Solar powered fan for obs - options?

[peter_4059 (Peter)]

I'm on the hunt for a solar powered ventilation fan for my Absco (pool pump cover) obs.

I found these on ebay and they look like a good option but I'm wondering if there is anything better?
http://www.ebay.com.au/itm/day-night...-/220890377608

I'm also wondering how I would attach this to the colourbond and maintain the weather-tightness? is there some type of flashing I need to get?

[DarkArts]

Have you looked at something like this? Seems like it would be easier to weather seal.

[peter_4059 (Peter)]

That does look like a good option. I'd still need to seal the area between the colourbond ridges as the unit would span two ridges.

[DarkArts]

Well, it mounts vertically (e.g. at the top of the North facing side), so I would probably use some flexible gasket or closed cell, UV stabilised foam that will compress into the gaps between ridges and silicon around the rest ... or something like that. Plus, you can easily put some flyscreen or filter cloth over the end if the interior tube, which, if everything else is sealed tight, ought to make it fairly bug proof.

I'm looking at one of these Absco things (with said solar-powered fan added) as a roll-away shed option for my own backyard.

[peter_4059 (Peter)]

I'm thinking the battery version is probably overkill as I basically want it to run when the sun is shining on the shed and stop when it is in the shade/at night.

This one might be a better option:
http://www.ebay.com.au/itm/Solar-POW...item4adb28dbe5

[DarkArts]

Whereas I want mine to keep running for an hour or two after sundown until the shed has cooled to ambient ....

Each to their own, I suppose.

[peter_4059 (Peter)]

Will the battery last if it gets discharged completely every day or are you planning to manually switch it on and off?

[glend (Glen)]

Originally Posted by peter_4059

I'm thinking the battery version is probably overkill as I basically want it to run when the sun is shining on the shed and stop when it is in the shade/at night.

This one might be a better option:
http://www.ebay.com.au/itm/Solar-POW...item4adb28dbe5

I have that one on my observatory and it does a decent job. It runs all day, and does not leak in heavy rain.

[astronobob (Bob)]

Originally Posted by peter_4059

That does look like a good option. I'd still need to seal the area between the colourbond ridges as the unit would span two ridges.

Maybe Expansion Foam, Its used by tradesmen for aircon ducting & the likes, its strong, durable, weatherproof and bonds to just about anything. You spray an amount and it will expand approx 5 times the size. Hardens in an hour then can cut with hobby knife for neatness and sand for a paintable finish

http://www.bunnings.com.au/sika-850m...-foam_p1210302

[byronpaul (Paul)]

Originally Posted by peter_4059

I'm thinking the battery version is probably overkill as I basically want it to run when the sun is shining on the shed and stop when it is in the shade/at night.

This one might be a better option:
http://www.ebay.com.au/itm/Solar-POW...item4adb28dbe5

Peter,

I have one of those installed in my ROR as well.

Easy to fit, has an included foam back, and battery lasts pretty much all night .... so it just runs 24 x 7 x 365 days per year. I've had it about 18 months I think and it's still running fine.

But, does it do the job??? Sure it moves hot air out of the observatory on hot days, and you can feel that by placing your hand over the fan, but it doesn't move enough air to do a satisfactory job in my set-up. I'm finding that the observatory is still getting to 10+ over ambient in Melbourne on those hot days which is too hot!!!!, so if I'm home I leave the doors opens which gives a better result.

I'm now looking at a 240v option that will move 250+ CFM and run that on hot days, and hook it up to a Temperature switch .... something like the following:

https://www.masters.com.au/product/9...an-white-150mm

http://www.ebay.com.au/itm/220-240V-.../281280638271?

Paul

[glend (Glen)]

Originally Posted by byronpaul

.......so if I'm home I leave the doors opens which gives a better result.

I prop the door open a little as well, it does seem to improve the performance of the solar extractor. Subfloor vents would do the job as well (my obs is built on a post foundation), and on slab versions lower wall vents would help.

[peter_4059 (Peter)]

It looks like those units only have a 1.2V battery in them. I imagine the fan would be spinning quite slowly? I wonder if there is a 12V version?

[deanm (Dean)]

I can't believe how expensive the units listed above are.

From A Big Green Hardware supplier, I can get half a dozen solar-powered garden lights for $25.

What's the difference between powering a small electric fan motor & multiple lights?

Dean

[peter_4059 (Peter)]

I had a chat with Jaycar today regarding building my own 12V version with a computer fan. Here's what he recommended:
1 x ZM9050 5W solar panel $29.95
1 x AA0372 DC-DC converter to limit the output voltage to 12V $9.95
10 x 1.2V NiMH 2500 mAh batteries (actually 3 x SB1738 @ $18.95 ea)
1 x PH9210 10 AA baterry holder $3.95
1 x YX2513 80mm 12V DC fan $19.95
1 x grille from Masters/Bunnings ~ $10

So all up about $130. How does that sound as an alternative with potentially higher air flow? The big cost is obviously the batteries and there might be a cheaper way to do this?

[peter_4059 (Peter)]

I pulled the trigger on the 12V solar fan today. Ended up going for the 5W panel:
http://www.jaycar.com.au/Ecotech/Sol...---5W/p/ZM9091

DC-DC converter:
http://www.jaycar.com.au/Power-Produ...-1-5A/p/AA0372

120mm fan:
http://www.jaycar.com.au/Electromech...e-Fan/p/YX2584

No batteries at this stage but might add them later if necessary.

Wired it all up today and it works!

Just waiting on some grilles to arrive at Masters
https://www.masters.com.au/product/9...?bmUID=l7831Ro

and need to get a 12V fuse holder.

[jjjnettie (Jeanette)]

When we built our first coffee cart we used this paint on the outside. It's amazing stuff. It made working inside a tiny tin shed on wheels tolerable even in summer. You could touch the inside of the metal roof and it would only be warm, not hot enough to fry an egg on.
http://www.solacoat.com.au/