Solar Energy

Can we say the size of the Solar panel is one of the limitations in a solar practical experiment? For instance size or number of solar panels matters in real time installation, I believe 24 volts solar panel will charge 24 Volts battery in real time depending on the solar intensity, and I know that 48 Volts Solar panel (connected in series) will charge the 24 volts Battery faster than 24 Volts solar panel. Kindly share your thought on this.

Cheers.

Parents
  • We had 10 solar panels installed in our garden at the end of last year. They are complemented by a 8.5kW battery and inverter in the garage. The panels generate up to 4.2kW corresponding to 21kW when it is sunny and about 10kW when cloudy. The battery has been topped up every day since February. The panels are connected in series.

    During the day the panels fill up the battery, feed the house and export to the grid. The house needs about 4.2kW per day. During the night the battery feeds the house but while doing that is also leaks energy to the grid and demands energy from the grid. Essentially the battery can't respond fast enough to changes in energy use and either leaks excess energy or demands missing energy for a short period. The changes in energy use are either around 10W or 100W when the fridge starts up.

    The inverter communicates with the supplier using wifi via our router. The link is done with a 2.4GHz Wifi dongle that didn't work with the router, which is 5GHz/2.4GHz, so I had to modify one of my RPI servers to connect to it at 2.4GHz.

    The solar panels are impacted by shading caused by clouds and they could be improved using micro-controllers.

    So by no means perfect. For the future I am considering adding another 10 panels or fitting a RidgeBlade to the roof and making use of wind throughout the day - but I am having trouble finding information and installers for that. Does anyone know anything about this?

    We installed solar panels because we had run out of ideas for saving energy in the home. We started in 2005 and have reduced it to half of what it was. This has saved us £15,000 over the years and that saving went to paying for the solar installation.

    I am in discussions with the Energy Saving Trust because they liked my innovative ideas for saving energy and I am in discussions with a councillor, helping them insulate their home. So it is good that I am retired.

  • A new problem has emerged with solar panel output during the recent hot spell of weather - apparently the output shrinks with temperature rise, It can be sunny but if the surface temp of the panel becomes too great, it's output falls away.

  • not new - its a feature of all semiconductors that the carrier mobility falls at higher temps - it is reversible, so will recover when it cools. The effect is not that dramatic on a well proportioned system considering that excess heat usually coincides with excess light as well. and the loss is less than 1% per degree rise  above 25C, so even if the panel is at an unlikely 50C, you might have lost 20-25% relative to the same panel cooled at that light level - so you still produce about 75-80%.  Amorphous thin film panels do better with about 1/4 % roll off per degree and are often specified  in hotter countries.

    Mike

  • As Mike says, this is not news, and is accounted for by any good simulation.

    And most well-designed systems in the UK are oversized for the inverters to make best use of plant installed - this might be by a considerable margin for larger installations - so the actual output is often still limited by the inverter rather than the array theoretical capacity anyway.

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  • As Mike says, this is not news, and is accounted for by any good simulation.

    And most well-designed systems in the UK are oversized for the inverters to make best use of plant installed - this might be by a considerable margin for larger installations - so the actual output is often still limited by the inverter rather than the array theoretical capacity anyway.

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