What resources to look at for building a quiet generator compartment?

[DoubleEagle]

If you're looking for some advice and guidance on soundproofing, the site I linked to earlier has lots of good information. Here's just one of their pages with advice: https://www.soundproofcow.com/soundproof-a-space-restaurant-office/soundproof-a-car-compressor-boat-pump-or-other-equipment/

There are a number of companies that sell soundproofing products, but I don't see much information about just what reduction in decibel levels are achieved in actual installations. Some of these products are very expensive and I would need to know what I would get for the money plunked down. Going by soundproofcow prices, I would refer to them as cashcow for short. We need before and after decibel ratings of specific installations.

[belfert]

I found this article on quieting a generator: https://800nonoise.com/tutorials/generator-set-noise-solutions/

[Utahclaimjumper]

 The Onan QD series are some of the quietest out there, They are totally enclosed in a box with all services done thru the bottom of the enclosure, fresh air is taken in at the bottom and released the same way. With water cooling temps are controlled in all environments.  Mine uses the Kabota three cylinder engine and has 2600 hours of trouble free use.>>>Dan

[buswarrior]

The kind of quiet i am after, and i expect Brian is too, is much quieter than an Onan Quiet Diesel.

Most, if not all of theirs are spinning at 3600 rpm now, and do not lend themselves well to the strategies to make one silent.

Imagine a bus conversion sitting in a field, and you can't tell the generator is running as you walk up to it.

That is a worthy, and challenging, goal.

Happy coaching!
Buswarrior

[belfert]

I'm not looking for a silent generator.  I just want it to be at least as quiet as my former Powertech generator and not overheat when operating it while driving.

The Powertech was probably just a little bit noisier than a Honda generator.  It did not really change in pitch like a Honda as the load shifts.  It was quiet enough that someone could sleep through the night in a bed directly above the running generator.  I think if the air conditioner was running the wind noise from that would mostly drown out the generator.  The generator mostly blended into the background when running, but it was noticeably more quiet when it was turned off.  One event I go to a lot of people run construction generators that I can hear from 100 yards away.  In those cases I had to be within about ten feet of the generator to even hear it running over the construction generator.

I go to a yearly event and one year a newbie at the participant's meeting asks if generators are allowed at night.  I about had a heart attack when the event director said no which was a change from previous years.   Our group was running a food stand so we had a 15 CF freezer and a household fridge that needed power.  I talked to the event director after the meeting and he said don't worry about it.  I could run my generator at night as it is not loud.  I have an auto start when the batteries get low.

[windtrader]

Hell with the genny - go solar - hear the ants marching!

[Utahclaimjumper]

 The QD series operate at max load at 2880 RPM and are controlled with AC to "on demand" RPM to meet the load.  At 1/2 load is 68DP at ten feet and 0.56 GPH..>>>Dan

[richard5933]

It seems that one way to keep the noise down is to go with a substantially smaller generator which is offset by a larger battery bank and a good hybrid inverter.

The hybrid inverter can be used to help carry the extra AC load when needed from the battery bank, and then it will recharge them when the load is reduced.

Seems like this smaller gen/hybrid inverter is being used in more and more of the higher end coaches, especially those with large lithium banks and solar on the roof.

[belfert]

I already purchased a Wrico 12.5KW generator.  I am not changing the generator now.  The 10KW generator may have been fine, but the 12.5KW really leaves no doubt and wasn't that much more money.  I run my generator a lot up at 4,000 feet so it won't give full power due to altitude.

I looked at Cummins/Onan, but it was quite a bit more money.  I'm also not sure it would fit in my bay.  The 12.5KW model runs at a fixed 1,800 RPM.  The hybrid quiet diesel seems to have been discontinued.

I don't use my bus enough to justify buying $5,000 or $10,000 worth of lithium batteries plus a large inverter and a bunch of solar panels or a smaller generator.  I don't think I could fit enough solar to generate as much power as my generator.  It makes sense for me just to buy a generator and burn fuel in it.  I have solar at home, but it makes sense there.

[windtrader]

Getting back to the make it quiet question. If you bought that 12k penny from Wrico, call back and get some specifics on options for quieting it down. You forked over a huge amount of cash, they need to step up to get you going. From what I have heard they are very good at support so try again.

[luvrbus]

My Onan 12500 is quite as a mouse they  run @ 1800 rpm like Brian stated.mine is bitch to service and on a slide with out the slide it would be impossible ,the top has to come off to change the air filter,the side has a door you remove to change the oil filter and you cannot see the fuel filter hidden , mine has nothing you can service from the bottom the oil plug is the only item you can remove from the bottom,it a good generator though ,I like the priming system on a Onan just hold the stop button down till it primes 

[chessie4905]

if you want to find out how the light tower generators or other units deal with noise, go to a large rental outfit. They have them. Go check them out.

[chessie4905]

if you want to find out how the light tower generators or other units deal with noise, go to a large rental outfit. They have them. Go check them out.

[luvrbus]

Air flow and vibration is the key to making a generator quite ,good mounts,the cooling,air intake,and exhaust,no need to buy a lot of sound  deading material  both my EPS and Onan quite boxes have about 3/4 of a inch of sound deading material in a metal box.Get around 59 DB and call it good your not building a recording studio   

[windtrader]

Agree that "air flow" is critical. That also means how well sealed the box is. We all have experienced even a very slightly opened window and the amount of noise is pretty amazing. Closing that tiny sliver of "air flow" cuts the sound off a bunch.


If you look at the design of good sound boxes that require lots of air flow you will see various bends that deflect and absorb the sound. It is a real science and no DIY guy will be able to create an adequate engineered design.


If you can't go to see a few sound deadened machines look on the internet for the construction details so you can get a good idea of the engineering principles applied for sound abaetemnt.