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white belt
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Discussion Starter · #1 ·
I have no trouble with a short time power out keeping my generator safe but I'm not sure how to really 'stealth out' a sound that loud, especially with the exhaust needing to be vented...

Any good methods out there?
 

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www.veggear.blogspot.com
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Search through the old posts. There have been a couple discussions about it already. I think it was in the energy section.
 

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I have no trouble with a short time power out keeping my generator safe but I'm not sure how to really 'stealth out' a sound that loud, especially with the exhaust needing to be vented...

Any good methods out there?
I've been wondering the same thing. When the powers out it gets real quiet in the neighborhood and that makes it twice as hard to hide any noise. I thought, when I get time, trying about 20 feet of pipe and a car muffler every ten feet???
 

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performing monkey
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I've been wondering the same thing. When the powers out it gets real quiet in the neighborhood and that makes it twice as hard to hide any noise. I thought, when I get time, trying about 20 feet of pipe and a car muffler every ten feet???
when you start adding exhaust pipe you can have compression issues, just a heads up ;)
 

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white belt
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Discussion Starter · #5 ·
Well the search function gave me one irrelevant post. Even just 'generators' gave me 3 posts.

apparently if you have a good size hose, 3 or 4 inches bigger than the muffler, there is no back pressure problem. Maybe bury 15 feet of hose under the dirt...

But you still need and air intake opening and heat escapement...
 

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It's easy.. I'm deaf and I have a Honda... I can't hear it so neither can anybody else..

OK..I'll stop .. I think there are very good after mkt mufflers for this problem.. I also know a guy who put his in a home made sound proofed box ...sorta.. which contained all but the muffler and it seemed to be really quiet..but as stated I'm deaf...

But the hondas really are quiet
 

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carl.net
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73 Posts
I have no trouble with a short time power out keeping my generator safe but I'm not sure how to really 'stealth out' a sound that loud, especially with the exhaust needing to be vented...

Any good methods out there?
It is a really good question and one that has never been researched sufficiently to make good easy answers available. I have spent the last 6 years researching quieting small gas powered generators (10kw or less). I have looked at the techniques used on both marine and industrial applications. I have also looked at the studies done in countries like India where small gas powered generators are a fact of daily life. The answer is there is no good cheap way to make a small generator quiet. With that said there are some things you can do to reduce the noise and depending on the amount of work you are willing to do, money you are willing to spend, and space you have you can make them close to silent.

So here is a list of techniques generally sorted by effectiveness.

1. Plant the generators feet or wheels in a tray of sand at least 3 inches thick and that extends 1 foot on every side. Thicker and further out the better. (vibration and noise reflection)
2. Put the generator on a woven sisal rug or equivalent. (vibration and noise reflection) [this was about the same as # 1]
3. Replace or extend the muffler using either a better muffler or a car muffler on a flex hose. (what I used to use)
4. Dig a hole and place the generator in the hole (some campers use this one)
5. Stick the generator in a shed and pipe the exhaust outside using a car muffler and flex pipe (great video of this on the I-net)
5. Buy a used marine genset and plumb water and the marine muffler and a water pump into the system. (still have one of these)
6. Build a soundproof shed and used a powered exhaust fan and chimney to pull the exhaust up and out of the shed directly upward. (what I currently use)
7. Build an underground bunker for your generator and used a powered exhaust that vents through water into another bunker and then naturally vents to the air some point away from your location. (what I want)

Obviously there are lots of variations and combination of all of the above and there are added dangers and complexities with each solution. Good luck and if you come up with another different direction let me know as I would love to hear about it.
 

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The wanderer
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A couple things I've heard mentioned in our off-grid neighborhood...

Be careful putting a generator inside a shed or any sort of containment. It isn't just the exhaust that can be a problem. For one, the generator can get too hot.

Second, like a guy in the next town over learned...it can set fire to your building. Make it as fireproof as you can.
 

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performing monkey
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4,230 Posts
A couple things I've heard mentioned in our off-grid neighborhood...

Be careful putting a generator inside a shed or any sort of containment. It isn't just the exhaust that can be a problem. For one, the generator can get too hot.

