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Old 06-18-10, 12:54 PM   #89
Xringer
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Default Tracking!

The tracking is excellent today. Never seen it track so accurately.
(I guess the mod doesn't have any major side-affects).

We are getting some pretty good sunshine today. Just a little high-thin haze.
The panels are 133 F on top and 145 F on the bottoms (hotter in the shade?).

The heat reduces the power output by quite a lot. Not too happy with today's power out.
Open voltage should be around 80v, is down to 76.8v.
Under load it drops to 62.6v.. Into 10 ohms, that's only about 392 watts of power.
When it was cooler (more cloudy) the output would get up to around 66v..

But, even with a mere 392 watts, the boiler has picked up 17 degrees
since I checked it early this morning.

The array gets some light between the trees when it's early, but the clear-shot over the trees
occurs around 10:15 (tracking starts at that time also).
The boiler went from 118 to 135 degrees by 13:30.

Hey! We might pick up another 8 or 10 degrees this afternoon..



Edit:
6/18/10 15:20
140 degrees (22 degree gain)!! about 3.5 degrees of gain per hour?

6/19/10 13:00
Water is up to 140 again and we are seeing a bit more voltage (cooler today?).
79.8 open and 65.5v under load. 6.55a = 429 watts. 37 more than yesterday.

6/21/10 20:30
Had a tracking failure today. The West side photocell jumped to high resistance.
The good east side cell showed 300 ohms in the same light as the west side had 1300 ohms.

MTM Scientific, Inc says the heat specification is 75C Maximum (167F ).
So, it looks like my Super-Duper water-resistant sensor pod might have been over-heated by the summer solstice sunshine.

Michael at MTM is going to send me a replacement matched pair of sensors..
In the mean time, maybe I can try some cheap RadioShack photocells that appear to be rated at a fabulous 80 degs F..
Not sure if these will be suitable for really sunny days.. It was about 90 here today..

I plan to make some mods to the sensor pod, to keep it from collecting so much heat.
(It does look kinda like a solar collector). I'll post some pics when I get it back together.

Last edited by Xringer; 06-21-10 at 07:48 PM.. Reason: new day new data
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