Last week we upgraded our solar power system for our home. Since we live off-the-grid in Hawaii, this was a major cause for celebration, which included dancing and lots of toasting well into the evening.

We now have a 48-volt system with 1600 Watts of solar panels on the roof. We also have 8 – 420 amp-hr batteries for storage and a 3 KW inverter.

With regard to how common off-grid living is in Hawaii, it’s mixed. On-grid is typical on Oahu, Kauai and the resort areas of Maui and the Big Island. Off-grid is more common on East Maui and the rest of the Big Island.

Here’s a run down of what we did:

• Installation of two new 175W SW 24 Volt solar panel modules, bring our tally on the roof up to 1600 watts.
• Connection of existing solar array strings to fused PV string connector.
• New wiring to charge controller.
• New MS60 Outback charge controller.
• 8 L16 High capacity 420 AH batteries
• New battery connectors 2/0
• Concrete slab 20″x 55″ for batteries
• Plywood enclosure for batteries
• Plywood cabinet for Outback 3048 sine wave inverter. (SEXY describes it well!)
• Indoor meter to monitor battery status and Voltage or Amp draw.
• 110 Volt Flojet pump. This replaced our old 12 Volt pump, meaning we have better water pressure now, too.
• All wiring below the string connector enclosed in conduit.
• New conduit run with #6 wire to house in back.
• Connection of house in back.
• New main breaker cabinet next to inverter.
• Removal of old batteries and equipment.

The total cost of the upgrade (i.e., ripping out then entire old system, save a few solar panels on the roof) was about $11,000. With the cost of grid energy in Maui hovering around 40 cents per kilowatt hour, this upgrade pays for itself in three years. If the price of diesel fuel keeps rising, the break even day will come even faster. There are also the environmental benefits of not spewing diesel fumes and CO2. And by not erecting power lines, we preserve the amazing ocean views. Here’s to solar power!