Thinking about a Bus/RV

Ted said:
I'm sitting here thinking a few things.

1) I hate my generator
2) I really hate my generator
3) See items 1 and 2 above

Ok, let me clarify that a bit. Our RV has an Onan QuietDiesel 7500. It's not an awful generator. It starts every time I push the button, starts easily at that. I've started it below 0F and other than the glow plugs needing longer to preheat before it engages the starter, it really is just fine. It's a bit undersized for this RV and will blow the breaker on the generator itself depending on what we're running. That's not the generator's fault, unless you want to blame it for only being a 7500W generator instead of a 10k or 12k unit.

However, it's loud. Anyone who's been around some of the newer portable generators that most people use will understand that you can barely hear those. This, you really hear.

So, I'm thinking about ways I can try to make it quieter. A few things have come to mind.

1) Obviously, the exhaust could be muffled more. I think this is something I'll need to do
2) The generator itself makes some level of noise inherently, and because it's in an enclosure box, I can put some sound deadening around the outside as well as on the front fiberglass panel to try to absorb some of the sound coming this way
3) However as I walk around the generator, it seems like a large portion of the noise is coming from the cooling fan, which has quite a bit of airflow. So...

#teddoingtedthings

The generator has its own cooling system, which is something that I don't fully understand the logic behind. It's not very efficient for it to have its own system when the engine has more than enough capacity, and also runs hoses right next to/past the generator for the forward heater (which I replaced). The current setup has several issues, noise being the most obvious one for this post, but the other thing that comes to mind is that the generator and the main RV engine aren't able to preheat eachother for cold weather ops.

I want to look at this some, but I'm thinking that I want to see if there's away to combine the cooling systems into a single one, and then disconnect the factory cooling fan so that I can save that noise.

I'm also back to thinking about solar panels and/or better house batteries, but I think getting the generator quieter is something that I want regardless of any of that.
Click to expand...

My only guess is that they keep them separate so if/when the generator comes from together, you can still operate the engine. If you're going to replumb it, though, I'm sure you could find a way to have emergency isolation when necessary.

As far as solar + batteries - take a look at RedArc systems. I have absolutely ZERO experience with them. They seem to be the go-to system (which probably just means they have a better marketing dept than anyone else) for the overlander folks that I follow on YT, etc. Looks like they can really be self-contained, which I imagine could be broken down to more manual control for folks like us that like to tinker. ;) I need you to try it out to provide a real-life review. :)

 
So, I have to ask. If you dislike the generator for being undersized for your needs, why not just replace it with a larger model that may be quieter anyway? I know, $$$. Gennies ain't cheap, but you might be able to sell yours to recoup much of the cost. Next problem could be space constraints as well, depending on what is available in your existing layout.
 
CJones said:
My only guess is that they keep them separate so if/when the generator comes from together, you can still operate the engine. If you're going to replumb it, though, I'm sure you could find a way to have emergency isolation when necessary.

As far as solar + batteries - take a look at RedArc systems. I have absolutely ZERO experience with them. They seem to be the go-to system (which probably just means they have a better marketing dept than anyone else) for the overlander folks that I follow on YT, etc. Looks like they can really be self-contained, which I imagine could be broken down to more manual control for folks like us that like to tinker. ;) I need you to try it out to provide a real-life review. :)

Click to expand...

Ok, get them to give me a free unit and I'll get right on that review. :D

SoonerAviator said:
So, I have to ask. If you dislike the generator for being undersized for your needs, why not just replace it with a larger model that may be quieter anyway? I know, $$$. Gennies ain't cheap, but you might be able to sell yours to recoup much of the cost. Next problem could be space constraints as well, depending on what is available in your existing layout.
Click to expand...

I have had that thought. But, generators aren't just not cheap - they're extremely not cheap. It would actually be cheaper for me to replace the 3126B in the back than to replace the generator up front. Like you said, I could probably recoup some of the cost from selling it. Basically I'd have to replace this QuietDiesel 7500 with a QuietDiesel 10000 or 12000 from what I can tell. As an alternate, I could go with some kind of gasoline generators (that are actually quiet) in parallel. But the reality of operation is that it being undersized isn't a problem unless I forget to turn off one of the overhead HVACs. It only gets overloaded if both of those are running and then we try to use other high-power accessories like the microwave, toaster, etc. I definitely don't want to try to replace this thing with gasoline generators, if nothing else because of the issues of carburetors and having to add another fuel tank and keep it filled.

