DEWENWILS 120W Landscape Transformer (HOSL03A): sensor, timer and specs

The DEWENWILS HOSL03A is a 120W transformer for low-voltage landscape lighting. It converts 120V AC household power to 12V AC and adds a built-in dusk-to-dawn sensor and a countdown timer, so garden lights can switch themselves on and off without a manual switch.

Converting household power to 12V

Landscape lights such as path, spot and deck lights usually run on 12V AC rather than mains voltage. The transformer sits between the outlet and the lighting cable. DEWENWILS says the unit steps 120V AC down to a 12V AC safety voltage, using 120W of capacity. Its power cord is 3.3 feet (about 1 m) long, STJW 18AWG, so the transformer needs to be mounted within reach of an outlet.

Three operating modes

Press the up and down arrows to choose between three modes:

• Always On: the lights stay on until you change the setting.
• Auto: the built-in sensor turns the lights on at dusk and off at dawn.
• Countdown: the lights turn on at dusk and switch off after a set number of hours, from one to nine.

The countdown mode is handy if you want evening light but not all-night light. DEWENWILS adds one caution: don't use the transformer with a dimmer switch.

Memory function

The transformer keeps your chosen setting even if power is lost, so a brief outage doesn't mean reprogramming. The brand notes that for the memory to work, the unit needs to have been in that mode for at least 24 hours.

Building and mounting

The case is metal. DEWENWILS describes it as corrosion resistant and waterproof, built to protect the transformer in extreme weather. It has built-in mounting holes for direct wall mounting on an outdoor wall. Size is about 4.0 x 4.7 x 7.3 inches (10 x 12 x 18.5 cm), and it weighs 5.5 lb (about 2.5 kg). Because the sensor reads daylight, it is best mounted where it isn't lit by the lights it controls or by other outdoor lamps, or it may misread the conditions. The manual covers placement.

Keeping within the capacity

The brand advises that total lighting load should not exceed 80% of the transformer's capacity. For a 120W unit that is about 96W. Add up the wattage of every fixture on the run; LED fixtures use little power each, so the limit can accommodate a good number of them.

Who it suits

It suits homeowners setting up or replacing the power supply for a small low-voltage landscape lighting system who want automatic dusk-to-dawn operation with an option to cut the lights after a few hours.

What to check before you buy

• Fixture type: confirm your lights run on 12V AC.
• Total wattage: keep the sum within 80% of 120W.
• Dimmers: it is not for use with a dimmer switch.
• Location: a spot within reach of an outlet, with the sensor not lit by the lights themselves.
• Cable length: long runs of low-voltage cable lose voltage, so check the manual for guidance.
• Local rules: follow local electrical codes and the manual when installing.

The short version

• A 120W transformer, model HOSL03A, converting 120V AC to 12V AC.
• Built-in dusk-to-dawn sensor and a 1-9 hour countdown timer.
• Always On, Auto and Countdown modes, with memory of the last setting.
• Metal case with mounting holes and a 3.3-foot power cord.
• Keep the connected load within 80% of capacity; not for use with dimmers.

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