TecMate OptiMate Solar DUO 20W Battery Charger & Maintainer Are you interested in charging or maintaining your batteries wherever you go The TecMate OptiMate Solar efficiently charges and maintains 12V batteries throughout the day using solar energy. It also monitors your battery's condition and displays its state of charge during nighttime hours. The system intelligently switches between charging and monitoring modes, automatically initiating the charging process when adequate sunlight is present. Features: Ideal for for Std, Gel, AGM batteries and lithium LFP batteries Charges and maintains a 12V battery during the day and monitors and displays the battery state of charge at night Saves flat batteries from as low as 4V with its unique pulse action The reach / distance between battery and panel is 124 (additional extenders sold separately) Draws less than 0.5mA during monitor mode Charging Amps 1.67A from 20W panel (max. average current), 3-5A pulse current Automatically switches to Charge when solar power is sufficient. Indoor / Outdoor lowest temperature: -4F / -20C Weatherproof charge controller case. No risk of overcharging. Totally safe for vehicle electronics. Sparks suppressed. Safe for long-term battery maintenance. Automatic shut-down if short-circuited or battery disconnected.