Some systems can be DC coupled but can also be set up as AC coupled. There are a few system which are AC coupled only.

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

Some systems have the hybrid inverter as part of the battery back, but can be separated into components, known as modular.  For example, the solar inverter, battery controller (inverter, rectifier, battery management system) and batteries can be replaced easily without swapping the entire system.  Hybrid inverters are modular since the inverter is separate to the battery.

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 a recommended % is kept in reserve.  This review compares usable capacity which is a more relevant measure for comparison. All lithium and sodium batteries will reduce the life expectancy if discharged below 8-10%.

Some batteries say “100% discharge capable” such as the Tesla Powerwall 3 – this just means the manufacturer has already deducted the “10%” reserve from the battery capacity advertised.

The charge/discharge is limited by the battery OR the battery controller – whichever has the lowest output. For comparison we use continuous (or recommended) charge/discharge rather than max charge/discharge, since it is more meaningful for comparison.

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 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 2 types of backup system:

1. Uninterruptible power supply (UPS)
2. Emergency Power Supply (EPS)

and 4 types of backup:

1. Backup Sockets from Inverter
2. Whole Home Backup from Gateway
3. Essential Loads from Inverter
4. Essential Loads from Gateway

See the article below explaining the benefits of each.

Systems labelled as whole home backup can often be set up to do essential loads or sockets 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 or throughput (energy delivered in the batteries life) in their warranty.