Some systems are DC Coupled but can also be set up as AC coupled.  This means you need two inverters – one for the solar and one for the battery.  You would only do this in a retrofit situation where you didn’t want to impact existing feed-in tariffs.

Click the link below to find out the benefits of DC Coupled and AC Coupled

Some systems can be a single all-in-one device, but are broken down into components.  For example, the solar inverter, battery controller (inverter, rectifier, battery management system), batteries and car charger can be replaced easily without swapping the entire system.

This is a crucial design if concerned about the environmental impact of potential component failure.

It is also very important cost consideration for the labour element of any warranty claims, typically not covered by the manufacturer.

There are two measures of capacity “total capacity” and “usable capacity”.  Total capacity is the size of the battery and usable capacity is the size of the battery after 10% is kept in reserve.  This review compares usable capacity so it is consistent.  All lithium batteries will reduce the life expectancy if discharged below 10%.

Tesla for example has a total capacity of 14kWh but is sold as 13.5kWh, which is the usable capacity.  In contrast Solax is sold as 5.8kWh, when the usable capacity is 5.2kWh.

This charge/discharge is limited by the battery OR the inverter/rectifier – continuous charge limit is used rather than max charge/discharge since it is more meaningful for comparison.

If you have a solar system generating 8kW; solar/hybrid inverter is 8kW; are not using any energy in the home; and the battery has a continuous charge limit of 5kW, then 3kW will be sent to the grid.

If you have a solar system generating 3kW; solar/hybrid inverter is 8kW; running a 12kW shower in the home; and the battery has a continuous discharge limit of 5kW, then 4kW (12 demand – 3 solar – 5 battery) will be imported from the grid.

This is the ultimate feature that many manufacturers are working towards. It looks at the weather forecast and predicts generation into the future and controls linked devices such as the battery system, hot water diverter, heat pump, smart plugs, car charger to maximise your profit.

All systems with weather forecast automatic planning also take into account your supplier tariff.

Some systems even use artificial intelligence to maximise your profit.

Be careful though since some companies charge a monthly subscription for this service.

A 3.68kW solar system is permitted by default in the UK, but if you want a larger system the Distribution Network Operator often imposes an export restriction. This is due to the grid not being designed or upgraded for microgeneration. There are three ways to restrict export by limiting:

1. the size of the solar system.
2. the size of the inverter.
3. export restriction at the exit of the property.

The best solution is option 3 and this is what is compared in the tables above.

There are 3 types of backup system which can all be manual or automatic changeover. See the article below explaining the benefits of each.

Systems labelled as whole home backup can often be set up to do essential loads as well.

The headline warranties are shown; however, most warranties have certain conditions.  Most warranties are reduced dramatically or voided if the conditions are not fulfilled.  For example, if a Tesla “Powerwall is not connected to the Internet for an extended period, or has not been registered with Tesla” the warranty reduces from 10 years to 4 years. GivEnergy requires the additional cost of three service visits during the lifetime of the system to keep the warranty.  Other batteries include the number of battery cycles in their warranty.