Any small power-miser fans that would run in a stored boat?

[Kittiwake]

A number of recent threads have touched on the issue of keeping one’s boat dry over the winter in northern climes. Ideally one might like to hang a small tungsten-filament bulb and/or run a small fan left inside the boat.

My trailer storage has no electrical power.

Of course there are the solar fans that one can mount right in the deck. But I am guessing they wouldn’t run much in a northern winter.
One can buy small solar panels fairly inexpensively; but my “1 watt” panel really only produces a tiny fraction of a milliamp at 20 volts in normal lighting.

Has anyone encountered any realistic solutions to the above ... ie. a reasonably-priced low-power-draw fan that will actually run on $100-worth of solar panel in say Washington State or BC (no guffaws from the eastern and southern rowdies please)?

Kittiwake

[kmclemore]

The lowest wattage fans I know of are the Hella Marine fans which draw 6.5 watts (.54 amps). I have one and it is silent and easily mounted & positioned. (http://www.hellamarine.com) Not sure how much wattage your "$100" solar panel puts out, but that's pretty much as low a power fan as you can get.

[Kittiwake]

Hm, these do look promising. Thank you KM.
The Blue Planet solar panel I currently own was picked up out of curiosity on sale for $10, so I can't complain. But as you know, one can get larger versions: a question remains as to whether a (for instance) "15 watt" version from the same manufacturer would permit one to run such a fan when exposed to the blinding sunshine(!) of a BC coastal winter.

Kittiwake

[mastreb]

Vent turbine placed over the forward hatch?

Or you can power a fan with another fan, directly wired. If you have never tried this, wire two 12VDC computer fans to each other--no battery, no power source, just wired black to red. Now turn one and watch the other one rotate. You could setup a vent fan powered by a larger DC fan that just catches whatever wind there is.

[Kittiwake]

Vent turbine placed over the forward hatch?

Or you can power a fan with another fan, directly wired. If you have never tried this, wire two 12VDC computer fans to each other--no battery, no power source, just wired black to red. Now turn one and watch the other one rotate. You could setup a vent fan powered by a larger DC fan that just catches whatever wind there is.

That is a really clever idea! I had never heard of this experiment - although it is logical in retrospect.
We may not get a lot of sunlight in the winter, but we get plenty of wind.

As a matter of fact, I picked up a 'computer' fan today that is supposed to draw 1.1 mA at 12 V. At this rate I could run the thing right off the house battery for a long time before recharging (and I tend to bring the boat battery home to recharge periodically in the winter anyway). So maybe I could position it over the ballast vent and compete with Doupirate for 'the most squirrel-friendly ballast tank in Canada' .... well, I guess not - he provides them a bit of heat as well.

Kittiwake

[Divecoz]

Hummm are all DC motors wound concentrically?? I never really thought about it.... Some ...Very Few , AC motors are wound in such a way as to produce Power if the windings are turned by an outside source.. i.e. wind or water etc etc.. I have to ask? Whats the power loss? If the loss is too great? Could you make the blades larger? Could you....Add a Cone to increase volume/pressure?? Interesting concept..?
Humm.....I wonder if my "son's" have a few of those muffin fans around the house that I could play with??

[Sumner]

If you are trying to move air in the boat or for that matter anywhere I was really disappointed in two fans...



...I made from computer fans. They only draw...



.... .13 amps or about 1.6 watts. Not much, and that is good, but they just don't move that much air. Put one just next to your face and you barely feel it.

On the trip we bought one of these....



.. Caframo Sirocco Model 807's at West Marine store at Marco Island and I mounted it in the boat. The West Marine number on the fan is Model #9835826. We liked it so much that when we found a West Marine store down a Marathon we bought a second one. One is mounted permanently in the V-berth where it blows air on us that is coming down the hatch there. The second can be put anywhere and we use it in the cabin.

They are not cheap at about $100 and I can hear it now...."I got a fan at a truck stop for $12.00" Well I have some of those also and they use a ton of electricity. The Caframo moves a ton of air on the low setting. And the low setting is only .21 amps (210 mA) and we run it on that and it blows air on the both of us. We hardly ever had it off of low. So it is 2.5 watts compared to the computer fan's 1.6 watts but the difference is like me running down the lake wide open on our outboard and one of you guys running past us wide open with your X or M. There is just no comparison to the amount of air being moved.

It has 3 settings .21, .27, .34 amps or only 210 mA or 2.5 watts on low or 4 watts on high. That isn't much electricity. I did see that West Marine shows a lower amperage than the manufacture's amperage that I mentioned above.

The other nice feature the fan has is that it has 4 timers. 2 hr., 4 hr., 6 hr., and 8 hr. If you start the fan it goes to the 2 hr. automatically. Each time you push the timer button, right arrow in the picture above, it adds another 2 hr.

The final outstanding feature of this fan is that you can point it anywhere from any location. I don't have one at home so I can't tell you how you could modify the wiring to override the timer, but I'll bet something could be done. You can get a 40 watt panel and a charge controller together for under $100 so for under $200 you could have a 40 watt panel for the boat for more than just fan use and a fan that moved some air.