For this RV, I'll leave it as-is. At some point if/when we get a different RV, I'm sure that a larger generator would be something we'd look for.
 
  • Like
Reactions: Ted
charheep said:
So, I had to look. Damn, you were right.
For the QD 10000, its 11k! https://www.norwall.com/products/Cummins-Onan-QD-10-0-Diesel-RV-Generator-10.0HDKCA-11506/

Thats like 7 new motorcycles for you
Click to expand...

Exactly. Like I said, I could replace the big Cat cheaper. Just not an expense working with.

If I was building an RV from scratch, I'd put some more thought into it and how I could set something up that might work better/be more economical.

The other thing with these Onans is that they're expensive because apparently they are really, really good. I've read very few stories of issues with them as they age, and there are stories of tour busses putting 6,000+ trouble-free hours. This one has something around 2,300 hours and, knock on wood, has been reliable for us. We've put a lot of the hours on it, it had around 1,400 hours when we bought this thing.
 
I really like idea of combining the generator cooling system with the Chassis Cooling system. Temporarily disabling the fan on the Generator would of course quickly give you an idea if it would help much with the noise.
Of course I am not the one having to figure out pumps and or thermostats and fan systems to make all that work.

I am sure originally it was more just an issue of lets just drop a generator unit in, rather than try to integrate with the other systems.

Brian
 
  • Like
Reactions: Ted
brcase said:
I am sure originally it was more just an issue of lets just drop a generator unit in, rather than try to integrate with the other systems.
Click to expand...

My opinion is that one should never assume that anything on an RV was actually engineered with any idea of how to make it optimal. Just basic things like welding all 4 sides of square tubes weren't done, and I'd imagine would do a ton for rigidity. It's more work to figure out how to integrate a generator cooling system with an engine cooling system.
 
Now I've got a repurposing idea. I wonder if I could attach the old muffler from the BMW (that I removed because it weighed 17 lbs to replace with a lightweight but louder muffler) to the generator exhaust as an additional muffler to make it quieter. One thing the BMW did have was a quiet exhaust. I also don't know the condition of the factory muffler, other than it's likely original and has 2300ish hours and 22 years on it, so that might be something else to consider replacing, but it's significantly harder to get at.
 
Bill said:
Ain’t nuthin about a 727 that whispers
Click to expand...

If you're near a 727, you'll never hear a whisper! :)

The way it was explained to me is that older generators from the 80s and earlier were truly horrendously loud. Compared to those, this is apparently significantly quieter. I could buy that. If you're sitting behind the bus, and on the passenger side (generator is in the front with exhaust on the driver's side), it's not bad even if it's working pretty hard. But I think there's a lot of room for improvement because, as my wife says, Ted doing Ted things.
 
I can't help you at all with re-designing the cooling system of the generator.

I can suggest that it should be pretty simple to setup a current monitoring and lockout system, so that the 2nd AC and the high power appliances are available for use, until one of them is in use, then the others are locked out. Given that they won't ever be switched under load, or very frequently, I'd suggest mechanical relays rather than solid state. Probably less expensive, and less heat.

"QuietGenerator" reminds me of a Dilbert cartoon. They designed a backup product that actually deleted the files instead. So they called it "SecureStore" or something like that.
 
My generator story: it isn’t much, just an observation. At a bbq contest about 3 yrs ago (pre-pandemic), we were setting up on Friday, mid afternoon, and a firefighter was standing just outside our area. I walked over to chat and see what was going on. Turns out an RV that someone parked in their spot was running a generator (allowed during the day). The problem was they were parked right against the spot next to them, a spot with a large shade cover. The firefighter said the CO levels inside that area were so high the FD wasn’t allowed inside without breathing apparatus. The folks with the RV were pitching a fit about having to either move or shut off the gen.

