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BigBattery NEXUS 51.2V 15kWH LiFePO4 Battery + APEX 10K Off - Grid Inverter - Off Grid Stores
by BigBattery

BigBattery NEXUS 51.2V 15kWH LiFePO4 Battery + APEX 10K Off-Grid Inverter

SKU: K0196
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Bundle Options: NEXUS 15kWH LiFePO4 Battery + APEX 10K Off-Grid Inverter

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Product Highlights

The BigBattery APEX 10K + NEXUS™ Off-Grid System is a complete, high-performance energy solution engineered for true energy independence. Combining the powerful APEX 10K hybrid inverter with the NEXUS 48V 15kWh LiFePO₄ battery, this system delivers reliable, efficient energy for homes, cabins, and remote installations.

The APEX 10K provides split-phase 120/240V pure sine-wave output at 50/60Hz, supporting both everyday appliances and high-demand loads. Designed to pair seamlessly with modern lithium battery systems, it accepts solar and generator inputs for continuous, all-day operation. With an 80A pass-through, large appliances and critical loads run smoothly without interruption.

Built with advanced battery protection, safe lithium technology, and U.S.-supported engineering, this system is ideal for off-grid living, backup power, and energy security in demanding environments.

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

Compatibility
Integrated & Optimized System (Closed-Loop Communication):

  • APEX 10K Hybrid Inverter + NEXUS 15kWh Battery

Expandable Design:

  • Scale battery storage from 15kWh up to 225kWh
  • Supports solar + generator input configurations
  • Designed for off-grid and backup power applications

Key Features

  • Complete Off-Grid System – Inverter + battery solution designed to work seamlessly together
  • 10kW Split-Phase Output – Powers 120/240V loads including large appliances and whole-home systems
  • 15kWh LiFePO₄ Battery – Safe, high-capacity energy storage with long lifespan
  • 6,000+ Cycle Life – Built for years of daily use and long-term savings
  • Solar + Generator Ready – Flexible power input for continuous energy availability
  • 80A Pass-Through – Supports high-demand loads and critical circuits
  • Advanced BMS Protection – Multi-layer protection for safe and reliable operation
  • Modular Expansion – Easily scale storage capacity as energy needs grow
  • UPS Backup Capability (15–30ms) – Seamless transition during outages
  • Indoor-Rated Design – Intended for installation in protected environments
  • Maintenance-Free Operation – No routine servicing required
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BigBattery NEXUS 51.2V 15kWH LiFePO4 Battery + APEX 10K Off-Grid Inverter

BigBattery NEXUS 51.2V 15kWH LiFePO4 Battery + APEX 10K Off-Grid Inverter

Introducing The APEX Inverter Series

Specifications:

