We have 4 kW of solar panels and a matching 4 kW of Enphase batteries. The system has performed without a hitch. The addition of batteries has significantly reduced our electricity bill. In fact, over the summer months we have not paid out anything at all. The income from the Feed In Tariff (~11c/kWh) has more than covered any electricity we've had to purchase.
If we use too many appliances at one time... we draw from the grid. We have overcome this to some extent by using large current appliances sequentially rather than at the same time. Overall we are very happy, and would recommend considering including Enphase batteries with any system.
-- Norm Cheale