Growatt ARK and HOPE batteries: models and specifications

Growatt sells two home battery families in the UK. The ARK 2.5H series is a modular high-voltage battery built as stacks of 2.56 kWh modules: you start with 3 modules and can expand the system up to 25.6 kWh without replacing any accessories, and it is designed for three-phase SPH hybrid inverters¹. The HOPE range is low-voltage, 51.2 V lithium iron phosphate (LiFePO4) storage in packs of roughly 5 kWh and 16 kWh, designed to work with Growatt WIT-HU hybrid inverters and SPF off-grid inverters².

What the batteries do for a household is what any home battery does: as Solar Energy UK puts it, "with a battery, any excess power produced during the day can be stored. This electricity can then be used at another time"³. The dependence that remains is real: an ARK or HOPE battery only stores energy, it does not generate it, and it only works as part of a Growatt inverter system, so the household stays tied to the grid, a supplier and one manufacturer's ecosystem of inverters, controllers and apps.

Growatt battery storage systems: an overview of ARK and HOPE

Growatt's domestic storage splits cleanly by voltage class. The ARK 2.5H series is the high-voltage (HV) family: modular stacks for three-phase SPH hybrid inverters, expandable from 3 modules up to 25.6 kWh without replacing accessories¹. The HOPE family is low-voltage (LV): the 5.0L series consists of compact LV rack modules for residential off-grid systems and single-phase hybrid inverters, easy to expand in parallel⁷, while the larger 16.0LM-A1 is a residential LV battery in its own right⁸.

Both families use LiFePO4 cell chemistry⁵. The practical difference for a householder is which inverter the battery attaches to: ARK stacks pair with Growatt's three-phase hybrid inverters, HOPE packs with WIT-HU hybrids and SPF off-grid inverters². A battery of the wrong voltage class will not work⁴, so the inverter choice settles the battery choice before capacity is even discussed. Growatt also makes an AXE rack series and an APX battery, covered separately on our Growatt home batteries page, and the modular stacking approach is explained in modular and stackable home batteries.

ARK 2.5H: modular stacks from 7.68 to 25.6 kWh

The ARK 2.5H-A2 module is the building block: 2.56 kWh per module, with 3 to 10 modules in series forming a 7.68 to 25.6 kWh system⁴. Growatt sells ready-made sets at several points in that range, each a fixed number of modules on a shared base.

The usable figures follow from a 90% depth of discharge, which Growatt applies across the sets⁵. A 15 kWh set is also listed, at about 13.8 kWh usable¹², though the set's nominal capacity appears as both 15 kWh and 15.36 kWh (6 × 2.56 kWh) on different pages, and its weight appears as both 27 kg per module and 205.90 kg for the set, so treat that listing with care and confirm the configuration with the installer.

The expansion promise is the range's main draw for a household planning ahead: the same base, controller and cabling carry the stack from 3 modules to 10, so capacity can grow with the household's needs rather than being fixed on installation day¹. That said, the stack still depends on one manufacturer's modules: adding capacity later means buying more ARK 2.5H-A2 units, not any third-party pack.

HOPE 5.0L-B1: 5, 10 and 15 kWh low-voltage options

The HOPE 5.0L-B1 is a low-voltage (LV, 51.2 V) LiFePO4 energy storage battery with around 5 kWh of capacity⁷, listed elsewhere as 5.1 kWh⁷.

Expansion is by parallel connection rather than series stacking: up to 48 packs in parallel, so capacity grows with the needs of the installation¹³. Weights rise accordingly: 98.90 kg for the 10 kWh set¹³, 148.40 kg for the 15 kWh set², with the 5 kWh set listed at a shipping weight of 66.50 kg¹⁴. The individual pack's weight appears as both 43 ± 2 kg and 46.25 kg on different pages.

These packs are aimed at residential off-grid systems and single-phase hybrid inverters⁷, which makes them the natural partner for smaller homes, retrofit single-phase installations and off-grid cabins. The chemistry is LiFePO4 throughout¹³, the same chemistry used across the ARK range and discussed in home battery chemistries.

HOPE 16.0LM-A1: 15.3 kWh usable from a 16 kWh pack

The HOPE 16.0LM-A1 is a residential LV battery offering 16 kWh of capacity, of which 15.3 kWh is usable⁸. Growatt lists it as a low-voltage LiFePO4 battery with a 10 year warranty⁸, and on its main product page as a residential LV battery covering a 16 to 768 kWh capacity range¹⁵.

