BYD Battery-Box in the UK: HVS, HVM and compatibility

A BYD Battery-Box HVS or HVM is worth comparing if you want to choose the battery and the inverter separately. That freedom has limits. The battery family (HVS or HVM), its control unit and the inverter must appear together on BYD's approved list, with the number of modules that inverter accepts. A quote that just says "BYD battery, 10 kWh" leaves out the part that matters most: the exact combination your installer will commission.

BYD publishes its datasheets, approved-inverter lists and warranties by product generation in its download centre. The current HVS and HVM towers use a control unit called BCU 2.0, which has its own documents. UK distributors also list newer BYD ranges (HVS+, HVM+ and HVB, on a different control unit called BCU+), a low-voltage family, LVS, and a Battery-Box HVE sold with BYD's own Power-Box hybrid inverters. This page covers only HVS and HVM. If your quote names another range, ask for that range's datasheet, inverter list and warranty.

If you are still deciding whether a battery is worth it at all, start with our guide to solar battery storage.

HVS or HVM: two sizes of step

HVS and HVM are high-voltage lithium iron phosphate (LFP) batteries that connect on the DC side to a compatible inverter. A tower is a stack of modules from one family on a control unit. HVS starts at two modules and HVM at three. BYD's datasheets we checked (BCU 2.0 editions, March 2025) give these usable capacities:

BYD's inverter list allows up to three towers in parallel, but each tower must have the same number of modules, and an HVS tower cannot be combined with an HVM tower. Three HVS 12.8 towers give 38.4 kWh, the maximum on the HVS datasheet.

These figures are DC usable energy under BYD's test conditions (full discharge at 25 °C), not what reaches your sockets. BYD's datasheet says system usable energy "may vary with different inverter brands", and conversion losses and any backup reserve reduce it further. To compare quotes, ask for usable kWh, the inverter's kW rating and the installed price of each option.

Example (illustrative): Ofgem's typical household uses 2,500 kWh a year, about 6.8 kWh a day (2,500 ÷ 365). If around half of that is used between the end of the solar day and the next morning, that is about 3.4 kWh a night. The smallest HVS tower (5.12 kWh) already covers that with room for losses and a reserve; an HVS 10.2 adds 5.12 kWh that such a home would rarely use. The extra capacity earns its keep only if you have the surplus to fill it, or a heat pump, an electric car or a time-of-use tariff that shifts more of your use into the evening or overnight.

The approved-inverter list decides

BYD's HVS/HVM approved-inverter list (version 2.21, August 2025) names models from several makers, including Fronius (Primo and Symo GEN24 Plus), SMA (Sunny Boy Storage and Sunny Boy Smart Energy), Sungrow (SH-RS single-phase and SH-RT three-phase), GoodWe, Kostal and three-phase Solis hybrids. For each model it gives the module counts allowed and the minimum firmware for the inverter and the battery. A brand on the list doesn't mean every model from that brand works with every tower: Fronius's single-phase Primo GEN24 Plus, for example, accepts two or three HVS modules, while the three-phase Symo GEN24 Plus accepts two to five.

Several single-phase hybrids that are common on UK quotes, including Sunsynk, Fox ESS and Growatt, were not on the HVS/HVM list we checked. BYD's low-voltage LVS family has a separate list for 48 V inverters; Solis, for example, includes BYD LVS models in its own battery list for the Solis L-PLUS hybrid.

This matters for the warranty as well as for the wiring. BYD's European warranty excludes faults when the battery runs with an inverter that is not on its approved list. Ask your installer to mark your inverter's row and your tower size on the current list and keep a copy with your handover documents. They should also check the firmware on both the inverter and the battery. The same check applies if you add modules years later: new modules on an older control unit are not automatically an approved combination.

The battery doesn't track your panels, decide when to charge or convert power for your home: the inverter and its meter do. At handover, check that the app shows solar generation, home use, export and battery charge correctly on your own login.

Adding a Battery-Box to existing panels

HVS and HVM connect on the DC side, so they need a hybrid or battery inverter from BYD's list. If your current inverter handles only the panels, you have two routes:

• replace it with an approved hybrid inverter, which runs both panels and battery; or
• keep it and add an approved battery inverter alongside, such as one of SMA's Sunny Boy Storage models, which charges the battery from the AC side.

Keeping the old inverter changes the grid paperwork. In Great Britain, on a single-phase supply, the G98 connect-and-notify route covers up to 3.68 kW of inverter output in total. MCS's installation standard counts every inverter at the property towards that limit, so an existing 3.68 kW solar inverter plus a new battery inverter means your installer must apply under G99 and get the network operator's approval before connecting. Replacing the old inverter with a single hybrid rated at 3.68 kW or less can stay under G98.

Ask for both routes priced with the same assumptions. The age and remaining warranty of your existing inverter matter as much as the capacity of the new battery.

