EG4 Electronics’ WallMount 314Ah Indoor battery stores about 16kWh in a single 51.2V lithium iron phosphate unit, with 12.86kWh usable at the company’s recommended 80% depth of discharge, according to EG4’s spec sheet (version 1.0.4) and user manual. It replaces the earlier 280Ah Indoor model in the same footprint, adds about 1.7kWh of capacity, and raises the rated cycle life to 10,000 cycles at 80% depth of discharge, backed by a 10-year or 10,000-cycle warranty. EG4 lists UL 1973 and UL 9540A certification, plus UL 9540 system listings with one to six identical batteries. Here’s what the specs mean in practice, how many units a home needs, and what the installation looks like.
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All figures come from EG4’s WallMount 314Ah Indoor product page, spec sheet and user manual, and EG4’s 280Ah Indoor spec sheet for the comparison. I haven’t installed this battery myself, so the runtime and sizing numbers are labeled estimates based on EG4’s published ratings.
Key specs at a glance
| Spec | EG4 WallMount 314Ah Indoor |
|---|---|
| Model | WM48314IN (WM-48-314-IN-XX) |
| Chemistry | Lithium iron phosphate (LFP) |
| Nominal voltage / capacity | 51.2V / 314Ah |
| Nominal energy | 16kWh |
| Usable energy | 12.86kWh at 80% depth of discharge (recommended) |
| Continuous charge / discharge power | 8kW / 10.2kW |
| Max continuous charge current | 157A (157A recommended) |
| Max continuous discharge current | 200A (157A recommended) |
| Peak power | 12.8kW for 3 seconds |
| Round-trip efficiency | 95% |
| Recommended voltage range | 47.5–57.6V DC; charge 56–57V |
| Communication | RS485, CAN; Wi-Fi/Bluetooth antenna for the EG4 app |
| Built-in breaker | 250A |
| Battery heater | 448W; on at ≤32°F, off at ≥37°F internal |
| Operating temperature | Charge 32–122°F; discharge −4–131°F |
| Max parallel units | 32 |
| Size (H × W × D) | 34.1 × 18.1 × 9.6 in |
| Weight | 293.2 lb (133 kg) |
| Enclosure | IP20, indoor only |
| Cycle life | 10,000 cycles to 70% capacity (0.5C, 77°F, 80% DoD) |
| Warranty | 10 years or 10,000 cycles |
| Certifications | UL 1973, UL 9540A; UL 9540 configurations listed by EG4 |
What’s new compared with the 280Ah Indoor
EG4 says the 314Ah model is “sized to fit where earlier models fit,” which makes it a straightforward choice for expanding or retrofitting an existing EG4 install. The main differences on paper:
| Spec | WallMount Indoor 280Ah | WallMount Indoor 314Ah |
|---|---|---|
| Nominal energy | 14.3kWh | 16kWh |
| Capacity | 280Ah at 51.2V | 314Ah at 51.2V |
| Weight | 286.6 lb (130 kg) | 293.2 lb (133 kg) |
| Rated cycles | 8,000+ at 80% DoD | 10,000 at 80% DoD (to 70% capacity) |
| Warranty | 10 years | 10 years or 10,000 cycles |
Beyond capacity, EG4 highlights active cell balancing at 2–3A, automatic configuration that removes manual DIP-switch setup, over-the-air firmware updates, and configurable NO/NC and 12V outputs that can trigger a generator start or an alarm. Internal fire arrestors and reinforced cell enclosures are also listed among its safety features.
What 12.86kWh runs: worked examples
Usable energy is the number that matters for backup planning. At EG4’s recommended 80% depth of discharge, one battery delivers 12.86kWh. After roughly 5% inverter losses, I plan on about 12.2kWh at the outlets. These are my estimates:
| Average household load | What that looks like | One battery* | Two batteries* |
|---|---|---|---|
| 300W | Fridge, internet, LED lights, phone charging | ≈ 41 hr | ≈ 81 hr |
| 500W | Above plus a chest freezer, TV and gas-furnace blower cycling | ≈ 24 hr | ≈ 49 hr |
| 1,000W | Above plus a well pump, microwave and laptop use | ≈ 12 hr | ≈ 24 hr |
| 2,000W | Above plus a mini-split running part-time | ≈ 6 hr | ≈ 12 hr |
| 3,500W | Central AC running steadily | ≈ 3.5 hr | ≈ 7 hr |
*Estimate: 12.86kWh × 0.95 ÷ load per battery. Example for 500W: 12,860 × 0.95 ÷ 500 ≈ 24 hours. Real-world loads swing with weather and habits, so start from a month of utility data if you have it. My guide to how many batteries it takes to power a house walks through that math in more detail.
Sizing for a whole day
The U.S. Energy Information Administration puts average residential use at roughly 29kWh a day nationwide, though it varies widely by region and season. Covering that fully from storage alone would take about three WallMount 314Ah units (3 × 12.86kWh = 38.6kWh usable, estimate). Most backup systems cover essential circuits rather than the whole house, which often brings the need down to one or two batteries.
| Batteries | Nominal | Usable at 80% DoD | Max continuous discharge (EG4 parallel table) |
|---|---|---|---|
| 1 | 16kWh | 12.86kWh | 200A |
| 2 | 32kWh | 25.7kWh | 400A |
| 3 | 48kWh | 38.6kWh | 600A |
| 4 | 64kWh | 51.4kWh | 800A |
| 6 | 96kWh | 77.2kWh | 1,200A |
Usable figures for two or more batteries are multiples of EG4’s single-unit 12.86kWh rating.