The key would be finding something that would be a low voltage switch to cut power off say whenever the batter is a 12.2 volts or so. That would make it run only when the panel was putting out power and you wouldn't have to worry about the battery. I haven't researched that, but I'll bet there is something out there. Even up north I'll bet the 40 watt panel would run the fan quite a bit.

I'm going to try and do something like that with one of the fans that we had on the Mac, but moved to the Endeavour. We could leave one behind and have it running when the boat is up on stands when we leave it.

The fan install is here....

http://purplesagetradingpost.com/sumner ... de-31.html

Anybody with links to low voltage switches?

Sum

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Our MacGregor S Pages

Mac-Venture Links

[Divecoz]

Computer / Muffin Fans , come in a Zillion Sizes ( and multiple Voltages) and there by a vast difference in the amount of air moved.. True none feel like a tornado..
How much is needed , just to move the air a bit when the boat is unoccupied as kittiwake describes??? I don't have the faintest idea..
I have ( and it works well IMHO )the larger SS Solar Fan ( W.M.) mounted in the forward hatch..I did end up using a Large Muffin Fan out of an Old PC to push air past a passive , Flame Contained ...outside - intake and exhaust, heater in my garage.. BUT... it was a 110 VAC Fan..

[Kittiwake]

If you are trying to move air in the boat or for that matter anywhere I was really disappointed in two fans...
...I made from computer fans. They only draw...
.... .13 amps or about 1.6 watts. Not much, and that is good, but they just don't move that much air. Put one just next to your face and you barely feel it.
On the trip we bought one of these....
.. Caframo Sirocco Model 807's at West Marine store at Marco Island and I mounted it in the boat. The West Marine number on the fan is Model #9835826.
... The Caframo moves a ton of air on the low setting. And the low setting is only .21 amps (210 mA) and we run it on that and it blows air on the both of us.
... I did see that West Marine shows a lower amperage than the manufacture's amperage that I mentioned above.
.......
Sum
..

Sum, my first thought (as a non-electrician somewhat-cynical type) was that there must be some mistake, because it sounded unlikely that one can get so much more wind power from the same electrical power. But as you suggest, it seems credible that the greater cost buys greater efficiency ... or perhaps computer fans aim for some different target such as silence and low vibration (or perhaps more airflow in computers is unnecessary and hauls in too much dust over time: computer fans do tend to become clogged with dust).

Of course Divecoz is quite right - that I was looking to push a small continuous stream of air eg. down through the V-berth ballast tank vent. Nevertheless, more air at approximately the same power cost could be nice.

So I collected 4 computer fans of various claimed power draws (from 0.092 amps to 0.54 amps). None of them showed any sign of life when hooked up to a small solar panel producing 0.0007 amps at 20 volts (as expected .... and by the way, I was pretty disappointed that this was all the current I got under a bright lightbulb).
So I hauled my Eliminator portable car-battery jumper out of the basement and plugged a cigarette-lighter adapter into it and touched the bare red and black wire ends to each of the computer batteries in turn and they all worked well (although, as responders to this thread have noted, the resultant air flow was unimpressive).

One bottom line seemed to be that computer fans may well serve to inexpensively provide a modest air flow through one's ballast tank (I will try for fun with one connected to the house battery) ... but not if you live in BC and want to use solar power in the winter!
Another seems to be that the fans described by Sumner & Kmclemore are of considerable interest.

Thanks for the great input.
Please note that I have edited 0.0007 mA to 0.0007 amps.
Kittiwake
ps. I have been very happy with the above battery jumper: about $70 on sale, and a very portable & dependable source of DC power via lighter adapter, USB port, and of course via jumper cables if you have killed the house battery by having a loose ground cable.

[dlandersson]

Forget PC fans.

Computer / Muffin Fans , come in a Zillion Sizes ( and multiple Voltages) and there by a vast difference in the amount of air moved.. True none feel like a tornado..
How much is needed , just to move the air a bit when the boat is unoccupied as kittiwake describes??? I don't have the faintest idea..
I have ( and it works well IMHO )the larger SS Solar Fan ( W.M.) mounted in the forward hatch..I did end up using a Large Muffin Fan out of an Old PC to push air past a passive , Flame Contained ...outside - intake and exhaust, heater in my garage.. BUT... it was a 110 VAC Fan..

[Sumner]

.....So I collected 4 computer fans of various claimed power draws (from 0.092 amps to 0.54 amps). None of them showed any sign of life when hooked up to a small solar panel producing 0.0007 milliamps at 20 volts (as expected .... and by the way, I was pretty disappointed that this was all the current I got under a bright lightbulb)...

Solar panels just aren't going to put out under an artificial light. Our MPPT charge controller has an LED that indicates state of charge by blinking at different rates. When I hooked up the panels (180 watts total at the time) and had the boat in the shop with the lights on the indicator light never came on at all. As soon as I got outside with the least amount of sun on the panels in overcast conditions it came on. Put the panel outside and try again.

