Product Summary:

The BigBattery NEXUS™ + EG4 12000XP ESS System is a powerful, scalable energy solution designed for both on-grid and off-grid applications. Combining high-capacity 15kWh NEXUS LiFePO₄ battery modules with the advanced EG4 12000XP hybrid inverter, this system delivers reliable, efficient energy for whole-home and commercial backup.

 

The EG4 12000XP provides up to 12,000W split-phase output per inverter with up to 24,000W PV input, enabling high solar production and seamless power management between solar, battery, and grid. With dual MPPTs, built-in breakers, and fast UPS switching (15–30ms), the system ensures uninterrupted power and optimized performance.

 

Expandable from 15kWh up to 225kWh and scalable up to 36kW output, the NEXUS battery system grows with your energy needs while delivering long-lasting, maintenance-free storage. Built with advanced battery protection, safe lithium technology, and U.S.-supported engineering, this system is ideal for residential, commercial, and off-grid energy independence.

Ships From: Texas, USA
Warranty: 12 Years (Battery), 5 Years (Inverter)
Support: Lifetime USA-Based Tech Support

 

Compatibility

Integrated & Optimized System:

  • EG4 12000XP Hybrid Inverter + NEXUS 15kWh Battery Modules

Expandable Design:

  • Scale battery storage from 15kWh up to 225kWh
  • Supports multiple inverters up to 36kW system output
  • Compatible with grid-tied, hybrid, and off-grid installations
Key Features
  • Complete ESS Solution – Battery + inverter system designed to work seamlessly together
  • 12,000W Output per Inverter – Reliable split-phase power for residential and commercial systems
  • 24,000W PV Input – High solar capacity with dual MPPT optimization
  • 15kWh LiFePO₄ Battery Modules – Safe, high-capacity energy storage with long lifespan
  • 6,000+ Cycle Life – Built for years of daily use and long-term savings
  • UPS Backup (15–30ms) – Seamless transition during outages
  • Smart Energy Management – Supports load control, AC coupling, and peak shaving
  • Built-In Breakers & Safety Protections – Simplifies installation and enhances system safety
  • Modular Expansion – Easily scale storage and output as energy needs grow
  • Remote Monitoring & Control – Real-time system tracking and performance insights
  • Maintenance-Free Operation – No routine servicing required

A high-capacity, scalable energy storage system built for performance, flexibility, and long-term energy independence – ideal for powering homes and businesses with confidence.

Introducing the Nexus

Sleek & Compact Design

Our stackable, compact design comes with all the hardware you need for a straightforward setup, letting you get your off-grid system up and running efficiently in less time. Engineered for reliability in any off-grid environment, it delivers consistent power when you need it most.

Off-Grid Energy Reliability

With 300Ah of capacity, 100A continuous discharge, and peak support up to 110A, NEXUS handles high-demand loads with ease. NEXUS’s smart thermal management enables charging from 32 °F to 113 °F and discharging down to -4 °F, making it a true all-weather energy solution.

Modular ESS That Grows With You

NEXUS supports parallel expansion up to 15 units, offering 225kWh total capacity per inverter. With RS485, CAN, and RJ45 communication ports, it’s ready to integrate seamlessly into new or existing inverter systems—ensuring full system transparency, automation, and control.

Legacy Product Parallel Compatibility

The NEXUS is compatible and parallel-able with all existing KONG and GRIZ products purchased between 2019-2024.


 

Battery Downloads

SKU#:K0154, K0155, K0156, K0160, K0161, K0162, K0163
Spec Sheet:DownloadDOWNLOAD
User Manual:DownloadDOWNLOAD

Battery Specifications

Battery Specifications:NEXUS 15KWh
System Voltage:48V
Nominal Voltage:51.2V
Chemistry:LiFePO4
Usable Energy (kWh):15kWh
Ah Capacity:300Ah
Cell Configuration:16S1P
Max Continuous Discharge:140A
Max Discharge Power:7.6kW
Max Discharge Peak Current:270A(1s)
Max Charge Current:140A
Charging Voltage Range:53.5V-57.6V
Operating Voltage Range:48V-57.6V
Max Charge Voltage:57.9V
Suggested Low Voltage Cutoff50.8V
Charge Temp Range:32°F to 113°F
Discharge Temp Range:-4°F to 113°F
Optimal Discharge Temp:59°F to 95°F
Storage Temp Range (SoC >50%):(1 month:-4°F ~ 113°F | 3 months: -4°F ~ 95°F | 6 months: -4°F ~ 77°F)
Humidity Range:10%-95% (No Condensation)
Weight (lbs):~315 lbs
Dimensions (WxHxD):19.7 x 27.5 x 15.7 in (500×700×400 mm)
Altitude Limit:<2000m
Max Connections:15 in parallel (up to 225kWh)
Communications:RS485 / RJ45 / CAN
Protection Rating:IP21
Installation:Indoor Floor-standing

