Potentially batteries can help you use more of the electricity generated by your PV system, saving you money on your electricity bill. But they're not for everyone, as you generally need to be generating 'surplus' solar electricity to store. It is also important to note that, contrary to expectations,some battery storage systems are not designed to work during power-cuts. In addition they are not cheap: at today's prices, poorly designed systems may not repay their initial investment (in what they save on electricity bills). But prices continue to fall and the technology is also improving, meaning that battery storage is becoming a viable economic option for some households and businesses.

The document linked below has been produced by the BRE and RECC (2016) and is titled "Batteries and Solar Power: Guidance for domestic and small commercial consumers"