Best Solid State Latching Relay Solutions for Your Projects
Solid state latching relays (SSLRs) provide reliable, contactless switching with bistable action that stays in its last state without continuous power. This article highlights five practical SSLR options ideal for DIY electronics, home automation, or industrial-control projects. Each pick is evaluated for typical makers and engineers who need compact form factors, clear input ranges, and safe DC-to-DC or DC-to-AC switching capabilities. Use these as a quick reference to choose the right SSLR based on voltage, current, and control requirements.
Buyer-friendly summary table of chosen products:
- Product A: Compact 1A SSLR with 3-32V input, 5-60V output; best for ESP32/Arduino hobbyists.
- Product B: Bulk-pack option of the same 1A SSLR; ideal for small batch projects or economy-minded builds.
- Product C: 25A DC-to-AC SSLR suitable for higher-power loads and quick prototyping.
- Product D: 25A DC-to-DC SSLR for DC-only switching with solid insulation features.
- Product E: Latching relay board with 0 power hold and adjustable timing for circuit detection.
AURTRR SSLR 1A, 3-32V Input, 5-60V Output
Brand: AURTRR. Features include input 3-32V DC and output 5-60V DC. A key note is that without a heatsink installed, the maximum current is 1A. Long lifespan is supported by optocoupler isolation, making it effectively contactless with no mechanical wear. Best for hobbyists and small-control tasks in ESP32, Raspberry Pi, Arduino, or e-bike applications that require compact form factors and safe control. Cautions: ensure adequate cooling if you approach 1A, and verify the DC polarity and voltage window for your load.
Best for: small hobby projects and microcontroller-based control where space is tight and a 1A ceiling is acceptable. Choose this if you need a compact 3-32V input to 5-60V output SSLR with long life and no mechanical wear.
AURTRR SSLR 10-Pack, 1A, 3-32V Input
Brand: AURTRR. This is a bulk-pack variant of the same 1A SSLR with 3-32V input and 5-60V output. It mirrors the single-pack’s voltage ranges and optocoupler isolation for a longer lifespan and zero mechanical wear. Best for small workshops or educational labs that need to wire multiple SSLRs in parallel for modular projects. Limitation: bulk packs do not change the electrical characteristics; cooling considerations still apply when approaching 1A per channel.
Best for: projects needing multiple SSLRs from a single vendor for consistency; ideal for instructional kits or multi-channel control panels. Choose this if you want predictable behavior across channels and a budget-friendly option.
CGELE SSR-25DA DC to AC, 25A
Brand: CGELE. This solid state relay handles 24-480 VAC output at up to 25A, with a DC input range of 3-32V. It ships with thermal grease for faster heat dissipation and a compact plastic cover for safe mounting. Best for higher-power loads where DC control must switch AC mains or large AC loads. Better for: industrial-style setups, motor control, or heating elements that require robust, fast switching. Caution: ensure proper heat management across larger loads; improper heat sinking can reduce performance.
Best for: higher-current DC-to-AC switching where more aggressive load handling is needed; choose this when you need a reliable 25A module with easy cooling options.
CGELE SSR-25DD DC to DC, 25A
Brand: CGELE. This 25A DC-to-DC SSLR provides a similar 3-32VDC input with an output range of 5-220VDC. It shares the same durable build and thermal management options as the 25DA model but is tailored for DC loads requiring higher DC output. Best for DC-powered devices and DC motor control with significant voltage headroom. Limitation: similar thermal considerations apply; ensure sufficient airflow and heat dissipation for continuous duty.
Best for: DC-only applications that require higher DC output voltage flexibility; choose this if your load operates primarily on DC and you need up to 220V DC switching.
FTVOGUE Latching Relay Module
Brand: FTVOGUE. This is a latching relay module with a bistable self-locking flip-flop and a 0 power hold switch, enabling energy-saving operation. Time control ranges from 0.1 seconds to 270 hours, giving flexibility for circuit timing and automation. Best for: projects requiring a stable on/off state without continuous current draw, such as detection circuits or state-holding switches. Caution: verify the control voltage matches DC12V and ensure the module’s timing range aligns with your application’s needs.
