Big Battery | 3x Nexus + 1x EG4 1200XP
Big Battery | 3x NEXUS + 1x EG4 12000XP Power System
The BigBattery 3x NEXUS + EG4 12000XP Power System delivers massive energy storage and high-performance power for home, off-grid, and commercial applications. Featuring three 48V 14.3kWh NEXUS LiFePO4 batteries paired with a 12,000W EG4 hybrid inverter, this setup offers an impressive 42.9kWh of total capacity with 120V/240V split-phase output. Built for long-term reliability, it uses advanced CATL LFP cells rated for over 7,000 cycles, ensuring sustainable power, seamless backup, and long-lasting performance.
KEY FEATURES
- 42.9kWh total storage capacity with three NEXUS LiFePO4 batteries
- 12,000W split-phase hybrid inverter for 120V/240V operation
- Compatible with solar systems up to 15,000W total PV input
- High-efficiency 99% MPPT solar tracking
- Supports grid-tied, off-grid, or hybrid configurations
- Expandable up to 16 units in parallel operation
- 7,000+ cycle life and 20-year design lifespan
- Smart BMS with CAN/RS485 communication for real-time control
- Reliable, maintenance-free backup power solution for whole-home systems





Specifications
AC INPUT
| Nominal AC Voltage: | 120/240VAC | 120/208VAC (L1/L2/N required) |
| Frequency (Grid | Generator): | 60 Hz (Default) | 50 Hz (Configurable) |
| Max. Continuous AC Current (Grid | Generator): | 100A @ 240VAC | 62.5A @ 240VAC |
| Max. AC Input Power: | 24000W |
| AC Bypass (Grid | Generator): | 100A | 90A |
| Recommended Generator Capacity: | 6000W – 15000W |
AC OUTPUT
| Output Voltage: | 120/240VAC | 208VAC |
| Output Frequency: | 60 Hz (Default) | 50 Hz (Configurable) |
| Max. Continuous Output Current: | 50A @ 240VAC | 57.7A @ 208VAC |
| Nominal Output Power (without PV): | 12000W @ 240V | 12000W @ 208V |
| Nominal Output Power (with PV): | 12000W @ 240V | 12000W @ 208V |
| Max. Continuous Wattage: | 12000W (L1/L2) | 6000W (L1-N/L2-N) |
| Surge Capacity: | 18000W (5 sec) | 15000W (10 sec) |
| Power Factor: | 0.99 |
| Total Harmonic Distortion: | <3% |
| Switching Time: | <10 ms (Single) | <20 ms (Parallel) |
PV INPUT
| No. of MPPTs (Inputs per MPPT): | 2 (2) |
| Max. Input Current: | 35A / 35A |
| Max. Short Circuit Input Current: | 44A / 44A |
| DC Input Voltage Range: | 100 – 480VDC |
| Min. Start Up Voltage: | 100VDC |
| MPPT Operating Voltage Range: | 120 – 385VDC |
| Nominal MPPT Voltage: | 320VDC |
| Max. Utilized PV Power: | 24000W (12000W per MPPT) |
| Max. Recommended PV Input: | 28000W (14000W per MPPT) |
| Max. Efficiency: | 99% (MPPT) | 93.5% (PV to Loads) | 92.8% (PV to Battery) | 92.5% (AC to Battery) | 90.2% (Battery to Loads) |
| Idle Consumption (Standby Mode): | <70W |
BATTERY
| Nominal Voltage: | 48VDC |
| Battery Voltage Range: | 46.4 – 60VDC |
| Max. Charge / Discharge Current: | 250A |
| Max. Charge / Discharge Power: | 12000W |
| DC Cut-Off Voltage: | 59VDC |
| Recommended Battery Capacity per Inverter: | >400Ah |
OPERATING ENVIRONMENT
| Max. Parallel Connections: | 6 |
| Protection Rating: | IP20 |
| Communication Interface: | RS485 / CANBus / WiFi |
| Operating Temperature (Full Load): | 32ºF – 113ºF (0ºC – 45ºC) |
| Storage Temperature: | 5ºF – 140ºF (-15ºC – 60ºC) |
| Altitude: | <6,561 ft (2000 m) |
| Relative Humidity (Non-Condensing): | 5 – 95% |
| Typical Noise Emission: | <60 dB |
| Cooling Method: | Fan |
DIMENSIONS
| Weight: | 104.7 lbs (47.5 kg) |
| Depth: | 5.9 in (150 mm) |
| Width: | 20.9 in (530 mm) |
| Height: | 34.25 in (870 mm) |
Manual & Downloads
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Most orders ship within 1–3 business days. You’ll get a tracking number as soon as it ships via email!
Do We Accept Returns?
Yes absolutely, we have a no-hassle, 30-day return policy on all items! To refer to the full policy, click HERE
Are Products Brand New?
Yes! By default, all products on Solar Guys Pro are 100% brand-new and in perfect condition.
If an item is used or refurbished, it will clearly indicate so in the title of the product as well as the discription.
For example, a used Battery will say:
XYZ Battery | 48V 100AH (REFURBISHED)
If you'd like to confirm, you can always send us a email at info@solarguyspro.com
Orders over $500 include a FREE (Normally $149.99) 80-Page DIY Solar eBook — added automatically at checkout.
Frequently Asked Questions
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