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Installing a Mobi-Arc 200X in Rivet the 101FC

The folks at Mobi-Arc have done a fabulous job in designing and producing a cutting edge onboard welder. It is 100% solid state, so the reliability should be excellent. The build quality is second to none, and that carries down to the wiring and other components that go along with the controller box.

With Mobi-Arc, you can use your existing alternator. On some alternators, the use of several types of components will require that the alternator be opened up and modified. After being modified, the controller box will regulate the alternator, but in the remote case of the controller box failing, there is a bypass system that will allow the alternator to be used as it was before the modifications were done. The bypass system also allows the controller box to be moved from vehicle to vehicle. All that is needed to move it is an installation kit in the other vehicle.

I've gas and MIG welded, but have never stick welded. I have to say, what a hoot it is to weld with this unit. It is really a lot of fun. The weld penetration is better that I can get with my MIG welder - that's with the engine running about 1800 - 1900 RPM. The only thing I am trying to get into my head is that I have to keep moving the stinger closer to the metal as I weld (I'm used to the wire feed).

The alternator - in this case a Delco 12SI - is very easy to disassemble. The included instructions are very clear and the whole operation only takes a few minutes.

The installation kit comes with a new brush assembly that has wires on it. Feed the wires through the opening on the case.

Line up the connections as shown and tighten down the brush assembly.

The alternator is finished. The bypass wires are also in place in case something should happen to the control box. The control box will now regulate the alternator output.

The alternator is reinstalled on the engine and belt installed and tightened. At this point all that is left to do is install the controller box and hook up the wires.

Finding a place for the controller box was the tough part in a 101FC. It should be near the battery box as well as the alternator. I wanted it inside the vehicle so I wouldn't have to pull the engine cover off to use it. The spot chosen is shown. It will locate the box near a large opening that already existed that the wires can be fed through. The bracket was mounted with 4 of the included sheet metal screws.

This is the controller box with the cables attached (alternator, battery +/-) and the wiring harness plugged in. The lugs are bent 90 degrees for the controller box connections, so the cables are nicely grouped to feed through the hole in the battery box.

Here is another shot of the back of the unit with the wires installed.

Feeding the wires through is pretty straight forward. I drilled a 3/4 inch hole in the bottom of the battery box to feed the wires into the engine bay. Not all wires go into the engine bay - some stay in the battery box, so the 3/4 inch hole was just the right size.

This is how the wires look after attaching the controller box to the bracket. The distance from the side of the battery box was measured to allow for clean feedthrough of the wires and also allow enough room to install a voltage module or remove the wiring harness should a need arise.

To protect the wires, self vulcanizing rubber strip was wrapped around the wire a bunch of times. The wires coming out of the bottom of the battery box have been protected with some corrugated wire loom.

Here the controller box is installed and ready for use. The compact size does not take a lot of space. The lights are also visible from the drivers seat. If the access cover to the engine needs to be removed, it can be by removing the controller box from the bracket and letting it hang from the wires as the access cover is removed. The middle access cover is not removed as often as the engine and rear transmission covers, so this should not make normal maintenance an issue.

A final shot of the alternator hook up with the wires protected. And yes... I did insulate the original connector and zip tie it out of the way.

The bypass plug is installed. This is a very forward thinking concept by Mobi-Arc. In the event that the controller box should fail, the bypass will revert back to the internal voltage regulator in the alternator so you can continue the expedition. This feature also allows the controller to be switched between multiple vehicles. Simply use the bypass on the vehicle that does not have the controller on board. Installation kits are available that will allow a controller to be moved between vehicles (bracket and wiring harness).

On the alternator side, the cable to the controller box has been disconnected and the original output wire reattached. The connection cables from the controller box to the battery are also disconnected in the case of bypass.

Shown is a 28 volt module inserted. The controller box now acts as a 28 volt power supply with current limited only by the alternator output. Several modules are available. For jump starting with the 101, a 14 volt module inserted and then hooking the welding cables to the other car is easier than taking the battery cover off. Plus the welding leads are 25 feet long and I don't have to drag along the jumper cables.

The welding cable connectors are lock on. Insert the connector and twist, and the connector locks to the unit so they don't detach when you least want them too.

Both welding cables attached. When welding, the controller unit will disconnect the battery and put the alternator into high output mode of 42 volts and what ever current capacity the alternator can deliver. The weld LED will light up. This happens instantly when an arc is struck. If no welding activity happens for 25 seconds, the controller unit will revert back to charging the battery and the charging LED will come on.

Final installation. The controller box is very compact and looks pretty cool. It is nice to know that should anything break, I can fix it on the trail. More probable is that I will get a chance to fix other peoples rigs.

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