Its expansion route is parallel connection: a maximum of 48 packs in parallel, taking 16 kWh up to 768 kWh total⁸, which Growatt describes as easy power output expansion¹⁵. Cycle life is stated as 6000 cycles⁸. For most homes a single pack is the realistic starting point; the 768 kWh ceiling is a multi-pack installation well beyond domestic scale.

Comparing key specs: storage size, depth of discharge, cycles and protection

The headline numbers across both ranges sit close together, but the detail differs by model.

The 90% depth of discharge on the ARK sets means roughly nine tenths of the nominal figure is available to the household⁵, a point explained in battery capacity and usable capacity. Cycle life of 6000+ cycles is a maker's figure, and what a cycle means for degradation is covered in home battery cycle life. The IP65 rating on the ARK sets indicates dust-tight construction with protection against water jets⁵, which widens siting options, though battery siting and location sets out the practical constraints. Charge temperature is listed at -10 to 50 °C across the ARK sets⁵, the operating condition most likely to bite in an unheated outbuilding in winter.

Matching batteries to inverters: the importance of voltage class

Voltage class is the hard rule: the battery must match the inverter's voltage class, otherwise the system will not work¹. Within that rule, each battery family has its partners.

• ARK 2.5H-A2 (HV): three-phase SPH hybrid inverters, including the SPH 7000 TL3 BH-UP¹⁷, the MIN 2500-XH2¹⁸ and three-phase MID TL3-XH inverters¹⁹.
• HOPE 5.0L-B1 and 16.0LM-A1 (LV): WIT-HU hybrid inverters, which list AXE 5.0L-C1, HOPE 14.3L-A1 and HOPE 16LM-A1 as compatible batteries²⁰, and SPF off-grid inverters including the SPF 6000ES, which lists AXE 5.0L-C1, ARK 2.5L-A2, HOPE 5.0L-B1 and HOPE 14.3L-A1²³.

The WIT-HU inverters state their battery class as low-voltage²¹, which is why the HOPE packs and not the ARK stacks attach to them. One flexibility worth noting: on the MOD 8000TL3-HU hybrid inverter, Growatt states the high-voltage battery can be added at any point without replacing the inverter²⁴, so some households can fit the inverter first and the storage later. The distinction between coupling arrangements is explained in AC and DC coupled battery systems.

Living with a Growatt battery: backup supply and app monitoring

Combined with a hybrid inverter, the energy storage battery keeps selected circuits running during a grid outage through the inverter's backup or EPS function⁵. That is selected circuits, not the whole house by default: what stays on depends on which circuits the installer wires to the backup output, a point covered in battery backup power and EPS. The WIT 25K-HU inverter includes a built-in EPS backup module²². How long the backup lasts depends on usable capacity: about 23 kWh from a full 25.6 kWh ARK set⁶, or 15.3 kWh from a HOPE 16.0LM-A1⁸.

Monitoring runs through the connected inverter: the ShinePhone app and the ShineServer portal show the state of charge (SOC), the charge and discharge power and the operating history, with fault notifications¹⁰. On the ARK 25.6 kWh set, battery management relies on the HVC 60050-C2 controller, with an integrated BMS monitoring cell voltages, temperature and cell balance⁶. Beyond the app, MCS notes that most battery storage systems monitor battery health and will alert you when a replacement is needed²⁵. The dependence here is on the manufacturer's servers and app for remote visibility, though the battery and inverter continue to operate locally without them.

What you need to know about fitting and warranty cover

The ARK sets carry a European service warranty of 10 years, per the manufacturer's terms⁵. The HOPE 5.0L-B1 based sets are covered for 5 or 10 years depending on the variant², so the exact term depends on which pack is supplied, and the HOPE 16.0LM-A1 is listed with a 10 year warranty⁸. The ARK-2.5H-A1 battery base, the mounting component that seats the modules, carries only a 1 year European service warranty²⁷.

What the warranty covers, and how retained-capacity and throughput conditions work across the market, is set out in home battery warranties. There is no published UK price for ARK or HOPE sets; prices are installer-quoted, and the factors that move a quote are covered in home battery cost. For a household weighing independence, the honest summary is that these batteries shift dependence rather than remove it: off the daytime grid and towards stored self-consumption, but onto Growatt's inverters, modules, controller and app for the life of the system.