Soundproofing Portable Generators--Building 12 volt generator

[Fearnoevil]

Moderators Note: I split this thread off and made a new one because the last was so old and this one has gone a different direction.
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I'm sure this has been asked before, but has anyone on the boards had any XP adding a muffler and soundproofing their enclosure to significantly reduce the decibel output of a standard portable generator? Except for a couple of rather dumb videos on Youtube (and one or two decent one's but not for RV's) I can't seem to find a good example of anyone who's done this.

This appeals to the inventor in me, plus there seem to be a lot more used/cheap portable generators (i.e. the noisy kind) on the market as opposed to the smaller/quieter/more expensive inverter generators. Plus I prefer to keep the inverter and generator separate, easier to repair individually I would think, and from some past xp I believe used inverters are going to give you more problems than used generators. One more thought, I'm planning to add solar and will need an inverter for that as well, so if I wanted to tie the two together, wouldn't I need a larger inverter (or at least two separate inverters)? That is if I had say a 2000-watt inverter/generator, and then add 8 6-volt gcb's 200-watt solar panel system, I'd have to have another inverter for that system, right? Yeah, electrical is one of my weak points, lol.

Anyway, my idea is to take a good brand used generator and go over the entire thing and make sure there are all non-moving parts are fitted with rubber anti-vibration pads, convert the pull start to electric start, remove the factory muffler and add a much larger muffler (say a small car muffler from the junkyard), then line the enclosure with sound-deadening material and finally install a baffle system on the air intake/exhaust (along with a thermostatically activated fan (again a salvaged small radiator fan perhaps). Sound doable, lol ;?D

 

[VanLifeCrisis]

I have a champion 1500 watt and honestly, 50 paces away it isn't even audible, and just barely audible beyond 3 parking spaces. Even less so in a noisy area. I have used it at pilot truck stop parked about 4 spaces away with the genny at my rear tire away from everything, and you couldn't hear it at the entrance. Not nearly as loud as idling trucks

It does have something on the tailpipe that looks like it was made to accommodate some sort of extra muffler.

 

[Optimistic Paranoid]

Plus I prefer to keep the inverter and generator separate, easier to repair individually I would think, and from some past xp I believe used inverters are going to give you more problems than used generators. One more thought, I'm planning to add solar and will need an inverter for that as well, so if I wanted to tie the two together, wouldn't I need a larger inverter (or at least two separate inverters)? That is if I had say a 2000-watt inverter/generator, and then add 8 6-volt gcb's 200-watt solar panel system, I'd have to have another inverter for that system, right?

As, I understand it, an ordinary generator is just an engine and alternator tied together via direct drive, and they take the raw ac output without using diodes to convert it to dc like a car alternator. The thing is, this has to run at a constant 3600 rpms in order for the output to be a stable 120 volts. Varying rpm would result in varying voltage.

Inverter generators take the same raw ac, convert it to dc, then run that dc through a built in inverter to invert it BACK to ac. These extra steps mean the output voltage is stable regardless of the engine rpm, and this is what allows the system to throttle back when demand is low, to save fuel.

The regular generator will use the same fuel, and make the same volume of noise, whether you are using them to power a 1 amp load or a 100 amp load.

If you are a homeowner, and you only use a generator during power outages, a cheaper regular generator can make sense.

If you are off grid and using your generator all the time, the expensive inverter generators pay for themselves in fuel savings over the long haul.

And yes, you still need a separate inverter hooked to your batteries if you want ac when you are not running your inverter generator. The inverter built into your generator can't help you there.

Regards
John

 

[akrvbob]

I'm sorry I don't know anything about reducing their noise. I have a Honda so noise is a non-issue.
I do many guys build boxes to hold them so they can be run inside the box and not have to lift them in and out. You can even buy boxes that mount on your bumper. So a box is easy. I'd google" add a muffler to a generator" and I'm sure you will get lots of help.

But a few comments in response:

1) If you are concerned with long-term life, nothing is going to beat a Honda or Yamaha inverter generator. You count their service life in decades not months or years. I fully expect the inverters connected to my battery bank to fail long before the Honda will.
2) Being able to throttle down for low loads is probably one of the reasons they last so long. The fuel savings at idle versus full-throttle is very significant. In fact I've wondered if the Honda 2000 might actually use less fuel than a Honda 1000 if you use mostly light loads because it would rarely do anything but idle while the 1000 would probably be at half or more most of the time
Bob

 

[compassrose]

I have a PDF on building soundproof boxes but it's on my other computer. But here is a similar enclosure (without all the data and formulas) http://www.doityourself.com/stry/ho...sure-around-your-power-generator#.U827B7Geg9E