Second, like a guy in the next town over learned...it can set fire to your building. Make it as fireproof as you can.
of course, you could advantage of all that incidental heat...

water pump & radiant-heat piping (very efficient)
 

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white belt
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Discussion Starter · #10 ·
Hi carlnet,

I could not find the video you refer to here: 5. Stick the generator in a shed and pipe the exhaust outside using a car muffler and flex pipe (great video of this on the I-net)

:(
 

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carl.net
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Hi carlnet,

I could not find the video you refer to here: 5. Stick the generator in a shed and pipe the exhaust outside using a car muffler and flex pipe (great video of this on the I-net)

:(
Quieten That Generator

See the end of the page should be a video.

Also as gypsysue mentioned the generator and attached piping will get very hot. I measured over 600 degrees near the motor and 250 to 300 degrees 3 feet down the flex tube. Also you will notice in the video (I did as well with my generator) that most of the noise is not exhaust noise but instead engine noise. So the noise blocking qualities of the shed are very important.
 

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a dude
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Honda...quiet...however, noise is something that works for you as well.

During some generator thefts what some SOB's did was start a lawn mower up and placed it by the generator, then they cut off the generators used at night and stole them.
 

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performing monkey
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apparently if you have a good size hose, 3 or 4 inches bigger than the muffler, there is no back pressure problem. Maybe bury 15 feet of hose under the dirt...
Isn't that the opposite of what you want to do? Wouldn't the issue then be overly lowered back pressure?
 

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Carinet: 5. Buy a used marine genset and plumb water and the marine muffler and a water pump into the system. (still have one of these)

I like the idea of a marine system offered by Carinet. Actually saw one for sale and thought it was too much hassle to change it over to conventional radiator and fan set up and exhausrt manifold from heat exchanger. Might just see if its still available.

I can see that water takes the heat out and much the vibration. The heat can easily picked up by reasonably common devices and this would sort that out.

Next problem..... what about the rooms 200 watt light bulb able to be seen in our windows. How can we make it look like a candle? :dunno:
Cheers
 

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carl.net
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73 Posts
Another idea is to use the thick plastic sheeting designed to line showers under the tile to create black out curtains. Works like a charm.
 

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Shoots to Thrill
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125 Posts
I've recently gone away from the idea of getting a generator and here's why:

1. Generators (though the most convenient means of 120AC power) are noisy. Draws attention, makes you a target (or a hospital).
2. Generators run on fuel, which is finite. Sooner or later, the natural gas will stop flowing or the propane or diesel tank(s) will run dry. Then you will be stuck venturing out to look for more fuel. What's the longest period a generator will run before exhausting its fuel? Then you are off to hunt for more.
3. Generators (at least those of significant capacity) are notoriously inefficient. Half of your energy is lost in heat and sound.

I've turned my attention to alternative sustainable power sources. Solar and wind have come along quite a bit over the past few years. That will be my approach if/when I have the option. Hopefully the technology will continue to improve and get cheaper in the future.

But, that being said, if I were pursuing a generator I would buy an enclosed generator (sound enclosure) and do everything I could to bury that generator and it's fuel tank(s) between earthen berms. Get it out of sight and do what you can to deaden line of sight sound transmission. That way you might get to use up the fuel supply before being discovered.
 

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I am making "blackout curtains" from the reflective space or emergency blankets. In addition to blocking light they will help insulate the windows against summer heat and winter cold. The cheapest ones I have found are at Emergency Essentials $1.25ea for a 84"x52". Their web site is Emergency Essentials - Be Prepared Emergency Preparedness Food Storage.
I use the emergency blankets on my windows in the summer to keep the heat down and they are not totally "not see thru" I can see thru them in the summer to the outside and at night you can see light thru them-- so if you depend on them for blacking the light out you will want to back them with something.
I have window quilts that have 4 layers in the winter to block out the cold(and they work well) and they are also not really blocking the total light during the day- but I bet if I got a dark layer for the middle they would block the light completely.
As they are now they do block candle light but not the big electric lights.
But I am really impressed on how much heat they blocked in the summer on the big windows.. I am thinking about putting them on the inside of the quilts to see if they reflect heat back into the room.
 
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