Wednesday, 24 August 2011

Three Extra Solar Panels Added to Our Power Supply System

Today Robert and Damien from Central West Solar called and installed an additional 3 X 190 watt BP Solar panels to our off grid power supply system, increasing the rated capacity from 2,625 watts to 3,215 watts, which in jargon terms equates to going from a 2.6 to a 3.2 kilowatt system.
Our decision to increase capacity was off the back of us over time placing more load on the system than we had originally planned leading to slightly greater generator run-times. The additional load has come from:

  • Our stock water pump draws slightly more power than we'd expected
  • We installed a refrigerated air conditioner rather than water cooled
  • Our solar hot water system has an electric boost rather than gas
We also now know that our generator uses 3 litres of diesel per hour rather than the 1 litre we believed to be the case at the time on installation. NB: We didn't ask the manufacturer how much diesel it would use at the time of purchase.

In this photograph you can see Damien and Robert putting the first of the 3 new panels in place on the frame that they assembled on site.

The frame assembly is a different design to what was used 2 years ago but does the same job. Here you can see that the 3 panels are loosely in place.

The next step after tightening the panels to the support frame was the run the leads across to the junction box.

In the last photograph you can see the finished product. We've now 18 panels rather than 15, with the rating of the original panels being slightly less at 175 watts each.

There were some new learnings for us that came out of general discussion during the installation:

  • The Government's practice of issuing 'Renewable Energy Certificates' is a bit off target in comparison to countries like Germany in that the power generation ratings (and ultimate sale price of the RECs) are based on the total theoretical energy capture of the panels rather than actual. In our case our panels are set up in the best possible position and we will in fact harvest 3.2 kW and above at various times. Many systems are not so installed (e.g. panels facing south meaning they have no chance of performing to rated specifications) but the owners will still receive the same number of certificates.
  • There is a significant difference in the quality of various panels, depending on brand.
  • BP Solar who at one point were market leaders has recently taken the decision to no longer sell panels via retailers. They will only supply to very large systems and will be directly involved in the installations.
  • To pass Australian standards for potential hail damage test panels have to be undamaged from 30 mm steel ball bearings being fired at them at 40 km / hour.
  • Solar panels have an inbuilt mechanism whereby power is diverted around connectors that are shaded, as in the case when, for example, birds poo on them. The impact of this is that the temperature of the panel in the area where the power is diverted increases relative to the rest of the panel, which can over time impact of panel performance. We will keep a closer watch on the panels during extended periods without rain and clean the bird poo off them if there's a build up.
  • Connected with the above, whilst dust on the panels can impact on solar energy capture performance it is not necessary to clean the panels as the film of dust is even ... and will wash off naturally when it does rain.

We are looking forwarded to having just that bit extra power generated from our own system here on Ochre Arch.

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