Lets Talk CNG Standby Generators
 

Folks, I want to install a standby generator powered by CNG. Any thoughts? I have 2 AC units but really only need to run one during an outage. Otherwise I got the standards stuff like 2 fridges, electric range. I think minimum to run my house is 20KW. I wouldn't mind finding something used and bumping up the KW.

The only consideration is that I want it to be quiet. I used to have a portable generator for some of the house but the neighbor would call at 10PM on the dot :rolleyes: saying it was too loud. Ok maybe he was right! Now I just want something quiet. My neighbor has a 84KW with a Chevy 350 running it but that is to literally power everything. For my house I think hers would make excess power. The thing is, the 350 runs at 1800RPM to make her power and you can't even really hear it.

So what do you have or what does your company install? Note: don't NEED an automatic transfer switch but it would be cool.

And to piggy-back. I want to do a similar thing if I buy a house out in the country, but the generator will have to run on propane. Is that a problem?

I have a 15kw Generac that runs on propane, not a difficult conversion. Had it in place for about six years. Very nice to have in the Adirondacks when the power goes out as it does quite frequently.

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You can get a gas genset from Home Depot. It looks like 20kW is a bit under $5k. Most of the gas units can be run on either natural gas or propane. If I had to choose, I would probably pick a Kohler over a Generac.
I work for a Cat dealership, and our smallest gas unit is a re-branded 25kW Generac. I have not heard much good about them, and frankly you can buy the generac at home depot for cheaper.

The last generator (natural gas burner) I bought for a job was a 13KVA unit that was just under 14HP IIRC. It was for a company project. I recall that there is a cut-off around 13.5 HP or so that requires an EPA permit if it was exceeded.

It may not apply to homeowners, but I would check just be sure your local codes.

I've seen a lot of Generac units out in the fuel plumbed for natural gas and the techs I've spoken to appeared to be satisfied with it. Propane or natural gas, it's an easy conversion with a few small parts. If I were to buy a NG unit, I would get the propane conversion parts just to have handy incase your NG supply was interrupted. The big difference is an orifice and maybe a regulator. All can be changed out in less than a minute if you are handy.

The OP's mention of his neighbor's Chevy 350 running a generator gives me a great idea. I've got a BMW 2.5 liter engine sitting around collecting dust that I could put to good use! How hard could it be to bolt up a generator to the engine if I build a stand for it.....hmmm I engine have a spare 911 engine :D (running hard on the track on weekend, the next weekend sitting on a skid cranking electricity to the house) For quiet ...I can weld up a good muffler.

LOL, we have a 38,000 hp steam turbine and a couple of pratt and whitney jet engines running generators here.
oh, that's not what you meant? sorry.
;)SmileWavy

It would be very easy... my uncle did it. You can get cheap generator ends (harbor freight has a 7.2kw generator for $300). Just make sure your engine is well governed.

20KVA should run the important stuff

Generac units are pretty nice natural gas is the way to go. If you don't have NG go propane.

They are fairly quiet.

Standby switch and weekly auto start are nice to have, keeps the unit battery charged and the engine lubed.

I have an 10KVA Kohler engined Miller Trailblazer It's saved my bacon a few times.
I bought it for power on job sites.

We've have had 12 Hour stints on the genny.

Come up with a priority circuit list. Don't overload it

AC is a big draw

Example

1.Septic Pump
2.Furnace Fan
3.Well
4.Refrigerator
5.Freezer
6.Bed room lights
7.Master Bath
8.Wall Outlets kitchen
9.One garage door operator
10.Computer

Yep, I just saw it on their site. $299 for the 10,000W/7,200W unit (20A@120VAC/30A@240VAC)

Northern has a nice one for $840. 10,000W/9,200W (80A@120V/40A@240VAC0


The Northern one looks like a good buy. I can have a 10KW generator for less than $1000 since I have the engine. $160 budget for angle iron, pulleys, etc to make it work. There is a Chinese brand of generator heads that's pretty cheap. 15kVA for something like $700, but quality may be iffy. I guess once I set up the engine on a mobile skid, I can bolt any generator head on it. Cool thing is that I can have the skid behind the shop and when needed I can back feed from the shop to the house with the main breaker off. 10KW should be enough to run the essentials I would think.

20kVA is a lot of power. You could probably run your house and the neighbor's on that don't you think?

My reasoning, most homes have 100A service.

Here's a neat site I just found to convert from kVA to KW, etc.

http://www.dieselserviceandsupply.com/Power_Calculator.aspx

Why can't we just use the free gererators????


Just sayin' we need to link these gererator threads together somehow!

The motors really draw the amps 1.5HP farm sized well pump needs the juice.
the reserve power makes the motor starts easy. If your not in a rural setting 10KVA is plenty I would think for a 1500Sqft city home 5KVA would be OK. Farm type needs 20KVA is the min.

Souk,
My uncle is using a chinese generator end - though unfortunately I don't remember anything more about it. He is moving out to the country and preparing for economic collapse, and he seems convinced that it will work reliably.
10 KW is more than enough for your typical power outages. As long as you don't have all the appliances on while your four daughters blow dry their hair, you should be fine.

Guys, if you are going to set this up do it right. Make sure you have a home transfer switch to make sure you don't send any power out thru the lines. Transformers work both ways. Generators have been known to kill linemen working on lines they thought were dead.
Another generator to consider is the Auragen by Aura Systems. It runs off of your truck and is mounted under the hood. Good systems. I have had two for years. I have the 5000 watt generators but they have some larger. A bit pricey but good equipment.

I think the Chinese genheads are "ST" brand. I think they may be fine. Just a few bad experiences posted on the web.

MT-makes sense about the start/peak power.

Used kohler?

You could look for a rv diesel generator. They usually run at 1800 rpm as opposed to some of the cheap ones at 3600 rpm. 3600 = loud.

Ok, I also have a question about this. I have a 10KW (12.5KW peak) Generac generator w/ a 2 cylinder Robin, 17 hp. engine I'm thinking of setting up as a backup generator (I also have a 7.2 KW transfer box that I can tie in to different circuits). Can I convert it to propane? If so, I think I'll look into that.

The CNG cylinders are pressurized to 3500 psi, and need hydro every 5 years or so. Would a propane tank work just as well?