PV Powered Grid-Tied Bedienungsanleitung PDF herunterladen (Seite 10)

Application Note

many conditions, especially on cloudy days, will require supplemental power to meet load and battery charging

demand.

Most of North America has 3-5 average sun hours per day which translates to 18 kWh to 30 kWh of available PV

power with a 6 kW array, notwithstanding various losses that could reduce the daily production significantly.

However, sometimes PV production will meet or exceed the PV module nameplate so for estimating purpose 18

kWh to 30 kWh are the working numbers to use in determining what to expect in sunny weather.

Assuming all loads in the previous example are on at once, they will be drawing an average of 1.4 kW per hour of

available power from the PV array through the GT inverter. That leaves 4.6 kW for battery charging if the PV array

is achieving its nameplate power production. If the three-string battery bank starts the day at 80% depth of

discharge (DOD), then it would take about 4.2 hours (19.5 kWh ÷ 4.6 kW = 4.2 hrs) to charge the battery while

simultaneously providing the 1.4 kW demanded by the loads. At the point of GT inverter shutdown when the

batteries are full, load demand can be sustained for nearly 14 hours before reaching 80% DOD on the battery

bank—likely enough to last from sundown until bedtime with enough power left in the batteries to provide a

power source to the GT inverter the next morning so it can deliver power from the PV array and start the cycle

over again.

However, on cloudy days or when daily sun hours are below average due to winter conditions, adding a generator

can assure adequate backup power under all conditions. A 5 kW generator would take 5.4 hours to charge the

battery bank for another 14 hours of operation while also maintaining the 1.4 kW load demand (19.5 kWh ÷ (5kW-

1.4kW=3.6kW) = 5.4 hrs). As stated before, a generator running at 85 to 90 percent of maximum output can

increase hourly operational fuel use significantly, compared to running the generator at low load conditions.

Avoiding noise, lack of fuel availability and high maintenance cycles are additional benefits to higher fuel

efficiency when using a generator with a battery-backed up inverter system.

A more detailed look of OutBack’s GSLC175-AC-120/240 AC Coupling solution (including some drawings) follows;

here is a list of the required AC Coupling components that come with the OutBack pre-wired AC-Coupling Radian

Load Center.

 50A DPST Remote Controlled Circuit-Breaker (ROCB; takes three CB spaces in the load center)

 12 VDC Outback Relay

 48 VDC OutBack Relay

 DIN Rail Hardware

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PV Powered Grid-Tied Bedienungsanleitung Seite 10