Micro CoGen.

Ker-ching!  Another contribution, with thanks for all the good work!

I haven't tried this, but it seems to me that one of those inverters that offers "generator assist" is just what you need.  You would put the utility power into the generator input, and program the inverter to "assist" at a certain load point, so it auto-magically shaves your peak load.  During light loads, the inverter would charge the battery.  No relay needed, just a smart inverter (and smarter operator).

Welders have an odd (to me) output curve.  When you get around the rated current (as set by the current control) you'll most likely have around 25 volts, which isn't going to charge a 48V battery.  So if you have a voltage and current meter, you should probably be OK to "try it and see".  But don't come back to me if the magic smoke gets out...

I'm assuming you've already checked and the welder output is DC, and not AC?

Looking at the pictures, it appears that the top radiator hose goes above the radiator cap before entering the engine.  That will make it difficult to get the system full of water and purge the air out.  Remember that water won't run uphill.  You may have to either tilt the engine up on the radiator end or provide a fill port at the highest point.

Another idea to use instead of a thermostat is to control the DC water pump.  Could be as simple as on at 195, radiator fan on at 205.  Or variable speed if a micro controller is your cup of tea.  Just be sure you're measuring temperature where it gets hot when the pump isn't running.

I've gotten good service from Messick's in the past.  They sell parts for Kubota tractors, so you may have to call them at first to find parts for your engine since the online lookup is based on tractor model number, not engine model.

www.messicks.com

Since you have an ST connected, you can get a mains-powered battery charger that runs off the ST to charge your battery and keep the accessories powered.  Much simpler than a car alternator and doesn't require any mechanical connection.

I've done a few trailer loads from the rental place, and my advice is DON'T, unless you live really close.  The aggregate settles to the bottom and water/cement floats to the top if you travel a few miles.  The result is you can't even open the gate and dump the load without mixing it by hand first, which is a lot of work! There's a reason they haul that stuff in mixers that constantly mix.

And yes, most places around here charge for a full truck load (9 yards?) as the minimum.  There is also a service here that has trucks with dry materials, they mix on-site and will do small batches but I haven't checked out their prices.

I keep forgetting about the ground freezing up north.  Here the maximum frost depth is 6 inches, and I've never seen the ground freeze at all.  But in a few years we're retiring to Wyoming and the frost depth is something like 4 feet there, so I'll need to keep that in mind.  Water lines are 6 feet deep, so I definitely need to add a backhoe to the list of power tools I need to acquire. Good to know about using sonotube or pipe to keep away the frost heaves!

I've heard of folks around here setting fence posts by digging the hole and pouring in the bag of mix dry - no water added.  The mix absorbs moisture from the soil and hardens, no mixing required!  I'm not sure how long it takes or if that's a good method.

The bags are already mixed (cement/sand/gravel), you really only need to mix them enough to mix in the water, so I think your method is OK.  Depending on how much space you have around the pole, you're also trying make sure there are no voids in the concrete.  I personally like to add some cement to the mix because the bags are pretty poor with cement.  I've also heard that the less water you use, the better - too much water causes the concrete to shrink a lot as it dries, which leads to cracks.

How big is the hole relative to the post?

You're not putting the sonotube all the way to the bottom of the hole, are you?  I can understand using the sonotube near the surface where it forms up the concrete above grade for a nice appearance, but I wouldn't let it extend very far into the hole.

So... do you have plans to travel a lot, or are you staying in a "permanent" location?

What about the shop/engines/etc?  Another trailer?  Shipping container?

Sounds like you've been listening to what we used to call the main stream media.  They are nothing but the propaganda arm of the democratic party.  No matter how good a job President Trump does, they will malign and disparage him.  He's not as bad as they try to make him out to be, and might actually turn out to be a pretty good president.  But you wouldn't know that listening to the alphabet soup propaganda artists.

I voted, so I get to complain, right?

I put in a little to - thanks for all the work as well.

I just happen to have an old 8N setting under the shed.  It gets run a few times a year to mow the pasture with a brush hog.  Does the job quite nicely, but I have other tractors for "real" work.  I've gone modern with it, it has a 12V alternator, super-capacitor for a battery, and electronic ignition so I don't have to file the points every spring.  Each time I use it, I shut the fuel off when done and let it run all the gas out of the carburetor so it doesn't gum up.  I'll keep your greenhouse idea in mind when I build my greenhouse...

I check in almost everyday, usually to read and learn.  I'm assuming everybody is running fine with no problems or there would be more posts.