Battery Storage

One of the biggest issues with solar PV is that any power not being used at the time of generation is exported to the electricity grid. For example if the solar PV system is generating 3.5kW but you are only using 2.5kW, the remaining 1kW of power is exported. Electricity providers will pay an export rate for the power exported but this is significantly lower than what they charge you for using electricity from the grid. The simplest way of increasing self consumption and reducing dependence on the grid is to install a battery storage system. This allows power to be stored and used when demand exceeds the power generated from the solar PV such as during dull periods or at night. Types of Battery Most solar PV battery storage systems use lithium ion or lithium ion phosphate batteries. Both have their advantages and disadvantages, but we recommend lithium ion phosphate for the following reasons: Long lifespan - Guaranteed discharge cycles between 6000-10,000 and warranties up to 10 years. General life expectancy of 15-20 years. Safety – Lithium ion phosphate batteries do not catch fire when the battery is punctured or damaged unlike lithium ion batteries.

DC Connected Battery Storage

A DC connected battery charges from the PV panels before it is converted to AC power. This can be either separate from the inverter or as part of a hybrid system with the inverter and batteries in the same unit. This is a more efficient and cost effective method of installing a battery storage system and are better suited to new installations rather than retrofitting to existing solar PV systems. They can also be more complicated to install if the PV system is on a separate building such as a shed or garage. The discharge power is also restricted to the size of PV inverter installed.

AC Connected Battery Storage

An AC connected battery is separate to the PV system and has its own battery charger. As the PV energy is converted from DC to AC and back to DC they are slightly less efficient than a hybrid system. They are useful for fitting to an existing solar PV system where replacing the inverter would not be cost effective or where it would be difficult to fit in the existing inverter location such as an attic. They can also be useful for new installations where the PV system is on a separate building such as a garage or shed. They can also allow for higher charge and discharge capabilities than a PV inverter may offer.