Programmable 4‑channel Morningstar Relay RD‑1 logic relay driver for voltage, temperature and parameter control in off‑grid and hybrid systems.

• Four independent programmable channels (each a 750 mA switch) that can operate separately or be combined with AND/OR logic; channels can also act as sensors to measure voltage or other parameters.
• Events that can trigger a response include: battery voltage or another voltage parameter reaching a high or low voltage threshold; connected Morningstar products (e.g., TriStar) generating an alarm or fault; device temperature rising or falling to set levels; or another TriStar/external sensor parameter reaching a defined threshold.
• Typical threshold control modes monitor a parameter — for example the battery voltage level (or a voltage level coming from another source) — and trigger actions such as Run, Pre‑crank (Pre‑Heat), Crank (Momentary Run), Load, Stop, etc.
• Practical example: monitor battery voltage and, when the battery is full, send excess solar charge to a dump load or trigger generator stop.
• Electrical specifications: Number of channels: 4. Nominal system voltage: 12 V / 24 V / 36 V / 48 V. Operating voltage: 8–68 V. Maximum channel current: 750 mA. Self‑consumption: < 20 mA. Transient surge protection: 1500 W per channel.
• Sensors, ports and temperature ranges: Temperature sensor range: -40 °C to +85 °C (-40 °F to +185 °F). Operating temperature: -40 °C to +45 °C (-40 °F to +113 °F). Storage temperature: -55 °C to +85 °C (-67 °F to +185 °F). Communication ports (opto‑isolated): RJ‑11 meter‑bus and 9‑pin serial RS‑232.
• Physical and connection details: Terminal size: 2.5 mm². Dimensions: 163 x 81 x 33 mm (6.42 x 3.19 x 1.30 in). Weight: 0.20 kg (0.44 lb).
• Warranty and documentation: This product is covered by a 5‑year warranty. Instruction manual and product datasheet are available to download; Morningstar MSView software is also available for download.

Compatible with Morningstar TriStar controllers and other external sensors; recommended for controlled installation with correct earthing and surge protection. Download manuals and MSView before commissioning.