AC Coupled storage connects to the AC side of a property working independently from the PV inverter. It’s an ideal
retrofit solution as there is no need to interfere with the existing PV system. They can even be installed on properties
without PV and used to charge from the grid making use of cheap overnight tariffs.

DC Coupled/Hybrid storage is connected to the DC side of a PV system – meaning that there’s no additional AC/DC energy conversion.

Most DC Coupled storage solutions are Hybrid inverters – meaning the inverter is a Hybrid of the two technologies, with the PV inverter and the battery controller in one single unit.

Capacity is the amount of energy in kWh (units) that a battery can store. Batteries should never be drained completely. However, some are misleadingly sold quoting ‘total/nominal’ capacity. Check what’s being stated. ‘Useable capacity’ is the figure you need to know. The Tesla Powerwall has a nominal capacity of 14kWh; however, it’s Usable Capacity is 13.5kWh. It will never fully discharge to prevent damage to the battery cells.

Despite expectations, some storage systems will not provide power during a power cut. Most systems are just for energy storage to increase the self-consumption of the electricity generated by your solar panel system. If this is a requirement, ensure battery capacity is in line with the loads on the backup circuit and the duration that the loads need to run. We would recommend the Tesla Powerwall as the best solution for this.

Your battery may use the grid to trickle feed the battery when the battery level drops around 20%, this is to protect the life of the battery, you will see this more in the winter when the battery is getting less charge from the solar in the daytime. Also, the battery will not discharge any more power from the battery to the house when below this level.

A cloud could drop the solar PV production suddenly and if the system was charging the battery, the grid may step in while the system adjusts its charge rate, this can take up to 12 seconds to adjust. You may see your portal showing solar and grid charging the battery, this will adjust itself and is normal operation. The portal can take up to 10 minutes to update its data, so you may see this being displayed for this time.

This happens mainly when the solar suddenly gains more sun and needs to adjust its charge rate or when the battery is full. This can take up to 12 seconds to adjust its flow to and from the battery. The portal can take up to 10 minutes to update its data, so you may see this being displayed for this time.

Yes, you ca still use your eddi. We will need to adjust the settings on the Eddi so that both systems don’t try to take the same exported energy. We do this by giving the Eddi a 30 second time delay before trying to take the surplus energy to heat the water, giving the battery priority.

A battery’s efficient lifetime depends on the technology and the way in which the battery is used – this is significantly affected by the number of ‘cycles’ (complete full battery charge and discharge) that they undergo. Manufacturers generally give an expected lifetime in years and/or in ‘charge-discharge cycles’. For example: ‘Life expectancy = 10 years or 10,000 cycles, whichever is the sooner’. Lithium-ion batteries last longer than lead-acid: with a 10-year lifetime expectancy as standard, with this longevity improving all the time.