Recharging from solar
Each battery accepts up to 8kW of continuous charge at EG4’s recommended 0.5C rate, so the inverter and solar array are usually the limit, not the battery. A rough way to estimate daily solar production is array kW × peak sun hours × 0.8. With 4.5 peak sun hours:
| Solar array | Estimated daily production* | Refills one battery’s 12.86kWh? |
|---|---|---|
| 4kW | ≈ 14.4kWh | Only if the house uses little during the day |
| 8kW | ≈ 28.8kWh | Yes, with surplus for daytime loads |
| 12kW | ≈ 43.2kWh | Yes, enough for two to three batteries in good sun |
*Estimates; actual output depends on location, roof angle, shading and season. Whether solar plus storage pays off depends on your rates and incentives; I break that down in is a solar battery worth it. If you don’t have panels, my guide to home battery backup without solar covers grid-charged setups.
Inverter compatibility
EG4 says the smart BMS automatically detects and communicates with EG4 inverters for plug-and-play operation. The user manual includes step-by-step installs with the EG4 18kPV, 12kPV and FlexBOSS18/21 using EG4’s Indoor Buildable Conduit Box, plus wiring diagrams for one to three FlexBOSS21 inverters with up to six batteries. Communication runs over RS485 and CAN, so closed-loop communication with other brands depends on that inverter’s protocol support; check EG4’s compatibility list before mixing brands. For a closer look at the EG4 inverter side, see my EG4 18kPV review, and for how EG4 stacks up against a Victron build, my Victron vs EG4 comparison.
Where it can go: location rules from the manual
- Indoor only. EG4 limits residential installs to attached or detached garages, sheds, enclosed utility closets, basements, storage areas or utility spaces, and says not to install in habitable living spaces or near marine environments.
- Spacing. Based on UL 9540A testing, EG4 recommends at least 4 inches between batteries, subject to your local Authority Having Jurisdiction (AHJ).
- Clearance. Keep at least 23.6 inches from all exposures and egress points, and install upright.
- Room volume. Without ventilation, EG4 specifies a minimum space of 50 cubic meters (about 1,766 cubic feet); proper ventilation per code can reduce that. Adding more batteries doesn’t raise the requirement, because testing showed no propagation between units.
- Weight. The wall shouldn’t carry the full 293 lb; pre-installed feet transfer part of the load to the floor.
Installation steps (summary of the manual)
- Move it safely. Use an equipment lift with the two M10 lifting eye bolts, or a team lift.
- Remove the mounting bracket from the back of the battery by taking out its four set screws.
- Mount the bracket level on the wall with the top at about 29 inches, keeping the required ground clearance. Drill six holes and use hardware suited to the wall; expansion bolts are included for concrete or brick.
- Hang the battery by hooking its rear flange onto the bracket, then secure it with the four side screws.
- Attach the Wi-Fi/Bluetooth antenna. Its cord is 80 inches long, and EG4 recommends mounting it on a magnetic surface away from the system.
- Add the conduit box if used, keeping 4 inches of clearance on both sides.
- Charge every battery to 100% before paralleling. EG4 calls this step crucial when installing multiple batteries or adding one to an existing bank.
- Connect power and communication cables, then confirm inverter charge settings match EG4’s parameters.
This is a high-current 48V system with a 1,700A short-circuit rating, so EG4’s manual and local codes call for qualified installers. Connecting to a home panel also needs the right transfer equipment; my article on transfer switches vs interlock kits explains the options.
Reading the front panel
The battery has ALM and RUN status LEDs plus four state-of-charge LEDs. RUN glows solid green at idle and flashes while charging or discharging; ALM turns solid red on a fault. The SOC LEDs show charge in 25% steps, with a red first LED meaning 0–15%. EG4 notes that paralleled batteries can show state-of-charge readings up to 10% apart during a cycle, which is normal and balances out over a full charge and discharge.
Who it’s for
- Good fit: homeowners building or expanding an EG4 hybrid inverter system who want a lot of storage per unit, a garage or utility-room location, and a long warranty.
- Think twice: anyone who needs an outdoor-rated battery (this one is IP20, indoor only) or a battery that’s easy to move. At 293 lb, it’s a permanent install.
FAQ
How much usable energy does the EG4 WallMount 314Ah Indoor have?
EG4 lists 12.86kWh usable at its recommended 80% depth of discharge, from a 16kWh nominal rating.
Is the WallMount 314Ah Indoor UL 9540 listed?
EG4 lists UL 1973 and UL 9540A certification and publishes supported UL 9540 configurations, which cover one to six identical batteries.
Can I add it to my existing 280Ah WallMount bank?
EG4 says the 314Ah fits where earlier models fit, but mixing capacities in one bank is a question for EG4 support and your installer. In any case, charge every battery to 100% before connecting them in parallel.
Can it be installed outdoors?
No. It’s rated IP20 and EG4 limits it to indoor spaces such as garages, basements and utility rooms.
Does it work in a cold garage?
It can discharge down to −4°F, but charging requires 32°F or warmer. The built-in 448W heater turns on when the cells reach 32°F and off at 37°F.
How many can I connect together?
EG4 lists up to 32 in parallel, though UL 9540 listings cover configurations of one to six batteries.
How long will one battery run my house?
At a 500W average load, about 24 hours (estimate). At 1,000W, about 12 hours.
What’s the warranty?
10 years or 10,000 cycles, with registration through EG4’s warranty page.
Bottom line
The EG4 WallMount 314Ah Indoor packs 16kWh into the same footprint as EG4’s earlier 280Ah Indoor, with 12.86kWh usable, 10.2kW of continuous discharge, a cold-weather heater, auto-configuration and a 10-year or 10,000-cycle warranty. For an indoor EG4 hybrid system in a garage or utility room, it’s one of the simplest ways to add a lot of storage per wall bracket, as long as you plan for its weight, clearance rules and a professional install.