12-Year Warranty
Full Battery Coverage
Product Summary:
The BigBattery ETHOS™ is a leader in both on-grid and off-grid solar installations, known for its quality, value, ease of installation, proven reliability and safety record. Expandable up to 80+ kWh, ETHOS adapts to your energy needs-perfect for home backup, off-grid, and hybrid systems.
Designed with UL 9540 certification, advanced battery management, and U.S.-engineered design, ETHOS delivers reliable, maintenance-free performance with seamless integration into leading inverter systems.
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Ships From: Texas, USA
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Warranty: 12 Years
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Support: Lifetime USA-Based Tech Support
Compatibility
UL 9540 Certified + Closed-Loop Communication (Grid-Tied):
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EG4 18kPV
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EG4 FlexBoss18
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EG4 FlexBoss21
Closed-Loop Communication (Off Grid Non-UL 9540 Installs):
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All BigBattery APEX Inverters
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All EG4 Inverters
Key Features
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LiFePO4 Battery Chemistry – Safe, stable lithium technology with long lifespan
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6,000+ Cycle Life – Built for years of daily use and long-term savings
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Advanced BMS Protection – Full protection against voltage, current, and temperature risks
- Outdoor-Ready Design – Built for durability in real-world environments along with indoor setup also
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Modular Expansion – Easily increase capacity without replacing your system
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Integrated Smart Control – Optimized performance with ETHOS controller
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Fast Installation – Simplified, plug-and-play modular setup
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Maintenance-Free – No routine servicing required
A future-ready battery platform built for energy independence-with the safety, support, and reliability you can trust.
BigBattery ETHOS | 48V – 10.24kWh | UL1973 | UL9540A | Home Battery Backup LFP
Battery Selected
2× BigBattery ETHOS
Total Capacity
10.24 kWh
Choose Your Battery Quantity*
Standard
Large
Complex
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Real Installations From Customers Like You!
Enter your build here to show off your build and receive a gift-box from us! Selected photos will be featured on our website and product pages.
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Battery Downloads
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GO TO LINKBattery Specifications
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
Real Installations From Customers Like You!
Enter your build here to show off your build and receive a gift-box from us! Selected photos will be featured on our website and product pages.
.
.
Battery Downloads
Battery Specifications
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
Frequently Asked Questions
Can I add more ETHOS batteries later?
Yes, that is the point of the design. ETHOS is modular and expandable up to 80+ kWh, so you can start at 10.24kWh with two modules and add capacity as your needs grow. Expansion kits are available in 2x and 3x module sets, and the system uses plug-and-play connections rather than a rebuild.
How many ETHOS modules do I need for my house?
Each module is 5.12kWh. Two modules at 10.24kWh cover essential circuits through a typical outage. A home wanting whole-house backup with air conditioning or electric heat generally needs four to six modules. Work out your daily kWh use first, then size for the number of outage days you want covered.
Is the ETHOS UL9540 certified for grid-tied?
ETHOS is designed with UL 9540 certification, but grid-tied closed-loop operation is certified with specific inverters: the EG4 18kPV, FlexBOSS18 and FlexBOSS21. For off-grid non-UL 9540 installs, it works with all BigBattery APEX inverters and all EG4 inverters. Confirm your inverter is on the certified list before a grid-tied install.
What inverters work with the ETHOS?
For UL 9540 certified grid-tied systems: EG4 18kPV, FlexBOSS18 and FlexBOSS21. For off-grid installations with closed-loop communication: all BigBattery APEX inverters and all EG4 inverters. Closed loop means the inverter reads true state of charge from the battery rather than estimating from voltage.
How long does the ETHOS last?
It is rated for 6,000+ cycles and carries a 12-year warranty with lifetime US-based tech support. At one full cycle per day that is well over a decade of daily use. It ships from Texas, so warranty service does not involve returning a pack overseas.
BigBattery ETHOS | 48V – 10.24kWh | UL1973 | UL9540A | Home Battery Backup LFP
