article: In the past year solar power in the UK has more than doubled while in the US it has grown by 30 per cent. But many current systems fail to solve the problem of how energy is managed and used overnight when the sun sets. Traditionally, energy gathered during the day is sent back to the grid, but this can prove costly if you need to buy it back - unless you have a smart battery that stores the excess energy in your home. Sonnenspeicher (pictured) uses a lithium iron phosphate battery to store energy harnessed by solar panels. This energy can be used throughout the day, and any excess is stored for when the sun goes down. Rather than selling this excess electricity back to the grid, homeowners can then use their stored supply for power . With this in mind, German firm Automatic Storage Device (ASD) and designer Wolfram Walter have created the Sonnenspeicher. It uses a lithium iron phosphate battery to store the energy harvested during the day by solar panels fitted to a roof. This energy is used throughout the day, and any excess is stored for when the sun goes down. Rather than selling this excess electricity to the grid, and potentially having to buy it back at a later date or time, homeowners can use this stored supply to power their home until the sun rises again. Sonnenspeicher features an intelligent management system that automatically controls the charging and discharging current, to make it easier to manage how much energy is being used. Sonnenspeicher features an intelligent management system that automatically controls the charging and discharging current, to make it easier to manage how much energy is being used. It additionally has a Sleep mode that ensures the storage system never runs low and will automatically go into standby when not in use . Although it is designed to be completely independent of the national power grid, it can equally be wired up in the case of emergency. For example, whenever there is energy in the battery available, the connection to the grid is locked. When this energy runs out, the Sonnenspeicher connects to the grid 'in a millisecond' ASD Sonnenspeicher uses a lithium iron phosphate battery to store the energy harvested during the day by solar panels. This energy is used throughout the day, and any excess is stored for when the sun sets. Rather than selling this excess electricity to the grid, and potentially having to buy it back at a later date or time, homeowners can use this stored supply to power their home until the sun rises again. Sonnenspeicher features an intelligent management system that automatically controls the charging and discharging current, to make it easier to manage how much energy is being used. It additionally has a Sleep mode that ensures that the storage system never runs low and will automatically go into standby when its not being used to increase efficiency. The system comes in different sizes ranging from the Sonnenspeicher 300, which is 4.8 kWh, to the Sonnenspeicher 600 at 8.06 kWh up to the 1000 model which offers 13.44 kWh. Prices start at €8,450 (£6,170). It additionally has a Sleep mode that ensures the storage system never runs low, and will automatically go into standby when its not being used to increase efficiency. And although it is designed to be completely independent of the national power grid, it can equally be wired up in the case of emergency. For example, whenever there is energy in the battery available, the connection to the grid is locked. When this energy runs out, the Sonnenspeicher connects to the grid 'in a millisecond'. This switchover works the other way too. If a home is predominantly powered by the grid, the Sonnenspeicher will still store energy and instead act like a generator during a power cut. 'We wanted to create a storage system that makes you truly independent of the national power grid, that adequately supplies all of your household appliances at all times, and that remains efficient and trouble-free for at least 20 years, so that you can have the peace of mind that your investment really is worth every penny,' said the firm. The system comes in different sizes ranging from the Sonnenspeicher 300, which is 4.8 kWh, to the Sonnenspeicher 600 at 8.06 kWh up to the 1000 model which offers 13.44 kWh. Prices start at €8,450 (£6,170). The firm said an average home can save around €1,200 a year (£876), so it would still take around seven years to recoup the costs, but the system will last for 20 years.
highlights: Sonnenspeicher was designed by Wolfram Walter and German firm ASD .
  Its lithium iron phosphate battery stores energy from solar panels .
  Cheapest model is €8,450 (£6,170), but it will save money on electricity bills .
  It also comes with 'intelligent management system' that controls current .
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