SolarWorld solar blog

Off-grid island solar and solving the issue of too much power

Posted 11 July 2016 12:00 AM by Kyle Bronstein, President of Florida Renewable Energy

Florida Renewable Energy - Cayo Costa - full house view

The owners of this island beach house were looking for a quality solar system so they contacted us at Florida Renewable Energy. The solar installation for this home is a complete off-grid system on the remote island of Cayo Costa near the coast of Fort Myers, Florida.

After running the load calculations for the beach house on the island, we determined that a 60 kWh battery bank would be sufficient to run the entire house without discharging the batteries more than 50%, leaving 30 kWh usable. I could tell that the homeowner was a man who valued quality, so I offered him the best components on the market for this system.

We went with 36 SolarWorld Sunmodule 285-watt solar panels and 2 SMA America Sunny Islands giving this system some serious power! When the system was ready to be commissioned it started up performing better than estimated. It was working beautifully. The batteries were discharging less than we calculated under max loads from the house. The system was a perfect success, except for one thing.

Florida Renewable Energy - Cayo Costa - SMA America Sunny Islands

Believe it or not, during peak hours the solar panels were making too much power. When the system is collecting max power and there isn’t room in the battery or a large enough load from the house it has to "dump" that power. In order to do this, the frequency of the system is momentarily altered. Unfortunately, the frequency change during the power dump began affecting the sensitive equipment in the house.

The radio controlled lights, security system, wi-fi controlled thermostat and other sensitive devices were flickering on and off and resetting themselves. Luckily we were quickly able to figure out what was happening and create an easy solution. First, we logged all of the frequency windows of each individual electronic. Next, we changed the parameters on the sunny islands to not go under or above those parameters during the next frequency change.

Florida Renewable Energy - Cayo Costa - Side view

No damage was done, but in the future, we and whoever is reading this can save some time troubleshooting by checking the frequency ranges on all items that will be plugged into the house. This is just one of many ways off-grid solar systems are different from grid-tied systems.

The solar system works beautifully now and helps to power a boat lift, elevator, all of the household appliances, large air conditioners, and much more without any problems. This beach house has by far the nicest solar system on the island and there are 55 individual solar systems located on the island of Cayo Costa.

Florida Renewable EnergyThis post was written by Kyle Bronstein, President of Florida Renewable Energy. Kyle and his team of experienced solar installers have been providing quality solar systems in the state of Florida for several years. See some of their work here.

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