In many cases, homeowners in the Nordic region have realized the benefits of adding a battery only after installing solar panels. Below, we explain what you need to consider when complementing your existing solar installation with an energy storage system.
1) Check If You Have a Hybrid Inverter
The first thing to check is what type of inverter you have, as it determines whether you can connect a battery. Specifically, you need to verify if you have a hybrid inverter. Hybrid inverters only require a single conversion from DC to AC since the battery is charged directly with DC from the solar panels.
A hybrid inverter is designed to connect both solar panels and a battery in the same unit. You can take a photo of the model label on your inverter and send it to your installer, who can verify if it supports batteries. Alternatively, check under the inverter for inputs labeled BAT, BAT+, or BAT-. If such labels are present, the next step is to determine which batteries are compatible with your inverter.
Note that not all batteries are compatible with external inverters, and you may need to purchase a battery from the same manufacturer as your inverter.
2) Replace Your Inverter with a Hybrid Inverter
If your current inverter is not a hybrid inverter, you can replace it with one that is compatible with a battery, such as a qapasity battery. This is often feasible, but you should be cautious if your current inverter is from SolarEdge or Ferroamp. These systems use different topologies than most other inverters on the market, requiring a unique approach. In such cases, it may be easiest to install a separate inverter for the battery system. This means you keep your existing inverter for the solar panels and add a dedicated inverter for the battery. However, this setup has a few downsides:
- You may need two separate apps to monitor your system.
- There are additional conversion losses since electricity is converted three times:
- From DC (solar panels) to AC.
- From AC to DC (into the battery).
- From DC (battery) back to AC for household use or export to the grid.
If you want to upgrade your system with an inverter compatible with qapasity batteries, we recommend Solis. By installing a Solis S6 (12-20 kW), you can connect your existing inverter to the generator input of the Solis inverter. This allows the Solis inverter to register all production from the third-party inverter without needing an additional meter. All data will be available in the Solis app.
Note:
- The third-party inverter must not have a higher rated output than the Solis inverter.
- If the third-party inverter’s output exceeds that of the Solis inverter, you can install a separate smart meter to measure the production. This meter connects to the Solis inverter.
- Some functionality, such as “zero export,” may not be supported when using inverters from different manufacturers.
There are other methods to connect systems with multiple inverters (one hybrid and one non-hybrid). Since many factors must be considered, it’s essential to consult a skilled installer before proceeding with a retrofit. This is especially important if you plan to use an external EMS system. For example, Enequi offers detailed guidance on integrating compatible inverters like Solis with EMS systems (LINK).