Good times.
 
Yeah, generators can absolutely do that especially if poorly exhausted.
 
We made it back from our last RV trip over the weekend. This was a "short" trip at a hair over 2,000 miles going to Roswell, Carlsbad Caverns, Guadalupe National Park, Big Bend National Park, and then back home.

Before this trip, the only real modification that I did was a tweak to the water tank heating system. Before leaving on our Christmas trip I'd installed heating pads on the tanks, and the fresh water tank suffered from freezing. For this trip, I added in a recirculation function, which would take hot water from the water heater and then dump that back into the fresh water tank. In doing so, this would provide extra heat to prevent the tank from freezing, and also help circulate water to keep water in the pipes/lines from freezing. I also insulated the lines (all PEX) in the bays that I could get at to help that a bit further. In setting up the system, I found that there was a bad ground and so the heating pads actually had not been functioning on the last trip. That certainly created some of our problem, but I think the end result was that extra work was needed.

One other thing that I did was I re-plumbed in coolant flow to the water heater. I did this using the return hose from the heater up front. What this means is that, while driving down the road, I should theoretically not need to run the water heater in order to keep the fresh water tank from freezing, it should just run the pump and circulate appropriately.

The system seemed to work fine. We left with the weather below freezing and I had the system set up to flow water into the tanks between 5C and 10C (the controller I bought doesn't speak American). It worked flawlessly. Nothing froze, although it didn't get much below 20F on our driving this trip, so it wasn't as thorough of a test as it could be. Still, I'm overall happy with that.

This trip saw a lot of warmer weather than the previous one, with temps in the upper 60s to mid 70s during some of the driving. Still not up to those hard summer days, but the cooling fans still did just fine. Keep in mind they're still limited to 70% PWM - I haven't resolved the issue that causes the controllers to shut the things off if held above 70% while driving - and the temperature stayed below 212F like that just fine under all conditions. So, no complaints there, and I still have good confidence in how it will work come summer.

At one point on the trip I had some time to walk around and look at a few things on the bus that I don't normally do. I found one of the engine doors had the louvered panels missing a few screws. Put those back in and that made a surprising difference in how much quieter the thing is from behind with the engine running. It's amazing what a little rattle can do like that.

The noise from the generator is the biggest complaint that I want to address before our next trip. With summer coming, we'll need to run the generator more (both while driving and boondocking). We had it running the other day and I put my ear next to the exhaust outlet, which is virtually silent. So that tells me that area isn't worth trying to attack, it won't make much of a difference. Ok, one area down.

I think that one of the things I will do is add some sound deadening around the sides of the generator, which should help to keep some of that sound internal.

I'm also considering putting some sound deadening/absorption around the fiberglass of the body/front. I'm trying to figure out what the best way to handle that is if I want to do anything. A spray-in setup would probably be the best.

As I've mentioned before, the cooling fan and airflow seems to be one of the biggest sources of noise from the generator. Putting some sort of acoustic panel underneath the generator I think is the best option there, but the catch is those things are usually foam (read: pretty weak and easy to fall apart) as opposed to something of a harder kind of plastic. I may be able to just put some sort of belly pan on (similar to modern cars) and have that reflect enough sound back up into the cab such as to make a noticeable difference. Not impacting airflow is important since I don't want the generator to overheat, too. But I think right now the biggest issue seems to be that the sound from the engine goes straight down, bounces off the ground, and then goes in all directions.

Getting the forward air conditioning working as well is going to be a high priority before it gets hot out.

Beyond that, the RV is pretty well sorted. I want to replace the front airbags, we have some other little details we want to do to it finishing things up. But really, it's in good shape.
 
I don't think you're looking at the sound problem from a scientific viewpoint. You need ANOTHER generator set up to have the pulses exactly opposite so that the sound waves cancel each other out. It solves your lack of generator power problem, too. You're welcome. :)

Edit: or have the family walk around with noise cancelling headsets when the genny is in-use.
 
Those are... solutions... that... umm...

