Basic Information Model: DJ400. Type: Maintenance-free Valve-Regulated Sealed Lead-Acid Battery1. Rated Voltage: 2V4. Rated Capacity: 400Ah4. Product Features Maintenance-free1: Special design overcomes electrolyte water loss during charging. Electrolyte volume and specific gravity remain almost unchanged during use, completely eliminating the need for water replenishment and simplifying maintenance. Sealed and Safe1: No free-flowing electrolyte inside, allowing vertical or horizontal installation. Leak-proof, no acid mist generated during normal charging, can be installed in ordinary rooms, reducing engineering costs. Long Service Life: Utilizes lead-calcium alloy grids with excellent corrosion resistance. Under 25°C environment, normal float service life can exceed 10 years1. High Power Discharge Performance1: High-quality plates with low internal resistance and glass fiber separators are used, assembled tightly with extremely low internal resistance. Capable of high-current discharge within -40°C to 60°C temperature range, output power is approximately 15% higher than conventional batteries. Easy Installation and Use1: Batteries are fully charged upon shipment, users can install and use directly after receipt. Low Self-Discharge Rate: Special lead-calcium alloy formulation results in extremely low self-discharge rate. After standing for 28 days at 25°C room temperature, self-discharge rate is less than 1.8%5. Safe and Reliable5: Dual-seal design for battery case cover and terminals prevents acid leakage. Safety valve prevents external gases and dust from entering. Equipped with a safe and reliable explosion-proof exhaust system, eliminating battery case swelling caused by excessive pressure. Technical Parameters Charging Voltage: At 25°C, float voltage is typically 2.23V-2.27V, equalize voltage is usually 2.30V-2.35V. Charging Current: Recommended charging current is 10%-20% of C10 capacity, i.e., 40A-80A. Operating Temperature Range5: Charging temperature 0°C-40°C, discharge temperature -20°C-55°C, storage temperature -15°C-50°C. Application Range5 Suitable for various backup and energy storage power applications, such as uninterruptible power supplies, electronic energy systems, emergency backup power, railway signals, aviation signals, security systems, electronic devices and equipment, communication system power, DC power supplies, automatic control systems, etc.