Solar sensor users, couple of ???

[project_x]

I have a couple of questions for those of you using your sensors outside and/or in conjunction with solar PV generation.

1. How do you keep moisture out of the RJ45 ports?

2. What filters are you using to attentuate the sunlight to keep the max of the scale below 300mV?

3. Has anyone calibrated the mV reading with the output of your panels? Which panels,......?

Thanks,
Rob

 

[SteveQ]

Rob,

I am using a single small solar cell (Radio Shack) as a sunlight sensor. I have placed the cell in the location that I plan to put a large panel. I am currently collecting data to see how much sun the panel will get (it will be in the shade part of the day). I simply measure the voltage output of the cell. Below is a sample graph.

Steve Q

 

[project_x]

Rob,

I am using a single small solar cell (Radio Shack) as a sunlight sensor. I have placed the cell in the location that I plan to put a large panel. I am currently collecting data to see how much sun the panel will get (it will be in the shade part of the day). I simply measure the voltage output of the cell. Below is a sample graph.

Steve Q

Steve,
Have you attempted to track the E-W path of the sun to see how much of an improvement you receive?

 

[SteveQ]

Rob,

No I have not because the panel will be roof mounted, no way to make it track the sun. Also, is there any data to show that tracking will improve the performance enough to ever recover the cost of the tracking mechanism?

Steve Q

 

[project_x]

Rob,

No I have not because the panel will be roof mounted, no way to make it track the sun. Also, is there any data to show that tracking will improve the performance enough to ever recover the cost of the tracking mechanism?

Steve Q

I agree that tracking is probably prohibitive, but the sun's path is very predictable. I am going to experiment with this prior to installing my array.
I think a very simple roof mechanism, that let's you manually adjust the inclination (4times a year, as the suns angle changes with the seasons) and a rotation that has the panel turn in a predefined pattern to follow the sun through out the day will pay for itself. Specifically in my region (Ontario), where they are not only subtracting the kwh you produce from your electric bill, they are also paying you an additional 81cents/kwh for each one you produce (on a 20yr contract). This puts the panel payback (with no tracking) in the 3-4yr range. Tracking should improve this.

 

[SteveQ]

Interesting. With a 3-4 year payback, I would think lots of people will be installing solar panels.

I have been reading http://www.solarpowerforum.net/forumVB/index.php for about 6 months and I have not seen anything about tracking the sun.

Steve Q

 

[djbowen]

This seems to be drifting off topic a bit for a hobbyboards post.

I am interested if any has some ideas (or data) for calibration for the HB Solar Sensor kit. Some way of calculating watts or lux from the current output would be handy.

Dan

 

[geoff]

Re outdoor installation ...

I purchased a little waterproof/UV stabilised box. Drilled a hole for the 1-Wire cable, and 2 tiny holes for the diode legs. I cut the diode off the board and mounted it on the outside top surface of the box, then rejoined the diode to the board. I sealed the holes with a dob of silicone.

This worked for a while, but I found that the sun was too bright and saturated the diode during the middle hours of the day. So the next mod was to insert a resistor in series with the diode to reduce the current.

This worked perfectly for a few months ... but then the diode died completely. I don't know whether it was excess solar radiation, some other environmental issue, or just bad luck.

Anyway, I'm now awaiting a new diode ... I have rebuilt the box a little and this time I plan to do the ping-pong ball trick as an attenuator. I have cut a hole in the bottom of a ping-pong ball, and will position the new diode approximately at its centre. I'm guessing the ping-pong ball might need replacing every year or two.

Will this work ? Who knows ... with luck I'll put it back into service this coming weekend.

Re-calibration ...
The best I could do was to guess that the solar radiation was approx 1000W/sqm at noon on mid-summers day under a perfect clear sky. This is just a guess.

 

[Clark Martin]

This seems to be drifting off topic a bit for a hobbyboards post.

I am interested if any has some ideas (or data) for calibration for the HB Solar Sensor kit. Some way of calculating watts or lux from the current output would be handy.

Dan

Put a resistor across the solar cell / panel. It's value should be one that loads the cell / panel as it would be in normal use. Then measure the voltage across the resistor and calculate power from P = V^2/R. You could divide that power by the devices surface area to get solar flux.