I am thinking about buying a Harbor Freight 2K power inverter see below:
2000 Watt Continuous/4000 Watt Peak Power Inverter
I would like to use this on my M1009 while engine is idling for short periods 2 -3 hours at night.
What exactly do you want to use the AC power on?
I've got several trucks with inverter systems, and my entire house and farm runs off of inverters. There are a lot of things to know, and . . . many cheap inverters are absolute junk.
That being said, I bought a few Harbor Freight 2000/4000 watt inverters and built two cabins - using them to run all my power tools. Zero problems and the inverters were $129 each.
If you just want enough power to watch a movie on a 21" TV off a DVD player, you can save a lot of trouble and just buy a Duracell Powerpack 600. It's a very handy unit. Has a built in 600 watt inverter, it's own 27 amp-hour battery, two 120 VAC outlets, and charges pretty quick from a 12 volt power outlet in the Blazer. You can find them around for $150. It also has plug-in jumper cables, a radio, etc.
If you opt for a bigger alternator, keep in mind that some of the very big alternators make LESS power at idle speed then somesmaller ones.
You can also buy a Leece-Neville AKA Prestolite alternator that has a DC and a AC outlet - NO inverter needed.
The idea of powering an inverter with a running engine is kind of a waste. You're better off having enough battery power to do the job, and use the engine just to recharge at lower amp levels. Few alternators can handle the surges needed to run an inverter. Even if you DID have an alternator that could supply 200 amps at low speed, you'd have to have huge 00 cables with a very short run.
Alternator specs at engine idle speed:
Delco 10SI - zero to 23 amps, depending on number code (61 and 72 amp)
Delco 12SI - 30 amps (66, 78, and 94 amp models)
Delco 17SI - 23-55 amps at idle (63,108 and 124 amp models)
Also remember that cheap inverters to not make the same type of AC power you get from the electric companies. It's modified wave and will not urn certain types of equipment.
My 86 diesel Blazer has dual deep-cycle 6 volt batteries mounted under the rear bumper. One on each corner. They are hooked in series to make 12 volts and I have three inverters inside. Total of 6000 watts. Charge current comes via a low-draw, full-time-duty relay. Two inverters are cheaper modified-wave, and one is a high-end sine-wave inverter. Blazer has a 21" TV, DVD player, god size refrigerator, many fans, four radios, power outlets to run power tools, etc. Sleeps four people when needed.