L3 Communications PS-835D

The L3 Communications PS-835D is a 24 VDC nominal emergency power system engineered to supply continuous standby power to critical flight instruments during aircraft power failures. This 150-watt unit delivers uninterrupted DC power to connected avionics modules without switching delay, ensuring essential systems remain operational when primary aircraft power is lost.

## Technical Specifications

• **Output Power:** 150 watts for 30 minutes continuous operation
• **Ampere-Hour Rating:** 5.0 Ah
• **Battery Life:** 2.5 to 5.0 hours supplying standby attitude gyros at 25°C
• **Input Voltage:** 28 VDC (from aircraft system)
• **Output Voltage:** 24 VDC
• **Battery Type:** Heavy duty sealed lead-acid wet cells
• **Recharge Time:** 50% capacity within one hour at 25°C; automatic full-charge maintenance during normal flight operations
• **Weight:** 12.4 lbs
• **Heater Operation:** Automatically controlled internal heaters with 55°C activation threshold

## Key Features

• Automatic power transfer from aircraft bus to battery during primary power loss
• Front panel and remote self-test capability
• LED indicators for voltage level, cell status, heater operation, and overtemperature alert (>55°C)
• Short circuit protection available on inverter and converter modules
• Sealed construction for enhanced reliability in severe thermal and operational environments

## Typical Applications

• Emergency attitude indicators and gyro horizons
• Standby transceivers and communication equipment
• Emergency lighting systems
• Flight instrument backup power for military, aerospace, and commercial transport operations

## Compatibility & Integration

The PS-835D accepts optional power conditioning modules for tailored output configurations, including 115 VAC (1Ø or 3Ø, 400 Hz), 5 VAC (400 Hz), and 5 VDC outputs via modules such as SI-100, SC-841, BC-815, or MTG-101A.