How Many Lights Can I Connect to my LEDTransformer?
To figure out how many lights you can safely connect to your 12-volt or 24-volt LED transformer, just add up the total amount of watts you need and make sure it falls between the minimum and maximum ratings for your transformer. (Here's a tip: If you think you might add to your lighting system later, leave a little extra room on the LED transformer.)
Keep in mind that electronic and magnetic transformers may have different maximum wattage requirements. Electronic transformers can use 100% of their rated wattage, while magnetic transformers should generally leave about 20% "extra" to compensate for loss.