Victron Energy BlueSolar PWM-Light 12/24V-20A20A 12/24V PWM solar charge controller with lighting timer

Overview

The BlueSolar PWM-Light 12/24V-20A carries 20A of charge and load current, about 240W of panels on 12V or 480W on 24V when multiplied by the nominal battery voltage. Panels must be voltage-matched: 36-cell for 12V, 72-cell for 24V. The two-digit display sets the lighting timer or dusk-to-dawn mode for the load output, and LEDs report charge stage and battery condition.

• 5A, 10A, 20A and 30A at 12/24V, automatic detection
• Fixed three-stage charging: bulk, absorption, float
• Load output with dusk-to-dawn, 1–13h timer and manual modes
• Two-digit display for setting the load function
• Low-voltage load disconnect at 11.2V / 22.4V
• Common-positive grounding, IP20, self-consumption under 10mA

How it works

The BlueSolar PWM-Light connects the solar array to the battery through a pulse width modulation switch and charges in three stages: bulk, absorption at 14.2V (28.4V) and float at 13.8V (27.6V). These voltages are fixed and cannot be programmed. The controller drops to float two hours after reaching absorption and starts a new cycle when the battery falls below 13V on a 12V system.

Because a PWM controller pulls the panel down to battery voltage, Victron specifies 36-cell panels for 12V and 72-cell panels, or two 36-cell panels in series, for 24V. Maximum solar voltage is 28V on 12V systems and 55V on 24V systems. The system voltage is detected when the battery is connected and shown on the display as 12 or 24.

Load output and display

A two-digit seven-segment display and a push button set the load function: 0 keeps the output off, 1 to 13 switch it on at sunset for that many hours, H gives manual control, C switches on battery voltage only, and L runs dusk to dawn. Sunset is detected when array voltage falls below 4V. Low-voltage disconnect stays active in every mode.

The load disconnects at 11.2V (22.4V) and reconnects automatically at 13.1V (26.2V), or manually with the button above 12.6V (25.2V). On overload or short circuit the output switches off and retries after 30 seconds. Green and multicolour LEDs show the charge stage, battery condition and load status.

Installation

Connect the battery first so that the controller recognises the system voltage, then the array and the load, and do not exceed the solar and load ratings. Grounding is common positive. The unit is designed for vertical wall mounting indoors with natural convection cooling, and operates at full load between -20°C and +50°C with humidity up to 95%, non-condensing. Terminals accept cables up to 5mm².

Questions and answers