Battery storage solutions are a great way of maximising your savings from your solar PV array – the battery storing any excess solar energy, so you can use when you need it. Some battery storage solutions are can also be used to store energy from the grid when it is available at a lower tariff, to be used later – another great way to save money.
If you’re a new array, then we can install a Hybrid inverter together with battery storage. Alternatively, if you have an existing solar array, it is likely that you’ll need an AC Coupled Battery – these include an inverter to change the solar energy from AC to DC current (see blog on “How do solar panels work?”). The storage solutions all work in much the same way, allowing you to store any excess solar energy generated for later use. All of the batteries we supply have a web-based portal or mobile phone app, to allow monitoring and control of the system – allowing you to control when the battery discharges etc. There are solutions available from Tesla and GivEnergy that provide ‘back-up’ functionality should there be a power-cut, from 13.5kWh battery storage, installed alongside a gateway, that provides switch-over for the whole house in milli-seconds. So, if you live in an area that has power outages, these can be a great option, to keep the home powered from any stored energy.
In terms of getting the right size battery, it will depend on your circumstances, for example the size of your solar array, whether you are at home during the day, the amount of electricity your household uses etc. We would recommend for a typical household using c.4,000kWh a year, battery storage of between 7 and 10kWh – although if you have access to a lower overnight tariff, it may be worth going for a larger battery. Many of the batteries we fit are able to be extended as they have a modular style, meaning that if circumstances change you can easily add more storage capacity.
We’re often asked, how long will the battery energy stored last – we always say, it depends! Not very helpful, but it really does depend on how much energy you use – if you boil the kettle, have the oven on to cook a roast and put on an electric heater – the battery stored energy won’t last very long at all. However, to keep a fridge/freezer, internet router and a few lights on the battery will keep going for around 6 hours.
A few things to consider when buying batteries:
Depth of discharge – the battery storage solutions we fit, do not every fully empty, as they require a certain amount of energy to keep the battery management system working, so you may see figures like 95% DoD, this means if you have a 10kWh battery, you’ll have 95% of it as usable energy, so 9.5kWh.
Battery cycles – this is the number of time the battery can be charged and discharged before it starts to become less efficient, so you may see 10,000 cycles on a data sheet for a battery – so the higher the better.
VAT – at the moment, there is NO VAT payable on battery installation either with or without solar PV installations.
If you have any questions about battery storage, drop us a message and we’d be pleased to help – email info@greenmansolar.com