iRhapsody 12V SPST Automotive Relay Kit - Pack of 6 40A 4‑Pin Relays with Wiring Harnesses, Durable Vibration‑Resistant

High-current 12V SPST relay kit for automotive and DIY electrical systems — six durable 4-pin relays with harnesses rated for 40A switching and long life.

These iRhapsody relays convert a low-voltage control signal into a heavy-current switch for headlights, fans, pumps, horns and other 12V circuits. Each relay uses a 12 VDC coil and tinned copper leads, is built to withstand vibration and shock, and includes a wiring harness for quick installation. The kit is designed for reliable on/off switching in vehicles, marine projects, and off-grid systems where a dedicated, protected switching device is required.

What electrical specs matter for using these relays?

Key performance figures tell you how much load the relay can safely handle and how the coil behaves. These relays use a 12 V nominal coil drawing about 1.8 W with an 80 Ω coil resistance, and the contacts are rated for 40A at 14V DC.

• Nominal coil voltage: 12 VDC; coil power ~1.8 W; coil resistance 80 Ω
• Contact rating: NO, 40 A at 14 V DC; maximum switching power ~560 W
• Operate/release voltages: operate ~6–8 V, release ~0.6–3.6 V; max applied voltage 15.6 V
• Contact resistance ≤100 mΩ (measured at 6 VDC, 1 A)

How durable and reliable are these relays under real-world conditions?

The iRhapsody relays are built for long service life and environmental stress typical of automotive and industrial use. They have both electrical and mechanical life ratings, and are engineered to resist common vibration and shock encountered in mobile applications.

• Electrical life: approximately 100,000 operations (at 30 ops/minute)
• Mechanical life: around 10,000,000 operations
• Temperature range: -30°C to +80°C; vibration tolerance 10–55 Hz, 1.5 mm
• Shock resistance: operational up to 10 g, damage threshold 100 g

How do I integrate these relays into automotive wiring projects?

Each relay comes with a harness to simplify wiring and to minimize soldering or crimping during installation. Use the relay to switch high-current loads by routing the power through the relay contacts and control the coil from a dash switch, ECU output, or another low-current source.

• Primary leads use 12 AWG tinned copper for high-current paths; coil leads use 16 AWG
• Keep continuous loads at least 10–15% below the 40A rating for safety and longevity
• Follow vehicle ground and fuse best practices — fuse the power feed close to the battery
• Operate time ~7 ms; release time ~5 ms for responsive switching

What electrical safety and insulation features are provided?

Insulation and dielectric ratings reduce the risk of shorts and ensure reliable separation between coil and contacts. The relays meet standard dielectric strengths for brief over-voltage and isolation testing, suitable for typical automotive electrical environments.

• Insulation resistance ≥100 MΩ at 500 VDC
• Dielectric strength between open contacts: 500 VAC for one minute
• Dielectric strength between contacts and coil: 750 VAC for one minute
• Humidity operation: specified for 40%–85% relative humidity ranges

Who is this for? If you build or repair vehicles, install auxiliary lighting, add winches, fans, or pumps, or design 12V control systems, this iRhapsody 4-pin SPST relay pack provides a cost-effective solution for switching heavy loads with a low-current control signal. The included harnesses make it especially useful for fast swaps or upgrades where dependable, high-current switching is required.