Automatic Power Source Switch

[unbusted67]

This might be better in the "Challenges" forum but here I go any way.

I just installed a composting head (yes!) I hooked the vent up to a Nycro solar exhaust fan but the manufacture recommended I leave the regular 12 volt muffin fan installed and hooked up for cloudy days etc.

My question is this: Is there a way to get the muffin fan to come on automatically when the solar fan stops working?

[Blue Stocking]

How about a photo-cell, such as used on those walkway solar lights. They switch the battery on when dark.

[delmarrey]

You would also need a small rely. So when one goes off the other comes on. >>electrical relay - Google Search

[hellosailor]

"Is there a way to "
Although an electronics hobbyist could build one cheaply, I don't know of anything you can buy off the shelf. Simplest cheapest solution might be to just buy a alarm or exit light battery for $20 and hook it up the muffin fan, recharge from ship's power as needed. $20 will buy you a 12v 7ah battery, or half of that, depending on how competitively you shop.

A relay will probably draw more power than the fan does. A phototransistor, optoisolator, etc. will draw very little power in comparison--but requires some design work. If the power requirements are not an issue...IIRC the solar fans are something like a 3V battery and motor? So you'd just hook up a 3volt relay that is turned on when the solar fan is, and turns off when that loses power. And connect your muffin fan to the relay's "NC" contact pair, which close when the relay turns off.

[Florida Mike]

Take a look at the third post it should give you an idea of how to get your fan to do what you want.
http://www.westmarine.com/webapp/wcs...&ci_sku=451184


Another option most probably better in the long run would be to get a solar panel with an output of three to four times the muffin fans power consumption. This should not overcharge your batteries and give you a very long service life.

Just my two cents, Mike.

[Nicholson58]

Originally Posted by unbusted67

This might be better in the "Challenges" forum but here I go any way.

I just installed a composting head (yes!) I hooked the vent up to a Nycro solar exhaust fan but the manufacture recommended I leave the regular 12 volt muffin fan installed and hooked up for cloudy days etc.

My question is this: Is there a way to get the muffin fan to come on automatically when the solar fan stops working?

Why make it complicated? First off, I did exactly the same - no broblems even in cloudy days in Michigan. Others who have had more or less success determined that sometimes the battery furnished with the Nicro was crap and replaced it with Lithium. I suggest go for the lithium and put in a big one. I would add a local solar charger and battery before I would wire in direct. Put in an additional manual switch if you really are worried. _ Love the head. It was a gread move especially in the Great Lakes ZDZ.

[hellosailor]

"Others who have had more or less success determined that sometimes the battery furnished with the Nicro was crap and replaced it with Lithium."
Swapping lithium (any type) for nicad or nimh is usually a bad idea. All the lithium cells are very picky abut charging voltage, and none are interchangeable with the other types. If the voltage is too low, you'll waste them. If it is just a little too high--there's a serious fire hazard. Personally, I wouldn't sleep under the same roof as lithium batteries that were randomly installed. Even with a smoke detector.

[Nemo55]

a small electromagnetic switch will do the job..

[RUSTYNAIL]

I would experiment with a small solar panel with enough voltage/current to energize an inline 12V normally closed relay contact for the muffin fan's positive wire. If there is enough sun to energize your solar fan, then there may be enough sun to activate the 12 volt relay's contact (<100 ma) and open the circuit to your muffin fan, saving your house battery charge on sunny days.

[GordMay]

Greetings and welcome aboard the CF, RUSTYNAIL.

[RUSTYNAIL]

Gord May,
I'm new to this, and don't understand when a reply is direct or just one on one. I've gotten one that seems to be to me only, but I'm not sure.
Greg ( RUSTY NAIL)

[bluetriguy]

rustynail,
fan issue aside - is this toilet in service now? How do you like it? We built several composting 'loos' in the 60's in cabins in California and Arizona and they all worked well though we weren't concerned with the 'slosh' factor... which on a boat will come into play (play being an ironic descriptor here) - seriously I love the concept but have not installed on my trimaran as even it (and i'm not taling catamaran here but a cat and a half) gets a bit violent sometimes - that the toilet would be throwing up on me as I throw up in it seems - well - cruel fate at best (or my mate says 'it's justice').
I really would like to know how this is working - really as the science works great and I know the smell (in a well maintained composter) is better than any other option. But just to be clear - your compost unit needs peat moss occasionally and the ventilation fan... right?

[GordMay]

Originally Posted by RUSTYNAIL

Gord May,
I'm new to this, and don't understand when a reply is direct or just one on one. I've gotten one that seems to be to me only, but I'm not sure.
Greg ( RUSTY NAIL)

Yes, mine was a directed one-to-one welcome to you, a new member.

[unbusted67]

Originally Posted by bluetriguy

rustynail,
fan issue aside - is this toilet in service now? How do you like it? We built several composting 'loos' in the 60's in cabins in California and Arizona and they all worked well though we weren't concerned with the 'slosh' factor... which on a boat will come into play (play being an ironic descriptor here) - seriously I love the concept but have not installed on my trimaran as even it (and i'm not taling catamaran here but a cat and a half) gets a bit violent sometimes - that the toilet would be throwing up on me as I throw up in it seems - well - cruel fate at best (or my mate says 'it's justice').
I really would like to know how this is working - really as the science works great and I know the smell (in a well maintained composter) is better than any other option. But just to be clear - your compost unit needs peat moss occasionally and the ventilation fan... right?

Hey Guys, I ended up just wiring a lighted switch into the muffin fan that you can see from peeing position, it seems to get the job done.

How is the head? I love the head!!! There is no slosh factor because the liquids and solids are separated. No more smell!!!! I don't think there is much composting going on because we are live aboards but the coir tends to dry out the solids enough to get rid of the really bad smells.