Question for Sumner.

Sumner · Mar 11, 2012

Ray Bowles said:
Sum, What is the operational noise level on the gen-set you built and mounted on your stern rail. Also, how did you mount the exhaust pipe and what did you do for vibration relief on the pipe. Sweet set-up.
Ray

Hi Ray. First for those that are reading this that don't know what we are talking about. We run everything (frig, computer, lights, etc.) on the boat on 12 volt except the occasional use of a small pure sine wave inverter to charge power tool batteries. Thus it didn't make much sense to use say a Honda generator on the boat and then get a 12 volt charger to charge our batteries. Also on our small boat there is no convevient place to store a Honda and then you have to get it out and run it and then do you put it away with gas in it or drain it and so on. We just needed to charge 12 volt batteries (or two 6 volt in series) as simply and as efficiently as possible

You can get a cheap, under $50 charger to do that. A GM alternator that will put out 60 amps (or more with a larger one) will do the job. So I researched making a gen-set and found that many people have done this. I considered a cheap HF 4 stroke for power, but when I read that the alternative energy people had used Honda's and gotten thousands of hours of use. So we spent a little more and got a...

...Honda. I have not regretted that. Starts on the first pull 90% of the time and the stock muffler on it is pretty quiet. Way better than say a lawn mower but not as quiet as one of their 110 generators that are so popular. Still I don't think anyone within 100 feet of you on anchor is going to really hear it to the point that it would bother them. On land you can't hear it 75 feet away at all. On the boat it also wasn't that bad and we used it that way for some trips.

The bad is that with it mounted...

...the way it is up on the stanchions it sends vibrations down to the hull. If the hull was as thick as most larger boats are then I don't think it would be much of a problem, but trailered sailboats aren't noted for very thick hulls. So the noise you mainly hear is not the exhaust, but the vibration and the noise resonates pretty bad down in the cabin where if you are sitting your head is right by the hull. It is actually better sitting in the cockpit just a few feet from the gen-set. If we are in the cabin we, or at least I, put on ear protectors.

I think this problem is surmountable and I was going to work on it by trying some different mounts at the base of the Honda, but then we added all of the solar and just don't have to use the gen-set that much. I think we ran it 3-4 hours total on the 7+ week Florida trip. There is no need to put a bigger alternator on it as I never saw more than 24 amps on the amp meter and the amps drops pretty quickly as the battery voltage rises.

One other option is that you can make (follow the link on my site) or buy controllers that will force the alternator to put out higher/constant rate amperage's even if the battery isn't calling for them. This would cut down the charge time, but you would have to watch what is going on as there are some negatives to doing this.

I also got a wild hair and made....

...a second muffler that bolts to the exhaust of the stock one one day. This was more of an exercise to see if I could make one that made a difference. It does as now the exhaust noise is so low that you can't hear the Honda running from 30 feet or so and the exhaust noise in the boat itself is negligible, but the vibration noise is still there. If you aren't in the boat you can't hear the vibration noise, so others don't hear it.

The exhaust pipe just slid into the original muffler and was held to it with a...

... spring arrow above and that worked fine. It was easy to put on or off. Now with the second muffler...

... it slides up onto the outlet pipe in a pretty similar way and I explain more about it on the mod pages (just added that info to the page). You do have to pay attention how the pipe is held away from the hull as it gets hot and it can transmit noise to the hull. I considered running the pipe into the water and tried it at home, but it made about as much noise blowing in the water as above it and I didn't know if the added back pressure on the exhaust was going to damage the Honda, so didn't do that. As mentioned the exhaust noise with the pipe pointed down is not bad.

To sum all of this up for us this has been a great mod. The gen-set is always ready to go. Just pull the cover off and start it and you have 12 volts going to your batteries. It is convenient and out of the way. I just don't see any other alternative that is as good and convenient for a small boat other than solar which we now have. Even with the solar chances are you need additional charge to the batteries now and then and the outboard that puts out 6 amps max, in our case, is not a good choice if you can avoid it.

If you don't have or can get rid of the vibration noise it would be no different than running your outboard (quiet 4 stroke) or just slightly louder than a Honda generator. We don't often anchor near others, but when we do we never run it before 8 am or after 7 pm and have never gotten any 'dirty' looks while running it like on a mooring ball at Marathon.

I can weld aluminum and have a mill, so I did some things on the build that don't have to be done. You don't need those resources to build one of these. I'd for sure use the Honda again and the other must is a good pulley on the Honda. Don't be tempted to use one from the hardware store unless it is a heavy cast-iron one.Hope this helps and let me know if I can help with anything else.

If anyone is interested in the full build details you can fine them here...

http://purplesagetradingpost.com/sumner/macgregor/outside-13.html

Sum

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Sumner · Mar 12, 2012

Ray Bowles said:
.... On a 23 foot boat solar power with enough output would be too large for the cockpit area..

I can understand that and one nice thing about it is that it works no matter if it is cloudy or sunny and you never have to worry about if it will bring the batteries back up again.

We did notice that if we had just the 40 watt panel that we didn't use it as much, so consider that. Like any engine driven charger it will take time to put the last 20% in the batteries. If you use the gen-set in the morning or when the batteries are the lowest it will quickly bring them up to 80% or better and then let the panel top them off. When we had the 40 watt though we didn't have the frig and it is the big user.

I'd give that mount a try and see how it works. Also even if you have some vibration noise you won't be running the gen-set for hours like you might be with a Honda and smaller charger. There again just one panel would help a lot.

I see that Solar Blvd doesn't have any 40 watt panels now, but they have 20 watts for $30. You could get 2 of those and a controller for probably $90 and possibly mount the two panels above the gen-set. They are 14" X 20" each...

http://www.solarblvd.com/Solar-Pane...20-Watt-12-Volt-Solar-Panel/product_info.html

You probably don't have room, but they have 100 watt panels for $135 (what we paid for a 40 watt a couple years ago).

One last thing and that is be sure to wire it like I show it on the site with the switch to use so you can start the engine. Also when the charging is done don't forget to turn it back off or you will discharge the batteries through the alternator. Did that a couple time

.

Good luck and take pictures and post them,

Sum

[FONT=Arial, sans-serif]============================[/FONT]

Our Endeavour 37

Our MacGregor 26-S Pages

Our Trips to Utah, Idaho, Canada, Florida

Mac-Venture Links