Fronius Reserva 6.3 kWh Battery Pack

Fronius Reserva 6.3 kWh battery: complete, ready-to-install system

The Fronius Reserve is a lithium battery from high voltage with DC coupling, designed to store the energy from your solar panels with minimal conversion losses. As it operates directly on DC with the inverter, the solar energy does not undergo a double conversion before entering the battery.

This pack includes everything needed to get the system up and running: You don’t have to order the parts separately or check that the quantities add up.

What’s included in the pack

• 2 × Fronius Reserva 3.15 kWh battery module
• 1 × Fronius Reserva BMS Unit and Base
• Total capacity: 6.3 kWh

The unit BMS and Base It is essential in any configuration. The reserve manages cell balancing, system safety and communication with the inverter. Without it, the modules will not work, and it is the component most often overlooked when buying parts separately.

Who is this feature for?

The 6.3 kWh system is the entry-level model in the Reserva range. It is suitable for a home with average energy consumption that wishes to cover the afternoon and evening periods using energy generated during the day, and is the standard choice for residential installations seeking to increase self-consumption without oversizing the storage capacity.

Compatibility with Fronius inverters

The Reserve is designed for investors Fronius GEN24 Plus, both single-phase (Primo) and three-phase (Symo). The suffix Plus This indicates that the inverter features a battery input: a GEN24 without ‘Plus’ is mains-only and does not support battery storage.

• Fronius Primo GEN24 SC Plus — single-phase, high-current generation
• Fronius Primo GEN24 Plus — single-phase
• Fronius Symo GEN24 SC Plus — three-phase, high-current generation
• Fronius Symo GEN24 Plus — three-phase

If you’re not sure which inverter you have or are planning to install, please contact us before placing your order and we’ll check this with you.

Can be upgraded without replacing anything

The Reserva is modular. This 6.3 kWh pack isn’t the limit: you can add modules later whilst keeping the BMS and the base unit you already have.

• Reserve 6.3 — 2 modules — 6.3 kWh
• Rating: 9.5 — 3 modules — 9.45 kWh
• Reserve 12.6 — 4 modules — 12.6 kWh
• Reserve 15.8 — 5 modules — 15.75 kWh

The system supports up to 5 modules per tower and even 4 towers in a row, which allows for growth well beyond the initial capacity if household consumption increases: for example, when installing an air-source heat pump or an electric vehicle charger.

Backup in the event of power cuts

When used in conjunction with a GEN24 Plus inverter and the corresponding backup accessory, the Reserva keeps the home running during a power cut:

• PV Point — basic power supply via a separate mains socket
• Backup Switch — full backing of the property

Without one of these two accessories, the system stores energy but does not operate in stand-alone mode.

Monitoring

The entire system — solar generation, battery charging and discharging, and household consumption — is monitored from Fronius Solar.web, both via the browser and the mobile app.

Purchased from an official Fronius System Partner

FVComponentes is Fronius System Partner and Official Service Partner in Spain, the highest tier in the Fronius partner network. For you, this means:

• Official warranty processed directly, with no intermediaries
• Direct access to Fronius technical support in the event of any issues
• Preliminary advice on sizing and compatibility
• Genuine product with traceability back to the manufacturer

Frequently asked questions

Which inverters are compatible with the Fronius Reserva battery?
Fronius GEN24 inverters Plus, both single-phase (Primo) and three-phase (Symo), including the SC versions. The «Plus» suffix indicates that the inverter has a battery input. GEN24 models without ‘Plus’ are grid-connected only and do not support battery storage.

Can I upgrade the battery at a later date?
Yes. The system is modular: you can add up to 5 modules per tower whilst retaining the BMS and the base unit from this pack, and connect up to 4 towers in parallel. There is no need to replace any of the existing components.

Does it work during a power cut?
Yes, provided the installation is fitted with the backup accessory: PV Point for a single socket, or Backup Switch for full home backup. The battery itself stores energy, but off-grid operation is enabled by the accessory.

How much range do 6.3 kWh provide?
It depends on each household’s consumption. In an average Spanish household, 6.3 kWh is usually sufficient to cover basic consumption during the afternoon and evening: lighting, the fridge, household appliances and electronics. These systems are not designed to sustain high-power loads such as heat pumps or electric vehicle charging for hours on end.

What is the difference between Fronius Reserva and Reserva PRO?
The range PRO Booking It uses higher-capacity modules (3.98 kWh compared to 3.15 kWh). If you’re unsure which one is best suited to your installation, please contact us.