BYD Battery Storage: Battery-Box HVS/HVM with Fronius – Sizes, Backup Power, Costs

A BYD battery storage system, the BYD Battery-Box Premium, is one of the most widely installed home batteries in Germany. At PVPro Solar, we install it in Hanover and Lower Saxony together with the Fronius GEN24 Plus hybrid inverter. The HVS series covers 5.1 to 12.8 kWh, the HVM series 8.3 to 22.1 kWh. With us, an HVS 10.2 costs about €7,700 to €9,200 extra when added to a new PV system. Here you’ll find which size suits you, what the battery costs, what the warranty really means and when it provides backup power.

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BYD Battery Storage: Key Facts at a Glance

Why BYD with Fronius, and Why a Battery at All?

A solar system produces most of its energy at midday, but power is mainly needed in the morning and evening. Without storage, a typical household therefore uses only 25 to 35% of its solar power itself; the rest goes into the grid for about 7.70 ct/kWh. With storage, self-consumption rises to around 55 to 70%. At an assumed electricity price of 37 ct/kWh, every kilowatt-hour stored and used in the evening is worth almost five times as much as power fed into the grid.

The BYD battery is a high-voltage battery without its own inverter. It therefore needs a suitable hybrid inverter. As standard, we combine it with the Fronius GEN24 Plus, which is on BYD’s compatibility list, and plan both as one coordinated system.

BYD Battery Storage HVS or HVM: the Real Sizes

Both series use the same LFP cell chemistry and the same modular design, but differ in module size, capacity and intended use:

Which Size Suits You?

The battery should roughly cover what you use from sunset to the next morning. With 5,000 kWh annual consumption and 8 kWp of PV, an HVS 7.7 or HVS 10.2 usually fits. With a 10 kWp system, the HVS 10.2 is the most common choice. With a heat pump or two electric cars, we tend to recommend an HVM 11.0 or HVM 13.8. A battery that is too large rarely fills up in winter, while one that is too small wastes potential in summer.

Your BYD Battery Storage from PVPro Solar: How We Build It

A Coordinated BYD and Fronius System

We don’t sell the BYD battery as a stand-alone part but plan it together with the Fronius GEN24 Plus and your PV system. That way, voltage range, output and backup function match, and you can see battery level, generation and consumption together in the app and the Fronius Solar.web portal.

An Example: Our System in Rethen

In Rethen near Laatzen, we installed a BYD HVS 10.2 with a Fronius GEN24 Plus and 10.2 kWp of JA Solar modules. The total investment for the system and battery was €21,400. You’ll find more projects in our references.

Our Own Installers and a Written Fixed Price

Our own certified installers fit the battery, and an electrician from our team connects it. You receive a written fixed price and pay according to the 30/70 model: 30% on order, 70% only after installation and commissioning.

How Much Does BYD Battery Storage with Fronius GEN24 Plus Cost?

Our guide price for the BYD HVS 10.2 together with a new PV system is about €7,700 to €9,200 extra, i.e. roughly €750 to €900 per kWh including installation. For the other sizes, that gives these guide prices:

The values for the other sizes are derived from the HVS 10.2 price per kWh. Smaller batteries usually cost a little more per kWh, larger ones a little less. A 10 kWp system with an HVS 10.2 costs about €22,200 to €26,700 in total with us. If you retrofit a battery to an existing system, different prices apply; see retrofitting a solar battery. You receive the exact fixed price in writing after the on-site visit. All sizes, with and without a retrofit, and how we work locally are on our page battery storage in Hannover.

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Technical Data of the BYD Battery-Box Premium

• Cell chemistry: lithium iron phosphate (LFP), cobalt-free, considered particularly safe and durable
• Protection class: IP55, so also suitable for a garage or utility room
• Operating temperature: about −10 to +50 °C; output may be limited in the cold
• Weight: about 38 kg per battery module; the location must carry the total weight
• Battery efficiency: at least 96% according to the data sheet; overall system efficiency also depends on the inverter
• Design: plug-in modules without internal wiring; each tower stands on a base unit with the battery control

Warranty: What BYD Actually Guarantees

BYD gives a 10-year warranty on the Battery-Box Premium HVS and HVM. The performance warranty guarantees that the battery retains 60% of its usable energy during this period or reaches a certain minimum energy throughput, whichever comes first. For the HVS 10.2, this throughput is about 25 MWh. If you use the battery very intensively, you may therefore reach the throughput before the 10 years are up.

The warranty is tied to the serial number. It is also important that the battery is registered and connected to the internet so that BYD can see the operating data. We set this up at commissioning. The full terms are in BYD’s official warranty document.

Can I Expand BYD Battery Storage Later?

Yes. Thanks to the modular design, HVS and HVM can be expanded with further modules of the same series, up to the limit per tower, and up to three towers can run in parallel. For modules bought later, the warranty runs from the date of their invoice. Only combinations approved by BYD are covered, so we check series, firmware and inverter before every expansion.

Backup Power: What a BYD Battery-Box Can’t Do on Its Own

A BYD tower on its own supplies no power during a power cut. Backup power only comes with a backup-capable inverter such as the Fronius GEN24 Plus:

• PV Point: a built-in backup socket for individual devices. According to Fronius, switching takes up to about 15 seconds.
• Full Backup: backup power for the whole house, which additionally needs a transfer switch for safe grid disconnection. Switching takes up to about 10 seconds. Full Backup isn’t available on the smallest GEN24 Plus power classes.

For the PV Point backup socket, we calculate about €300 to €800 extra, and about €1,200 to €1,800 including installation for Full Backup with a transfer switch. If the existing inverter is not backup-capable, a retrofit also needs an inverter replacement for about €1,500 to €3,000. We clarify which option suits your inverter before the quote. More under solar backup power systems.

Which Inverters Work with BYD?

BYD publishes a list of approved inverters. The Fronius GEN24 Plus is on it, as are devices from some other manufacturers. Inverters that only work with their own batteries are not compatible. Even with approved devices, limits apply, for example on the number of parallel towers and the minimum firmware. That’s why we combine BYD with the Fronius GEN24 Plus as standard and check the approval before every quote.

Is VAT Charged on BYD Battery Storage?

Supply and installation of a battery on or at a residential building are subject to the zero rate under § 12 (3) UStG, i.e. 0% VAT, even if you retrofit the battery to an existing PV system. In other cases, the full rate of 19% may apply.

Conclusion

With us, a BYD battery is not a stand-alone product but part of a fixed combination with the Fronius GEN24 Plus. The HVS suits most single-family homes, the HVM households with a heat pump, wallbox or small business. We calculate which size suits you during the on-site visit. Basics on batteries are under home battery storage, and a brand and test comparison under best battery storage.

Request your free, no-obligation quote now, or call us on +49 511 3360603 or message us on WhatsApp at +49 176 2399 8536.

As of October 2026.

Frequently Asked Questions About BYD Battery Storage