Best for: circuits needing a self-holding, power-saving latch with adjustable timing; choose this if you want a robust, energy-efficient latch in a compact module.
Carlo Gavazzi SSLR RD0605-D
Brand: CARLO GAVAZZI. This SSLR is listed with limited descriptive data in the provided listing. It is a known brand in industrial controls and commonly used for panel mounting and higher-reliability environments. Best for: industrial or professional settings where Carlo Gavazzi components are standard. Limitation: explicit electrical specifications beyond basic labeling are not clearly provided in the listing, so verify input/output ranges with the supplier before selection.
LCLCTC SSLR DD 3.3V-24V, 1.5A
Brand: LCLCTC. Features include input 3-32V DC and output 5-60V DC with no-contact operation and a note that without a heatsink, the current should not exceed 1.5A. Best for: compact, DIN-rail ready control panels or PLC integration where no physical contacts are desired. Caution: exceed 1.5A without a proper heatsink and cooling may lead to performance loss or thermal risk.
Best for: DC-to-DC switching in small control panels or PLC applications where silent operation and long life are priorities; choose this if you need DIN-rail compatible packaging.
Buying Guide: Key Considerations For SSLRs
What is an SSLR and when should you use one?
An SSLR uses solid-state switching with optocoupler isolation to control loads without mechanical contact. It is ideal where long life, fast switching, and low maintenance matter. Use SSLRs for DC-to-DC or DC-to-AC control in automation, motor drives, heating elements, and smart-home projects where you want a clean, silent switch.
Input and output voltage ranges
Check that the input control voltage matches your microcontroller or control circuit (commonly 3-32V DC). Confirm the output type and voltage range (DC or AC, and the maximum current/voltage). If your load is DC-only, a DC-DC SSLR is usually more efficient; for mains or AC loads, choose a DC-to-AC SSLR with adequate amperage.
Current rating and thermal considerations
Most SSLRs in consumer form factors are rated from 1A to 25A. Always consider continuous current, surge current, and heat sinking. If you approach the product’s current limit, ensure adequate cooling or select a higher-rated model to avoid thermal throttling or failure.
Lifetime, reliability, and isolation
Optocoupler isolation provides electrical separation between control and load circuits, extending life and safety. SSLRs with no mechanical contacts reduce wear, but thermal management remains important for performance and longevity.
Form factor and mounting
Compact modules for microcontroller projects are valuable, but consider DIN-rail or panel-mount options for professional installations. Plastic covers can aid safety, while metal enclosures may improve EMI robustness in industrial environments.
Special features to consider
Look for latching (bistable) behavior if you need the relay to stay in its last state without continuous control power. Some models include 0 power hold switches for energy savings and adjustable timing to tailor switching actions. These features can simplify power management in automation tasks.
Safety and compliance considerations
When integrating SSLRs into consumer devices or machinery, ensure compatibility with safety standards and local electrical codes. Verify manufacturer documentation for wiring diagrams, heat-sinking recommendations, and maximum operating conditions before installation.
How to compare options quickly
- For hobby projects with microcontrollers: look for 1A SSLRs with 3-32V input and 5-60V output.
- For multi-channel setups: bulk-pack SSLRs can reduce cost per channel while keeping electrical specs consistent.
- For higher-power mains loads: prefer 25A DC-to-AC SSLRs with clear cooling guidance.
- When energy efficiency matters: consider latching SSLRs with 0 power hold features.
Frequently asked questions
- What is the main advantage of a latching SSLR over a standard solid-state relay?
– A latching SSLR maintains its state without continuous drive current, saving power in certain control applications. - Can SSLRs be used for DC motors?
– Yes, many SSLRs support DC-to-DC or DC-to-AC switching; verify current and voltage ratings for motor loads. - Do SSLRs require heatsinking?
– Some do, especially at higher currents. Check the product’s thermal guidance and ensure adequate cooling. - Are optocouplers enough for isolation?
– Optocouplers provide electrical isolation between control and load sides, enhancing safety and reducing interference. - What should I consider when choosing between 1A and 25A SSLRs?
– Match the load current, voltage, and duty cycle; larger loads typically require higher current ratings and better heat management.