Batteries have been difficult to justify in recent years, but with significant rises in energy costs and the price of batteries coming down they are beginning to look viable.

Whether they are worth it depends on the output of the PV array, your annual electricity consumption and how much of the PV generated electricity you use.

For example:-

If your PV system produces 3600kWh over the year and your house consumption is 5500kWh, but you are out all day, then typically you may only be using 20% of the PV system production. If you add a 10kWh battery this would increase to 80%.

Below is an example of the tables used to determine how much additional PV production you will use. These have been produced by the MCS.

Below is a typical schematic showing how the batteries will fit into the existing system

Below are the answers to the questions you are likely asking yourself

Can I charge the battery from the mains?

Short answer is yes but it will require a hybrid inverter. This would mean you could charge the battery at a cheap night rate from the grid as well as charging the battery from the solar PV.

Can I have an Uninterrupted supply (UPS) if there is a powercut?

Yes but would need to be wired to a dedicated circuit within the house, for example the upstairs sockets and downstairs lighting, this would then provide you with emergency power in the event of you losing the mains.

What’s the best location for batteries?

They work best in a room that doesn’t get too hot – Ideally they would go in a garage but they can go in a loft or any other room but the warmer they get the less efficient they become. The operating temperature ranges from -10 to 50 degrees but will see efficiency drops below 0 and above 40 degrees

Are Batteries safe?

Batteries are no more unsafe than any other electrical installation, as with anything there are risks but these are very small and should be a great consideration.

Can you recycle batteries?

Yes, not all batteries can but the lithium ion ones we supply can be.

How do I know if its working?

All the batteries are WIFI enable and will give you access to a web portal where you can see all your data.

Is there any maintenance?

There is no ongoing maintenance as with any electricity based product it worth keeping an eye on so you know it is functioning efficiently but there is no periodic testing required.

Can I add more batteries at a later date?

Yes, the Alpha Smile B3 can accept a further 5 battery packs taking

the total capacity to 17.2kWh. Other models can go further than this.

How long do they last?

This is actually determined by the number of cycles the battery goes through, this means a full charge and discharge. On average a battery will last around 10 years and all batteries have at least a 5 year warranty and most can be extended to 10-years.

What’s the difference between Capacity and useable capacity?

Most batteries will have a capacity and a useable capacity – this can be confusing but in basic terms batteries should never been fully discharged and as such the useable capacity takes this into account.

Do I keep my export tariff?

If you have a deemed export tariff then yes. However if you have an export meter fitted then you will not be paid unless the electricity is exported to the grid