Yeah no. :)
 
I will have to listen to your next time we are in the vicinity, mine just doesn't seem that loud to me, maybe it is because I am deaf, then mine is usually running at low idle not really generating that much power
 
tmyers said:
I will have to listen to your next time we are in the vicinity, mine just doesn't seem that loud to me, maybe it is because I am deaf, then mine is usually running at low idle not really generating that much power
Click to expand...

There is definitely a big difference between low idle, charging the generator vs. higher power running the rooftop AC/heat. The latter is the bigger concern as summer comes up.
 
My wife and I are out on our first “big” RV trip…just over two weeks. Learning lots, found a couple of leaks that were/should be easy to fix, and I’ve got a pretty good project list going. I’ll have a more full report when I’m back in internet coverage, but in the meantime…

@Ted or anyone know where to get the 1 1/4” wide support strapping material for holding tanks? My black tank is going to have a couple of ratcheting straps holding it on the way home.

thanks!
 
My RV doesn't have straps for holding the tanks in like you're talking about, at least nothing visible. You'll probably want to check with your RV manufacturer or else just fabricate up what works. But a rachet strap will work fine to get you. :)
 
Our 8kw diesel genset is exhausted into the exhaust system for RV engine.
It is quiet enough to sleep with for 10 days straight at Osh and Sun and Fun. We never turn it off. It also connected to the twin 100 gal fuel tanks for the RV engine. I think it could run for a month or more on the fuel on board. Uses less than 1/4 tank during 10 days use.
 
Last edited:
We have driven approximately 40k miles with the genset running exhausting into the exhaust system the Diesel engine is using.
RV now has 100k miles on it.

RV and genset is 20 years old this year and has 3300 hours on the genset. I am on my second exhaust tail pipe.

MVC-009S-9.jpg

I custom made it to replace the original. You can see the connection for the genset exhaust. It does not go through the muffler yet is quiet.
MVC-010S-9.jpg

MVC-010S-4.jpg
 
Last edited:
Sun N Fun Genset runs for a week or so at at time to power the AC. We do have a inverter to power TVs without the genset running.
IMG_17171.jpg
 
With the school year coming towards a close and summer trips approaching, it's time to get down to some of the RV projects.

Saturday I got a solid day to work on the RV and handled some of the items it needed. The front airbags are something that I've been putting off for a long time mostly because I was going to have to make a tool to get at the bottom nuts, and I just had other things that were higher priority. I've actually had the new airbags for over a year, just haven't gotten to them. Cut a socket off, welded it to a wrench, and I was able to get at it just fine with that. The airbags really aren't a bad job once you have the tool. I did a little video to show it:


I also went through the various fluids and filters. Oil and filters for the engine and generator, fuel filter on the engine, greased up all the zerk fittings. The ends on the front panhard bar have the rubber broken on both of them, so I need to get some new ones and swap those out. Easy job, couple bolts and a hammer ought to do it. Tightened the coolant hose clamps as I'd had a slight seep in the cold after shutting down the engine, and several of them needed tightening so that makes sense.

I found a couple of other little things to address. One of the lower alternator bolts fell out (those bolts I've had perpetual issues with - both with the AC compressor before I removed it all and now also with the alternator I put in there. Those bolts just get beat up a lot with the engine. But otherwise, things are looking good.

I then looked into a weird electrical issue I'd been dealing with, where the brake lights, marker lights, and turn signals were all having weird interactions. Turns out that was caused by the trailer light adapter. Cut that out, and that was solved.

I'm still chasing a right turn signal issue. With the marker/headlights turned on, the right turn signal indicator on the dash is on. The turn signal is not on, and the right side marker light (the one in front of the rear wheel) is not turned on. When I turn on the right turn signal, it works normally, except that marker light doesn't blink like it should. With the headlight/marker lights off, that marker light blinks correctly.

This is a pretty minor issue, but I'd like to figure out why it's doing it. I haven't been able to find a wiring diagram that shows how this portion of the system is supposed to work, though.

I'm also looking at trying to make the generator quieter. I'm not going to have much luck with this I don't think, but I'm putting some deadening in and I think I'm going to try adding a splash shield and sound deadening underneath the thing. But there's not a ton I can do.

