Big Battery | ETHOS 3x Expansion Kit
ETHOS 3x Expansion Kit
Expand your energy storage with the ETHOS 3x Expansion Kit—a high-performance, scalable solution designed to seamlessly integrate with your existing BigBattery 48V ETHOS System. Offering 15.36kWh of additional capacity, this kit empowers homeowners, small businesses, and off-grid enthusiasts to enhance their energy independence, reduce utility costs, and build a smarter, more resilient power system.
What is the ETHOS 3x Expansion Kit?
The ETHOS 3x Expansion Kit includes:
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Three (3) 48V ETHOS battery modules (5.12kWh each)
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Heavy-duty rack base
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All necessary power and communication cables
These stackable, plug-and-play LiFePO4 battery modules are engineered for durability, safety, and long-lasting performance. With support for up to 16 modules per Control Box, you can scale your residential energy storage to fit your exact needs. (Note: Control Box sold separately.)
Why Choose the ETHOS 3x Expansion Kit?
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15.36kWh capacity for extended backup power
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Tier 1 lithium iron phosphate (LiFePO4) technology for maximum efficiency and safety
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Modular and space-saving design—stack and expand as your power needs grow
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Advanced BMS with auto cell-balancing and thermal protection
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Supports CANBus and RS485 communication protocols for system monitoring
Ideal for:
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Off-grid homes, tiny houses, cabins, and homesteads
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Residential solar energy storage
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Emergency backup power systems
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Grid-tied setups seeking net metering benefits
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Businesses optimizing power during peak demand hours
Seamless Integration, Maximum Rewards
Designed to work in harmony with BigBattery’s ETHOS Control Box and inverter systems, this expansion kit allows you to build a powerful, future-proof ESS (Energy Storage System). Plus, it’s eligible for federal solar tax credits and clean energy rebates, making your investment even smarter.
What's Included
3 × 48V ETHOS 5.12kWh Stackable Battery Module
1 × ETHOS RACK BASE
2 × Ethos Parallel Power Cable 4.9 ft (1500mm)
1 × Ethos Parallel Comm Cable 4.9 ft (150cm)
Specs and Downloads
Tech Specs
| SKU: | KIT0699 |
| GTIN-12 (U.P.C.): | 850061252180 |
| System Voltage: | 48V |
| Nominal Voltage: | 51.2V |
| Chemistry: | LiFePO4 |
| kWh Capacity: | 15.36kWh |
| Ah Capacity: | 300Ah |
| Charging Voltage Range: | 55.6 - 57V |
| Max Charge Voltage: | 57V |
| Operating Voltage Range: | 48 – 57V |
| Suggested Low Voltage Cutoff: | 48 – 50.8V |
| BMS Cutoff Range: | 42 - 47V |
| 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) |
| Weight: | 387 lb (175.5 kg) |
| Depth: | 6.7 in (170 mm) |
| Width: | 26.5 in (674 mm) |
| Height: | 59.8 in (1520 mm) |
| Max Connections: | Up to (16) parallel connections per control box |
| Protection Rating: | IP65 |
| Communications: | CANBus / RS485 |
Are Solar Guys Pro Authorized Retailers?
Yes! We are proud to be one of the few online retailers who are authorized retailers for every single product we carry!
Being an authorized retailer means we carry the same warranty as the manufacturer, protecting your purchase!
When Will My Order Ship?
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
Get your 30% Tax Solar Credit!
Unlock substantial savings with the government's Solar Tax Credit, which offers a robust 30% deduction on the installation costs of solar systems. This attractive incentive is your ticket to leveraging solar energy's eco-friendly potential while enjoying the financial benefits.
At Solar Guys Pro, our commitment is to you. Please be reminded that our expertise does not extend to tax advice. Nonetheless, our dedicated staff is eager to guide you through the process and ensure you capitalize on this exceptional offer.
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