The BigBattery ETHOS is a 48V LiFePO4 stackable battery module built for home energy storage. Rated at 5.1kWh, it is designed to expand into larger banks as your storage needs grow. This page covers one module: SKU FETHS-48051-G1.
Note: If you would like to review the manufacturer Product Specifications, Warranty, Brochure, etc., for this system, please refer to the "Resources (System Manuals and Warranty)" Tab above on this page.
Why This Battery, From a Field Perspective
Home storage buyers care about two things: how much energy is actually usable, and how safely the system handles daily cycling. The ETHOS module is rated 5.1kWh at 48V, using LiFePO4 chemistry — the same chemistry family used in UL-certified stationary storage because of its stable thermal behavior under repeated deep cycling. UL1973 certification, noted in the product title, is the relevant safety standard for stationary energy storage systems.
Battery Characteristics
Chemistry: LiFePO4 (Lithium Iron Phosphate)
Format: Stackable-type module, 48V nominal, 5.1kWh capacity
Beyond these figures — voltage, capacity, and chemistry — the manufacturer has not provided module dimensions, weight, cycle life, BMS current limits, terminal type, or operating temperature range in the source data supplied for this listing. These fields are flagged below rather than estimated.
Wiring & Configuration Limits (Series/Parallel)
ETHOS is described as a stackable-type module, which indicates it is designed to expand into multi-module banks. However, the source data provided does not specify the maximum number of modules permitted in series or parallel, nor the compatible rack/stacking hardware. [NEEDS VERIFICATION]
Do not combine ETHOS modules with lead-acid, AGM, or other lithium chemistries in the same bank. Do not exceed manufacturer-stated stacking limits — confirm exact series/parallel maximums in the Resources tab before ordering additional modules.
Pro-Installer Tip
Stackable lithium modules are frequently over-paralleled or over-seriesed by installers who assume "more is better" without checking the rated bank limit. Exceeding the stated maximum module count per bank can cause cell-group imbalance across modules and trigger BMS lockout during charge or discharge. Before wiring a multi-module bank, verify the maximum stack count with a shunt-based battery monitor set up to track pack-level voltage divergence, not just total bank voltage. As a professional standard, plan cycling around an 80-100% depth of discharge ceiling typical for LiFePO4, and confirm this module's specific DoD rating in the manufacturer documentation before commissioning the system.
Key Benefits
- LiFePO4 chemistry — more cycle-stable under daily charge/discharge than lead-acid or AGM at equivalent capacity
- Stackable module format for expanding home storage capacity over time
- UL1973-relevant certification pathway for stationary storage safety
- 48V nominal platform suited to home/off-grid inverter systems
Technical Table
| Spec | Value |
|---|---|
| Voltage | 48V nominal |
| Capacity | 5.1kWh |
| Chemistry | LiFePO4 |
| Certification | UL1973 |
| Format | Stackable-type module |
| Amp-hours (Ah) | [NEEDS VERIFICATION] |
| Max Continuous Discharge (A) | [NEEDS VERIFICATION] |
| Max Continuous Charge (A) | [NEEDS VERIFICATION] |
| Peak Discharge (A) | [NEEDS VERIFICATION] |
| Cycle Life | [NEEDS VERIFICATION] |
| Dimensions | [NEEDS VERIFICATION] |
| Weight | [NEEDS VERIFICATION] |
| Terminal Type | [NEEDS VERIFICATION] |
| Operating Temp Range | [NEEDS VERIFICATION] |
| Low-Temp Charging Protection | [NEEDS VERIFICATION] |
Note: See "Resources (System Manuals and Warranty)" Tab above for full specifications.
Compatibility & Fitment
ETHOS is a 48V LiFePO4 home/off-grid storage module intended for stationary storage applications compatible with 48V-platform inverter and charge-controller systems. It is NOT a golf cart, RV, or marine starting battery. It is NOT compatible with standard lead-acid or AGM chargers — LiFePO4-specific charge profiles are required; using a lead-acid charger risks BMS lockout or permanent capacity loss. Do NOT mix this module with batteries of different chemistry, age, or state of health in the same bank. Maximum stacking configuration (series/parallel module count) is not specified in the manufacturer data provided and should be confirmed in the Resources tab before purchase of additional units.
FAQ
What chemistry does the ETHOS module use?
It uses LiFePO4 (Lithium Iron Phosphate), the chemistry referenced in its UL1973-relevant certification.
Can I mix this module with an existing lead-acid or AGM bank?
No. Do not mix chemistries, ages, or states of health within the same battery bank.
How many ETHOS modules can I stack together?
The manufacturer data provided for this listing does not state a maximum stack count. Confirm this in the Resources (System Manuals and Warranty) tab before ordering additional modules.
Can I use a standard lead-acid charger with this battery?
No. Standard lead-acid chargers are not recommended. LiFePO4 batteries require a charge profile matched to their chemistry.
What is included with the FETHS-48051-G1 SKU?
This SKU is a single stackable-type ETHOS module. Rack hardware, busbars, or additional modules are not confirmed as included in the data provided. [NEEDS VERIFICATION]
Warranty & Support
Warranty terms for the ETHOS module are not included in the data provided for this listing. Refer to the "Resources (System Manuals and Warranty)" Tab above for warranty coverage and manufacturer documentation. If you have questions before ordering, ask us — we always reply back.
