Has anyone quieted the NPS 5500 generator?

[jonesytriumph]

I didn't even know they released the eco kit that provides the throttle stepper motor that is informed by load--something every portable inverter generator has! I contacted them about this eco kit and within less than a day they called be to get payment and shipped the unit. Also, I asked about getting the sound box and the guy said it came with the eco kit?

Anyway, I'm looking forward to less wear and tear on the engine, less fuel consumption, and less noise when not fully loading the generator. I've always been running a portable overnight to save fuel and not be the "guy with the loud generator" keeping everyone awake at the track all night so it will be nice to have the option to keep the NPS running if I don't feel like getting the portable unit out.

[Maitiu C]

I’ve been reading the posts regarding the NPS genset and i want to install the ECO kit on our Hperlite. But…

I can’t get the generator out of the compartment it’s in. It doesn’t fit through the door. Any suggestion would be greatly appreciated.

FYI: we bought this in February 2021, used it two days, and it went in the shop for two months for repairs. We then used it one day and we are waiting for approval from FR for additional repairs. 3 day use out of 7 months.

[wades3]

Originally Posted by SgtTomVA

I know this is somewhat of an old thread. We have been dealing with this issue since our first trip using the generator. If you have never experienced how loud this thing is let me elaborate. I used to work in aircraft maintenance and we had generators on the flightline that were quieter than this thing.

What I found was the bulk of the noise is generated by the highspeed flywheel fan. This noise echoes off the ground and is trapped by the bottom of the RV amplifying the sound kinda like pointing the speaker of your cell phone into a cup to play music.

My approach to this problem was to make a sheet metal duct lined with heat resistant sound absorbing material to duct the airflow and the sound horizontally away from the generator and at a more gradual slope to the ground. This deadens the initial noise while not limiting air flow and also prevents the bounce back effect of the sound reflecting off the ground under the RV. This was a major success but did not cure the problem 100% because I still needed to deal with the intake side of the generator. I used the same material to make an airbox of sorts with overlapping passages that would still allow the air to freely flow to the generator while still redirecting and absorbing the sound. This probably deadens 85% of the sound from the generator, now you can actually hear the exhaust, before you couldn't even hear it over the whine.

It is no where near as quite as my super quite inverter generator but I think it is about as good as it will get unless I can tackle the load sensing throttle so the generator isn't running at 85% all the time.

Do you have any pictures of what you did? I used our Vengeance this past week and had people complain about the noise.

[asr524]

Originally Posted by wades3

Do you have any pictures of what you did? I used our Vengeance this past week and had people complain about the noise.

Your better off looking at the eco kit.

https://youtu.be/4KRxC6_cVY0

https://www.npsrvpower.com/product/eco-kits/

They sell a sound box (was free with my eco kit) but im convinced it doesnt help much. The eco kit was a great upgrade and well worth the cost.
https://www.npsrvpower.com/product/sound-box/

[wades3]

Originally Posted by asr524

Your better off looking at the eco kit.

https://youtu.be/4KRxC6_cVY0

https://www.npsrvpower.com/product/eco-kits/

They sell a sound box (was free with my eco kit) but im convinced it doesnt help much. The eco kit was a great upgrade and well worth the cost.
https://www.npsrvpower.com/product/sound-box/

Would you mind showing pic on how the box looks when installed? I will probably get the kit but I am not able to do the work. Physical issues right now.

[asr524]

Originally Posted by wades3

Would you mind showing pic on how the box looks when installed? I will probably get the kit but I am not able to do the work. Physical issues right now.

This is how its installed on my 5th wheel. The box basically just redirects the air flow out of the enclosure and has some sound dampening material attached to it.

[FollowTheSun]

Originally Posted by DirtRoadLife

I am getting ready to put some dampening material in the box and seal the area. I was just wondering if anyone had any luck with the exhaust. I am debating on trying a gensilencer.

Your mention of a "GenSilencer" got me curious as I also would like to silence my Onan generator more. I added a resonator to the exhaust which did reduce the popping noise and make things a little quieter. I couldn't find any real information about the GenSilencer on their website. Other than price, does anyone know what the difference between a $190 GenSilencer and a $50 Generator Exhaust Resonator?

[wades3]

Originally Posted by asr524

This is how its installed on my 5th wheel. The box basically just redirects the air flow out of the enclosure and has some sound dampening material attached to it.

Thank you.

[blank77]

OK, I just completed the Eco Kit installation and the soundbox in my 2021 FR3 and the results are impressive. The jet engine noise is gone. In my installation, I did not have to completely remove the generator. I removed the ground, the 12v, but left the fuel lines inact and "spun" it out. Start to finish was around 4 hours for me, but I take my time. If you have any questions, feel free to ask.