Hi Everyone! I’m freshly back from a trip to Whangarei to do some testing on the 97 prior to delivery. While Todd and Sarah relaxed in the boardroom with flat whites enduring endless meetings, I was able to get aboard the 97 and do some eagerly anticipated testing of the electrical system. For starters, the boat is amazing. Circa has done a fabulous job of taking the vision and turning it into reality, many kudos to the crew.
Now to the fun stuff…The 97 has a large, 2000 amp-hour traction battery bank aboard giving us a ton of storage capacity and range. Between our standard Electrodyne alternator setup, which we know has the capacity to deliver up to 600 amps of charging capability and our solar array, we theorized a potential output capacity upwards of 790 amps.
How awesome it was to record 898 amps during one of my tests!!
We worked closely with Salt Service of Florida to come up with this array.
During the design phase we calculated that our 20 Sunpower 320 Watt * panels had the capacity to deliver 195-200 amps of charging capacity at 28.8 VDC (which included the inefficiencies of the charge controllers).
*Note: Through further refinements, Sunpower has been able to increase the Wattage on the newer version of these panels to 345 Watts.
During one run at 11:30 am, with the average battery state of charge at 40% and a heading of 158° True (Summer- Southern Hemisphere), I observed an output of 238.8 amps from the Outback MPPT solar charge controllers.
The panels were pretty clean during our testing.
Where the system was truly impressive though was in its ability to provide 40-60 amps late in the day, or when it was cloudy as shown in the photo below. As a note, the battery SOC was 58% and the voltage without the solar array attached.
True to their word, the panels have a very long “solar day”, giving them a huge advantage over others.
Based on my testing, I calculate the boat could realize a gain of 1200-1300 amps per day.
One of the design criteria has been to keep the array cool. In 78°-85°F ambient temperatures with the sun directly overhead, the face temperatures ranged from 112-118°F while the underside never exceeded 101°F. We will continue to monitor as the boat gets into warmer climes, since we assume the face temperatures will climb and inhibit the output somewhat.