Solar storage overview

DC vs AC

Offgrid vs Grid-tied

Offgrid systems are becoming much more popular over time, even for whole house solutions. In the UK, offgrid systems typically need a backup generator and/or wind turbines. They have a distinct advantage since everything in the home can run on DC, without the inefficiencies of converting to AC.

Being grid-tied means you can sell excess electricity back to the National Grid and use the National Grid in the winter when there may not be enough solar energy.

Off grid – the system is not connected to a mains connection.
Grid tied – the system is connected to a mains connection – the National Grid.

DC vs AC coupled battery

Choosing between DC and AC coupled systems is an important decision, so it is useful to know the key differences to empower yourself to make the right decision.

DC coupled – battery attached to DC
AC coupled – battery attached to AC

Types of battery systems

There are several types of battery systems suitable for home use. They are split into DC coupled and AC coupled systems – they start with separate components moving to partially integrated systems (hybrid systems) and finally fully integrated systems (all-in-one). Here are two of the six different systems:

DC coupled – separate components
DC coupled – hybrid
DC coupled – all-in-one
DC coupled – all-in-one with DC car charging
AC coupled – separate components
AC coupled – all-in-one

Types of battery backup

In the UK, where the grid is quite reliable, for most people there is little need for battery backup. However, some people might desire battery backup for self-sufficiency and resilience or might live in locations where the grid is less reliable.

Uninterruptible power supply (UPS)

UPS is designed so there is little interruption to the power supply when there is a power cut. Customers with sensitive electronic equipment such as computers or medical equipment might require a high power supply quality.

Emergency Power Supply (EPS)

EPS are suitable for the majority of customers – it is typically a little slower to transfer into backup mode and the quality of supply is not as consistent.

Standby Backup

This is an alternative name for EPS backup systems.