The generator maintenance is starting to bug me a bit. My generator is not on a slide out, and so it needs to be fully removed to get the top cover off to get at the belt. So I'm probably somewhat on borrowed time with that, having no idea whether or not that was ever changed. And given the effort required to do that, my guess is no. So that might be something I need to put on the list.

Also hoping to get the griddle mount figured out before the next trip and ideally also get my forward AC working. I've got metal for mounting the compressor and need to do that, then also need to work on figuring out the various fittings etc for it, but that's overall a lower priority.
 
Ted said:
I'm still chasing a right turn signal issue. With the marker/headlights turned on, the right turn signal indicator on the dash is on. The turn signal is not on, and the right side marker light (the one in front of the rear wheel) is not turned on. When I turn on the right turn signal, it works normally, except that marker light doesn't blink like it should. With the headlight/marker lights off, that marker light blinks correctly.
Click to expand...

Either one stupid small bulb is burned out somewhere or one stupid small socket has a bad ground, or one stupid small bulb/socket is corroded.

Remembering this advice comes from someone that used to work on big trucks and quit that 39 years ago.... So things might be a little different now.
 
Zeldman said:
Either one stupid small bulb is burned out somewhere or one stupid small socket has a bad ground, or one stupid small bulb/socket is corroded.

Remembering this advice comes from someone that used to work on big trucks and quit that 39 years ago.... So things might be a little different now.
Click to expand...

Given that this bus is 22 years old, the tech is probably not much more advanced than what you were dealing with. The thing that's throwing me is that the marker light is a 2-wire, so it's either on or off as far as power goes at the light itself. The fact that it's working correctly with the marker/headlights off but not with them on is where I'm trying to figure out where to look.

And of course it's 40' long and there's a remarkable amount of wiring. :(
 
Zeldman said:
Headlight corrosion.??
Click to expand...

The headlights are new. Although I did cut out one of the turn bulbs as part of my diagnostics, so I'll put that back in.
 
This sounds a lot like a bad ground(s).

Here is what that can look like. The resistance of the various lamps varies with their rating AND is a lot lower when they are cold. Various weird **** occurs.

Bad-Earth.jpeg
 
I agree that bad ground(s) seems to make sense... the question being where they would be. I'll probably do some more digging into it over the weekend.
 
Ted said:
I agree that bad ground(s) seems to make sense... the question being where they would be. I'll probably do some more digging into it over the weekend.
Click to expand...

The semi trucks that we used to use as fertilizer tender/nurse rigs were notorious for having oddball lighting issues after a couple of seasons of use. Usually ended up being a corroded socket that was the culprit. No easy way to pinpoint it - just a rainy day in the shop with a phillips head screwdriver removing covers until you found the 'really' bad one - 'regular' bad was acceptable. :)
 
CJones said:
The semi trucks that we used to use as fertilizer tender/nurse rigs were notorious for having oddball lighting issues after a couple of seasons of use. Usually ended up being a corroded socket that was the culprit. No easy way to pinpoint it - just a rainy day in the shop with a phillips head screwdriver removing covers until you found the 'really' bad one - 'regular' bad was acceptable. :)
Click to expand...

Well, in that case I think I have an idea of what it is... then the real question is pinpointing it. I've thought about replacing all the marker lights with LEDs just because that helps to update the look of the bus.
 
I decided to just go ahead and order some LED marker lights to replace the old ones. That was on the list anyway, and I figure that with that being a fairly likely potential cause (and for how cheap the things are), it made sense. I also got some new taillights coming (I've wanted to update the look on those since we bought it), so I'll just try to shotgun the lighting and get it solved while updating the look on the bus at the same time.
 
Ted said:
I decided to just go ahead and order some LED marker lights to replace the old ones. That was on the list anyway, and I figure that with that being a fairly likely potential cause (and for how cheap the things are), it made sense. I also got some new taillights coming (I've wanted to update the look on those since we bought it), so I'll just try to shotgun the lighting and get it solved while updating the look on the bus at the same time.
Click to expand...

You might need a new blinker relay in order to keep the LED blinkers from "hyper-flashing" due to the lower resistance values.
 
You must log in or register to reply here.
Back
Top