This is a packaged home energy storage system: EG4 Wallmount All Weather batteries paired with the EG4 FlexBoss21 hybrid inverter. It is sold as a grid-tied ESS (Energy Storage System), scalable from 14.3kWh up to 85.8kWh depending on how many battery units you configure, with PV input ranges from 21kW to 63kW. Because this is a system-level product with multiple configuration options, most of the detailed electrical specifications for this listing are best confirmed against the manufacturer documentation described below.
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 System Matters
Grid-tied home energy storage requires matching the battery bank, the inverter, and the site's PV array so all three work within the same operating envelope. This listing bundles the EG4 Wallmount All Weather battery with the EG4 FlexBoss21 hybrid inverter as a single ESS package, rated for solar arrays from 21kW to 63kW and carrying UL9540 system-level certification. UL9540 is a recognized safety standard specifically for energy storage systems, and it is one of the first things an installer or AHJ (Authority Having Jurisdiction) will ask about during permitting.
Because this is a scalable, multi-unit system rather than a single fixed-spec battery, several field-level electrical details — chemistry cell-level Ah rating, individual BMS continuous/peak amp limits, cycle life figures, terminal type, and operating temperature range — are not included in the manufacturer data provided for this listing. These are flagged below as [NEEDS VERIFICATION] rather than estimated.
Battery & System Characteristics
- System type: Wallmount All Weather Battery + FlexBoss21 Hybrid Inverter (ESS)
- Capacity range: 14.3kWh to 85.8kWh (scalable by number of battery units)
- PV input range: 21kW to 63kW
- Certification: UL9540 (system-level ESS safety standard)
- Grid configuration: Grid-tied
- Chemistry: [NEEDS VERIFICATION]
- Battery weight and dimensions: [NEEDS VERIFICATION]
Wiring & Configuration Limits (Series/Parallel)
This system scales by adding EG4 Wallmount All Weather battery units to reach the listed capacity range of 14.3kWh through 85.8kWh, paired with the FlexBoss21 inverter sized to the corresponding PV array (21kW-63kW). The exact number of battery units per capacity tier, and the specific series/parallel wiring configuration between units, is not provided in the source data for this listing. [NEEDS VERIFICATION]
Not confirmed for this listing: maximum series string count, maximum parallel battery count per inverter, and whether battery units can be mixed with other battery models or firmware versions. Do not assume compatibility with non-EG4 battery units. Do not mix battery units of different ages or cycle counts within the same string.
Pro-Installer Tip
Multi-unit ESS installs fail most often not from a bad battery, but from mismatched state-of-charge between units wired into the same bank — this creates cell imbalance and can trigger BMS lockout on the newest unit while older units are still cycling normally. Before commissioning, confirm every EG4 Wallmount battery unit is charged to the same voltage and SOC with a shunt-based battery monitor rated for the full bank voltage, not a single-cell voltmeter. For lithium ESS installations, plan around an 80-100% depth of discharge as the professional standard, and verify the FlexBoss21's charge parameters match the battery manufacturer's specified charge voltage before energizing the system — never rely on default inverter charge presets for a mixed or scaled battery bank.
Key Benefits
- Single-source ESS pairing — battery and hybrid inverter sold together as one system, reducing compatibility guesswork between separately-sourced components.
- UL9540 system certification supports permitting and AHJ approval for grid-tied residential installs.
- Scalable capacity from 14.3kWh to 85.8kWh lets you size the bank to the home's actual load profile rather than a fixed single-unit capacity.
- PV input range of 21kW-63kW supports a range of array sizes without changing inverter models.
Technical Table
| Spec | Value |
|---|---|
| System Type | Wallmount All Weather Battery + FlexBoss21 Hybrid Inverter (ESS) |
| Capacity Range | 14.3kWh - 85.8kWh |
| PV Input Range | 21kW - 63kW |
| Certification | UL9540 |
| Grid Configuration | Grid-tied |
| Chemistry | [NEEDS VERIFICATION] |
| Voltage | [NEEDS VERIFICATION] |
| Max Continuous Discharge (A) | [NEEDS VERIFICATION] |
| Cycle Life | [NEEDS VERIFICATION] |
| Operating Temp Range | [NEEDS VERIFICATION] |
| Terminal Type | [NEEDS VERIFICATION] |
| Dimensions / Weight | [NEEDS VERIFICATION] |
Note: See "Resources (System Manuals and Warranty)" Tab above for full specifications.
Compatibility & Fitment
This system is designed to be installed as a matched pair: EG4 Wallmount All Weather battery units with the EG4 FlexBoss21 hybrid inverter, in a grid-tied configuration supporting 21kW-63kW of PV input.
NOT confirmed compatible with: other manufacturers' battery banks, off-grid-only inverter configurations, or PV arrays outside the stated 21kW-63kW range. This listing does NOT include installation hardware, PV panels, conduit, or balance-of-system wiring unless separately stated. Standard lead-acid chargers are NOT applicable to this lithium-based ESS. Do not substitute a non-EG4 inverter with these battery units without manufacturer confirmation of charge/discharge parameter compatibility.
FAQ
Q: What capacity range does this system cover?
A: This ESS package scales from 14.3kWh to 85.8kWh depending on the number of EG4 Wallmount All Weather battery units configured.
Q: What size solar array does this system support?
A: The paired FlexBoss21 inverter supports PV input from 21kW to 63kW.
Q: Is this system UL certified?
A: Yes. This system carries UL9540 certification, which is a recognized safety standard for energy storage systems.
Q: Is this a grid-tied or off-grid system?
A: This listing is configured as a grid-tied system.
Q: Does this listing include chemistry, cycle life, and BMS amperage details?
A: Those specifications were not included in the manufacturer data available for this listing. Refer to the "Resources (System Manuals and Warranty)" Tab above for full manufacturer documentation before ordering.
Warranty & Support
Warranty terms for the EG4 Wallmount All Weather battery and FlexBoss21 inverter are not included in the data provided for this listing. Refer to the "Resources (System Manuals and Warranty)" Tab above for manufacturer warranty documentation. If you have questions about this system before ordering, ask us — we always reply back.
