On-board welder, aka "the weldernator"

[sdspearo]

So this is a project that I've always wanted to do and I've finally got around to it. Yeah, I could've just bought a ReadyWelder and be done with it, but there's not much fun in that, plus you need at least two batteries to get a decent weld.

If you're not familiar with a "weldernator", you modify an alternator by bypassing the voltage regulator to give full field voltage, and in this case I used an external bridge rectifier to convert the 3 phase AC to DC. My original intent was to use the internal rectifier that came with the alternator, but turns out the diodes in the particular CS144 alternator I bought were "avalanche" diodes. Can't use avalanche diodes since they're designed to breakdown beyond a max voltage to protect overcharging the vehicle.

Major expenses for this project were the CS144 140 Amp alternator ($107), external 3-ph bridge rectifier ($40), and 4AWG welding cable ($35).

Seems like most people that have these weldernators run a dual alternator set-up, leaving the existing alternator as-is and running the second alternator dedicated for welding. Since I couldn't see a way to run dual alternators in my XJ with air conditioning, I rigged up a mounting system above the engine that allows you to easily and quickly mount (temporarily) the weldernator assy for welding. The weldernator assy consists of the alternator and control box mounted to an alum plate. The idea is that when you need to weld on the trail you just pop open the hood, mount the weldernator assy, adjust engine RPM, and you're ready to weld. Welding V-output is adjusted by engine RPM.


Completed weldernator assy mounted and ready to weld.



The weldernator assy mounts to these three studs.


Goals for this project were:
- No permanent modifications within the XJ engine bay
- Quick and easy set up, no tools required
- $300 budget
- Decent welds on 1/8 and 1/4" thick material

Although I'll probably never use it, I also connected a receptacle to the control box since most tools with universal (brushed) motors can also run on DC voltage.

The most challenging part was figuring where to attach the fan belt that drives the weldernator. I ended up machining a custom pulley to piggyback against the pwr steering pulley. The issue is that there's not much clearance between the pwr steering pulley and aux fan. I could only squeeze in a 1/4" wide V-belt in that space. This skinny 1/4" belt is barely cutting it since there's signs of slippage when the alternator kicks on under load. If anyone knows of a thinner aux fan vs stock for a '96 that would give more clearance let me know. I also made pulleys for a 1/2" wide belt but it interferes with the aux fan. The pics shown here are with the 1/2" wide belt with aux fan removed.


Piggyback pulley



Aux fan doesn't fit with 1/2" wide belt (it does fit with 1/4" wide belt).


Here's some pics of the very first welds with different rod types. Don't scrutinize too much since these are literally the first welds I did on this set up without paying too much attention to V-output and Amperage. Thickness of the plates were 1/8 and 1/4".












I was pleasantly surprised with how the welds turned out and I'm sure they could improve with dialing in and fiddling with it more. But for now they're good enough and hopefully should work for any quick trail fixes. If there's any interest I can post up more details on the required modifications with more photos.

[Nimrod]

Impressive!

[cloudedjudgement]

I wouldn't mind seeing some detailed plans on how it all comes together, I could seriously see this coming in handy. Good Job!!

[XJlimitedx99]

WOW. I love this idea. I've heard of on board welders, but I've never seen somebody make one like this. I love it. Great job. Seems super functional and non-intrusive. I like how you have it setup with what I'm assuming are a volt meter and ammeter, along with a breaker. Do you have a capacitor in the circuit or is it straight alternator juice? I can't imagine the alternator would be very happy maintaining conditions like that for very long.

Neat!

So, I'm curious. What do you do for work? What kind of experience do you have that gave you the confidence/inspiration to tackle this?

Also, just thinking out loud here. Would this be possible using the vehicle's alternator? Thinking that if you found an alternator that uses the proper style diode (I'm unfamiliar with "avalanche" diodes) you could use a dual-battery style isolator between the alternator and an external regulator. Switched one direction you're on 12 V DC power to the vehicle, switched the other direction you're on unregulated DC voltage to the welding leads. Sounds plausible, but I know just enough to be dangerous when it comes to electrical of this nature. I'm assuming those isolators are rated for 12 V DC and finding one that would be able to accommodate welding conditions would be challenging/expensive.

[75SV1]

I would wonder if an alternator would fit under the PS Steering pump. The WJ uses that location for the A/C compressor. Or put the A/C Compressor there. and then Two Alternators on the passenger side. Also, I am looking at the ZJ setup for the alternator. Its a bit different than the XJs. They do fit the 136 amp alt in there.

[Unclewolverine]

Rhd pully set up puts a spring loaded tensioner where lhd has ac compressor. Perfect place to mount anything extra.

[75SV1]

Originally Posted by Unclewolverine

Rhd pully set up puts a spring loaded tensioner where lhd has ac compressor. Perfect place to mount anything extra.

Interesting. I would want to add a spring tensioner, like the WJ and more modern setup have. I'll have to check it out.

[RCP Phx]

You can do the same if not better and definitely cheaper with batteries.

[Anak]

Originally Posted by RCP Phx

You can do the same if not better and definitely cheaper with batteries.

It takes more than 2 batteries to get there, and that means you need at least one more rig. This has the advantage of being more independent.

[RCP Phx]

If you break something that bad and you are out there alone you screwed up big time!

[Jim Malcolm]

A little off topic, but not too far... If you ever come across a Hobart Trek 180, I wholeheartedly recommend it. It's really too bad Miller discontinued it when the bought Hobart; I guess it impinged on their Passport too much. Other than not being able to take a spool gun, being either flux core or gas, it really is the cat's meow... I'll probably cry when the magic smoke escapes from mine...

[denverd1]

very cool!

[75SV1]

Originally Posted by Anak

It takes more than 2 batteries to get there, and that means you need at least one more rig. This has the advantage of being more independent.

There is the Genisis Dual battery kit. Or a second battery on the driver's side.

[Anak]

Originally Posted by RCP Phx

If you break something that bad and you are out there alone you screwed up big time!

I would love to live in that perfect world.

Lamentably, I don't.

[WAZZUXJ]

Very cool.