AC coupled battery storage

In simple terms, AC Coupled Solar Battery Storage is where you add a battery set to a regular Solar PV System. It can be installed as a retrofit battery storage system to add to an existing solar panel array or as a part of a new solar panel installation.

The batteries store the electricity that your solar panels generate and export to the grid. You can then use that power at night, during the daytime or in the event of a power-cut. In some cases, AC coupled systems built so that the solar panels continue working and charging the batteries even in the event of a power cut.

1. 1. The solar panels – The Direct current (DC) travels into the solar inverter as usual. Other renewables can also be used such as Wind turbines etc.
2. 2. Solar Inverter – The Solar Inverter turns the Direct Current (DC) into Alternating Current (AC) the power then gets sent to the battery inverter. If the batteries are full then power is sent to other appliances or the national grid.
3. 3. Payback meter – Before the power either gets used or sent for storage it is counted as normal on the feed in tariff payback meter.
4. 4. The battery inverter / controller – The Alternating Current (AC) then gets sent to the battery inverter which converts the energy from AC to DC and is stored in the batteries. The inverter then converts the DC from the batteries back to AC when the power is needed.  
5. 5. The batteries – The batteries store the power until needed in the home or business.
6. 6. Off-grid cut off switch – on selected systems, If the grid fails then an automatic switch kicks in and switches to off-grid mode, allowing your solar panels to continue to charge your batteries and the grid to be completely isolated.
7. 7. The national grid – The system is also grid connected so if there is any surplus power then this is sent back as normal.

AC coupled solar battery storage systems are exceedingly popular with households that already have solar panels. Homeowners see the benefits of storing their solar-generated energy and using it at a time more suited to their electricity requirements.

Batteries that Store Solar Power for use in the Home

The AC coupled / grid-interactive system is scalable.  You can pretty much have any size of storage capacity. A typical domestic system costing around £2,500-£9000 will be able to store between 2.4- 16kWh’s Plus of useable storage.

Numerous AC coupled solar battery storage systems can change at night using off-peak electricity enabling them to use up all their solar energy in the evening and recharge at night ready for the morning. Depending on your electricity tariff, you could be charged as little as a penny a unit off-peak.

An ac coupled battery system is relatively simple. Your solar panel system stays as it is. A trained installer will install some batteries, a battery controller inverter and a changeover unit. The power from the solar panels charges the batteries. The batteries supply the house. Any solar energy that is left over gets sent back to the grid as usual. Your feed-in tariff continues as normal.

The batteries come with a minimum of a 5-year warranty, and it is possible. In some cases to extend this to 10 years for an additional fee.

Summary

When Installing batteries to your solar PV system it will help you to be more independent from the grid. It’s possible to harness the sun’s energy by using the power at night and in times of low light. The stored power can be built for off-grid, if the system is set up to do so and when they are low you can use the power from the national grid as normal.

Further content

Another solar battery system to consider is the hybrid battery.

Here is a link to a solis AC coupled battery storage system.