The ETHOS Battery and APEX-6.5K Inverter kit from BigBattery is a packaged off-grid storage system. The manufacturer's listing describes a capacity range of 10.24–46.1kWh, sold as a variable parent SKU with six configuration options. Most detailed specs for this particular listing were not provided by the manufacturer on this page — see the notes below and the Resources tab for anything not covered here.
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.
E-E-A-T Intro: What This Kit Is
This is an off-grid Energy Storage System (ESS) built around BigBattery's ETHOS battery line paired with the APEX-6.5K inverter. The manufacturer positions the capacity range at 10.24kWh to 46.1kWh depending on how many ETHOS units are stacked, which points to a modular, expandable battery bank rather than a single fixed-capacity unit. Beyond the capacity range and the six listed configuration variants, the manufacturer did not supply chemistry cell details, cycle life numbers, BMS discharge/charge limits, dimensions, or terminal type on this page. Those figures are marked [NEEDS VERIFICATION] below rather than estimated.
Battery Characteristics
- Chemistry: [NEEDS VERIFICATION] — product name "ETHOS" and BigBattery's typical product line suggest LiFePO4 (Lithium Iron Phosphate), but this was not explicitly confirmed in the supplied data and is not stated as fact here.
- Nominal System Voltage: [NEEDS VERIFICATION]
- Capacity Range (as listed): 10.24kWh – 46.1kWh
- Group Size / Form Factor: [NEEDS VERIFICATION]
- Inverter: APEX-6.5K (off-grid type, per product name)
Wiring & Configuration Limits (Series/Parallel)
The manufacturer's data indicates this product ships as a "variable parent" with six variations, implying multiple stacking or capacity tiers achievable by adding ETHOS battery units to reach the stated 10.24–46.1kWh range. Exact series and parallel wiring limits (maximum units in series, maximum in parallel) were not included in the supplied data.
Positive fitment: Compatible for expansion with additional ETHOS battery units up to the manufacturer's stated maximum configuration reflected in the 46.1kWh top-end figure. [NEEDS VERIFICATION for exact unit count and series/parallel topology.]
Negative fitment: Do not mix this ETHOS/APEX-6.5K kit with battery banks of a different chemistry, brand, or age. Do not exceed the manufacturer's rated series/parallel configuration once confirmed via the Resources tab. This system is not confirmed compatible with grid-tied inverter setups based on the data provided — treat it as off-grid only unless the manufacturer documentation states otherwise.
Pro-Installer Tip
Stacking lithium battery modules to hit a target kWh number is common, but it's also where series/parallel mistakes happen most often on off-grid builds. If modules from different production batches or state-of-charge levels get paralleled together without balancing first, you risk long-term cell imbalance that shortens pack life and can trigger a BMS lockout mid-discharge. Before commissioning any multi-unit ETHOS stack, verify state-of-charge parity on each module with a shunt-based battery monitor, and confirm the manufacturer's documented max unit count for series and parallel wiring in the Resources tab before final connection. As a professional standard, plan your daily discharge depth against the ETHOS's rated DoD (LiFePO4 packs typically support 80-100% DoD, but confirm this system's exact rating before sizing daily loads) — this keeps the pack in a state the BMS is designed to manage indefinitely.
Key Benefits
- Modular capacity range (10.24kWh–46.1kWh) allows scaling a home off-grid bank in stages instead of buying full capacity up front.
- Paired APEX-6.5K inverter is sold as part of the same kit, reducing separate compatibility sourcing between battery and inverter.
- Six available configuration variants under one parent SKU, giving buyers a capacity tier that matches their load profile. [Cycle life, BMS discharge/charge limits, and weight savings figures: NEEDS VERIFICATION — not supplied in manufacturer data for this page.]
Technical Table
| Spec | Value |
|---|---|
| Voltage | [NEEDS VERIFICATION] |
| Capacity (kWh) | 10.24kWh – 46.1kWh |
| Chemistry | [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] |
| Terminal Type | [NEEDS VERIFICATION] |
| Weight | [NEEDS VERIFICATION] |
| Inverter Model | APEX-6.5K |
Note: See "Resources (System Manuals and Warranty)" Tab above for full specifications.
Compatibility & Fitment
This kit pairs the ETHOS battery line with the APEX-6.5K inverter as a matched off-grid ESS. Charger and inverter compatibility outside this paired APEX-6.5K unit was not specified in the supplied data — do not assume compatibility with other inverter brands or models without confirming with BigBattery documentation first. Standard lead-acid chargers are NOT recommended for this system if it is LiFePO4-based; confirm charge profile requirements in the Resources tab before connecting any third-party charge source. This system is NOT confirmed for use as a vehicle starter battery or marine cranking application — it is described here strictly as a home/off-grid storage battery kit.
Options & SKUs
| Variant | SKU | Price (USD) |
|---|---|---|
| variable parent (6 variations) | K0954-V-1 | $3655.00 |
This parent SKU represents six selectable configuration variants at checkout. Individual per-variant SKUs and pricing beyond the listed parent SKU were not itemized in the supplied data; confirm your specific configuration and price at the time of order.
FAQ
What capacity range does this ETHOS system cover?
The manufacturer lists a capacity range of 10.24kWh to 46.1kWh, depending on which of the six available configurations you select.
Is this system for off-grid or grid-tied use?
The APEX-6.5K inverter is described as an off-grid unit. Grid-tied compatibility was not specified in the manufacturer data, so treat this as an off-grid system unless confirmed otherwise.
What battery chemistry does the ETHOS use?
Chemistry was not explicitly stated in the supplied manufacturer data for this listing. This is flagged as [NEEDS VERIFICATION] — check the Resources tab for confirmation before ordering if chemistry is a deciding factor for your build.
Can I expand this system later by adding more ETHOS units?
The listing structure (variable parent with six configuration tiers spanning 10.24–46.1kWh) suggests expandability, but exact series/parallel wiring limits were not provided. Confirm maximum stack configuration with BigBattery's documentation before planning an expansion.
Does this kit include the inverter and battery together?
Yes. The product name and listing bundle the ETHOS battery with the APEX-6.5K inverter as one off-grid ESS kit.
Warranty & Support
Warranty terms for this system were not included in the supplied manufacturer data. Refer to the "Resources (System Manuals and Warranty)" Tab above on this page for the manufacturer's warranty documentation before you order. If you have questions about which of the six configurations fits your load, ask us before you order — we always reply back.
