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Tom Richmond

By Tom Richmond
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Tom Richmond Proficient

Tom Richmond

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Hi, 

looking to install a computer fan or two in under bed storage to try and draw some air through and keep the dreaded mould away. Two questions:

1) Suggested makes/spec for quiet low consumption fans. There seems to be a massive world of options out there and I don't really know what I am looking at. 

2) Power will come direct from main distro. I don't want the fans to run all the time (noise in the night!) but would like them automatic, otherwise we will forget to turn them on, or off! Was thinking a voltage sensitive relay, set to 14v, so they only come on once the solar is making good progress, or if shore line connected and charger on. Does this sound sensible? Any alternative ideas?

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jonathanA Experienced

jonathanA

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18 minutes ago, Robbo said:

Small fans make more noise than big fans, so bigger the better.

Not sure that's true -big fast fans move a lot of air and that makes a lot of noise....

I'd suggest the op wants some fans that don't move too much air as they are likely to be quiet and not use too much electrickery

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dor Veteran II

dor

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Big range in computer fans, both in price and air flow.  What you are looking for only needs a very small amount of airflow, so go for one that has the lowest rating you can find.  It shouldn't need to draw more than about 100 ma at 12V.   Maplins or ebay will give you plenty of choices.  You can also get small relays in Maplins which you could use to just switch it on when something else runs.  Assuming oyu haven't got a lot of wet bilges etc, it only needs an hour or so a day, just to change the air.  Think about where the air will come from as well, and whether you will have it suck or blow.

 

You may not even need a fan at all, just some vents placed in suitable locations.  My underbed storage space has no fans and has no mould.  Slats under the mattress help, both to reduce condensation under the mattress from your body and to help ventilate the storage area.

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Drayke Rising Star

Drayke

Posted
Posted (edited)
2 hours ago, Tom Richmond said:

Hi, 

looking to install a computer fan or two in under bed storage to try and draw some air through and keep the dreaded mould away. Two questions:

1) Suggested makes/spec for quiet low consumption fans. There seems to be a massive world of options out there and I don't really know what I am looking at. 

2) Power will come direct from main distro. I don't want the fans to run all the time (noise in the night!) but would like them automatic, otherwise we will forget to turn them on, or off! Was thinking a voltage sensitive relay, set to 14v, so they only come on once the solar is making good progress, or if shore line connected and charger on. Does this sound sensible? Any alternative ideas?

Brought some small fans, 40mm x 40mm from Maplins, can’t remember how much but not a lot, 12v & 0.12A so not a lot of power either, very quiet.

Edit to add. We had a lot of condensation under our bed so put some carpet of the floor no more condensation.

Edited by F DRAYKE
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Robbo Veteran II

Robbo

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Posted (edited)
8 hours ago, jonathanA said:

 

Not sure that's true -big fast fans move a lot of air and that makes a lot of noise....

I'd suggest the op wants some fans that don't move too much air as they are likely to be quiet and not use too much electrickery

You control the speed and air flow with a PWM controller (or reduce the voltage for the fan using resistors). For the same airflow the bigger fan is much more quieter as it doesn't need to run as fast.   It was common on PC builds to upgrade the fans to a bigger ones and run at 7v.  Now the speed is controlled by temperature tho via PWM.

Edited by Robbo
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ditchcrawler Veteran II

ditchcrawlerDonate to Canal World

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4 hours ago, Robbo said:

You control the speed and air flow with a PWM controller (or reduce the voltage for the fan using resistors). For the same airflow the bigger fan is much more quieter as it doesn't need to run as fast.   It was common on PC builds to upgrade the fans to a bigger ones and run at 7v.  Now the speed is controlled by temperature tho via PWM.

I use 3 X 12 volt fans wired in series on a 24 volt supply

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Tom Richmond Proficient

Tom Richmond

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Hi all,

Thanks for replies.

I have experimented with venting the space over the last year, pretty sure that I could avoid the fan route, but to no avail. So I have plenty of holes to draw the air from, and know where I will put a fan sucking through the space. 

Yes, an hour a day sounds about right.

But how to do this from the main distribution panel? I do not access this on a daily basis. Can I configure a relay to activate when I turn something on elsewhere in the boat? Maybe it could be the water pump? If so, I wouldn't need to worry about noise...

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Drayke Rising Star

Drayke

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Posted
22 minutes ago, Tom Richmond said:

Hi all,

Thanks for replies.

I have experimented with venting the space over the last year, pretty sure that I could avoid the fan route, but to no avail. So I have plenty of holes to draw the air from, and know where I will put a fan sucking through the space. 

Yes, an hour a day sounds about right.

But how to do this from the main distribution panel? I do not access this on a daily basis. Can I configure a relay to activate when I turn something on elsewhere in the boat? Maybe it could be the water pump? If so, I wouldn't need to worry about noise...

How about a time switch.

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WotEver Veteran II

WotEverDonate to Canal World

Posted
Posted
25 minutes ago, jddevel said:

Is the advised principle that you draw the air out of the bilge into the cabin space or do you draw it out and then vent overboard please?

Into the cabin space. It's just to get the air moving through the bilge. 

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jonathanA Experienced

jonathanA

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On 28/03/2017 at 06:30, Robbo said:

You control the speed and air flow with a PWM controller (or reduce the voltage for the fan using resistors). For the same airflow the bigger fan is much more quieter as it doesn't need to run as fast.   It was common on PC builds to upgrade the fans to a bigger ones and run at 7v.  Now the speed is controlled by temperature tho via PWM.

Oh right if only I'd been able to receive that vital info by telepathy....

give me strength...

I've found many fans on redundant servers pcs and other electronic equipment being skipped. In most cases I've grabbed the fans and heatsinks (great for home made ECO fans) and weighed the rest in for scrap and been up a couple of quid on the deal 

 

 

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