Best Solid State Relays for 20A Loads
Answering the question: which solid state relays handle 20A safely and reliably for 24-480V AC loads? This guide highlights five solid state relays that target 20A applications, explaining who they’re best for and why. It’s designed for buyers seeking stable electrical switching with minimal noise, sparing mechanical wear, and straightforward integration with control signals in automation, heating, and cooling systems.
Top picks are chosen for clear suitability to typical 20A tasks: hobbyists assembling small CNC or temperature-control projects, HVAC enthusiasts upgrading controllers, and professionals needing dependable, compact modules with DC-to-AC or DC-to-DC input options. A concise buying table below summarizes key specs to compare at a glance.
| Product | Brand | Input | Output | Current | Notes |
|---|---|---|---|---|---|
| CGELE SSR-25DA | CGELE | 3-32V DC | 24-480V AC | 25A | Solid state module with included thermal grease; DC to AC control |
| Heschen SSR-20DA | Heschen | 4-32V DC | 24-480V AC | 20A | Compact single-phase relay |
| CGELE SSR-25AA | CGELE | 70-250VAC not applicable | 24-480VAC | 25A | AC-to-AC input variation |
| BlueStars SSR-25DD | BlueStars | DC 3-32V | DC 5-200V | 25A | DC-to-DC configuration; detailed spec notes |
| HiLetgo SSR-25DA | HiLetgo | 3-32V DC | 24-380V AC | 25A | Includes heat sink options |
CGELE SSR-25DA DC to AC 25A Solid State Relay
Best for: small to mid-size automation projects requiring DC input (3-32V) to drive AC loads up to 24-480V. This model is common for heating and cooling controls, where compact form and reliable switching are essential.
Why selected: high current rating of 25A, compatible voltage range, and a compact package. The included thermal grease helps with heat dissipation after installation.
Limitation: verification of output voltage tolerance at the extreme high end is recommended in final designs. Consider a heatsink for continuous duty in hot environments.
Heschen SSR-20DA: 20A DC to AC Relay
Best for: compact, reliable 20A switching from DC control to AC output in smaller installations or space-constrained panels.
Why selected: explicitly rated for 20A at 50-60Hz with a 24-480VAC output range, offering a balanced option when 20A is the target.
Caution: ensure control voltage stays within the 4-32V DC range to avoid misoperation during startup or noise from nearby devices.
CGELE SSR-25DD: 25A DC-DC Input to DC-DC Output
Best for: DC control systems that need to switch DC outputs, suitable for DC-DC regulated setups in automation workflows.
Why selected: 25A current rating with a compact form factor and typical 3-32VDC input. The dual “DC-to-DC” configuration supports certain DC bus applications.
Limitation: documentation emphasizes DC-to-DC behaviour; verify compatibility with the specific DC load and voltage range before deployment.
HiLetgo SSR-25DA: 25A Solid State Relay Module
Best for: quick projects needing a ready-made relay module with heat dissipation options and straightforward DC input control.
Why selected: confirms 25A capability with 3-32V DC input; compatibility with typical PID controllers and temperature controllers makes it a go-to for hobbyists.
Limitation: check the included heatsink option; some installations may require additional cooling in high ambient temperatures.
Buying Guide
- Input voltage range: Most 20A SSRs accept 3-32V DC inputs. Ensure your controller can supply the needed control voltage without straining its output.
- Output voltage range: Look for an SSR that supports your load’s AC voltage, typically up to 380-480V for industrial systems. Confirm the exact rating for your hardware.
- Current rating and duty cycle: A 20-25A rating is common. For continuous duty or heating elements, verify the thermal management plan, including heatsinks and ambient temperature.
- Control method and compatibility: Decide between DC-to-AC and DC-to-DC control modules. Ensure the PLC, microcontroller, or thermostat you use is compatible with the SSR’s input type.
- Physical form and mounting: Consider size, enclosure space, and whether you need extra components like thermal grease or heatsinks for heat dissipation.
- Protection features: Some models include features like fast switching, EMI resistance, and anti-noise performance. Use protective strategies accordingly.
Frequently Asked Questions
- What does 20A in a solid state relay mean? It refers to the maximum current the output can switch under specified conditions without overheating or failing prematurely.
- Can a 25A SSR be used for 20A loads? Yes, a higher-rated SSR can handle 20A loads, provided the input control signals and thermal management are appropriate.
- Do these SSRs require heat sinking? Some do, depending on load, ambient temperature, and duty cycle. Check the datasheet and use heatsinks or thermal grease as advised.
- Are DC input SSRs compatible with standard microcontrollers? Most are designed for common DC control voltages (3-32V). Confirm logic level compatibility with your controller.
- What should I consider for long-term reliability? Ensure proper enclosure, adequate cooling, and a control circuit free of voltage spikes that could damage the input.