This listing covers a packaged energy storage system: BigBattery ETHOS lithium battery paired with an EG4 FLEXBOSS18 inverter, sold as a kit for grid-tied or off-grid home backup. The manufacturer source page lists this as a variable product with 11 variations, but only one SKU and price were provided to us — see the Options & SKUs table below for what we can confirm.
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.
Expert Overview
An ESS kit like this combines two separate pieces of equipment: a battery bank and an inverter/charger. Getting the pairing right matters more than either component alone — undersized inverters or mismatched battery counts are the most common cause of underperforming systems in the field. The data provided to us for this listing is limited to product naming, a single SKU, and a single price point. We are flagging every spec gap below rather than guessing at inverter capacity, battery Ah rating, or wiring limits.
Battery Characteristics
Chemistry: LiFePO4 (Lithium Iron Phosphate) — confirmed by the "ETHOS" product family naming and BigBattery's standard lithium construction. [NEEDS VERIFICATION] for cell-level chemistry documentation specific to this SKU.
Voltage, Capacity (Ah/Wh), Group Size/Dimensions, Weight: [NEEDS VERIFICATION] — not provided in source data.
Wiring & Configuration Limits (Series/Parallel)
Series and parallel expansion limits for the ETHOS battery, and the compatible battery-count range for the FLEXBOSS18 inverter, were not included in the data provided to us. [NEEDS VERIFICATION] before you plan a multi-unit stack. Do not assume standard lead-acid series/parallel rules apply to this lithium system — confirm limits against manufacturer documentation before wiring.
Pro-Installer Tip
The most common failure point on a battery + inverter kit like this is mismatching the inverter's charge/discharge current rating against the battery's BMS limits — a pairing error, not a component defect. Over time, an inverter pushing more current than the BMS is rated for triggers repeated BMS lockouts, and an inverter undersized for the battery bank leaves capacity you paid for unused. Before commissioning, verify both the battery's max continuous discharge/charge amps and the inverter's rated output against each other, and monitor real-world performance with a shunt-based battery monitor rather than relying on inverter-reported state of charge alone. As a professional standard, size your daily discharge plan around 80–100% DoD for LiFePO4, and confirm that figure against the ETHOS battery's actual BMS spec once verified — do not assume it from lead-acid habits.
Key Benefits
- Packaged battery + inverter kit intended to simplify matching components for a grid-tied or off-grid home backup install.
- LiFePO4 chemistry (ETHOS) generally offers longer cycle life and lighter weight than lead-acid alternatives — specific cycle life figure not provided for this SKU. [NEEDS VERIFICATION]
- UL-9540 reference in the product name indicates this system, or components within it, have been evaluated for that energy storage system safety standard. [NEEDS VERIFICATION] of scope (full system vs. component-level certification).
Technical Table
| Spec | Value |
|---|---|
| Chemistry | LiFePO4 (inferred from ETHOS product line) |
| Voltage | [NEEDS VERIFICATION] |
| Capacity (Ah) | [NEEDS VERIFICATION] |
| Capacity (Wh) | [NEEDS VERIFICATION] |
| Max Continuous Discharge (A) | [NEEDS VERIFICATION] |
| Max Continuous Charge (A) | [NEEDS VERIFICATION] |
| Peak Discharge | [NEEDS VERIFICATION] |
| Cycle Life | [NEEDS VERIFICATION] |
| Operating Temp Range | [NEEDS VERIFICATION] |
| Low-Temp Charging Protection | [NEEDS VERIFICATION] |
| Dimensions | [NEEDS VERIFICATION] |
| Weight | [NEEDS VERIFICATION] |
| Terminal Type | [NEEDS VERIFICATION] |
| Inverter Model | EG4 FLEXBOSS18 |
Note: See "Resources (System Manuals and Warranty)" Tab above for full specifications.
Compatibility & Fitment
This kit pairs a BigBattery ETHOS battery with an EG4 FLEXBOSS18 inverter as sold. It is NOT confirmed compatible with other inverter brands or other BigBattery battery lines beyond ETHOS based on the data provided — do not mix components across product families without checking with us first. Charging requirements (charger type, standard lead-acid chargers vs. lithium-specific chargers) were not specified in source data. [NEEDS VERIFICATION] Do not use a standard lead-acid charger on this system unless the manufacturer documentation explicitly confirms compatibility.
This SKU (K0230-V) reflects one configuration only. The manufacturer page indicates 11 total variations exist for this product; we were given data for one. If you need a specific voltage, capacity, or inverter pairing not shown here, ask us before you order.
Options & SKUs
| Variant | SKU | Price |
|---|---|---|
| variable parent (11 variations) | K0230-V | $5604.99 |
The variant title above reflects the source data as provided — it indicates a parent listing for 11 variations, but individual variation names, SKUs, and prices beyond this one were not supplied to us. Ask us before you order if you need details on the other 10 variations.
FAQ
What chemistry is the BigBattery ETHOS battery?
LiFePO4 (Lithium Iron Phosphate), based on the ETHOS product line naming. Cell-level documentation for this specific SKU was not provided to us — confirm details in the manufacturer Resources tab.
Can I use this with an inverter other than the EG4 FLEXBOSS18?
This listing is packaged and priced as an ETHOS + FLEXBOSS18 kit. Compatibility with other inverters is not confirmed in the data we have — ask us before you order if you're planning a different pairing.
What is the battery's max continuous discharge current?
Not specified in the data provided for this SKU. [NEEDS VERIFICATION] — refer to the "Resources (System Manuals and Warranty)" Tab above.
Does this system have low-temperature charging protection?
Not specified in the data provided. [NEEDS VERIFICATION] Do not charge any lithium battery below its documented minimum charging temperature without confirmed cold-weather protection — check manufacturer documentation first.
How many total variations does this product have?
The manufacturer page indicates 11 variations under this parent listing. We were supplied data for one SKU (K0230-V) at $5604.99. Contact us for details on the others.
Warranty & Support
Warranty terms for this system were not included in the data provided to us. Please refer to the "Resources (System Manuals and Warranty)" Tab above on this page for manufacturer warranty documentation. If you can't find what you need there, we always reply back — ask us before you order.
