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Power supply and voltage selection for a long run of LED strip lights
I need to install a 19-ft run of LED strip lights am confused about whether I should pick 12 or 24 volts.
The LED strip spec sheet for the 24 volt version says it can have a max length of 32 ft, but when I calculate out the wattage for the 19-ft run, it comes to 105 watts, which exceeds the power capacity of the 24 volt power supply (96 watts). Your 12 volt power supply has a capacity of 120 watts. Should I choose the 12 volt versions instead?
In terms of the run length and power draw question, there are two separate limitations that we will need to consider.
First, the 12 volt LED strip lights to have a recommended max run length of 16.4 feet. Exceeding this 16.4 ft maximum length may lead to safety risks, resulting from the excess heat generated by the higher levels of electrical current that a longer run length would require. While the 19 ft run does not exceed the 16.4 ft limitation by much, we would nonetheless not recommend exceeding this length for safety reasons.
On the other hand, as you mention, the 24 volt LED strip lights can safely be used at a 19 ft length, as their maximum run length specification is 32.8 ft.
(The reason for the higher max-run length specification is that the 24 volt versions operate at half the electrical current, which is the limiting factor).
Secondly, we will want to take a look at the power draw and capacity of the power supply units. The 24 volt TRIAC Dimmable Power Supply has a maximum capacity of only 96 watts, which is unfortunately insufficient for the power draw needs of a 19 ft length of LED strips lights. The reason for this specification is to allow for installation as a Class 2 power supply, which is a commonly designated electrical code rating.
Although the 12 volt version of the TRIAC Dimmable Power Supply has a capacity of 120 watts and could theoretically power the entire 19 ft length, due to the maximum run length mentioned above, this would unfortunately not be a recommended option either.
This may not be a convenient solution, however, for maximum safety, we would recommend installing separate sections that do not exceed 16.4 ft, or depending on the flexibility of the installation, modify the run lengths to two runs of 16.4 ft each. Alternatively, a third-party 24 volt power supply with a capacity of 105 watts or higher may also be an option.
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LED power suppliesLED strip lights