Converting 240V AC to 12V DC for Outdoor Use: Building a Custom Circuit

To step down from 240V AC to 12V DC for a unit drawing 80W, you will need to use a transformer and a rectifier circuit.

Here's what you need to do:

1. Choose a transformer with a voltage rating of at least 240V AC and a secondary winding that outputs 12V AC.
2. Connect the primary winding of the transformer to the 240V AC power source.
3. Connect the secondary winding of the transformer to a rectifier circuit, which will convert the AC voltage to DC.
4. Connect the output of the rectifier circuit to your unit drawing 80W at 12V DC.

Note: It's important to choose a transformer and rectifier with an IP55 rating, as it will be used for external use.

The tools you will need are:

• Multimeter
• Soldering iron and solder
• Heat shrink tubing
• Wire stripper
• Drill

Pros:

• You can choose a transformer that fits your specific power requirements.
• A custom circuit allows you to optimize the conversion efficiency.

Cons:

• Building the circuit yourself can be time-consuming and requires a certain level of technical knowledge.
• If the circuit is not assembled properly, it can result in a dangerous situation.

You can look for off-the-shelf AC to DC converters or power supplies with the right voltage and current rating, but if you don't find one with an IP55 rating, you may need to build a custom circuit.

To give a more accurate answer, I would need additional information such as the distance between the power source and the unit, and the ambient temperature range of the environment the unit will be used in.