Fox ESS · Home battery model
ECS battery
Fox ESS ECS is a family of modular high-voltage LFP battery towers, with capacity and stack limits set by the exact module series.
Specifications
| Specification | Value |
|---|---|
| Type | modular high-voltage battery |
| Cell chemistry | LFP |
| Nominal capacity (kWh) | 8.06 to 28.21 for an ECS4100-H2 to H7 tower |
| Module nominal energy (kWh) | 4.03 for ECS4100 |
| Module count | 2 to 7 for ECS4100 |
| Round-trip efficiency (%) | >95 battery-pack figure for ECS4100 |
| Scalable | yes |
| Maximum stack capacity (kWh) | 28.21 for ECS4100-H7 |
| Warranty (years) | 5 from installation, capped at 65 months from manufacture; further 84 months conditional |
| Warranty throughput (MWh) | 14.5 per 4.03 kWh ECS4100 module |
| Warranty retained capacity (%) | 70 |
| IP rating | IP65 for ECS4100 |
| Operating-temperature range (°C) | charge 0 to 55; discharge -10 to 55 for ECS4100 |
| Depth of discharge | 90% for ECS4100 |
| Maximum charge/discharge current (A) | 50 for ECS4100 |
Fox ESS ECS is a modular high-voltage LFP battery format. A tower combines a battery control unit with battery modules. ECS is not one specification: Fox ESS documentation names ECS2900, ECS4100, ECS4300H and ECS4800 families, so the suffix is part of the product and service record.
As of 23 July 2026, the current UK range gives its detailed modular-battery coverage to newer EQ and CQ products. ECS is mentioned on current H3 pages, but without a corresponding current UK product page or model schedule. Current UK new-product availability for ECS is therefore unconfirmed.
ECS4100 example
The figures in the specification apply to ECS4100. Its modular arrangement shows why ECS alone is not enough to establish a tower’s energy, current or operating limits. Another suffix may use a different module size or controller even where the cabinets look similar.
Those figures do not apply automatically to other ECS suffixes. Module energy, permitted stack height, current and the matching battery control unit vary between families.
ECS controller and inverter matching
The inverter model, battery control unit, module family and count all affect whether the combination is supported. Being inside an inverter’s broad voltage window is not enough.
ECS extension and throughput limits
The Fox ESS UK and Ireland policy in force on 23 July 2026 gives named ECS families standard cover for 60 months from installation but no later than 65 months from manufacture. A conditional extension applies when registration and FoxCloud requirements are met. Performance cover ends at the stated time or energy-throughput limit, whichever comes first, and requires the listed operating conditions.
For ECS4100 towers, the policy applies its throughput boundary per battery module rather than as one allowance for the complete tower.
The applicable policy, installation date, serial numbers, module count and registration evidence should stay with the handover documents.
Related entries
Manufacturer and reference sources
Brand
Reference type
Home battery model
Last reviewed
23 Jul 2026
Current status
UK new-supply status is unconfirmed.