Also panels are getting really cheap now. A 20 watt for $29.00, a 40 watt for $55, and a 60 for $80 and an 80 watt for $129. I wouldn't put on anything less than a 40.

On why the fan we have moves so much more air without using that much more electricity my guess is two things. Look at the size of the blades. Compare the prop on say an 8 HP outboard to one on a 6 HP. I have both and the prop size and thrust of the 8 is way more than the 6 HP, but is only about 33% higher in HP. The computer fans we have been looking at are normally in desktop computers that are connected to 110 volts. Yes they normally run at 12 volts off of the computers power supply, but there is no need to try and make them as efficient as possible. The fan I gave a link to is sold by a company that is trying to sell to our market where buyers are more concerned with energy efficiency, so I think they have done their homework.

Now saying that for your application I'm not sure if you can adapt one or not,

Sum

Our Endeavour 37

Our Trips to Utah, Idaho, Canada, Florida

Our MacGregor S Pages

Mac-Venture Links

[Kittiwake]

.....So I collected 4 computer fans of various claimed power draws (from 0.092 amps to 0.54 amps). None of them showed any sign of life when hooked up to a small solar panel producing 0.0007 amps at 20 volts (as expected .... and by the way, I was pretty disappointed that this was all the current I got under a bright lightbulb)...

Solar panels just aren't going to put out under an artificial light. Our MPPT charge controller has an LED that indicates state of charge by blinking at different rates. When I hooked up the panels (180 watts total at the time) and had the boat in the shop with the lights on the indicator light never came on at all. As soon as I got outside with the least amount of sun on the panels in overcast conditions it came on. Put the panel outside and try again.
..........
Sum

OK, IMPORTANT TIP FROM Sum !!!!!!!
He is absolutely right: I just took the same solar panel outside ... and the output jumped from 0.7 mA indoors under a bright light to 7 mA outside on an overcast day in BC. Voltage output was little changed.

In my own defence, I had read that this panel worked inside .... and I guess it does, but a factor of 10 could be very significant.
Clearly the solar panel cares a whole lot about the wavelength of the light (no surprise scientifically), and presumably gets a real kick from UV wavelengths.

Kittiwake

[Catigale]

I'm going to stick my neck out and guess that the difference between inside and outside is actually mostly due to luminous intensity and not wavelength mix. I'll find someone who knows something about optics and run the calc and report back...

[Russ]

Solar panels just aren't going to put out under an artificial light. Our MPPT charge controller has an LED that indicates state of charge by blinking at different rates. When I hooked up the panels (180 watts total at the time) and had the boat in the shop with the lights on the indicator light never came on at all. As soon as I got outside with the least amount of sun on the panels in overcast conditions it came on. Put the panel outside and try again.

Exactly,
I thought my 80W panel had something wrong because indoors with the strongest light it hardly put anything out. In direct sun, it kicks.

I'm going to learn more about your MPPT controller. I seem to recall you mentioning they are vastly superior.

RE: PC fans. They move air, but in no pointed direction. So the volume might be there, but not the directed force. They are also made very cheaply.

I'm not sure what the point is to blowing air into the ballast tank. It gets yucky and I add a chlorine tab when I fill it.

[mastreb]

Hummm are all DC motors wound concentrically?? I never really thought about it.... Some ...Very Few , AC motors are wound in such a way as to produce Power if the windings are turned by an outside source.. i.e. wind or water etc etc.. I have to ask? Whats the power loss? If the loss is too great? Could you make the blades larger? Could you....Add a Cone to increase volume/pressure?? Interesting concept..?
Humm.....I wonder if my "son's" have a few of those muffin fans around the house that I could play with??

Yep, all DC motors are generators (at least, all common ones). It's rare for AC motors to be alternators as you say.

As for how much air, if we say that we want to swap out the air in the cabin twice a day, a cube the size of the Mac would be 8' x 26' x 6' = 1248cf. Presuming the interior volume of the Mac is something like half of that, we'd want to move 624 c.f. per 12 hours or 52 c.f./hr., or about 1 cfm. Any cheap computer fan can best this. You might not be able to feel it, but if you place it in an exterior opening it will keep your air rotating.

If I'm not mistaken, we're talking about fans for ventilating the cabin during long-term storage, which is a whole different problem than fans to make the interior comfortable. Ventilation only requires consistent replacement of stale inside air with fresh outside air, and the speed doesn't really matter that much.

For storage, I'd make a custom companion-way hatch out of a piece of corian or lexan with ventilation holes drilled and fans mounted to blow from inside to outside to it on the inside of the panel. Blowing out means that you're not sucking rain or snow in through the fans. Air will come in through all the cracks in the boat (Funk warning: including through the ballast tank if you leave the gate open and the plug out).

Direct wire it to a cheap solar panel on the outside of the hatch (mounted horizontally off the hatch with a slight decline so that it forms a rain/snow shield over the vent holes) and when there's sun, the fans will run. When there's not, they won't. When you're done storing, take the storage hatch off and replace it with the regular hatch. Easy.