BigBattery NEXUS 51.2V 15kWh LiFePO4 Battery
System Voltage 48V
Nominal Voltage 51.2V
Chemistry LiFePO4
Usable Energy (kWh) 15kWh
Ah Capacity 300Ah
Cell Configuration 16S1P
Max Continuous Discharge 100A
Max Discharge Power 7.6kW
Max Discharge Peak 110A
Max Charge Current 100A
Charging Voltage Range 53.5V-57.6V
Operating Voltage Range 48V-57.6V
Max Charge Voltage 57.9V
Suggested Low Voltage Cutoff 50.8V
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%) -4°F ~ 77°F
Humidity Range 10%-95% (No Condensation)
Weight (kg) ~142.8 kg ±5
Dimensions (WxHxD) 19.7 in x 27.5 in x 15.7 in
Altitude Limit <2000m
Max Connections 15 in parallel (up to 225kWh)
Communications RS485 / RJ45 / CAN
Protection Rating IP21
Certifications UN38.3
Installation Indoor Floor-standing
BigBattery APEX 10K Off-Grid Hybrid Inverter
Model APEX-10kW
Inverter Output
Rated Output Power 10,000W
Surge Capacity (Peak Power) 20,000W
Rated Output Voltage 120/240 Vac (single-phase/split-phase)
Load Capacity of Motors 6 HP
Rated Frequency 50 / 60Hz
Output Wave Pure sine wave
Switching Time 10ms (typical value)
Battery
Battery Type Lithium-ion battery / Lead-acid battery
/ User-defined battery
Rated Battery Voltage 48V
Voltage Range 40–60Vdc
Max. Solar Charging Current 200A
Max. Grid / Generator Charging Current 120A
Max. Hybrid Charge Current 200A
Solar Input
No. of MPPT 1 + 1
Max. Input Power 5,500W + 5,500W
Max. Input Current 22A + 22A
Max. Open Circuit Voltage 550Vdc + 550Vdc
MPPT Voltage Range 125–450Vdc
Grid / Generator Input
Input Voltage Range 65–140Vac
Input Frequency Range 50 / 60Hz
Bypass Overload Current 63A
AC Inputs 1 Input – Grid or Generator
THD (V) <5%
Efficiency
Max. Efficiency 99.9%
MPPT Tracking Efficiency 92%
Parallel Capacity Up to 6 units (More than 3 units in
parallel can form a three-phase output)
General Data
Dimension 28.46 in × 17.64 in × 5.91 in
Weight 62 lbs
Protection Degree IP20 (Indoor Only)
Temperature 14 – 131°F, >113°F Derate
External Module (Optional) Wi-Fi / GPRS
Certificate UL1741 / RoHS / EN61000-6-1 / EN61000-6-3 /
FCC Part 15 Class B / IEC62109-1 / IEC62109-2
Noise <60dB
Cooling Method Intelligent fan
Communication RS485 / CAN / USB / Dry Contact
Integrated Circuit Breaker Utility / Load / Battery / PV
Overload Protection
Overload Protection Behavior After overload protection is enabled, the inverter output
will be restored after 3 minutes, and after 5 times of overload,
the output will be off until the inverter is restarted.
(102% < APEX-10K load < 110%): an error will be reported
and the output will be turned off after 5 minutes.
(110% < load < 125%): an error will be reported and the output
will be turned off after 10 seconds. Load > 125%: an error will
be reported and the output will be turned off after 5 seconds.
Protection Features Has PV input current limiting protection, PV input over-voltage
protection, PV night reverse current protection, AC input
over-voltage protection, AC input under-voltage protection,
battery over-voltage protection, battery under-voltage protection,
battery over-current protection, AC output short-circuit
protection, heat sink over-temperature protection, inverter
over-load protection.

PACKAGE INCLUDES

BigBattery NEXUS 51.2V 15kWH LiFePO4 Battery + APEX 10K Off-Grid Inverter

BigBattery NEXUS 51.2V 15kWH LiFePO4 Battery

x 1

2AWG 3FT Ring to Ring Terminal Cable (Black and Red)

x 1

BigBattery APEX-10K Off-Grid Hybrid Inverter

x 1

Frequently Asked Questions

How do I connect this battery into my existing system?

These batteries use a standard M8 terminal. This battery can be connected directly to the onboard wiring system. You may also purchase additional cables from BigBattery.

How many times can I put this battery in parallel/series?

These batteries are not series capable but can be connected in parallel up to ten times. Make sure that the total amount of these batteries in your configuration never exceeds 15 total batteries. When connecting batteries in parallel, ensure all batteries are within 1 volt of one another.

How long will my battery last, and what do I do at the end of its life?

Lithium iron phosphate (LiFePO4) batteries can be cycled from 3500 - 5000 times. If you cycle the battery daily then you can get more than 12 years of use from your battery. When your battery is at the end of its lifespan, contact us and we'll recycle it for you, free of charge!

Can the inverter work on-grid and off-grid?

Yes. The APEX is a true hybrid inverter. It syncs with the utility for grid use and runs independently from solar + batteries during outages, switching automatically for uninterrupted power.

What batteries are compatible with the APEX inverter?

The Apex series inverters support most lithium batteries and are designed to work best with BigBattery batteries such as NEXUS, ETHOS, and HUSKY 2. RS485 and CAN enable smart integration; without communication, they operate in voltagecontrolled mode. Tip: use a CAN-enabled BigBattery pack for optimal protection and performance reporting.

How much solar input can the APEX inverter handle?

The APEX inverter supports a wide PV input range of up to 600 VDC, with dual independent MPPT trackers to optimize energy harvest from multiple solar strings. This design allows flexible array configurations, ideal for installations with varying roof angles or mixed sunlight exposure. The high input voltage and dual MPPT architecture ensure maximum solar utilization and stable operation under changing conditions.

Product Documents:

BigBattery NEXUS 51.2V 15kWH LiFePO4 Battery User Manual

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BigBattery NEXUS 51.2V 15kWH LiFePO4 Battery Specification Sheet

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BigBattery APEX 10K Off-Grid Hybrid Inverter User Manual

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BigBattery APEX 10K Off-Grid Hybrid Inverter Specification Sheet

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