Power Logging with a Classic

ChrisOlson
ChrisOlson Banned Posts: 1,807 ✭✭
in Off Grid Solar & Battery Systems #1
I got 6 kW of solar capacity on a single Classic 150 with 3.75 kW facing south at 30° tilt, 1.5 kW facing east on a 22.5° roof slope, and .75 kW facing west on the other 22.5° roof slope. Today was the first perfectly clear day we've had in weeks. I logged the output from 7:00 AM to 5:00 PM with the Classic and graphed the CSV export from the Status Panel in Excel. This is what it looks like, with some comments on it below.

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From about 8:15AM to 8:45AM there's a dip in the power due to shading on the east facing array from a wind turbine tower.

That same tower causes a dip in the output from 10:30 AM to 12:30 PM due to shading on the south-facing array. Today the turbine was running and the blades caused shadow flicker on the south-facing array, which really screwed it up for about two hours as the shadow moved across the array, knocking out series strings of three panels one at a time for two hours.

Damned 90 foot tall wind turbines.........

The bank went into absorb at around noon and was done with absorb at 3:00 PM where the big dip in amps occurs. Although the controller did hit darned near 90 amps (about 5,400 watts) for a very brief time, the FET's got hot and it de-rated pretty fast. Then you can see the arrays being "throttled" most of the afternoon in absorb - the bank and loads didn't require the full output of what it could do. At about 2:20 PM you can see a spike where it goes up to 88 amps or so. That was due to me doing some welding in the shop and the big load on the system caused the controller to put out max power for a little bit.

The other up's and down's are caused by varying loads in the house - 'fridge and freezer starting and stopping, wife doing whatever - turning her stuff on and off, etc.. And that's why the morning curve is smoother - it was basically requiring everything the arrays and controller could put out - right up to where the turbine tower caused some problems. In the afternoon, with the arrays "throttled", the controller would adjust output as necessary to meet charging requirements and loads on the inverter.

Just thought I'd post it. Not many people do this sort of thing. But it's useful for somebody that might consider doing what I did - putting over-capacity on a single controller with the sections of the arrays faced in different directions. It works fine.
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Chris
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