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BigBattery ETHOS 3x Expansion Kit

BigBattery ETHOS 3x Expansion Kit
$4,040.00 - $4,040.00
$4,040.00
$4,040.00 - $4,040.00
$4,040.00
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BigBattery ETHOS 3x Expansion Kit

The BigBattery ETHOS 3x Expansion Kit adds three stackable 5.12kWh LiFePO4 battery modules to your existing ETHOS energy storage system, expanding capacity by 15.36kWh and 300Ah without replacing any of your current equipment. Designed for seamless parallel integration, the kit connects to your existing ETHOS controller via rack-to-rack communication and power cabling, letting your system scale alongside rising household energy demands — whether you're extending backup runtime through multi-day outages, absorbing more production from a growing solar array, or shifting additional load off peak-rate hours. Built on safe, stable lithium iron phosphate chemistry with advanced BMS protection against overcharge, over-discharge, and thermal extremes, the modules deliver the same maintenance-free operation as the rest of the ETHOS platform inside IP65 / NEMA 4X rated enclosures.

Certified to UL9540A, UL1973, and UN38.3, the expansion kit maintains the code-compliant, UL-certified status of your grid-tied or off-grid installation and is CEC listed for California solar projects. CANBus and RS485 communications keep the added modules in closed-loop sync with your inverter, and with support for up to sixteen parallel connections per control box, the ETHOS platform leaves plenty of headroom for future growth. Backed by BigBattery's 12-year warranty, the ETHOS 3x Expansion Kit is the straightforward path to scaling the home energy system you've already invested in.


ETHOS 3x Expansion Kit Specs

System Voltage:
48V
Nominal Voltage:
51.2V
Chemistry:
LiFePO4
kWh Capacity:
15.36kWh
Ah Capacity:
300Ah
Charging Voltage Range:
55.6V – 57V
Max Charge Voltage:
58.8V
Operating Voltage Range:
48V – 57V
Suggested Low Voltage Cutoff:
48V – 50.8V
Cell Configuration:
16S 3P
Max Continuous Discharge Current:
250A
Max Continuous Power:
12800W
Max Discharge Peak Current:
300A (Max 5 seconds)
Max Charge Current:
200A
Charge Temperature Range:
32°F – 113°F (0°C – 45°C)
Discharge Temperature Range:
-4°F – 140°F (-20°C – 60°C)
Optimal Discharge Temperature Range:
59°F – 95°F (15°C – 35°C)
Storage Temperature Range (SoC >50%):
-4°F – 113°F (-20°C – 45°C) (Max 6 months)
Dimensions (DxWxH):
6.7 x 26.5 x 59.8 in (170 x 674 x 1519mm)
Weight:
387 lbs (175.5 kg)
Max Connections:
Up to (16) parallel connections per control box
Communications:
CANBus / RS485
Protection Rating:
IP65 / NEMA 4X
Certifications:
UL9540A, UL1973, & UN38.3

ETHOS 3x Expansion Kit Features

  • Adds 15.36kWh to Your Existing System: Three 5.12kWh LiFePO4 modules substantially extend your backup runtime and solar storage capacity without replacing any of the ETHOS equipment you already own.
  • Seamless Parallel Integration: The kit connects directly to your existing ETHOS controller with rack-to-rack communication and power cabling, making expansion a stack-and-connect process rather than a system redesign.
  • UL-Certified Safety Platform: Certified to UL9540A, UL1973, and UN38.3, preserving the code-compliant, permitted status of your residential energy storage installation as it grows.
  • Closed-Loop Inverter Communication: CANBus and RS485 protocols keep the added modules in constant sync with your 48V hybrid or off-grid inverter for optimized charging and reliable performance.
  • Room to Keep Growing: With support for up to sixteen parallel connections per control box, the ETHOS platform leaves substantial headroom for future expansion beyond this kit.
  • Weather-Resistant IP65 / NEMA 4X Enclosure: Sealed against dust and water jets, allowing confident installation in garages, utility rooms, and other demanding environments.
  • Advanced BMS Protection: Built-in battery management guards against overcharge, over-discharge, and temperature extremes, delivering the same maintenance-free operation as your original ETHOS modules.
  • Slim Full-Height Tower: The added three-module tower stands just under 60 inches tall and 6.7 inches deep, adding serious capacity while staying flat against the wall.

Your Satisfaction with BigBattery is Guaranteed:

  • 12-Year Limited Warranty