Fox ESS EP12
An 11.52 kWh high-voltage LFP battery from Fox ESS, scalable to four units (46.08 kWh), with 90% depth of discharge and IP65 protection.
- Best for high-voltage stacking
- Installed battery
- 11.52-46.08 kWh
- IP65
- Made by Fox ESS.
- Energy: 11.52 kWh nominal per unit, 90% depth of discharge, up to four units in parallel (46.08 kWh).
- A battery only: it needs a compatible Fox ESS hybrid inverter; the sources we read do not name models.
- High-voltage (384 V nominal), IP65, floor or wall mounted, indoors or outdoors.
- Newer than the EP11 (10.36 kWh); Fox ESS lists both on its battery page.
Not tested by us
We have not tested the Fox ESS EP12. The figures on this page come from the sources listed at the end of the page, checked on 12 November 2026, and we do not show prices. "Best for" is based on what the maker says the product is designed for, not on our own tests.
Key figures
11.52 kWh
Per unit
46.08 kWh
Maximum, 4 units
90%
Depth of discharge
Specifications
Last checked on 12 November 2026. The grey text under each name explains what the value means. To see it next to other products, compare it in our comparison tool.
| Specification | Value |
|---|---|
| Storage | |
| CapacityHow much energy the battery stores. Bigger means longer runtime or more of your own solar power used later. | 11.52 kWh nominal per unit (30 Ah at 384 V); up to 46.08 kWh with four units |
| Usable capacityThe part of the stored energy you can actually use. It is lower than the nominal capacity. | Not stated (the datasheet gives 90% depth of discharge) |
| Depth of dischargeHow much of the battery can be emptied without harming it. 90% means 10% is kept in reserve. | 90% |
| Battery chemistryLFP (lithium iron phosphate) cells are known for long life and stable behaviour with heat. | LFP (LiFePO4) |
| Cycle lifeHow many full charge and discharge cycles the cells are rated for before they hold less than the stated share of their original capacity. | Not stated in the datasheet or manual |
| ExpansionExtra battery units that add storage to the same system. | Up to four units connected in parallel |
| Power | |
| Charge and discharge powerHow fast the battery can take in and give out energy. It sets how many devices it can serve at once. | Maximum charge and discharge current 30 A (15 A recommended for charging); peak discharge 65 A for 60 s and peak charge 36 A for 5 s at 384 V nominal. Fox ESS gives amps, not kW. The manual gives the peak discharge time as 30 s |
| Round-trip efficiencyThe share of the energy you put in that comes back out. The rest is lost as heat. | At least 95% (battery pack) |
| Backup in a power cutWhether it can keep selected circuits running during a grid outage. | Depends on the inverter: the battery itself is not an inverter |
| Solar | |
| Solar inverterTurns the DC power from solar panels into AC for the home. Built in means no separate solar inverter is needed. | None: this is the battery only. It connects to a Fox ESS inverter over CAN; the datasheet and manual do not list compatible inverter models |
| Solar and off-grid | |
| Works with solar panelsWhether you can charge it from solar panels. Yes means a built-in solar input or a compatible solar setup; read the detail for the voltage and power limits. | Yes: through the inverter it connects to; the battery has no solar input of its own. |
| Off-grid useWhether the maker describes it running with no grid connection at all, for example in a cabin, van or off-grid home. Backup only means it covers power cuts but needs the grid the rest of the time. | Partly: backup and off-grid operation depend on the connected inverter; Fox ESS does not describe a stand-alone off-grid system. |
| Connection and housing | |
| Grid connectionThe supply type it is built for. Check it matches your home's supply. | Not applicable: the battery connects to an inverter (384 V nominal, 348-438 V operating range, high-voltage DC) |
| Dimensions (W × H × D)Width, height and depth of the unit, so you can check that it fits. | 710 × 640 × 185 mm |
