Solar with smarts: Part 2
We are now well into our solar project (read Part 1 here).
The home has enjoyed over two months of solar power with storage and the associated smart reporting and monitoring. We have become avid weather heads, adjusting our daily routines like clever chipmunks.
With a forecast of sunny days the BMW i3 will get a full charge to maximise the free solar generated electricity. It very quickly became evident that the most effective use of the Enphase battery storage is for time shifting of solar electricity for use in the evening. The batteries are limited by their respective micro-inverters in contributing electricity flow to the home. Thus, it is best to run appliances during the day with the solar electricity being sourced directly from the panels.
The month of April saw over 302kWh generated and 374 kWh of electricity consumed from the grid, down significantly compared to the previous April when allowing for the electric vehicle consumption (approximately 100 kWh). The Envoy system reveals the best days saw 17kWh generated with fully charged batteries supplying the home until the wee hours. The batteries were able to store 73 kWh throughout April and return that sun juice back to the home after dark. And this is post the autumnal equinox with the tree shading now having a greater negative impact on PV electricity generation – bring on summer.
The sizing of the batteries suits our home activities but to continually run an electric vehicle at, say, 50 km range per day, it would be advantageous to increase the solar panel capacity from 3.4 kW to 5kW to minimise grid usage.
We are close to the winter solstice and yet the batteries are still receiving a full charge on a sunny day. The key to sizing a new system is not to over capitalise on the investment. The system is designed to be grid connected and the batteries should cycle down once a day.
Check back in closer to the spring equinox for a wrap up/data dump of our first six months with smart solar.