We will be using a similar enclosure (2 insulated boxes with a few inches of space between & lined with Soundbrace or accoustical ceiling tiles, Anti-Fatigue Vinyl Foam Mat - the kind you stand on for the closed cell vinyl nitrile mat - with multiple turn ducts ) for our CHEAP NOISY open frame Harbor Freight Predator 8750 Peak/7000 Running Watts, 13 HP 420cc Generator EPA III (item#69671) and a homemade genturi to pipe the exhaust above the bus. It is a gasoline genny but we will convert it to LP. Yes, it is a noisy unit. But it will be used mostly in parking lots (for a couple of hours AM & PM to chill down the refrigeration and power the electric water heater plus recharge the battery bank) and while running down the road. It is a bit large for our needs but I prefer that it run as close to a half load as possible (uses less fuel that way). We have also heard this genny running (and could compare it to a Honda). After much research, we believe this will suit us. We are not into "boondocking". We just want to be able to occasionally freedom park (where ever we choose) for a few days before pulling back into a campground or homebase to dump waste tanks and refill our fresh water supply.

 

[Fearnoevil]

Thanks for all the great info, I'm beginning to rethink the generator thing, or at least I realize I need to learn a LOT more before I commit one way or another. Thanks Optimistic for the heads up on the AC output on the standard generators. I've looked for DC generators and they're seem to be fewer options and they tend to be more expensive, even more so when they have a built in inverter (like the Honda or Yamaha), and I'm not able to pay $1500 for one (and used ones at a cheap price are scarce and get scarfed up pretty quick it seems :dodgy.

Akrvbob, I have looked at the Honda and other top brands, they do sound like the best option, but they're pretty pricey and at present I can't fit it into my budget, at least not at this point, maybe down the road in a couple of years :-/
I like the idea of putting it on the back "porch" since I don't think I've got the room underneath, at least not with the soundproof enclosure I'd need (for my own peace of mind, knowing I'm not being a nuisance to my neighbors, keeping the noise down is a priority).

Rose, thanks for that link, it's given me a good idea of the materials I'd need (man some of that sound dampening material is pretty spendy :s). If you get a chance at some point (certainly no rush ;?) I'd sure appreciate a copy of that PDF please. And the genturi is definitely a good idea, on a still day I'd prefer to know the carbon monoxide is being exhausted out above my living space (I've got too few grey cells left as it is, lol).

One option I'm considering is investing in a much larger bank of batteries than originally planned (how many I still don't have figured either, but then that's a ways off for now), but how to keep them charged when not parked at/near an AC outlet is the question. Actually questions, plural lol.

First, can you wire your vehicles alternator so that it also helps to charge your main bank of batteries?

Second, and I know this is tough to answer without some hard numbers, but lets say I'll need X amount of watts during peak usage, and lets say my solar panels only provide Y number of watts so that X minus Y leaves a shortage of Z watts, can I just get a small DC generator dedicated strictly to charging the batteries (making up for the Z shortfall)? Ya, I don't know if that makes sense either, lol, I'm pretty clueless in this area (gonna to have to do some serious reading on the subject methinks ;?).

Well I'm sure I had a "Third" before I started this post, but now I can't remember what it was, lol, so guess I'll have to come back to that another time.
;?D

 

[Fearnoevil]

YEAH, this is right up my alley, lol

[video=youtube]

Here's a link to the full post,My Improvised DC Generator really not a bad idea for building a cheap DC charger. And for a LITTLE extra $$ I bet it could be made to look cleaner as well as more compact. Anyone on the boards ever tinker with this kind of setup? Somewhere in the distant past I vaguely remember a friend telling me that any electric motor can be turned into a generator, just need a motor to spin the shaft, so that's one avenue to pursue perhaps ;?D

 

[Zil]

Not that good of a generator.

 

[akrvbob]

If you are handy and able to do the work yourself, it's very good way to go.

However, I think you are underestimating solar. Unless you are a very heavy power user or want AC, solar is almost always your best choice. Tell us what you need to run that needs so much power.
Bob

 

[poprouge]

Anyone have any experience with the smarter tools generator?
http://www.amazon.com/Smarter-Tools...UTF8&qid=1406059500&sr=1-6&keywords=generator

Ignore the price, if you look you can get it for $599 via amazon, or at costco same price. It appears to have a yahama engine. Is this a good deal or skip it?

 

[Fearnoevil]

Zil, I realize that what he built isn't that good, but then what do you expect for less than $20. I'm thinking something better can be built for a couple hundred, and again all I want is a small DC generator to HELP charge the batteries when/if the solar isn't enough.

Akrvbob, yeah I can tinker with small engines, not an expert by any means, just a jack of many skills and fairly mechanically inclined. But I suppose there's always some nits that'll need to be picked to make it reliable tool, but then that's half the fun, lol.

