Solid State Relay 100 AMP

Haltech 100A Solid State Relay: The Ultimate Power Switching Solution

When high-speed switching and extreme current handling are required, mechanical relays fall short. The Haltech 100A Solid State Relay (SSR) is a heavy-duty semiconductor device designed to control massive electrical loads with precision and reliability. Unlike mechanical relays that use physical contacts, an SSR uses internal transistors (MOSFETs) to switch power. This enables two critical advantages: zero mechanical wear and PWM (Pulse Width Modulation) capability. This relay is the definitive solution for controlling variable-speed cooling fans, high-pressure fuel pumps, and trans-brakes where response time and cycle life are paramount.

Engineering Deep-Dive: PWM and Thermal Management

The Haltech 100A SSR is designed for Low-Side or High-Side switching applications (depending on wiring configuration, though typically used for PWM control on the ground side or simple switching on the power side with proper drivers). Because it has no moving parts, it can be pulsed at high frequencies (e.g., 100Hz to 1000Hz) by an ECU. This allows for progressive control of electric motors—instead of shocking a radiator fan with 100% current instantly, an ECU can ramp the duty cycle from 0% to 100%, reducing mechanical stress on the fan blades and electrical stress on the charging system.

Critical Engineering Note: While efficient, solid-state devices generate heat proportional to the current flow (I²R losses). This 100A unit must be mounted to a metal surface or heatsink using thermal paste to dissipate this heat effectively. Furthermore, when driving inductive loads like large motors or solenoids, the back-EMF generated when the field collapses can damage the SSR. External flyback diode suppression is mandatory across the load to protect the relay.

Operational Benefits

• Speed Control: Enables PWM control for variable speed fans and fuel pumps.
• No Arcing: Safe for use in fuel-rich environments as there are no sparking contacts.
• Silent Operation: No clicking noise during activation.
• Extreme Durability: Immune to vibration and mechanical shock that kills standard relays.

Fitment and Compatibility

Ideal for use with any Haltech Elite or Nexus ECU capable of PWM output.

• Applications: Thermo-fans, Fuel Pumps, Nitrous Solenoids, Trans-brakes.
• Control Signal: Requires a pull-up resistor (included) for certain ECU output types.

Technical Specifications

Summary & What’s Included

Includes:

• 1 x 100A Solid State Relay
• 1 x 1K Pull-up Resistor

Note: Inductive loads (Motors, Solenoids) MUST have diode suppression installed to prevent damage to the SSR. Ensure unit is mounted to a metal chassis or heatsink with thermal paste.