My elderly neighbor has a 2001 BX 2200 and he put a Original Cab on it and wants to use an electric (12V) heater to keep him warm in the winter while plowing his drive.
Do the math. You have a 12v system. How much power do you need to keep that cab warm? Well, that's hard to say for sure, but we can probably get close.
A standard plug-in house heater maxes out at 1800 watts (15 amps X 120 volts = 1800 amps).
Would that be big enough? Sure. Not a problem. You are trying to heat a pretty small space.
But wait, that space is drafty and not insulated well. Based on knowing what a plug in house heater can do in a similar small space (my 4x5 office in my basement) I'm guessing you need at least 1,000 watts to keep that cab warm in cold, windy weather.
For the sake of doing a calculation let's call it 500.
To get 500 watts out of 12v you need 40 amps. (500 watts / 12 volts = 40 amps). Continuously.
Can you get that out of a larger alternator on that small machine? Yes, in theory. It will suck less than 1 HP out of your engine (electricity isn't free!) but that's not bad. It's 0.6 HP, actually. You have plenty of HP to spare, right?
But if you need 1,000 watts, it's a different story. It's going to take 80 amps and 1.2 HP. At 1500 watts, you need 125 amps (2 HP).
That's getting ridiculous.
So it's all about how much power you need to do the job you want to do; heating a drafty,
uninstalled uninsulated cab in cold weather.
That diesel fired heater is looking mighty attractive.
(EDITED TO CORRECT AUTOCORRECT'S AUTO-ERROR)