During summer, when you have an energy storage system on your house, as long as it is sized correctly and you have enough solar PV, you should always be able to fill your batteries to full capacity on a daily basis. You will probably generate excess electricity and export it to the grid, although you will rarely be paid enough to justify this as a useful use of your green energy production system.

In summer, you can generally just ignore your energy storage system and it will cover as much of your power needs as you have designed the system to provide.

However, in winter the situation changes as the hours of solar generation decrease and the sun is lower in the sky, so often produces less PV generation on your solar panels. This is particularly relevant when you have several days in a row of rainy and / or cloudy weather with little to no PV generation. In order to maximise the solar PV available and get the most use from your batteries it may be a good idea to change the way your battery is utilised.

Instead of only filling your battery from solar which is the cheapest and most environmentally friendly way to fill a household battery you can fill it using off-peak power then using the battery system to provide electricity to your house during peak power usage times, often 3 – 9pm each day. Not as good as charging the battery with the sun but better than paying peak electricity rates.