Battery storage

This customer already had an existing solar system with a heat pump. The customer wanted to have the facility to store any excess energy generated from their solar panels and to store electricity from a cheap overnight tariff for use in the day.
During a site visit, we discussed all possible options regarding the addition of battery storage, including current electricity demands, the battery location, and the cost of electricity per unit (throughout the day and during an overnight cheaper tariff).
We opted for a GivEnergy 3.0 kW AC-connected inverter with a 9.5 kWh battery storage unit. This would allow the customer to fully charge the battery up during the night, at a total cost of about 70 p. The stored electricity would then be used throughout the day when the solar could not cover the electrical demands.