Inverter Downloads

SKU:K0154, K0155, K0156, K0160, K0161, K0162, K0163
Spec Sheet:DownloadDOWNLOAD
User Manual:DownloadDOWNLOAD
UL1741 Certificate:DownloadDOWNLOAD
UL9540 Certificate:DownloadDOWNLOAD
WiFi Configuration Guide:DownloadDOWNLOAD
CEC Listing – EG4 12000XP:Go to linkGO TO LINK

Inverter Specifications

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
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)
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)
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
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
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:5 – 95% (Non-Condensing)
Typical Noise Emission:<60 dB
Cooling Method:Fan
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)

BigBattery batteries are backed by a 12-year warranty, giving you reliable long-term performance and confidence in every charge. Designed for durability and engineered to last, our batteries are built to power your setup for over a decade. For more information, please visit our policy page

Introducing the Nexus

Sleek & Compact Design

Our stackable, compact design comes with all the hardware you need for a straightforward setup, letting you get your off-grid system up and running efficiently in less time. Engineered for reliability in any off-grid environment, it delivers consistent power when you need it most.

Off-Grid Energy Reliability

With 300Ah of capacity, 100A continuous discharge, and peak support up to 110A, NEXUS handles high-demand loads with ease. NEXUS’s smart thermal management enables charging from 32 °F to 113 °F and discharging down to -4 °F, making it a true all-weather energy solution.

Modular ESS That Grows With You

NEXUS supports parallel expansion up to 15 units, offering 225kWh total capacity per inverter. With RS485, CAN, and RJ45 communication ports, it’s ready to integrate seamlessly into new or existing inverter systems—ensuring full system transparency, automation, and control.

Legacy Product Parallel Compatibility

The NEXUS is compatible and parallel-able with all existing KONG and GRIZ products purchased between 2019-2024.


 

Battery Downloads

SKU#:K0154, K0155, K0156, K0160, K0161, K0162, K0163
Spec Sheet:DownloadDOWNLOAD
User Manual:DownloadDOWNLOAD

Battery Specifications

Battery Specifications:NEXUS 15KWh
System Voltage:48V
Nominal Voltage:51.2V
Chemistry:LiFePO4
Usable Energy (kWh):15kWh
Ah Capacity:300Ah
Cell Configuration:16S1P
Max Continuous Discharge:140A
Max Discharge Power:7.6kW
Max Discharge Peak Current:270A(1s)
Max Charge Current:140A
Charging Voltage Range:53.5V-57.6V
Operating Voltage Range:48V-57.6V
Max Charge Voltage:57.9V
Suggested Low Voltage Cutoff50.8V
Charge Temp Range:32°F to 113°F
Discharge Temp Range:-4°F to 113°F
Optimal Discharge Temp:59°F to 95°F
Storage Temp Range (SoC >50%):(1 month:-4°F ~ 113°F | 3 months: -4°F ~ 95°F | 6 months: -4°F ~ 77°F)
Humidity Range:10%-95% (No Condensation)
Weight (lbs):~315 lbs
Dimensions (WxHxD):19.7 x 27.5 x 15.7 in (500×700×400 mm)
Altitude Limit:<2000m
Max Connections:15 in parallel (up to 225kWh)
Communications:RS485 / RJ45 / CAN
Protection Rating:IP21
Installation:Indoor Floor-standing

Inverter Downloads

SKU:K0154, K0155, K0156, K0160, K0161, K0162, K0163
Spec Sheet:DownloadDOWNLOAD
User Manual:DownloadDOWNLOAD
UL1741 Certificate:DownloadDOWNLOAD
UL9540 Certificate:DownloadDOWNLOAD
WiFi Configuration Guide:DownloadDOWNLOAD
CEC Listing – EG4 12000XP:Go to linkGO TO LINK

Inverter Specifications

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
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)
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)
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
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
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:5 – 95% (Non-Condensing)
Typical Noise Emission:<60 dB
Cooling Method:Fan
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)

BigBattery batteries are backed by a 12-year warranty, giving you reliable long-term performance and confidence in every charge. Designed for durability and engineered to last, our batteries are built to power your setup for over a decade. For more information, please visit our policy page

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