Delco Remy 8600473 55SI High-Output Alternator – 12V 420A Brushless Standard Pad (80mm) with Remote Sense | Fire Truck, Utility Truck, APU Applications

Features

• DELCO REMY'S HIGHEST-OUTPUT 12V ALTERNATOR Genuine Delco Remy 55SI, 420A at 12V; purpose-built for fire trucks, utility and work trucks, and long-haul trucks equipped with auxiliary power units (APUs) delivers the massive sustained output required by today's most electrically demanding commercial vehicles
• ONLY 80MM PAD MOUNT IN 12V The 8600473 is the only 55SI alternator available in a 12V standard 80mm pad mount configuration, making it a precise OEM-spec replacement for vehicles originally equipped with this mounting style verify your current mount before ordering
• BRUSHLESS DESIGN FOR MAXIMUM DURABILITY Fewer moving parts and internal connections compared to brush-style units means significantly reduced wear; compact 8-inch frame length and 43 lb. weight leave more underhood space while delivering class-leading 420A output
• REPLACES DUAL ALTERNATOR SYSTEMS The 55SI's 420A output is engineered to replace two-alternator setups, freeing underhood space for other accessories and simplifying the charging system without sacrificing total electrical capacity
• REMOTE SENSE FOR OPTIMIZED CHARGING Remote Sense technology reads actual battery terminal voltage and automatically boosts output to compensate for voltage drop, reducing battery charge time by up to 50% critical for high-draw applications like emergency lighting, power inverters, and plug-in tools

Description

Delco Remy 8600473 55SI Brushless Alternator – 12V, 420A, Standard Pad 80mm with Remote Sense The Delco Remy 8600473 is the brand's highest-output 12-volt alternator, delivering 420 amps via the 55SI brushless platform in the only standard 80mm pad mount configuration available in 12V. Designed for fire trucks, utility and work trucks, and long-haul trucks running auxiliary power units, this unit handles the most demanding commercial electrical loads on the market. It is also engineered as a direct replacement for dual alternator systems, consolidating output into a single, compact unit and freeing underhood space. Specifications Model: 55SI | Voltage: 12V | Output: 420A | Mount Type: Standard Pad (80mm) | B+ Output Terminal: 5/16" | Fan Type: External | Remote Sense: Yes | Ground: Negative | Design: Brushless | Frame Length: 8 inches | Weight: 43 lbs | Condition: New OEM Key Features Highest- output alternator in the Delco Remy 12V lineup and highest in its class industry-wide. Brushless design with fewer moving parts for extended service life. Remote Sense technology reduces battery charge time by up to 50%. Compact 8-inch frame length maximizes underhood airflow and accessory space. Can replace dual alternator configurations. Designed for vehicles with significant sustained electrical loads including emergency lighting, power inverters, tool circuits, and APU systems. Vehicle & Equipment Applications Fire trucks and emergency response vehicles; utility and work trucks with high electrical accessory loads; long-haul trucks with auxiliary power units (APUs); industrial and agricultural equipment. Confirm part number match before ordering — this is the only 80mm pad mount 55SI unit in 12V. Cross Reference Numbers Replaces Delco Remy 8600628, 8600707; see also related 55SI unit 61006079. Verify your OEM part number to confirm fitment.

Manufacturer: ‎Delco Remy

Brand: ‎DELCO REMY

Model: ‎Delco Remy

Item model number: ‎8600473

Exterior: ‎Painted

Manufacturer Part Number: ‎Delco-8600473

Date First Available: April 9, 2026