RV generator

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tl3883

Member
Joined
Sep 16, 2009
Posts
5
Location
Texas
I am looking at a Powermax 8500e generator.  8500 surge watts and 7000 running watts  This generator is listed on ebay for $700.  Has anyone used a Powermax generator or know anything about them?  Thanks for your help.
 
I have the 4400E and love it! I built a box for it to keep it quieter than stock, but stock is only 68dba at 21 feet. With the box it is 42dba. I don't know the dba rating of the one you are interested in. The engines are Honda knockoffs. the only thing I found with mine was that the breaker kept tripping when using the RV adapter. I studied the wiring diagram and found that the factory had the wiring incorrect. The company Maxtools was very good to me too when i called about the breaker problem [before I found the cause] they immediately shipped a new breaker even though it was out of warranty.
 
69 is still a little loud for a campground, but not nearly as loud as a contractors generator. Those are more like 85dba. With mine in the open (68dba) I can have a normal conversation at 15 feet or so, but I built the box for camping at a local beach reservation. With the box the campers right next to me don't know it is running and if I forget to shut it at the cut-off time, the ranger walks right by not noticing that it is running. I love mine. It performs well and cost little.
 
Most portables, and I am assuming that yours is, need a lot of cool fresh air and are not designed to run in an enclosed area. They will run very hot which tends to cause problems and shorten the service life.
 
Roy, my box has two fans @ 600cfm each. One blows in and one exhausts. They both have insulated duct connected to them to cut noise. The generator actually runs about 15 degrees cooler than if in free air.
 
I love this site and the great feedback.  Regularguy, What material did you build your box out of?  Where did you buy your fans? Is it always on the generator or do you put it on when you get where you are camping?  Pictures, plans, anythng else? 
Did you insulate it?  What is insulated duct?    ???????
 
regularguy said:
Roy, my box has two fans @ 600cfm each. One blows in and one exhausts. They both have insulated duct connected to them to cut noise. The generator actually runs about 15 degrees cooler than if in free air.

That sounds like a pretty cool box, all puns intended.  Could you post some pictures of your box and or a sketch of the plans?  That is very impressive indeed.
 
I made it in three pieces. The base, the side enclosure and the lid. The base is 3/4 plywood, the sides and lid are of aluminum sheet riveted to corner molding. The whole assembly is lined with 2" rigid duct insulation (the kind you see on duct-work and is silver in color). The fans (duct booster fans, 600 cfm ea)are mounted in the side assembly. One blows in and one blows out. The insulated duct is just that. It is flexible duct used in the HVAC industry and usually runs from a main rigid duct to a ceiling mounted diffuser. The was I use it is I roll the generator onto the base, put the side assembly over and then put the lid on. the lid and side assembly have the two halves of hinges that slide apart. There is a small cut-out for the cords and one for the exhaust. I put a piece of rigid foil faced pipe insulation in the hole and it mates with the muffler by way of an old speaker magnet. I also installed a temperature sensor on the head of the engine and set it at 20 degrees above its free air operating temperature. The sensor / relay will cut both lines to the breaker and ground the ignition. That way no electrical appliances etc will suffer low voltage as the generator shuts down on temperature safety.

one more note: the fan that blows in... blows on the engine
 
regularguy said:
I made it in three pieces. The base, the side enclosure and the lid. The base is 3/4 plywood, the sides and lid are of aluminum sheet riveted to corner molding. The whole assembly is lined with 2" rigid duct insulation (the kind you see on duct-work and is silver in color). The fans (duct booster fans, 600 cfm ea)are mounted in the side assembly. One blows in and one blows out. The insulated duct is just that. It is flexible duct used in the HVAC industry and usually runs from a main rigid duct to a ceiling mounted diffuser. The was I use it is I roll the generator onto the base, put the side assembly over and then put the lid on. the lid and side assembly have the two halves of hinges that slide apart. There is a small cut-out for the cords and one for the exhaust. I put a piece of rigid foil faced pipe insulation in the hole and it mates with the muffler by way of an old speaker magnet. I also installed a temperature sensor on the head of the engine and set it at 20 degrees above its free air operating temperature. The sensor / relay will cut both lines to the breaker and ground the ignition. That way no electrical appliances etc will suffer low voltage as the generator shuts down on temperature safety.

one more note: the fan that blows in... blows on the engine

How much bigger is your box than your generator? 
Where can one find aluminum sheet? 
I am having a hard time visualizing "two halves of hinges that slide apart".  Do you mean you pull the pin out of the hinge to disassemble them? 
I am also trying to visualizing the mating of the speaker magnet and the muffler.  Is the speaker magnet like a donut?
What kind of temperature sensor did you use?  Where can you buy one of those?

Sorry for all the questions.  I am very interested in this box and would like to make one too. 
 
While on the topic of generators, I was wondering if anyone has tried attaching a more substantial muffler to a generator?  I always wondered if I were to make a new exhaust system with a small car muffler or similar, and some longer exhaust pipe, if that would hush it down quite a bit.

 
naterv said:
While on the topic of generators, I was wondering if anyone has tried attaching a more substantial muffler to a generator?  I always wondered if I were to make a new exhaust system with a small car muffler or similar, and some longer exhaust pipe, if that would hush it down quite a bit.

I believe that the majority of the noise from a generator comes from the mechanics of the generator and motor. Most generators aren't that noisy as far as the exhaust goes. Most of them have a pretty good muffler.
 
Adding a muffler may increase the exhaust back pressure and impair the operation of the generator.
 
naterv said:
While on the topic of generators, I was wondering if anyone has tried attaching a more substantial muffler to a generator?  I always wondered if I were to make a new exhaust system with a small car muffler or similar, and some longer exhaust pipe, if that would hush it down quite a bit.

I have seen some modifications to generators that have a square tube framework around the Genny.  I'm thinking it takes someone to build a new exhaust flange and bend some tubing for an exhaust pipe and then to weld it up.  But the muffler itself was really meant for ATV applications.  The one I looked at was a muffler meant for a Artic Cat quad that was bolted vertically onto the genny framework and worked pretty slick.  The muffler was maybe about 10" long by 4" in diameter and quieted the 5K watt genny down considerably.  Might be something to think about if you have access to someone at a machine shop.
 
regularguy said:
I made it in three pieces. The base, the side enclosure and the lid. The base is 3/4 plywood, the sides and lid are of aluminum sheet riveted to corner molding. The whole assembly is lined with 2" rigid duct insulation (the kind you see on duct-work and is silver in color)....

one more note: the fan that blows in... blows on the engine

Regularguy, I'd love to see a picture or two as well. I'm having a bit of a problem visualizing it. I'd like to quieten down a small champion generator for campground use.

Thanks is advance!
Saddle
 
Ned said:
Adding a muffler may increase the exhaust back pressure and impair the operation of the generator.

True, depending upon the size of the muffler.  The opposite could be true as well.
 
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