Overcoming –30°C Extremes: How HoyUltra 2 Secures PV+Storage Reliability in Northern Europe

Extreme weather puts energy storage systems through the toughest real-world test: stability, safety, and lifespan. During a severe snowstorm in Utrecht, Hoymiles’ fully liquid-cooled HoyUltra 2 (261 kWh) supported a local farm’s PV + storage project in achieving smooth grid connection, delivering safe, reliable, efficient power in harsh cold conditions.

Extreme winter weather is becoming more frequent and severe across parts of Europe. For agricultural operations—especially in high-latitude regions—reliable electricity is critical for heating, ventilation, water pumping, lighting, and other energy-intensive activities that cannot be interrupted.

Recently, Utrecht, the Netherlands experienced extreme snowfall and severe winter conditions. To support on-farm energy self-sufficiency and keep power supply steady in challenging weather, the farm required an energy storage solution that could be deployed quickly and operate reliably in low temperatures.

Hoymiles deployed four HoyUltra 2 fully liquid-cooled energy storage units, supported by on-site technical team assistance and fast local inventory supply from the European warehouse. The complete system commissioning and grid connection were completed in just one day.

Four core advantages of HoyUltra 2 that enable stable operation at extreme low temperatures:

1) System-level thermal management (Module temperature difference < 2°C)

A PACK + PCS fully liquid-cooled architecture, combined with high-efficiency heat-transfer fluid and intelligent temperature control, keeps the temperature difference between battery cells and IGBT modules within 2°C, helping ensure stable system operation in extreme cold environments as low as -30°C.

2) Intelligent liquid-cooling control (Auxiliary power consumption reduced by 30%+)

The system intelligently switches liquid-cooling modes to match varying temperature and power demands. Testing shows auxiliary power consumption reduced by 30%+. The “dual-loop (inner/outer) circulation + dual heat exchange” design helps isolate external environmental impact.

3) High-protection design (IP55 + C5, designed protection life > 15 years)

A top-mounted liquid-cooling unit design, with IP55 protection and C5 anti-corrosion standard, supports long-term operation in complex environments; designed for a protection life exceeding 15 years.

4) High power density & efficiency (Up to 90.3% cycle efficiency; 88.4% equivalent cycle efficiency)

With precise temperature control and efficient heat dissipation, the system achieves up to 90.3% maximum cycle efficiency and over 88.4% equivalent cycle efficiency, maintaining efficient energy conversion even under long-term high load.