Best for
Couldn't load pickup availability
Energy Storage System · 36kW · 61.44kWh · 54kW PV
A UL 9540 certified whole-home energy storage system: 12 stackable ETHOS 48V LiFePO4 modules (61.44kWh, 4 modules + 4 modules + 4 modules) matched with 3 EG4 18kPV hybrid inverters for 36kW of continuous three-phase 120/208V capable output and up to 54kW of solar input.
The K0967 configuration of the BigBattery ETHOS + EG4 18kPV ESS combines 12 ETHOS 5.12kWh battery modules with 3 EG4 18kPV hybrid inverters. ETHOS modules stack on a rack base with a control box on top - no wall mounting, no rack cabinet - so 61.44kWh of storage installs in a footprint of 26.5 x 6.7 inches per stack. Every stack is IP65 / NEMA 4X rated and the batteries are UL1973, UL9540A and UN38.3 certified; together with the 18kPV the system is UL 9540 listed, which is what most utilities and inspectors now require for permitted home storage.
Each EG4 18kPV supplies 12,000W of continuous 120/240V split-phase power (15,500W surge with PV), accepts 18kW of solar on three MPPTs, and passes through 200A of grid power. It works on-grid with export or zero-export, off-grid, or as backup, and talks to the ETHOS control box in closed loop so charging current, state of charge and protection are coordinated automatically. With 3 inverters in parallel the system delivers 36kW continuous and up to 54kW of PV input and can be configured for 120/208V three-phase output.
61.44kWh is roughly 2.8 days of typical household consumption (22kWh/day) without sun, and the ETHOS platform scales past 80kWh by adding modules to each control box (up to 16 per box). BigBattery ships from Texas with a 12-year battery warranty, a 10-year inverter warranty and lifetime US-based technical support. Solar panels and racking are not included - pair the system with any 100-600Vdc PV array up to 54kW.
Browse all BigBattery backup systems, BigBattery lithium batteries and EG4 inverters.
ETHOS battery and EG4 18kPV are certified together as a complete energy storage system, with UL9540A fire-safety testing, UL1973 and UN38.3 on the battery.
12 modules of 5.12kWh / 100Ah each, 6,000+ cycles, 16S cells and a smart BMS in every module; expand to 80+ kWh by adding modules.
EG4 18kPV: 12kW per unit, three MPPTs, 100-600Vdc input, 200A pass-through, generator input, RSD support and Wi-Fi monitoring.
CANBus link between control box and inverter for coordinated charging, accurate state of charge and protection.
Battery stacks and inverter are weather rated for garages, covered patios and utility areas.
Stack, connect the included cables, and go - no routine servicing, 12-year battery and 10-year inverter warranties.
Estimates assume 85% usable energy and typical load ratings; actual runtime depends on your appliances, weather and settings.
About 2.8 days for a typical 22kWh/day home with no solar input; with solar panels connected to the 18kPV (up to 54kW) the batteries recharge daily.
No. This is a battery + inverter ESS. Connect any PV array within the inverter limits (100-600Vdc, 18kW per inverter), or run it as grid-charged backup without solar.
Both. The EG4 18kPV is UL1741 certified for grid interaction (export or zero-export) and also runs fully off-grid; it has a generator input as well.
Yes. Each ETHOS control box supports up to 16 modules, and BigBattery sells single ETHOS modules, so the system can grow past 80kWh.
Yes - free freight shipping within the contiguous USA, $0 sales tax in most states, and the ECO100 code takes another $100 off at checkout.
BigBattery ETHOS 48V 5.12kWh Stackable Battery Module (per module)
| Battery | |
| System voltage | 48V (51.2V nominal) |
| Chemistry | LiFePO4 |
| Capacity per module | 5.12kWh / 100Ah |
| Cell configuration | 16S per module |
| Charging voltage range | 55.6-57V |
| Max charge voltage | 57V |
| Operating voltage range | 48-57V |
| Suggested low-voltage cutoff | 48-50.8V |
| BMS cutoff range | 42-47V |
| Max continuous discharge current | 100A per module (200A per control box) |
| Max discharge peak current | 300A (max 5 seconds) |
| Max charge current | 200A per control box |
| Cycle life | 6,000+ cycles |
| General | |
| Charge temperature | 32-113°F (0-45°C) |
| Discharge temperature | -4-140°F (-20-60°C) |
| Optimal discharge temperature | 59-95°F (15-35°C) |
| Storage (SoC >50%) | -4-113°F, max 6 months |
| Module footprint | 26.5 in W x 6.7 in D (674 x 170 mm) |
| Max connections | Up to 16 modules per control box |
| Protection rating | IP65 / NEMA 4X |
| Communications | CANBus / RS485 (closed-loop with EG4 18kPV) |
| Certifications | UL9540, UL9540A, UL1973, UN38.3 |
| Warranty | 12 years |
EG4 18kPV All-in-One Hybrid Inverter (per inverter)
| AC Output | |
| Output power | 12,000W continuous |
| Output voltage | 120/240Vac split-phase |
| Max continuous output current | 50A |
| Max continuous line wattage | 8,000W per 120V leg |
| Surge with PV | 14,700W (10 min) / 15,500W (5 min) |
| Surge without PV | 13,500W (10 min) |
| Power factor | 0.99 (full load) |
| THD | <5% (full load) |
| Transfer time | 10-20ms (single) / 20ms (parallel) |
| Max parallel | 10 units |
| AC Input | |
| Grid input | 120/240Vac, 50/60Hz, 180-270Vac |
| Max AC input power | 12,000W |
| Max AC bypass | 200A (grid) / 90A (generator) |
| PV Input | |
| MPPT trackers | 3 (2 inputs on MPPT 1, 1 each on MPPT 2 and 3) |
| Max PV array power | 18,000W |
| Max input current | 25A (MPPT 1) / 15A (MPPT 2 and 3) |
| DC input voltage range | 100-600Vdc |
| Start-up voltage | 100Vdc |
| MPPT operating range | 140-500Vdc |
| Max efficiency | 94-99.9% |
| Battery and General | |
| Battery voltage | 48Vdc nominal, 40-60Vdc |
| Max charge / discharge current | 250A |
| Idle consumption | ~70W normal / ~18W standby |
| Operating temperature | -13 to 140°F (-25 to 60°C) |
| Altitude | <6,561 ft (2,000 m) |
| Noise | 68dB at 3 ft |
| Protection rating | IP65 / NEMA 4X |
| Communications | RS485 / CANBus / Wi-Fi |
| Dimensions | 20.5 x 11.2 x 34.3 in (520 x 285 x 871 mm) |
| Weight | 121 lb (55 kg) |
| Warranty | 10 years |
Free shipping on all orders within the mainland US (Hawaii, Alaska and overseas territories excluded - a freight forwarder is required). Orders ship directly from our brand partners' warehouses across the U.S. Order confirmation is emailed immediately; if an item is unexpectedly backordered we notify you before your card is charged. In-stock items are processed within 1-4 business days (cut-off 4:00 PM EST), transit is 3-6 business days, and tracking is emailed within 24 hours of shipment. Typical delivery is 4-10 business days from purchase. Minimum order value is $69.
You have 30 days from the delivery date to initiate a return (35 days for orders placed Nov 25-30 and Dec 25-31). Items must be unused, in original packaging with tags attached, and returns require prior authorization from our team.
To start a return: +1 (307) 317-7213, hello@ecosolarkits.com, or live chat. Read the full return and refund policy
