DC or AC Coupled Battery?

DC Coupled systems are more efficient since there are less conversions of energy between AC and DC and vice versa. 3-4% of energy is lost at each conversion.

If your solar panel output is being restricted by the size of your inverter (for example 7kW of solar and 6kW inverter), DC coupled has less energy being wasted – also known as being “clipped”.

DC coupled systems typically have less potential power being exported to the grid, therefore National Grid is more likely to approve them without imposing export or generation restrictions.

DC coupled have one DC to AC inverter, whereas AC coupled systems have two DC to AC inverters.  This allows AC coupled systems to put more energy into your home.  However, by upgrading the DC coupled inverter to 12kW, in the example below, also achieves the same power output to your home.

For some AC coupled systems, if there is a power cut the solar system will stop producing energy – only the battery will provide power until it is empty.  We select systems to allow the solar system to continue working in power cut backup mode and check compatibility with your existing solar system.  A DC Coupled Hybrid solution will always allow the solar to continue working in backup mode.

Having a separate solar inverter and AC battery charger/controller may be beneficial in the future.  Solar inverters tend to last 8-10 years but are easily and cheaply replaced.  Having a one box solution for battery, solar inverter, battery charger controller, like Tesla, may be expensive or impossible to repair after the warranty expires, compared to a very modular system.  Some systems, such as Solis, are compatible with a wide range of batteries which makes them more resilient.