We are going to be off the grid when we build on our new land. My husband thinks we need a generator and a gasoline powered compressor. The compressor he's looking at is $789, from Harbor freight; it's 5 1/2 horse power. My question is, is it better, cost wise, to buy a separate generator and gas compressor, or should we get a generator with enough hp to power a regular electric compressor (which he already has). My husband is a carpenter so knows a lot about woodworking and his tools but neither of us know much about electrical stuff. He'll be using the compressor constantly as he uses a lot of nail guns etc while building. I hope I've been clear enough; I guess my feeling is that the nearly $800 for the gas compressor could be better spent on a beefier generator but I know nothing about what I'm talking about:o)

-- Elizabeth in E TX (kimprice@peoplescom.net), July 29, 2001

Answers

You'll pay a lot more than $800 for a good generator with the output for a heavy duty compressor, but then you will be able to use that generator for more than one thing. I would advise getting a good generator if you will be off-grid. You already have a compressor. With a 7500 watt generator, you can power the compressor, any other power tools, the well pump, lights, computer, etc. etc. With the gas powered compressor all you can do is blow air.

In my opinion, anything on the homestead should be as versitile as possible. Check the tags on all your electrical devices and write down the voltage and wattage on each. Get a generator that matches the maximum number of watts that you would possibly NEED at any one time. Remember that some devices, like a well pump, have a low operating wattage, but very high "kick-in" wattage. On our system, the watt meter on the transfer switch spikes to the top when the pump starts (3/4 hp), but when the pump is running, the meter barely registers any wattage at the bottom of the scale. An electric compressor would be very similar with high demand at startup, but low demand while running. You need roughly double the kilowatts in horse power to run a generator. In other words, our 7.5 KW generator is powered by a 13HP gas engine.

-- Skip in Western WA (sundaycreek@gnrac.net), July 29, 2001.

Also depends on how portable the compressor needs to be. If your husband is going to be doing work (such as roofing) away from home... a gas powered compressor may be a good idea. I'd still get a generator powerful enough to run a compressor.

cheers,

-- Max (Maxel@inwindsor.com), July 29, 2001.

When we tried to operate my friends compressor off my 5000 generator it didn't work well. It kept bogging down thus less air pressure. In an older issue of CS there is an article on Powering the Homestead offgrid. Maybe someone here can tell you which issue (I forget). I do remember the writer had 2 books on the subject.

One other note. I have had fair success with items ordered from Harbor Freight. My only complaint is If you try to get any warranty work done DO NOT RELY ON Harbor Freight to Help.

-- Kenneth in N.C. (wizardsplace13@hotmail.com), July 29, 2001.

CS did a wonderfull article on how to use compressed air for pumping well water [a 100' was listed, if I remember correctly]. I just don't remember the issue. anyone got the index?
Use the same setup as an aquarium -- bubbling air up from the bottom causes lift and [if I remember correctly] pressures the water flow up top.
How much air does he really need?
Do you plan on running the genny all the time, or only during big loads? Will you be using battery / inverters for smaller stuff?

-- (perry@ofuzzy1.com), July 29, 2001.

A diesel powered generator is much prefered, runs at a lower rpm for less noise and vastly improved fuel efficiency, plus at least twice the life expectancy than the gas generator. You can always resell the diesel after you are done with it at no loss in price practically too.

Buy from a dealer you can drive to so you can get service easily, mail ordering parts is a major pain, and warranty work by mail an even bigger pain!!!

-- Annie Miller in SE OH (annie@1st.net), July 29, 2001.

Sounds as if your husband would likely be doing work away from the homestead as well. I don't think he needs to cart a complete homestead generator kit around with him, as well as a compressor. I'm not sure you'd really want him to go away with the homestead's power source either; and the more you move it the more likely it is to break.

-- Don Armstrong (darmst@yahoo.com.au), July 29, 2001.

Thanks guys for all the responses. Neither the compressor nor generator would be used off the land. My husband does all his carpenter work at home in his shop or just outside--he got tired of dealing with the public so builds storage buildings and small cabins on spec. Lots easier to have people come pick something out you've already built than to try to build something for them the way they've pictured it!! He's worried that the compressor will bog the generator down, the way Kenneth describes. I don't know yet if we would be running the generator most of the time--we are still at the planning stage. Probably run things off the generator at first until we can afford solar. I think I need to do more research before I can frame some better questions for this forum.

-- Elizabeth in E TX (kimprice@peoplescom.net), July 29, 2001.

You might have to end up with both!! A genny would have to be pretty chunky to be able to handle the times when hubby wants to use the nail guns--the well pump kicks on,--and may be the fridge cycles on,--and what ever else is on in the house!!!!! Not good for a puter or tv when those other things are hitting your system with a HUGE surge [startup] demand!!! So-------seperate systems--that way his nail guns won't effect the house demands??

-- Jim-mi (hartalteng@voyager.net), July 29, 2001.

You might have to end up with both!! A genny would have to be pretty chunky to be able to handle the times when hubby wants to use the nail guns--the well pump kicks on,--and may be the fridge cycles on,--and what ever else is on in the house!!!!! Not good for a puter or tv when those other things are hitting your system with a HUGE surge [startup] demand!!! So-------seperate systems--that way his nail guns won't effect the house electrical demands??

-- Jim-mi (hartalteng@voyager.net), July 29, 2001.

Your going to need a big generator to start a 5+ hp compressor. You want a generator that will power your home when your primary power will not or to charge batteries when primary source is not avaialble. I would go with a seperate gas powered compressor.

-- gary (gws@redbird.net), July 30, 2001.