-capacitors charged through from the vehicle via a power resistor? Those things can pump out more then enough current to satisfy any welding needs without breaking a sweat

This way you can limit the wire gauge needed to the bank and still get the full current. The resistor could hold the current to something like 50 amps to charge the bank. When you strike the arc the current will be higher until you draw the voltage down on the bank, then it will be limited to whatever the resistor is.

The problems I see is the 14 volts from the vehicle is not really that great for holding an arc. That leaves either a second alternator set to 24 volts or so or a battery bank like you are asking about.

If you want to use lithium over lead acid then I would use LiFePo4 over any other chemistry. They are far more tolerate of abuse and have much better current output then most any other.

One option could be those headway cells. They seem pretty cheap and the 38120 can do 120 amps continuous. Still need a BMS and charger so not so simple

 

[Chevy1925]

Yeah that’s getting much more into it then with the second alt. It would be much easier to just make the second alt an a/c arc welder at that point.

Biggest thing I’m finding is getting LOW enough amperage to not blow through thinner steel. Thus far, I’ll be limiting it with the 3/32 6011 rod I’ll use but still will be pretty hot. See if I can’t do a little practice at controlling that by start/stop welding.


Any how, got jumper leads made up, hooked the batteries in series and went to strike and arc....

All I got as a “beeeeeep” and nothing. Not even a spark. It’s coming from the box on the jumper leads, not the battery pack so either it doesn’t like the “short” I’m putting them up against or the fact they are all jumped together in series at 36v. I’ll bypass that box after the kids go to bed and re-test

 

[DAVe3283]

A lot of those lithium jump packs have safety circuits that try and prevent you from hooking them up backwards or getting a spark when connecting a battery, so they disconnect until they see a certain voltage, then they turn on the batteries.

Since a spark when connecting is exactly what you want, you'll probably just have to cut the protection circuitry out.

Subbing for the lithium fire. Take pics!

 

[Chevy1925]

Oh there will be video, dave. Way better.

 

[2004LB7]

I'm going to guess that those two little mosfets are not going to pass the current you want with out a little fireworks show

Like DAVe said, you are going to have to bypass the protection circuit to use as you want. You may also want to add an inductor inline to suppress current spikes and stabilize the arc.

From what little I can see of those jump packs in the photos, I think they are way undersized for welding. See if you can get the numbers off the cells so we can look at the specs for them

 

[Cougar281]

What about using a bank of super-capacitors charged through from the vehicle via a power resistor? Those things can pump out more then enough current to satisfy any welding needs without breaking a sweat

This way you can limit the wire gauge needed to the bank and still get the full current. The resistor could hold the current to something like 50 amps to charge the bank. When you strike the arc the current will be higher until you draw the voltage down on the bank, then it will be limited to whatever the resistor is.

The problems I see is the 14 volts from the vehicle is not really that great for holding an arc. That leaves either a second alternator set to 24 volts or so or a battery bank like you are asking about.

If you want to use lithium over lead acid then I would use LiFePo4 over any other chemistry. They are far more tolerate of abuse and have much better current output then most any other.

One option could be those headway cells. They seem pretty cheap and the 38120 can do 120 amps continuous. Still need a BMS and charger so not so simple

The headway cells in the video I linked are rated at 200A I believe, but have been tested to push over 300A, and like you said, LiFePo4 is the safest lithium chemistry. It's nearly impossible to make them burst into flames, unlike the 18650 batteries. Overcharge the 18650's and they'll start popping, and potentially take their neighbors with them.

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[TheBac]

Oh cmon -- you know we all want to see something burst into flames. :roflmao:

 

[Cougar281]

You should watch the video I linked... He has at least a short clip of one of his tests where he took a few of the headway cells and direct shorted them with a wrench... The wrench got red hot and ended up melting. The batteries were like 'that all you got?'.

You want to see stuff bursting into flames? Here you go . This is what can happen with the 18650's if you're not careful.

https://m.youtube.com/watch?v=WdDi1haA71Q

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[Chevy1925]

Undersized?! No way, they claim 22,000 mAh! I can weld for days!

But seriously, they claim that kind of rating which is no where near what they are. I pulled them apart and found they are 4 cell, 14.8v 5900mAh batteries. Well more than the Viking one.

All I want is weld with power behind it. It’s a field fix, not a fab shop so keep that in mind. If I had to use it, we are talking about wrenches, bolts, sockets, spare bits of metal being used as filler or bracing. As long as I have the power to burn that shit together well, that’s all I’m after. Not saying we can’t improve on this but let’s get a base first on if/how this works out, run time, and I’ll try to get an ammeter on it.

Not against building a pack but at 300 bucks all in for what I have (battery’s which self balance and have built in chargers, 2 ga jumpers, 300amp stinger, 2lbs 3/32 6011, leather helmet and gloves), that’s kinda hard to beat if it welds for decent time and can be used a few times.

Down the road, I definitely want to build a pack but I would also want to be able to vary amperage (not sure how there) if I did that.

Anyhow, some pics inside. The only limiter is for sure the little box on the leads. It’s direct battery power inside to the leads in the box. I will need to monitor the box charge level since it won’t self limit if I bypass the box. Not a big deal.

 

[2004LB7]

Just to be clear everyone, 18650 is the dimensions and shape of the cell and not the chemistry. LiFePo4 can be had in 18650

James. If you want to adjust the amperage then think ohm's law. Raise or lower the voltage to adjust the current. Not the easiest thing to do with a battery bank unless you skip some cells but then it will be massively unbalanced.

I think your best bet is to build your alternator welder and be happy it does exactly what you want. I don't see any battery version doing anything thin and jumping up to heavy, or adjustable current if you will, without some heavy duty PWM circuitry or something. The only other way I can see varying the heat, at least to some degree, is changing your electrode size. Or under size your cables to promote voltage drop

On the other hand I might be over thinking what you want

 

[Chevy1925]

Well I was going to cut down the 20ft of cable but decided against that for more resistance. I may try the 6 ga I have too and see what it does.

I need to look into the variable amps part a bit. Hobart and some other company did/do make a battery powered welding unit for 3-5k using LiFePo batteries and variable amperage so can be done. But within a decent price range and skill set is another deal.

If varying the sticks or wire gauge works, screw it, we stay with it.