48V LiFePO₄ Battery · 4-Module Bank · 12-Year Warranty
This configuration is four BigBattery ETHOS modules (5.12kWh each) stacked on a single shared control box — 20.48kWh of total storage from a system built to scale from a starter bank up to 80+kWh without changing platforms. It's the longest-warrantied battery in BigBattery's lineup at 12 years, sealed to an IP65/NEMA 4X rating for indoor or outdoor installation.


Four 5.12kWh LiFePO₄ modules on one shared control box, built to scale from a small starter bank up to 80+kWh on the same platform.
Up to 16 modules can connect to a single control box, so capacity can grow later without replacing what's already installed.
The control box delivers up to 200A (10,240W) continuously regardless of module count — more modules mean more runtime, not more peak power.
Sealed for both indoor and direct outdoor installation, with two overlapping weatherproofing standards rather than just one.
Rated for years of daily charge and discharge cycles before capacity meaningfully declines.
The ETHOS controller manages the bank's performance automatically, coordinating every module behind it.
Modules connect together without custom wiring runs between them, simplifying both first install and later expansion.
The longest manufacturer's warranty across BigBattery's lineup, on top of UL 9540, UL9540A, UL1973, and UN38.3 certification.
ETHOS is built differently from a lot of home batteries: instead of each unit being a fully self-contained battery, individual 5.12kWh modules stack onto one shared control box, which is what actually connects to the inverter and handles charge/discharge current. This configuration — four modules — banks 20.48kWh of storage, but the control box still caps continuous output at 200A (10,240W), the same as it would with two modules or sixteen. Adding modules buys runtime and reserve capacity, not a higher power ceiling.
That tradeoff is the point for a lot of installs: a bank sized for multi-day autonomy or a large home's overnight draw, without needing the power electronics to scale alongside it. An IP65/NEMA 4X rating covers both indoor and outdoor placement, and the 12-year warranty is the longest of anything in BigBattery's own catalog — this isn't a value-tier battery, it's the one they stand behind longest.
| System voltage | 48 V |
| Nominal voltage | 51.2 V |
| Chemistry | LiFePO₄ |
| Cell configuration | 16S |
| Capacity per module | 5.12 kWh |
| This configuration (×4) | 20.48 kWh |
| Charging voltage range | 55.6–57 V |
| Max charge voltage | 57 V |
| Operating voltage range | 48–57 V |
| Low voltage cutoff | 48–50.8 V |
| BMS cutoff range | 42–47 V |
| Max charge current | 200 A |
| Max continuous discharge current | 200 A |
| Max continuous power | 10,240 W |
| Max peak discharge current | 300A (5 sec max) |
| Charge temp range | 32–113°F |
| Discharge temp range | -4–140°F |
| Optimal discharge temp | 59–95°F |
| Storage temp (SoC >50%) | -4–113°F (6 mo. max) |
| Protection rating | IP65 / NEMA 4X |
| Weight | 273 lbs |
| Dimensions (D×W×H) | 6.7 × 26.5 × 43.3 in |
| Communications | CANBus, RS485 |
| Max connections | Up to 16 per control box |
| GTIN-12 (base unit) | 850061252005 |
| Cycle life | 6,000+ |
| Warranty | 12 years |
Power figures above are per control box, fixed regardless of module count. Physical dimensions are BigBattery's stated figures for their base unit; a 6-module order's total footprint and shipping weight are worth confirming directly. Certifications: UL9540, UL9540A, UL1973, UN38.3.
This battery needs a compatible inverter to function — which inverters qualify depends on whether the install is grid-tied (requiring UL 9540 certification) or fully off-grid. Note this list is narrower than some other BigBattery batteries for grid-tied installs specifically — EG4 12kPV is not UL 9540-certified with ETHOS the way it is with some other packs.
UL 9540 certified + closed-loop comms
Closed-loop comms, non-UL 9540

Each ETHOS module holds 5.12kWh. Four modules on one control box total 20.48kWh of usable storage — enough for a full-size home to draw on through an evening or an extended cloudy stretch.
No — that's a common assumption worth correcting. The control box that every module connects to is rated for 200A (10,240W) continuous output regardless of how many modules are behind it, up to 16 per box. More modules mean more stored energy and longer runtime, not a higher instantaneous power ceiling.
Yes — it carries both an IP65 and a NEMA 4X rating, covering indoor and direct outdoor installation.
Grid-tied installations that need UL 9540 energy storage system certification are limited to EG4's 18kPV, FlexBOSS18, and FlexBOSS21 inverters. Fully off-grid installs (not pursuing UL 9540 certification) have a wider range: any BigBattery APEX inverter or EG4 inverter.
It's rated for 6,000+ charge cycles and backed by a 12-year manufacturer's warranty — the longest warranty across BigBattery's own battery lineup.
Yes — up to 16 modules can run on a single control box, so a 4-module bank has plenty of room to grow toward BigBattery's stated 80+kWh ceiling without switching platforms.
Given the voltages and currents involved, installation should be handled by a qualified, licensed electrician or solar installer familiar with your local code requirements.
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