Home battery buyers often choose between a fixed-capacity all-in-one unit and a stackable home battery storage system that grows over time. The EH04 is built from 5.12 kWh LiFePO4 modules under a 5.5 kW or 11 kW hybrid inverter, so a household can start at roughly 10 kWh and add modules later up to about 41 kWh without replacing the inverter, as long as the module count stays inside the inverter’s supported range.
How the EH04 Module System Works
Each EH04 battery module holds 5.12 kWh (100 Ah, 51.2 V nominal, 16S1P LiFePO4 configuration). Modules stack on top of a base unit that houses the hybrid inverter, and the whole stack sits on castors so one person can position it without lifting equipment. The 5.5 kW inverter version accepts 2 to 4 modules (10.24-20.48 kWh); the 11 kW version accepts 4 to 8 modules (20.48-40.96 kWh). Both inverters take PV input directly - up to 6 kW for the 5.5 kW unit and up to 12 kW for the 11 kW unit - so the battery and the solar array are sized together, not as separate purchases.
Capacity Progression, Module by Module
The table below shows nameplate capacity at each module count, plus the inverter tier required and a usable-energy estimate. The usable figure applies the datasheet’s 80% discharge rating, tied to the 6,000-cycle life, to the nameplate capacity above - it isn’t a separate spec, just that percentage carried through the table.
| Modules | Nominal capacity | Usable at 80% DoD | Inverter tier required |
|---|---|---|---|
| 2 | 10.24 kWh | ~8.2 kWh | 5.5 kW |
| 3 | 15.36 kWh | ~12.3 kWh | 5.5 kW |
| 4 | 20.48 kWh | ~16.4 kWh | 5.5 kW or 11 kW |
| 5 | 25.60 kWh | ~20.5 kWh | 11 kW |
| 6 | 30.72 kWh | ~24.6 kWh | 11 kW |
| 7 | 35.84 kWh | ~28.7 kWh | 11 kW |
| 8 | 40.96 kWh | ~32.8 kWh | 11 kW |
The key planning decision sits at 4 modules. Below that, either inverter works. Above that, only the 11 kW inverter is supported. An installer sizing a system for a household that might expand past 20 kWh in a few years should specify the 11 kW inverter from day one and start with 4 modules, the minimum the 11 kW tier supports, to avoid a later inverter swap.
Sizing Logic: Matching Modules to Load, Not Just Capacity
Capacity is only half the sizing question. The inverter’s rated output caps how much the household can draw from the battery at any one moment, independent of how many modules are stacked behind it. A 5.5 kW inverter delivers 5.5 kW continuous regardless of whether it is paired with 2 or 4 modules. A 5 kW inverter delivers 5 kW continuous regardless of whether it is paired with 2 or 8 modules.
Practical sizing steps for an installer:
- Confirm the household’s peak simultaneous load (from the switchboard or an existing bill breakdown) against the inverter’s rated output power - 5.5 kW, 11 kW (EH04) or 5 kW (EH04E).
- Confirm the daily energy the household wants to cover from battery, then divide by 0.8 (the stated DoD) to get the nameplate capacity needed, then round up to the nearest module count the inverter tier supports (2 to 4 for the 5.5 kW inverter, 4 to 8 for the 11 kW inverter).
- Check the module count against the inverter tier table above before finalising the inverter model.
- Size the solar array against the inverter’s max PV input (6 kW, 12 kW or 12 kW respectively) so the array is not bottlenecked by the inverter on sunny days.
Stackable vs Fixed-Capacity: A Direct Comparison
A fixed-capacity all-in-one unit like the EH10K-16 ships with a 10 kW inverter and a 16.0768 kWh battery built into one cabinet. It cannot be expanded module by module - the only way to add capacity is to parallel a second complete unit (up to 6 units, 60 kW / roughly 96 kWh combined), which also adds another 10 kW of inverter capacity whether the site needs it or not. That is a different growth pattern from the EH04, where the inverter stays fixed and only the battery modules are added.