| WeightMatters for lifting, wall mounting and moving it. | 98 kg (±5%), of which the cells weigh 70 kg |
| Protection ratingIP ratings show protection from dust and water. IP55 and IP65 are rated for outdoor-style exposure; check the installation guidance. | IP65, indoor or outdoor, floor or wall mounting, natural convection cooling |
| Operating temperatureThe range it is rated to work in. Cold and heat can reduce performance. | Charging 0 to 55 °C; discharging -10 to 55 °C; storage -10 to 40 °C in the datasheet (0 to 35 °C in the manual); a warm-up function is optional (-25 to 55 °C when on) |
| ConnectivityHow you monitor and control it, usually through an app. | CAN to the inverter; 5 LED status display |
| CertificationsSafety and grid standards the maker says the product meets. | IEC 62619, EN IEC 61000-6-1/2/3/4 and UN 38.3 |
| Warranty | |
| WarrantyThe period the maker covers. Read the terms: conditions and capacity guarantees differ. | Not stated for this model: the datasheet gives none, and the Fox ESS UK and Ireland battery warranty policy (V4.2) names the EP11 but not the EP12 |
Compatible with
What Fox ESS says this product works with. Anything not listed here is not confirmed.
- Inverters
- Fox ESS connects the battery to an inverter over CAN. The datasheet and manual do not list inverter models, so ask your installer which Fox ESS hybrid inverter fits.
- Expansion
- Up to four units in parallel.
- Mounting
- Floor or wall mounting.
Rules where you live
An installed battery normally needs a qualified electrician, and in many countries you must also tell your grid operator, especially if it can export. It is not a plug-in battery. Rules, incentives and tax treatment differ by country: see our country guides for what applies where you live.
Strengths and things to check
Strengths
- 11.52 kWh in a single unit
- Scalable to 46.08 kWh with four units
- At least 95% battery pack round-trip efficiency
- IP65, floor or wall mounting
- Optional warm-up function for cold conditions
Worth checking before you buy
- A battery only: you need a compatible Fox ESS inverter as well
- Heavy at 98 kg per unit
- No cycle rating or warranty term is given for this model
- Fox ESS gives current in amps, not power in kW
Change log
We record changes to this page here, so you can see when figures such as the warranty were last updated.
- 12 November 2026
- Page published. Datasheet used: EP12 V1.3, 26 May 2026. Warranty at publication: not stated for this model. The manual also covers an EP12 Plus (w) variant with a warm-up function.
- 12 November 2026
- Added the Solar and off-grid specifications (solar panels and off-grid use).
Where this information comes from
We have not tested this battery. Every figure above comes from Fox ESS's EP12 datasheet (V1.3, 26 May 2026), the Fox ESS EP battery manual (V1.0.1) and the EP12 page on fox-ess.com, last checked on 12 November 2026. The datasheet and manual call the model EP12 Plus and also describe a (w) variant with a warm-up function; the product page says EP12. Where the two documents differ (storage temperature, peak discharge time) we show both. A value that the sources do not state is shown as not stated.
We do not show prices, because they depend on the installer's quote.
- Manufacturer Fox ESS EP12 datasheet V1.3
- Manufacturer Fox ESS EP battery user manual V1.0.1 (EP3/EP5/EP6/EP12 Plus)
- Manufacturer Fox ESS battery warranty policy, UK and Ireland (V4.2)
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Common questions about Fox ESS EP12
How much does the Fox ESS EP12 store?
Fox ESS lists 11.52 kWh nominal per unit with 90% depth of discharge. Up to four units can be linked for 46.08 kWh.
Does it include an inverter?
No. It is a high-voltage battery only and connects to a Fox ESS inverter over CAN. Ask your installer which inverter fits your home.
How long is the warranty?
We could not confirm it. The datasheet gives none, and Fox ESS's UK and Ireland battery warranty policy (V4.2) lists the EP11 but not the EP12. Ask your installer for the current terms before you buy.
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