Gratefully, the solar array is working as designed. Most days, it meets all our needs, keeps the batteries charged and sells power back to the grid.
Our Sol-Ark 15k hybrid inverter is a marvel. It connects directly to our 200 amp service and feeds the entire breaker panel – no need for a separate critical load panel. The PV DC solar feeds the inverter as well as our propane generator and the battery bank. When it’s light, solar powers our loads, using batteries as needed. When solar output exceeds our needs, the batteries get charged. Then, once fully-charged, the inverter sells to the grid.
At present, we have 30 kWH of battery capacity. We may need additional capacity for the Winter months with the shorter days and overnight heat pump electricity demands. Batteries are expensive!
It’s too early to tell if selling to the grid is worth all the fuss. It was expensive and time-consuming to get an interconnect agreement with the utility. Plus, they charge us $25/month for the privilege of selling them power and only pay 2 1/2 celts per kWH wholesale rate for the electricity. It will likely take us a year or more to break even. The only other positive of sending power to the grid is that it allows us to power the guest house during the day, saving us having to pay retail rates ($0.18/kWH) for any power that house consumes.
And when the grid goes down, we don’t skip a beat! That’s already happened a couple of times, although for short durations.
Next project will be figuring out the most cost-effective way to power the guest house and provide emergency back-up (since we have two chest freezers there).