Backup depends on the inverter

In a power cut, a grid-connected solar system must disconnect from the grid. The Battery-Box doesn't supply your home by itself: backup depends on the inverter, the changeover switch and how your consumer unit is split. BYD's datasheet lists on-grid with backup as an application, but only if the inverter and installation support it.

Ask your installer which circuits stay on (lights, fridge, router), the inverter's continuous and peak backup power, the reserve setting, whether the panels can recharge the battery during the cut, and to test the changeover at handover. An electric shower or car charger changes the power needed completely.

The warranty in detail

BYD's European warranty for HVS and HVM (English, version 1.2) is issued by BYD Smart Device Hungary Kft. and covers towers installed in Europe from 1 December 2021. BYD's download centre also lists it under BCU 2.0; the document we downloaded under that label had the same text. Ask your installer to confirm in writing which edition applies to your system.

• Product warranty: 10 years against defects.
• Performance warranty: the tower keeps 60% of its usable energy for 10 years, or until it has delivered a minimum amount of energy in total, whichever comes first. For an HVS 10.2 that throughput is 30.82 MWh, about 3,000 full charges (30,820 kWh ÷ 10.24 kWh), or roughly 0.8 full cycles a day over 10 years. A battery that charges from solar by day and again from a cheap overnight rate can reach the limit before 10 years are up.
• Start date: six months after the production date, or 30 days after delivery if you can prove the delivery date. Keep the delivery note.
• Conditions: tell BYD's service partner within 30 days of noticing a fault; install within a month of the warranty start date; use an approved inverter; don't leave the battery out of use for six months or more; and give BYD access to the battery's performance data online when you make a claim.
• Costs: BYD repairs, replaces or partly refunds. It may charge for the inspection if it finds no fault or the warranty doesn't apply. The text doesn't say who pays for your installer's time to remove and refit a tower, so ask your installer before you sign.

UK support and checking a quote

BYD's European service partner is EFT-Systems GmbH, which lists a UK phone line (+44 20 3769 5998) and service@eft-systems.de. The warranty expects claims to go to that partner, with your installation date, invoice number, tower configuration, serial numbers and inverter details. In practice your installer gathers these, so keep the commissioning report.

There is no single installed price for a Battery-Box: the tower, the inverter, backup wiring and labour all change the total. Our solar battery cost guide covers typical UK prices. A quote you can compare should list:

• the BYD family, tower size and control unit (for example HVS 7.7 on BCU 2.0);
• the inverter model, its kW rating and its row on BYD's approved list;
• total usable kWh and the backup circuits, or a statement that there is no backup;
• the G98 notification or G99 application;
• where the tower goes, and whether that spot meets PAS 63100:2024, the BSI fire-safety specification for home batteries.

The ENA type-test register lists inverters, not DC battery packs, so check the inverter's listing rather than the battery's. Bought as part of an installation in your home, the battery carries 0% VAT up to 31 March 2027; unless that relief is extended, 5% applies from 1 April 2027. Supply-only, without fitting, it is standard-rated at 20%.

A BYD system has two manufacturers behind it, and a fault can sit in the battery, the inverter or the communication between them. Your legal rights don't depend on sorting that out: under the Consumer Rights Act 2015 the goods must be of satisfactory quality and installed with reasonable care and skill, and that claim is against the installer who sold you the system. Ask the installer to agree in writing that they will handle diagnosis between BYD and the inverter maker. Since MCS dropped its consumer-code requirement, check the RECC or HIES register as well if deposit protection and a workmanship guarantee matter to you. Our guides to comparing solar quotes and choosing an installer cover the rest.

Our view: BYD is a good choice when the freedom to pick the inverter is worth something to you and the exact combination is on BYD's list. An all-in-one system from one maker can be simpler to own if it suits your home equally well. Our best solar batteries guide compares the options.

BYD Battery-Box FAQs

Can I mix HVS and HVM modules?

No. They are separate families. BYD's list doesn't allow an HVS tower in parallel with an HVM tower either, and parallel towers must have the same number of modules.

Will a BYD battery work with my GivEnergy or Sunsynk inverter?

Not the HVS or HVM with a single-phase GivEnergy or Sunsynk hybrid: neither brand was on BYD's HVS/HVM list when we checked. Some low-voltage BYD models appear on other inverter makers' lists, so ask your installer for the written approval for your exact inverter.

Does the 10-year warranty mean the same capacity every year?

No. BYD guarantees at least 60% of usable energy for 10 years or until a set amount of energy has passed through the battery, whichever comes first. Capacity falls gradually with use.

Is BYD's warranty valid in the UK?

BYD's European warranty covers towers bought and installed in Europe, and its European service partner lists a UK phone line. Ask your installer to confirm in writing which warranty document applies to your system.