The EH04E uses the same 5.12 kWh module and 10-41 kWh range as the EH04, in a rack format for installers integrating into an existing cabinet.
| Model | Format | Starting capacity | Max capacity | Expansion step | Inverter |
|---|---|---|---|---|---|
| EH04 | Stackable floor cabinet on castors | 10.24 kWh (2 modules) | 40.96 kWh (8 modules) | 5.12 kWh per module | 5.5 kW or 11 kW |
| EH04E | Rack modules or built frame | 10.24 kWh (2 modules) | 40.96 kWh (8 modules) | 5.12 kWh per module | 5 kW (fixed) |
| EH10K-16 | All-in-one cabinet | 16.0768 kWh (1 unit) | ~96.5 kWh (6 units paralleled) | 16.0768 kWh + 10 kW inverter per unit | 10 kW per unit, up to 60 kW |
| MG12K-40 | Modular, indoor/outdoor, IP65 | Scaling confirmed per project | 40.96 kWh (8 modules) | 5.12 kWh per module | 12 kW (fixed) |
The practical difference for a procurement team: EH04 and EH04E let you scale the battery independently of the inverter, inside the tier limits described above. EH10K-16 scales in large 16 kWh + 10 kW blocks, which suits homes or small commercial buildings that will genuinely need more inverter power as they grow. The MG12K-40 sits between the two - modular battery, fixed 12 kW inverter, but rated IP65 for outdoor installation where the EH04/EH04E indoor rating is not specified.
The EH10K-16 ships as one sealed 16.0768 kWh + 10 kW unit; extra capacity means paralleling a second complete unit, not adding a module.
Physical Installation: What the Castors Change
Because each module sits on the stack and the base unit is on castors, an installer can move and position the cabinet without a pallet jack or second person, and can add modules to an already-installed base unit without re-running the DC wiring from scratch. This matters for retrofits where a homeowner buys 2 modules now and 2 more next year - the base cabinet, wiring path and mounting footprint do not change, only the module count.
When to Choose the Rack Format Instead
The EH04E uses the identical battery module and the same 10-41 kWh range, but drops the floor-standing cabinet in favour of rack modules that install into an existing rack or a supplied frame, with a fixed 5 kW inverter. It suits installers who are integrating the battery into a purpose-built enclosure (a plant room, a comms cabinet, a small commercial switch room) rather than placing a standalone cabinet in a garage or utility area. For a straightforward residential retrofit where the battery stands on its own, the EH04’s castor-mounted stack with the 5.5/11 kW inverter choice is the simpler specification. For wiring and mounting details on the rack format, see the EH04E rack-mount installation guide.
Related Reading
For a fixed-capacity comparison point, see the EH10K-16 day-and-night sizing example and the notes on 51.2 V LiFePO4 safety for residential installs. The same DoD and inverter-tier logic scales up to larger sites too; see the step-by-step commercial sizing guide for the higher-power version of this math.
Getting a Quote
If you are specifying an EH04 stack for a residential retrofit or a distributor order, confirm the target module count against the inverter tier table above before ordering, and check current lead times and container loading with the factory. Request pricing and technical drawings at /get-quote/.
Frequently asked questions
Can I add EH04 modules to an existing installation later?
Yes. The EH04 is built from 5.12 kWh LiFePO4 modules that stack on the base cabinet. A 5.5 kW inverter supports 2 to 4 modules (10.24-20.48 kWh) and an 11 kW inverter supports 4 to 8 modules (20.48-40.96 kWh). If the household starts on the 5.5 kW inverter and later needs more than 4 modules, the inverter has to be upgraded to the 11 kW version.
What is the usable energy of an EH04 stack, not just the nameplate capacity?
The datasheet rates the battery for 6,000 cycles at an 80% depth of discharge. Applying that 80% figure to the nameplate capacity gives roughly 8.2 kWh usable from a 2-module (10.24 kWh) stack and about 32.8 kWh usable from an 8-module (40.96 kWh) stack.
What is the difference between EH04 and EH04E?
Both use the same 5.12 kWh LiFePO4 module and the same 2-to-8 module capacity range (10-41 kWh). EH04 is a floor-standing stack on castors with a 5.5 kW or 11 kW inverter. EH04E is a rack-format version with a fixed 5 kW inverter, supplied either as individual rack modules for an existing cabinet or as a complete built frame.
Is a stackable battery cheaper than buying a large fixed-capacity unit upfront?
That depends on the site and is a procurement decision for the installer or homeowner. Battery pricing isn't published here; it's confirmed for each project through a quotation. The technical point stands regardless of price: a stackable system lets the buyer purchase only the modules needed today and add more later without discarding the inverter, as long as the addition stays within the same inverter tier.
