Features: 1. Build-in industrial micro controller. 2. Fully 4-stage PWM charge management. 3. One-key setting,digital display, auto memory function. 4. Dual mosfet Reverse current protections, low heat productions. 5. Build-in short-circuit protections, open-circuit protections, reverse protections, over-load protections. Specifications: Buck charge: 28.8V. Float charge: 27.4V. USB output: 5V/3A. Self-consume: <10mA. Discharge stop: 21.4V. Voltage: DC 12V/24V. Max solar input: <50V. Current: 10A/20A/30A/40A. Rated working current: ≤20A. Discharge reconnect: 25.2V. Working temperature: -35℃~60℃. Output voltage: 12V/24V Automatically distinguish voltage. Feature: With Timer and light sensor, it could work for solar light system(Only For off-Grid PV Solar System): -For 10A 12V Pv System: 120W Solar Panel, 12V Lead-acid Battery, 21V for Max input Voltage. -For 10A 24V Pv System: 240W Solar Panel, 24V Lead-acid Battery, 42V for Max input Voltage. Safety Instructions: 1. Make sure your battery has enough voltage for the controller to recognize the battery type before first installation. 2. The battery cable should be as short as possible to minimize loss. 3. The regulator is only suitable for lead acid batteries: OPEN, AGM, GEL(It is not suited for nickel metal hydride, lithium ions or other batteries). 4. The charge regulator is only suitable for regulating solar modules. Never connect another charging source to the charge regulator. System Connection: 1. Connect the battery to the charge regulator - plus and minus.it will show 1 ,if it detects 12V battery, 2 if it detects 24V battery. 2. Connect the photovoltaic module to the regulator - plus and minus. 3. Connect the consumer to the charge regulator - plus and minus. Package includes: 1X Solar panels Battery Charge Controller(10/20/30/40A). 1X User Manual