The Fox ESS HV BMS-V2 is the control unit that turns a stack of Fox HV2600 high-voltage battery modules into a single, coordinated storage system. Fitted between the battery stack and the inverter or AC charger, it continuously monitors cell voltage, current, and temperature, balances every module in the chain, and enforces the protection limits that keep a high-voltage lithium stack safe to live with. One BMS unit is required per battery stack — it is not a battery itself, and it is not required on Fox AIO (all-in-one) systems, only on AC-coupled and hybrid inverter installations. 60–500V DC Operating Range 50A Charge / Discharge >98% Round-Trip Efficiency 2–13 Batteries per Stack RS485 / CAN Communication IP21 Protection Rating Compatibility Correction: Despite the "V2" naming, the Fox ESS HV BMS-V2 is backward and forward compatible with both generations of HV2600 battery — the original FE-HV2600 and the newer FE-HV2600-V2 — confirmed directly by Fox ESS. It is not restricted to V2-generation batteries only. Key Features Cell-Level Balancing Actively balances every module in the stack during charge and discharge, so the whole battery bank ages evenly rather than being limited by its weakest cell — the single biggest factor in long-term lithium storage capacity retention. Dual-Channel Voltage Monitoring Two independent measurement channels track total stack voltage to ±1.0% accuracy (FSR), giving the inverter's energy management system an accurate, real-time picture of available capacity. Precision Current Sensing Monitors charge and discharge current across a −65A to +65A range, enabling the fast, accurate cut-offs that protect cells from overcurrent damage. Fast Fault Response Built-in protection against overcharge, over-discharge, short-circuit and thermal runaway conditions, isolating the stack automatically before a fault can propagate. RS485 / CAN Communication Talks directly to Fox H1-series hybrid inverters and AC1/AC3 chargers, reporting state of charge, health, and fault status without any third-party gateway hardware. Wide Operating Envelope Rated for −10°C to 50°C operating temperature and 10–90% non-condensing humidity, making it suitable for garages, plant rooms and most unheated utility spaces. Technical Specifications Electrical Model BMS-BOX Operating Voltage Range 60–500V DC Rated Charge / Discharge Current 50A Current Measurement Range −65A to +65A Total Voltage Measurement Accuracy ±1.0% FSR Voltage Measurement Channels 2 independent channels Isolation Measurement Accuracy ±5% @ ≤100kΩ Available SOC Range 10–100% Charge / Discharge Efficiency >98% Communication RS485 / CAN bus Mechanical Dimensions (L×W×H) 420 × 480 × 116mm (see amber note above) Weight 4.5kg ±1kg Protection Rating IP21 Operating Temperature −10°C to 50°C Storage Temperature −20°C to 50°C Humidity 10–90% (non-condensing) Compatibility & Stack Configuration Compatible Batteries Fox HV2600 — both FE-HV2600 and FE-HV2600-V2 generations Compatible Inverters Fox H1 series (hybrid), AC1 / AC3 (AC-coupled chargers) Not Required For Fox AIO (all-in-one) systems Single-Phase Stack Size 2 batteries minimum Three-Phase Stack Size 3 batteries minimum BMS Units per Stack 1 (one BMS manages the entire stack) Please Note: Stack sizing depends on your inverter phase configuration: single-phase systems need a minimum of 2 batteries per stack, three-phase systems need a minimum of 3. Fox AIO (all-in-one) inverters do not use this BMS at all — it is required only for AC1/AC3 chargers and H1-series hybrid inverters. Good to Know: The HV BMS-V2 carries a 10-year product warranty when the installation is registered with Fox ESS after commissioning. Unregistered installs default to a 5-year standard warranty. Registration takes a few minutes on the Fox ESS warranty portal and is worth doing at handover. Frequently Asked Questions Do I need one HV BMS-V2 per battery, or per stack? One BMS-V2 unit manages an entire stack of HV2600 batteries — you do not need one per battery. A single-phase stack needs a minimum of 2 batteries, a three-phase stack a minimum of 3, all controlled by the one BMS unit. Do I need this BMS if I have a Fox AIO inverter? No. The HV BMS-V2 is required only for AC-coupled chargers (AC1/AC3) and H1-series hybrid inverters. Fox AIO (all-in-one) systems integrate their own battery management and do not use this external unit. Is this BMS only compatible with V2-generation HV2600 batteries? No — despite the naming, distributor documentation confirms the HV BMS-V2 works with both the original FE-HV2600 and the newer FE-HV2600-V2 battery modules, so it can be used on mixed or legacy stacks. What warranty does the HV BMS-V2 carry? 10 years when the installation is registered with Fox ESS after commissioning, or 5 years as standard if left unregistered. Registration is done through the Fox ESS warranty portal. What's included in the box? The BMS unit itself, mounting hardware, battery interconnect cabling and the RS485/CAN communication cable. Fox HV Battery Wall Mount Brackets for the stack are supplied separately.
