Quiet generator

adam greene

adam greene

Well-Known Member
Joined
Sep 9, 2008
Location
morganton
I bought a generator a few weeks back. It's a cheap tractor supply brand but got a good deal on it and it has the rv plugs so it works good for my use. Any way is there a way to quiet it down some? Thought about re doing the exhaust and adding a motor cycle muffler. Would that help or is the loudness just coming from the motor and everything else?
 
If the exhaust is loud, you'd want to add the longest muffler you can to quiet it down. From what I've seen those "stealth" kits work pretty good on fourwheelers.
 
you got a Champion ?

I wouldn't add anything to the muffler, I've seen where that can add to the back pressure of the exhaust and cause other issues.

go get you a sheet of foam board (1/2" or 1" thick) build a box that you can easily disassemble and reassemble and also store. leave openings for air circulation in and out of the box, leave space around the genset to allow air movement. you'll have to experiment with box shape, but for the most part enclose all sides the foam will absorb most of the sound. it's cheap and portable, adding a 12v pancake fan to help circulate air in and out of the box is a plus
 
I should elaborate...

The longest, straight through muffler you can get. Not sure what kind of selection you'd have with smaller stuff like that though.
 
So this raises the question - what is the "secret sauce" of the Honda and Yamaha Gensets? It's still an air-cooled 4-stroke motor.
 
Ear plugs? FTW :D




.....err i have to agree with the honda brand. The little ones we sell to rescue units are tits. Can't be much worse than my Ranger welder gen. unit. Sometimes it is worse than the grinder.
 
RatLabGuy said:
So this raises the question - what is the "secret sauce" of the Honda and Yamaha Gensets? It's still an air-cooled 4-stroke motor.
Click to expand...
smaller stroke and displacement. over all a more efficient motor. smoother running ect. I bet somebody could add to the actual generator side of that too......
 
Honda uses an elaborate exhaust system on their generator engines, but only on the EU series or "enclosed" systems. They are similar to a car muffler, then enclosed further in a sound-deadening enclosure. Aside from that, there's really nothing extraordinarily different from other OHV engines. You DON'T want to know how much a muffler costs for one.
 
Don't they also run a variable regulator for inversion for the RPMs only cycle up as the draw increases? Fro man engine standpoint thats the same but I can see how running much lower RPMs most of the time would help out a lot.
 
The Honda 350 I used at work was so quiet it was eiry. Most 13+seer package unit HVAC systems were louder than this thing.
 
I suspect Honda holds tolerances tighter, balances rotating mass better, tunes the isolation dampers to the vibration better, uses better fasteners and what ever else discovered in pre-production testing that's unacceptable to some criteria set by their management team. I have used some of their generators and they are sweet. Not so much with the "mainstream" box store gensets. The "cheaper" the genset you pick the more likely diminishing returns were never part of the original design and test program consisting of shelf parts and "we want it yesterday and less cost than all others". Just my $0.02.
 
I have a Honda EU3000is Makes power at a much lower rpm, increases on for more load. Very well insulated throughout.
I have seen others that were quiet, but none as quiet.
to quiet it down, built the sound shield like was noted above, a longer bigger exhaust, and a large, heavier gauge drop cord to get it as far away as you can.
 
Much of the quiet come from just flat out better quality and manufacturing practices/tolerances. Better design.
Most less expensive generators are nothing more than a lawnmower engine with a power pack bolted to it.
Some of the things I've seen to keep'em quiet ....
-foam enclose
-cheap generic glass pack or similar auto muffler
-On an RV'd schoolbus, a piece of flexpipe connected the exhaust in the vehicle exhaust( you could literally hear the rotating mass move)
-cheapest easiest way, 200 ft of heavy gauge extension cord
-extended pipe on the end of stock motor, 6ft. tall straight up


Matt
 
The Honda Eu series are what most everyone is talking about as the "super quiet" ones.

Without nerding out here that is known as an inverter style generator.
Honda
Yamaha
Onan(used to make them now have quit but lots still floating around)
and a host of others make the same style.

Full disclosure I am employed by Generac Industrial Power so my view is biased. Generac just released the IQ2000 it is a ground up in house design. The parameters given to the design team were:
1- Must be quieter than a Honda
2- Must make more power than the comparable sized Honda
3- Must be smaller and lighter than the comparable size Honda
4- Must be more fuel efficient than the Honda
5- Must be at a minimum 15% cheaper than the Honda and will include a 5 year comprehensive warranty.

They hit every benchmark. Ive got one of the pre-release ones Ive been testing and it badass.



FWIW a straight pipe adds backpressure, less so than a bent one for sure but it still adds significant (depending on length) back pressure.
 
Regular generators have to run a 3600RPM for the alternator to generate a 60Hz with the windings that are built into the alternator. This fairly high RPM creates vibration, lots of exhaust volume, and a medium frequency din that is annoying to our human ears.

Inverter generators use a slower RPM engine to generate DC that is then inverted to AC using electronics. The engine only spins fast enough to generate the DC needed to feed the load. As the load increases, so does the RPM of the engine. Since they use less fuel on average they also generate less heat, so adding sound damping materials to the case is easier.
 
I think I'm gonna try the foam enclosure first see how that works. I'd love to have a Honda or camp arable but $200 vrs $2k is a big difference. If I relied on it every day yea I could see it. But I may never use it again just figured it was cheap enough to have in case power was out.
 
just remember this.
2 things in that box need air. The engine is obvious. The alternator is just as important. If you restrict air flow too much (even just a tsad too much) you wont get a second chance with that one.
 
If u could measure the resonance frequency of the generator, you could build a harmonic damper to add on top the engine. That would quiet it down a bunch.

I like the box idea also. I have built one that has 3 sides and top. Point the open side away from you. Let's air flow but directs the sound away. Your buddy next door won't be as fond.
 
upnover said:
I have a Honda EU3000is Makes power at a much lower rpm, increases on for more load. Very well insulated throughout.
I have seen others that were quiet, but none as quiet.
to quiet it down, built the sound shield like was noted above, a longer bigger exhaust, and a large, heavier gauge drop cord to get it as far away as you can.
Click to expand...
I have slept in a tent next to this guy's generator.
 
Sleeping beside a running generator is no big deal. As long as it's running when you go to sleep. But if someone cuts that sucker off the silence is astounding and will wake anyone immediately!


Matt
 
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