There are 12 Kaneka Thin Film Silicon PV Modules mounted on his house roof. The roof is southwest facing and gets sun all day long. These panels are 60 volt 60 watt panels, and are great value for the money (150.00) per panel. The panels are connected to a Xantrax DC disconnect box in the basement of the house. This Xantrax DC disconnect box also contains the breakers to shut of the power from the panels, power to the charge controller and the DC power from the battery bank.
The battery bank is a 24 volt DC 1500 AMP hour AGM battery bank. The AGM batteries are maintenance free, never gas and don’t need to be watered. With good care this battery bank should last 15 to 20 years.
The charge controller used is an Outback Power Systems unit. This takes the high voltage from the panels and converts it to 24 volt DC to charge the battery bank. The unit does the MPPT tracking to get the most efficient use of the solar energy into the battery bank.
The inverters that were used are Xantrax DR Series Inverter/Charger. They are 24 volt DC input and 120 volt AC output at 3600 watt. The output is non-sine wave. These units are connected together using the communication cable so that there is 240 volt power to the sub panel. The inverters are also used to charge the battery bank where there has not been enough sun for 3 days or more. Power is sent from the inverters to the sub panel that was installed alongside the existing panel.
We installed a 24 circuit FP sub panel next to the existing circuit breaker panel; it is fed from the inverters and has a 60 amp 2 pole circuit breaker protecting the panel. We moved 90% of the house circuits to this panel. The only circuits that we left on the old panel are the AC, Inverter charging, generator start panel/timer, and 1 duplex outlet in the basement beside the panel.
Charging of the battery bank is mostly done by the solar panels but there are times when there is not enough sun over the period of a week and the system needs to charge the battery bank using grid power. This is done 2 ways. The customer had previously bought an 8 KW NG generator with transfer switch.
The charging of the battery bank is controlled by a generator start panel, it measures the battery bank voltage and when it drop to a pre-set level will signal either the generator to start or for the system to charge from the grid. A Omron timer controls when the system goes to generator or to grid to charge based on the time of the day. The generator will start during the day (peak hydro time) and run for 4 hours to charge the battery bank up, at night it will go to grid (non-peak time).
The system works and looks great. The customer is thinking of installing 14 more panels in the spring.