Putting together a solar power system

[Lippyp]

well a smal scale solar power system. This is for my holiday home in France. We've been getting some damp there when its shut up and have come to the conclusion we need to improve the ventilation. Over thge winter we do use a number of those crystal type damp traps around the house and all the bedding etc is sealed in vacuum bags with big silica gel bgs so its more some odd patches of mould on walls in quiet corners.

The setup isgoing to be a panel, probably initially a 50W panel, maybe a 100W if I can persuade the wife it isn't going to be too ugly, a 100AH deep cycle battery controlled by a solar charge controller thta will stop the battery overcharging and control the voltage going in.

I've fitted a few vents out through the eaves upstairs and the idea is to add a fan to a couple to pull air through. The vents happen to be 90mm so a pc case fan is an ideal size. I'm going with a couple of 12V DC coaxial fans rated at 2100L/min drawing 300mA each, these will only run during the day as it gets very cold at night (I've seen -16C there over winter) and to save the battery. This will be controlled by a seperate photocell switch.

I also want to run an ultrasonic sound generator to try and get rid of my fat dormouse problem, these critters are a bit like squirrells and we have a population living between the ceiling and roof (the room is inside the roof so has a pitched ceiling) I've ordered a ultrasound generator that switches frequency randomly so they don't get used to it and four external speakers to cover the whole roofspace. Again this runs off 12V and draws only 100mA and will run 24/7.

I'm hoping a 50W panel will keep up with the current draw even on cloudy days.

Anyone done something similar, got any advice?

Thanks
Phil

 

[gayler]

No, but I'd like to add solar to my garage and house if I could aford it.

 

[Lippyp]

Its all coming together and the pile of parts in my didning room is growing. I have two 92mm coaxial fans, they shift 2100 litres/min of air each. A 30A solar charge controller, an 88AH deep cycle battery, assorted piles of cable, a photocell switch to turn the fans off at night, now waiting on an 80W panel and the ultrasonic stuff for the pest repeller. Probably going to mount the panel on the roof as then it'll be out of sight.

 

[theoldwizard1]

My gut says you will need more solar panels.

 

[Lippyp]

Maybe, we'll see how this 80W panel copes over the winter, after all, it is only drawing less than an amp. This kind of illustrates the problem with solar if you need half a roof full of panels to power a system this small.

 

[Lippyp]

Well heres a few pictures of what I put together. the panel was going to be a 120W panel but my supplier let me down at the last minute so its an 80W panel but next year I'll add another 80W panel as the supplier is sending me an extra one free. They'll also go up on the roof at that point out of sight. The grey box houses the photcel switch that turns the fans off at night. It was purring like a kitten when we left, the fans come on pretty much the same time the panel starts generating and it was kicking out about 1.5A on a cloudy day. The two fans and ultrasonic generator pull about 650mA so it should keep up,

The charge controller and ultrasonic pest repeller.

Fan on existing vent

The full wiring and battery

Plan next year is to build a little cupboard around the battery etc with a louvre door on it for ventilation.

 

[bacpacker]

Just ran across this thread. Some question that comes to mind. How far North are you? Does your panel mount have a Tilt capability? The reason I ask, from the pics it looks like they it is pointed more horizontal that up toward the sun. I have a engineer friend who did some studies with 4 different brand panels over a 60 day period. His results showed that unless he was tracking the sun, both at the right angle and with the movement across the sky, his charging numbers fell off drastically in the morning and evening. Just something to consider if it's not bringing your battery up to the level of charge you want.

Otherwise looks like a great set up.

 

[Lippyp]

Its just mounted temporarily for this winter, its pointing as far upwards as I can with the brackets I used so it is off the vertical. It is a south facing wall and during the winter the sun stays fairly low so it gets sun most of the day. Its in southwestern france so a fair way south.

 

[Falcon67]

SW France puts him on about the same latitude as Chicago.

 

[rsanter]

Thin film panels are more tolerant of off angle sunlight than the other types of panels. They are cheaper but have half the output.
However considering the fact that they do better with off angle I recommend their use for fixed systems

Bob

 

[where2]

Better than nothing I suppose. Not sure what keeps the battery from freezing?

One advantage of the 85 degree tilt on the panel is no snow buildup. Americans can look up their solar #s in the NREL Red Book (based on city) to get approximate efficiencies for flat, latitude tilt, latitude +/- 15 degrees and vertical mounting of the solar panel. There are also charge controllers available that can run things for timed periods each day. They were intended to run lights for set periods after sunset. I've been debating using one on my dock for lighting. I too have a 50W panel for fun and experimenting around the house.

Looking forward to results.

 

[Lippyp]

Like I said, the panel is only mounted temporarily for this winter, next year it'll go up on the roof paired up with another 80W panel. It is tilted upwards as much as I could get it with the mounts I used (basically just big angle brackets with multiple holes) The total current draw on the system is 650mA daytime and 50mA at night so its really not pulling a lot.

The charge controller I have does have the lighting control facility but I don't need to run lights. This is why I went with a seperate photocell switch that turns the fans off when light levels get below 20 lux whereas the built in controller only has the capability to turn stuff on at this point.

I don't think freezing will be a problem, even at 25% of charge it won't start to freeze until -15C (5F) and we've never seen that low in the house on the max/min thermometer we leave in there. At 50% charged its -23C (-10F). For next year maybe I'll wrap the bulk of the battery in some of that bubble wrap/silver insulation for a bit more protection.

 

[Lippyp]

Well just an update, we arrived at the house last Friday to the sound of the fans running sweetly away. It seems the panel has kept up with the charging requirements over the last five months quite happily despite it being a very cold wet winter. The net result indoors was great, it was very dry with none of the mildew we've had in odd corners the last couple of winters so over-all it's been a great success. I do plan a second panel on the roof as we may add more fans and just to make sure the battery is happily charged but I will leave the original on the wall as we do get a lot of snow and any panel on the roof will get covered whereas the wall one won't and so will keep charging. Several times during our stay I saw the charge controller had slipped over into battery full..pulse maintain mode so as the days get brighter that should only continue to improve. The wife is convinced now she's seen the benefits of the setup.

The ultrasonic pest repeller seems to have worked as we heard no fat dormouse activity in the roof BUT it is quite early for them to have been out of hibernation so we'll only find out for sure come the summer. One side bonus seems to have been a noticeable reduction in the amount of cobwebs as apparently it also deters spiders!

I'm hoping now when we go back in August that it might not be quite so stiflingly hot inside with the improved ventilation

 

[theoldwizard1]

Well just an update, we arrived at the house last Friday to the sound of the fans running sweetly away. It seems the panel has kept up with the charging requirements over the last five months quite happily despite it being a very cold wet winter.

GREAT !

Personally, I would be nervous about leaving the batteries unattended for that long. Are they wet cell ?

 

[Lippyp]

It's a deep cycle gel leisure battery, basically a car battery like an optima. At the rate it's charging at the chances of it overcharging even if the charge controller allowed it is minimal.