Mel, now THAT'S pretty close to my price range/limit, and it's small/lightweight (very important) and if it's really quiet enough would make the whole soundproof thing pretty much moot (saving me more $$ and work). So yeah, I'm gonna put that on the wish list. Thanks a lot for heads up! Sadly that'll mean I won't need to try and reinvent the wheel, and I was all fired up ready to make one, lol.
;?D

 

[Fearnoevil]

As for my electrical needs, I'm still trying to figure that out. I have a list of the stuff I absolutely have to have, for my personal happiness, and includes: Small refrigerator/freezer (3-4 cu ft), small stackable washer/dryer or a combo unit, either a 10k AC or two 5k's (I like the idea of being able to cool just the area I'm occupying), small 900 watt microwave oven, a 32" LED flatscreen TV, my laptop, probably an auxiliary electric flat panel heater, and a few lights should do it. Oh yeah add a hotplate for quick gas-free cooking.

Of course figuring out what peak usage would be is tough, but then I suppose the system I can AFFORD will inform/limit my usage to a large extent. I mean if it's 110 F outside and I'm nuking dinner while watching the game on TV, I suppose I'll have to wait till bedtime or morning to do laundry, lol.

So this brings up another question as to how others have approached this problem, and I guess it's the old conundrum of not putting the horse before the cart. So is it best to figure out how much power I can afford and then sizing my appliances around that, or vice versa (which could be a bit more difficult since I'm trying to do it on the cheap and buy used when possible/available)? Or get the appliances I can and try to build the power supply to fit, but on the cheap meaning shorter lifespan for stuff like batteries, solar panels, inverters, etc. I know in the long run that it's more expensive that way but it does defer the expense until I can afford it later. Of course a third option is doing it right the first time by financing some of the more expensive stuff via a bank loan, which certainly has a lot of advantages, but on the downside ties me to a loan payment for a couple of years maybe (still might fit within my timeframe.... decisions, decisions, lol).
;?D

 

[Fearnoevil]

Ahh, moho must mean "motor home", but still don't get the "8d battery 1400 cca in parallel" but then I'm still pretty green around the edges, lol.

BTW Mel, that Smarter Tools 2k generator got pretty rave reviews on Costco.com (comes with a 3-yr warranty so that's great) and that company also has a 3000W Running/3500W Peak Portable Generator w/ Electric Start and Battery, EPA and CAB Approved for just $299 shipping included, THAT has got to be the best deal I've seen anywhere and gotta love that it has an electric start, something you just don't see in that price range!

 

[Zil]

I'm sorry for the confusion. Most any DC motor can be a generator, but not a good generator. Most motors are wound for efficiently converting energy to motion. Generators the opposite.
It would be easy to build a DC generator. Salvage yard generator or alternator with diodes. A gasoline or other engine large enough to drive the generator. Pulley sets to get the correct RPM at the generator.
When i was younger, there were still battery re-builders in my neighborhood. They used large generators driven by AC electric motors to charge batteries.

 

[poprouge]

Yes, it's on my wish list as well. While I'm looking to purchase a diy van, I currently car camp when we travel. Honda Fit. So size matters for me at the moment. I have a goal zero yeti 400. Just can't beat the inverter and charge controller in closed and it's rather easy to chain like size batteries (AGM type) as my needs grow. I have one of those 100w throw aways, again size. Once I make the move to outfit a van, I'll upgrade the gen.

 

[user 423]

Anyone on the boards ever tinker with this kind of setup?

I've used a 'poor boy' gen. in the past made from an internally regulated car alternator spun by a Harbor Freight 5 hp motor.

I have an electric-start Honda 125 cc motor out of an ATC that I will someday convert to LP to power a similar setup. The Honda overhead cam motors are pretty smooth and fuel-efficient. The total weight would be a bit heavy at about 60-65 lbs. or so.

I'm also trying to figure out how to do a PTO adapter to spin a car alternator off the chain of my CT90 trail bike while it's sitting on the center stand.

 

[Zil]

That Honda 125cc could power a large generator. Or multiple car alternators.

 

[akrvbob]

FearnoEvil, you want an apartment on wheels and I don't see it happening with less than a 30 foot RV or a school bus you convert.

Everything you want is going to be very expensive and power hungry.

What are you planning to live in with a big enough generator and holding tanks to handle a washer-dryer and two AC units? Or are you just planning to be in RV parks?
Bob

 

[akrvbob]

I just re-read your other post and remembered you have a transit bus. How long is that inside and do you think you will have room for a washer-dryer in it? Have you done the research to find out how much power it draws, especially the dryer? How much water does it need? If you get a propane dryer, where will you put the propane tanks? Where are you going to put holding tanks for that much water? Will you just drain the waste water on the ground?

Where are you going to put a generator able to run that and an AC?

Right now you have very lofty goals and they are attainable but they won't be cheap and they won't be easy.
Bob

 

[SternWake]