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Some electrical advice please...


Kilps
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The roof of the garage I rent might as well not be there. It leaks like a seive and the car is probably better off outside. This summer I will sort it out.

 

As well as sorting the roof I want improve ventilation in the garage, in an attempt to reduce condensation. I can't cut holes in the walls or doors as it's rented.

 

My plan is to fit a fan or two to the wall(s) inside, to get the air moving at least, which will hopefully encourage fresh air in through the gaps around the door etc.

 

The next issue is that there's no power anywhere near the garage as it's in a block.

 

My plan at the moment is to use a 12V fan run off a solar panel, with a battery in the circuit to keep the fan going when sunlight is lacking. The solar panel needs enough oomph to charge the battery back up when the sunlight comes back, whilst keeping the fan going.

 

Is this a sensible solution? I have very little electronics experience. What do I need to know about the fan, battery and solar panel to ensure this will work properly? Is there a better idea than a solar panel? I've considered a small wind generator outside (as well as or instead of the solar panel) but this'll be more obvious than a solar panel sat flat on the roof. I don't know if this is overkill or if I've got no chance of getting enough power out of these things.

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The battery might be overcomplicating things. I would have thought a fan draught during daylight hours would suffice, therefore not needing a bettery?

 

Go for the highest power output solar panel you can. I've read on here that anything else is a false economy/won't work.

 

What you'll need to know (and what I can't help with) is whether you can run a fan directly from the solar panel. I'm thinking you might not be able to, due to insufficient current. So you might be back to charging a battery by day, and circulating some air by night. Even an hour or two of fan should be enough to give you decent air circulation.

 

Unless you've got garage doors that you can fit your fist around the door frame though, I'm not sure if it will be able to draw enough fresh air from outside. You might just end up moving the stale air around.

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You're probably right. Keeping it going constantly is the ideal, but just during the day would at least be an improvement over the current situation.

 

I will have a look at running the fan directly off the solar panel. Part of my thinking behind the battery was that it'd maintain a constant current/voltage to the fan, where the solar panel may vary. As long as the average output of the solar panel is capable of charging the battery, I guess it should be able to keep itself going, save for any very dull periods. I'm not sure how efficient these panels are in dull conditions.

 

I agree on the issue of enough fresh air from outside. Unfortunately I'm pretty restricted on that... I don't expect he'd be very pleased if I started putting holes in his garage.

 

There's always bloody leaves blowing under the door, so some air gets in!!!

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Small wind turbine and solar panel. there both exspensive. battery wise go with what you can afford the more amp per hour the better and then get yourself a good charging circuit.

 

look into the boating world :) they all run 12v systems and have to try to be self suficiant :)

 

Can always start with a solar panel and add as and when you can/have a need too but as said above your more than likely need a battery to.provide enougjt current and a charging circuit so you dont kill the battery.

 

Charging the battery could eve be done at home :) but if you can do it by solar or wind then it is free :)

 

what is the current draw of your fan?

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I haven't bought a fan yet... so I've no idea! I haven't bought any of it, I've just been trying to work out how best to sort it out. I need to sort the roof first otherwise it'll all be pointless.

 

Boating stuff is a good shout, I'll have a look. I've just had a look at wind turbines and they're much more expensive than I expected! More so than solar panels.

 

What do I need in a charging circuit? I was thinking solar panel, battery and fan all in parallel.

 

I've also seen mention of charge controllers (I think) and diodes to stop reverse charging when there's no current. Will I have to look at these separately or are they likely to be included with the solar panel?

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You can get a charging circuit for a solar panel (used alot in boating)

 

It will be cheaper to buy a charging circuit already on the market than design one yourself. if you put a wind turbine directly charging the battery they it would blow the battery when wind goes pushes the turbine which would push too much current into the battery to quick and pop it.

 

http://www.pkgreenshop.co.uk/10a-12v-solar-charge-controller-regulator.html?fee=1&fep=136&gclid=COHcm_GusMQCFcdf2wodaJYATg

 

note the above link the charger maxium solar panel would bee 80w panel. Just something to note when you do start looking for panels and chargers.

 

When I say charging circuit I mean charge controller sorry.

 

http://www.bestecoshop.com/100w-12v-solar-panel-kit-with-adjustable-frame-10-amp-dual-battery-controller-5m-extention-cables-brach-connectors.html?gclid=CIiQqu2wsMQCFeme2wodoGMABA

 

above is a complete kit for a solar battery charger.

 

When you know what fan your going to use with the current draw you can then work out the size of battery you will need to run it for X-amount of hours.

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It also has an additional output control circuit: this is not normally used on caravans or motorhomes, however it is a great addition to control lighting circuits in sheds or similar.

 

In addition, with battery level control, this unit will automatically turn off your lights when the battery level is low. This protects the battery from running too low and causing damage due to excessive discharge.

 

This suggests I can wire the fan(s) directly into this unit and just let it control everything, keeping the fans going until the battery gets too low and there's no sunlight to get things going. If that's the case, this looks like it's exactly what I'm after!

 

 

Following a (very quick) google search, I was just reading about this: http://www.sunstore.co.uk/12v-20w-Monocrystalline-Solar-Panel.html

Does that look sensible or is 20W not going to be enough do you think?

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As well as all this, I want to set up a separate circuit to keep the Supra's battery topped up when it's in there for extended periods. Presumably I can use the same setup (just without the fans included)?

 

Yer just use it to charge/float the supras battery. as long as its ok with acid based batterys.

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That's what I thought. Just wanted to make sure I hadn't missed something.

 

Would one of the 40W ones be suitable to keep the Supra battery topped up?

 

Trickle charging seems to be better than quick charging from what I've read, but I don't know if that makes a difference if I'm only keeping it topped up, not charging from empty.

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Sorry I haven't looked at the other links but is something like this suitable? According to the advert you can power TV, laptop, fans etc - Worth having a look at.

 

http://www.maplin.co.uk/p/30w-solar-panel-n97df

 

With regards to low light I set one up in a village in Bangladesh, even on a cloudy day it topped up the battery. It was a truck battery which I used & it can mainly power the lights & charging phones but you could even run the TV off it. Not sure if you can buy a similar package in the UK. Good point re checking out boating, perhaps caravan sites too?

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Yeah that's similar to the one linked above that I've decided I need two of. Although the one above is 40W and cheaper!

 

I actually dropped into Maplins in town earlier to ask some of these questions but the didn't seem to help. I also popped into CEF who I thought might have more idea, but they were even less help and thoroughly unprofessional!

 

So I resorted to the font of all knowledge... this forum! And it worked!

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Oh, I got sidetracked and forgot your last bit. That's good to hear about the low light. I think I'll have this all set up before I stick it in the garage, so I can get an idea of how well it works. I need to sort the roof before it goes in anyway or it'll all get soaked.

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